All-position automatic pipeline welding refers to the pipeline at a relatively fixed, the welding torch along the rail car to drive around the wall motion, in order to achieve automatic welding. In general, all-position welding automatic welding equipment by part car, walking tracks, automatic control systems and other components.
Welding carriage is to achieve automatic welding process, the drive mechanism, which is mounted on welded rail, with the torch along the wall in a circular motion, is an important part of achieving automatic welding nozzle. Welding carriage should have a beautiful appearance, small size, light weight, easy operation. It is a core part of the running gear, wire feeder and torch oscillation adjustment mechanism. Running gear from the motor and gear bodies, to make walking motor position and speed instruction execution issued by the computer control unit, the motor speed feedback mechanism should have, in order to ensure the motor at various locations pipeline girth accurate alignment, but with a more good speed tracking. Wire agencies must ensure that accurate and stable wire feed speed, has a smaller moment of inertia, better dynamic performance, but should have sufficient driving torque. The regulatory agencies should have a gun swinging around the weld torch relative to swing left and right ends of stay, up and down gesture control, torch angle adjustable function. Each of the above part of the welding trolley, a computer-implemented by a programmable automatic control, the program starts, the operation of each part of the welding carriage according to the logic of the coordination program order.
Track is chucking in the pipe welding trolley travel and positioning altar dedicated mechanism which directly affects the structure and location of the weld smooth trolley travel, also affect the quality of welding. Track should satisfy the following conditions: easy assembly and disassembly, easy to locate; reasonable structure, lighter weight; there is a certain strength and hardness, wear and corrosion resistance. Track divided into rigid and flexible rail track two. The so-called rigid body stiffness of the track means the track is large, easily deformed, and the flexible track is relatively rigid orbits. Two types of tracks each have their own characteristics. Rigid track positioning accuracy, after chucking small deformation, welding carriage to ensure smooth running, welding torch radial adjustment is small, but the larger the weight, assembly and disassembly inconvenient. The flexible track assembly and disassembly, lighter, high accuracy is not rigid track.
Smooth wire feeding directly affect the degree of weld quality. Wire mode can be simply pushed into the drawing and silk in two ways. When drawing the gun from the mounting position closer to the wire feeder, the smaller the process after welding wire feeder wire left by the resistance, so you can ensure a smooth wire feeding process, but the wire feeder and welding wire tray must be installed in the car's on the increase in the weight of the welding carriage, give artificial assembly and disassembly increases the difficulty, but also likely to cause an increase in weight is not stable welding trolley travel.
Currently, in addition to using manual welding, the pipe welding is the use of more automatic submerged arc welding process and GMAW processes. Submerged arc welding has good weld, welding, high efficiency, low cost welding for pipeline construction, the submerged arc welding can be used for dual inline welding, referred to as "the second pick one," that the torch is fixed at a certain position, the tube is rotated. Obviously impossible to make long-distance pipeline welding tube rotates, thus "two pick one" can only be used prefabricated pipe. If the pipeline all-position welding using automatic submerged arc welding process, you must add the welding device with solder delivery, supporting the recovery mechanism, so that the structure of the welding device becomes more complex to operate and dismantle the inconvenience, and increased a trolley load, impact trolley smoothness. Submerged arc welding is generally coarse, high current welding for all-position automatic welding may occur due to high deposition rates drop droplet flow, such as welding defects, affecting the quality of the weld forming and will therefore submerged arc applies to all position welding automatic welding pipe is quite difficult to implement.
Using gas-shielded flux-cored welding process plus, if multiple passes molding, the surface of the weld slag each time and labor; if forced molding, shall be equipped with a gun plus a molded copper sliders move together and pass into cooling water, can greatly improve the welding efficiency, so that not only the structure of the complex welding apparatus, and increased weight. Because of higher prices flux cored wire, while also addressing the protective gas gas source, so the higher the welding costs. Single-use self-shielded welding wire, shielding gas, although savings, but there are difficult issues slag. Using solid core wire welding gas welding process, if multiple passes molding, the welding process can be simply divided into primer, filling, cover three stages faces, no clean weld surface and directly next step, but welding speed is relatively slow in terms of forcing molding. Usually the shielding gas is pure carbon dioxide gas, carbon dioxide and argon or a mixed gas of carbon dioxide and oxygen. Gas mixture of carbon dioxide and argon arc welding can make combustion stability, spatter small, but when the field work hard to find the source of argon gas, higher prices, from economic considerations, when welding the pipeline, the best possible using pure carbon dioxide as a protective gas.
Friday, October 31, 2014
Thick-walled steel key to the quality and maintenance
Critical mass to the number of thick-walled steel wall thickness uniformity, thickness of the thick steel pipe is not under control will directly affect the quality and use, thick-walled steel pipe, large diameter thick wall steel pipe is generally used in a variety of machining, thick-walled parts processing, even thick-walled steel pipe wall will directly affect the quality of post-processing of parts, thick-walled steel pipe wall is not controlled, the overall quality of steel is not strict. Select the appropriate venue and thick-walled steel warehouse storage site or warehouse, should be selected in clean, smooth drainage area, away from harmful gases or dust in factories and mines. Presence on the ground to clear weeds and all sorts of things, thick-walled steel pipe to keep clean. In the warehouse shall not with acid, alkali, salt, cement and other aggressive on the thick-walled steel materials stacked together. Thick-walled steel pipe different varieties should be stacked separately, to prevent confusion, to prevent contact corrosion.
Large steel, rails, shame steel, large diameter thick wall steel pipe, forgings, etc., may open dumps. Small steel, wire rod, rebar, the diameter thick wall steel pipe, steel wire and wire rope, etc., can be stored in a well-ventilated shed material, but on the thatch must underlay. Some small thick-walled steel pipe, sheet, strip, silicon, or thin-walled small diameter thick-walled steel, a variety of cold-rolled, cold drawn thick-walled steel pipe and high prices, corrosive metal products, can be stored for storage. Treasury should be selected according to geographical conditions, the general ordinary enclosed warehouse, that roof with walls, doors and windows tight, with the Treasury ventilation device. Treasury requires attention to ventilation sunny, rainy close attention to moisture, keep proper storage environment. Reasonable stacking, advanced first put principle requires stacking is stable under palletizing ensure safe conditions, so by species, size palletizing, different varieties of materials to be stacking respectively, to prevent confusion and mutual corrosion, banned in store near the pile of thick-walled steel bits have a corrosive effect items, principles of open dumps steel, the following must be wood or stone mat, pile surface is slightly tilted to facilitate drainage, and pay attention to the material placed flat against bending caused deformation.
Large steel, rails, shame steel, large diameter thick wall steel pipe, forgings, etc., may open dumps. Small steel, wire rod, rebar, the diameter thick wall steel pipe, steel wire and wire rope, etc., can be stored in a well-ventilated shed material, but on the thatch must underlay. Some small thick-walled steel pipe, sheet, strip, silicon, or thin-walled small diameter thick-walled steel, a variety of cold-rolled, cold drawn thick-walled steel pipe and high prices, corrosive metal products, can be stored for storage. Treasury should be selected according to geographical conditions, the general ordinary enclosed warehouse, that roof with walls, doors and windows tight, with the Treasury ventilation device. Treasury requires attention to ventilation sunny, rainy close attention to moisture, keep proper storage environment. Reasonable stacking, advanced first put principle requires stacking is stable under palletizing ensure safe conditions, so by species, size palletizing, different varieties of materials to be stacking respectively, to prevent confusion and mutual corrosion, banned in store near the pile of thick-walled steel bits have a corrosive effect items, principles of open dumps steel, the following must be wood or stone mat, pile surface is slightly tilted to facilitate drainage, and pay attention to the material placed flat against bending caused deformation.
Wednesday, October 29, 2014
Advantages of cement mortar lining anti-corrosion pipe
As the cement mortar lining anti-corrosion steel raw cement mortar use is great, in construction, foundation and masonry wall can be used to make adhesives massive masonry materials, such as rubble, red brick use cement mortar; the second is used for interior and exterior plastering. Cement mortar when in use, but also often incorporated additives such as micro-foam agents, water powder to improve its workability and viscosity. Cement mortar in proportion to join the stones, they become concrete.
The biggest advantage of the cement mortar lining of steel corrosion, since the concrete inside the steel pipe, it is possible to absorb large amounts of heat, so the temperature of the cross section of the steel pipe when subjected to uneven distribution of the fire, increasing the fire resistance of steel, slowing the rate of temperature rise of steel, and once the pipe yield, also be able to withstand most of the dirt load, to prevent structural collapse. The experiment proved refractory three hours to achieve the level of savings compared to the requirements of fire and steel pipe coating 1/3 a 2/3 or even more, as the pipe diameter increases, the more savings paint.
After the cement mortar lining of steel corrosion completion of the last step is particularly important, it is dried, refers to the dried 2-3 days in a natural state, is mainly to prevent the shipment of the process due to the turbulence leads to cracks in the cement mortar.
The biggest advantage of the cement mortar lining of steel corrosion, since the concrete inside the steel pipe, it is possible to absorb large amounts of heat, so the temperature of the cross section of the steel pipe when subjected to uneven distribution of the fire, increasing the fire resistance of steel, slowing the rate of temperature rise of steel, and once the pipe yield, also be able to withstand most of the dirt load, to prevent structural collapse. The experiment proved refractory three hours to achieve the level of savings compared to the requirements of fire and steel pipe coating 1/3 a 2/3 or even more, as the pipe diameter increases, the more savings paint.
After the cement mortar lining of steel corrosion completion of the last step is particularly important, it is dried, refers to the dried 2-3 days in a natural state, is mainly to prevent the shipment of the process due to the turbulence leads to cracks in the cement mortar.
Testing process of Straight seam steel pipe and straight pull steel tube
For the strip progressively coiled tube and straight seam welded steel pipe, depending on the welding process when used in its production can be divided into a continuous furnace welding (forge welding) pipe, tube and arc resistance welding Li key welding pipe three.
1. The continuous furnace welding (forge welding) riveting
Continuous furnace brazed (forge welding) of the pipe is in the heating furnace for heating the steel strip, and then forming edge Pat mechanical pressing method so that the welding together to form a straight seam having a pipe. Its features are: high efficiency, low production costs; but the weld quality is poor, poor mechanical properties. Currently, it is mainly applied to the design temperature of 0-100 ℃, the design pressure of not more than 0.6 MPa water and compressed air systems.
2. The resistance of bare steel
Pipes are produced by resistance welding riveting resistance or induction welding method, a straight pipe with a seam, which is characterized by high efficiency, high degree of automation, deformation and residual stress after welding small; but its high investment in equipment, the quality of welded joints requirements are relatively high; and because the joint is inevitable impurities, so fitting plastic and low impact toughness. At present, it is mainly applied to the design ju not higher than 200 ℃ of water, gas, air, steam and other heating and oil and gas industry can be fluid and non-tender fluid, low-pressure pipe.
3. The arc tube bad record
Arc welding pipe is produced by electric arc welding steel pipes. Its characteristics are achieved complete metallurgical bond joints, the mechanical properties of the joint can fully meet or achieve the mechanical properties of the base material. After saying after appropriate heat treatment, arc welding straight seam steel pipe seamless steel pipe can be achieved using conditions will replace it with conditions. At present, it is mainly applied to the design not higher than 200 ℃ of water, gas, air, heating and other design pressure less than 5.0 MPa steam pipes.
1. The continuous furnace welding (forge welding) riveting
Continuous furnace brazed (forge welding) of the pipe is in the heating furnace for heating the steel strip, and then forming edge Pat mechanical pressing method so that the welding together to form a straight seam having a pipe. Its features are: high efficiency, low production costs; but the weld quality is poor, poor mechanical properties. Currently, it is mainly applied to the design temperature of 0-100 ℃, the design pressure of not more than 0.6 MPa water and compressed air systems.
2. The resistance of bare steel
Pipes are produced by resistance welding riveting resistance or induction welding method, a straight pipe with a seam, which is characterized by high efficiency, high degree of automation, deformation and residual stress after welding small; but its high investment in equipment, the quality of welded joints requirements are relatively high; and because the joint is inevitable impurities, so fitting plastic and low impact toughness. At present, it is mainly applied to the design ju not higher than 200 ℃ of water, gas, air, steam and other heating and oil and gas industry can be fluid and non-tender fluid, low-pressure pipe.
3. The arc tube bad record
Arc welding pipe is produced by electric arc welding steel pipes. Its characteristics are achieved complete metallurgical bond joints, the mechanical properties of the joint can fully meet or achieve the mechanical properties of the base material. After saying after appropriate heat treatment, arc welding straight seam steel pipe seamless steel pipe can be achieved using conditions will replace it with conditions. At present, it is mainly applied to the design not higher than 200 ℃ of water, gas, air, heating and other design pressure less than 5.0 MPa steam pipes.
Tuesday, October 28, 2014
Detection of seamless steel pipe
Detection methods are mainly magnetic particle inspection of seamless steel pipe or penetrant testing can be effectively found surface cracks, folding, surface defects heavy leather, hairline, pinholes. For ferromagnetic materials, magnetic particle testing method should be given priority, because of its high detection sensitivity; for non-ferromagnetic material, such as stainless steel seamless pipe, is used penetrant testing method.
When both ends of the cut is less reserve margin, due to structural reasons, detection means, both ends of the head may not be effectively detected, and the end is the most likely site of the presence of cracks or other defects. If the end of the cracks tend to have potential, weld heat affected during installation is also possible to make a potential crack. Therefore, it should be noted that after the detection of certain seamless steel tubes welded area, the expansion pipe ends to detect defects on the online use of austenitic seamless steel pipe, when the insulation is damaged or there may be rain infiltrated the site, it should be noted penetration testing to find stress corrosion cracking or pitting and other defects, but the magnetic particle or penetrant testing can only be detected on the outer surface of the pipe, internal and surface defects are powerless. Detection of the inner surface, in particular the crack defect class detection must be carried out by ultrasonic testing.
When both ends of the cut is less reserve margin, due to structural reasons, detection means, both ends of the head may not be effectively detected, and the end is the most likely site of the presence of cracks or other defects. If the end of the cracks tend to have potential, weld heat affected during installation is also possible to make a potential crack. Therefore, it should be noted that after the detection of certain seamless steel tubes welded area, the expansion pipe ends to detect defects on the online use of austenitic seamless steel pipe, when the insulation is damaged or there may be rain infiltrated the site, it should be noted penetration testing to find stress corrosion cracking or pitting and other defects, but the magnetic particle or penetrant testing can only be detected on the outer surface of the pipe, internal and surface defects are powerless. Detection of the inner surface, in particular the crack defect class detection must be carried out by ultrasonic testing.
High-pressure boiler tubes clear the depth effect
Severe temperature change occurred after burning high sulfur anthracite through the boiler corrosion. Analysis of water wall tube at a high temperature corrosion temperature conditions in a reducing atmosphere high temperature sulfur corrosion mechanism of chlorine corrosion and high-temperature corrosion and corrosion mainly produce, combined use of low sulfur coal than the Yangquan Datong bituminous coal the actual situation, the combustion system transformation. High pressure boiler tube clear the depth shall not exceed the nominal wall thickness of the negative deviation, its cleanup at the actual wall thickness of not less than the minimum allowed. Prevent high-pressure boiler in the fire rapidly warming deformed slump, its measures are varied, the key is to take different approaches depending on the circumstances, such as the use of insulation, refractory steel barrier direct flame burning, reduce the speed of heat transfer postpone the steel temperature, the strength becomes weak time. But no matter what method adopted, the principle is the same. Fire retardant paint is a kind of fire in recent years, more advanced technical measures. Since the impurity elements for high-pressure boiler quality impact, high levels of harmful elements in steel products and the inclusion of control has very strict requirements, to try all kinds of impurity elements are required to control at very low levels, often in production using secondary refining the production process in order to protect its cleanliness.
Special reminder, high pressure boiler tube One installation is difficult, especially supercritical once-through boiler no drum, increasing the starting system, heating pipe systems, bulky traditional subcritical boiler rigid beam than quantity, and all with the heating surface welding installation difficult. High-pressure boiler tubes often in high temperature and pressure conditions when using the tube under the action of high temperature gas and water vapor, oxidation and corrosion will occur.
Special reminder, high pressure boiler tube One installation is difficult, especially supercritical once-through boiler no drum, increasing the starting system, heating pipe systems, bulky traditional subcritical boiler rigid beam than quantity, and all with the heating surface welding installation difficult. High-pressure boiler tubes often in high temperature and pressure conditions when using the tube under the action of high temperature gas and water vapor, oxidation and corrosion will occur.
Friday, October 24, 2014
The cause of the pipeline peeling
Line pipe having a high compressive strength is required, they also require a higher low temperature toughness and excellent weldability. However, in the production and use of the Central Standing Committee found that certain finished steel pipe welds on both sides and there are a lot of varying lengths from the skin defect, seriously affecting the material properties.
Under the inspection and analysis, from the skin defect causes are the following:
(1) oxide inclusions. Slab of large inclusions mainly from powder entrapment. In analyzing the composition of slab surface cracks found near the crack contains a lot of O, Ca, Al and Si and other elements, brittle inclusions composed of high melting point such elements can not easily be adsorbed on the protection of molten slag, it is easy into the liquid steel billet and thus remain in the interior. In the casting process, the large inclusions (such as Al2O3 inclusions) will first be peeled and shell matrix form nascent microcracks, this crack propagation along the strand matrix shell spherical inclusions, and then in the slab surface cracks. Such cracks can lead to lamellar tearing, serious damage to the welding properties of the material, thick steel plate to reduce ductility.
(2) the impact of Cu. Cu case of low melting point elements, easy to segregation at the austenite grain boundaries, and precipitates between the iron oxide layer and the substrate layer, resulting in the formation of low-melting slab surface enrichment-rich phase. Meanwhile, Cu segregation reduces the austenite grain boundary energy to reduce the grain boundary strength.
(3) N elements effect. Steel [N] content and plays a significant layer defects correspondence. The parameters in the mold and cooling the same water flux performance is substantially the same conditions, with the steel [N] content is reduced, significantly reduced from the skin defect. Tests showed that the steel of the [N] is the mass fraction of less than 60 × 10-6 from the skin when the defect rate of 5.8%, [N] is equal to the mass fraction of from greater than 60 × 10-6 at a substantial increase in the defect rate of the skin, can be as high as 76.2 %. For aluminum-containing steel, since Al forms AlN precipitation can reduce the low temperature ductility of the steel, at the same time, AlN tend along the austenite grain boundaries under stress in the vicinity of precipitates will form micro-cracks, leading to crystallization boundary embrittlement. This can be found from the detection of high aluminum slab cracks containing proven.
(4) mold cooling water, pouring temperature and casting speed impact. Appropriate to reduce the amount of water can reduce mold slab surface microcracks, improve the slab quality, reducing hot-rolled sheet rolled skin defects. Reduce the amount of water mold, in essence, with the use of high crystallization rate fluxes similar effect is to reduce the heat transfer rate, slow to realize the slab in the mold of cold, promote uniform growth of shell to improve slab quality. The ability to reduce the pouring temperature and casting speed will help to improve the slab quality, which is a slab mold shell thickness related to high pouring temperature and casting speed will increase the heat flux density, shell thickness thinning, solidified shell to withstand external forces lower, the larger the probability of cracks.
Under the inspection and analysis, from the skin defect causes are the following:
(1) oxide inclusions. Slab of large inclusions mainly from powder entrapment. In analyzing the composition of slab surface cracks found near the crack contains a lot of O, Ca, Al and Si and other elements, brittle inclusions composed of high melting point such elements can not easily be adsorbed on the protection of molten slag, it is easy into the liquid steel billet and thus remain in the interior. In the casting process, the large inclusions (such as Al2O3 inclusions) will first be peeled and shell matrix form nascent microcracks, this crack propagation along the strand matrix shell spherical inclusions, and then in the slab surface cracks. Such cracks can lead to lamellar tearing, serious damage to the welding properties of the material, thick steel plate to reduce ductility.
(2) the impact of Cu. Cu case of low melting point elements, easy to segregation at the austenite grain boundaries, and precipitates between the iron oxide layer and the substrate layer, resulting in the formation of low-melting slab surface enrichment-rich phase. Meanwhile, Cu segregation reduces the austenite grain boundary energy to reduce the grain boundary strength.
(3) N elements effect. Steel [N] content and plays a significant layer defects correspondence. The parameters in the mold and cooling the same water flux performance is substantially the same conditions, with the steel [N] content is reduced, significantly reduced from the skin defect. Tests showed that the steel of the [N] is the mass fraction of less than 60 × 10-6 from the skin when the defect rate of 5.8%, [N] is equal to the mass fraction of from greater than 60 × 10-6 at a substantial increase in the defect rate of the skin, can be as high as 76.2 %. For aluminum-containing steel, since Al forms AlN precipitation can reduce the low temperature ductility of the steel, at the same time, AlN tend along the austenite grain boundaries under stress in the vicinity of precipitates will form micro-cracks, leading to crystallization boundary embrittlement. This can be found from the detection of high aluminum slab cracks containing proven.
(4) mold cooling water, pouring temperature and casting speed impact. Appropriate to reduce the amount of water can reduce mold slab surface microcracks, improve the slab quality, reducing hot-rolled sheet rolled skin defects. Reduce the amount of water mold, in essence, with the use of high crystallization rate fluxes similar effect is to reduce the heat transfer rate, slow to realize the slab in the mold of cold, promote uniform growth of shell to improve slab quality. The ability to reduce the pouring temperature and casting speed will help to improve the slab quality, which is a slab mold shell thickness related to high pouring temperature and casting speed will increase the heat flux density, shell thickness thinning, solidified shell to withstand external forces lower, the larger the probability of cracks.
Passivation process of line pipe
Where the line pipe parts, such as electroless plating or other coating requirements, are generally required in pretreatment (including pickling go black, polished, etc.) through the passivation treatment to use when finished or assembled parts. Passivation can improve the thermodynamic stability of line pipe in environmental media, localized corrosion prevention line pipe, line pipe surface so that cleanliness has sufficient and can also eliminate thermal processing line pipe surface oxide.
Passivation process line pipe can be divided into two types of wet and dry. Concrete can be divided into many types. Passivation effect depends both on line pipe passivation process, but also on line pipe material itself, the specific factors are contained elements line pipe, line pipe metallurgical structure, line pipe processing status. In the composition of the elements, chromium, nickel and strong elements belonging passivating iron followed by passivation, and therefore, chromium and nickel content, the higher, the stronger the passivation of the line pipe. Austenitic, ferritic steel pipeline with a more uniform structure, can be passivated better, martensitic steel pipeline through heat treatment to strengthen its multi-phase microstructure of the organization, thus passivation is not strong. Line pipe by passivating the surface finish after machining is preferably, casting, sand blasting, etc. The resulting surface roughness is not conducive to passivation.
Passivation process line pipe can be divided into two types of wet and dry. Concrete can be divided into many types. Passivation effect depends both on line pipe passivation process, but also on line pipe material itself, the specific factors are contained elements line pipe, line pipe metallurgical structure, line pipe processing status. In the composition of the elements, chromium, nickel and strong elements belonging passivating iron followed by passivation, and therefore, chromium and nickel content, the higher, the stronger the passivation of the line pipe. Austenitic, ferritic steel pipeline with a more uniform structure, can be passivated better, martensitic steel pipeline through heat treatment to strengthen its multi-phase microstructure of the organization, thus passivation is not strong. Line pipe by passivating the surface finish after machining is preferably, casting, sand blasting, etc. The resulting surface roughness is not conducive to passivation.
Monday, October 20, 2014
The superiority of spiral pipe in uses
According to the nature of doing HDPE plastic spiral coil, with a light texture, high strength, good toughness, easy to lay, water resistance, low cost, corrosion resistance, etc., its performance and economic benefits far exceed the reinforced concrete pipe and general specifications iron pipe, engineering pipe replacement products. In metallurgy, petrochemical and other industries exchanger design, there are various forms of heat, but the presence of a conventional heat exchanger ineffective, difficult to clean, fouling resistance and large more drawbacks, can not meet production of customer needs. According to the spiral knot spiral hose heat exchanger to do its good effect of heat transfer, easy to clean, low fouling resistance, compact structure and so on.
Plastic spiral steel pipe (also called hollow wall winding plastic tube) is a wall structure is very reasonable plastic tube. The overall use spiral structure. In for urban drainage projects, improve drainage capacity facility (or narrow diameter) and engineering service life, easy construction, shorten the construction period, when the water table is high, the depth of excavation and restoration of large or require high road, the project cost significantly reduced. Spiral has many superior heat transfer characteristics and structural features straight tube. Heat transfer coefficient is higher than the straight tubes, more heat transfer area can be obtained in the same space, the longer the pipe is arranged to reduce the seam to improve the safety. So spiral heat exchangers and steam generators in the field of power engineering, chemical, aerospace, and nuclear energy has been widely applied.
Large plastic spiral steel pipe is formed with a "T" shaped ribs with a sheet of polyvinyl chloride (UPVC) mixing the carbon black or high density polyethylene (HDPE) using a hot press method. Then on the volume of the machine roll cut into spiral. By quickly locking mechanical connection, the application of an adhesive or melted PVC reinforced molded plastic spiral. It has a large diameter, high corrosion resistance, good anti-leakage effects, quick construction and other characteristics.
Plastic spiral steel pipe (also called hollow wall winding plastic tube) is a wall structure is very reasonable plastic tube. The overall use spiral structure. In for urban drainage projects, improve drainage capacity facility (or narrow diameter) and engineering service life, easy construction, shorten the construction period, when the water table is high, the depth of excavation and restoration of large or require high road, the project cost significantly reduced. Spiral has many superior heat transfer characteristics and structural features straight tube. Heat transfer coefficient is higher than the straight tubes, more heat transfer area can be obtained in the same space, the longer the pipe is arranged to reduce the seam to improve the safety. So spiral heat exchangers and steam generators in the field of power engineering, chemical, aerospace, and nuclear energy has been widely applied.
Large plastic spiral steel pipe is formed with a "T" shaped ribs with a sheet of polyvinyl chloride (UPVC) mixing the carbon black or high density polyethylene (HDPE) using a hot press method. Then on the volume of the machine roll cut into spiral. By quickly locking mechanical connection, the application of an adhesive or melted PVC reinforced molded plastic spiral. It has a large diameter, high corrosion resistance, good anti-leakage effects, quick construction and other characteristics.
Friday, October 17, 2014
Galvanized surface pretreatment
In order to get a good layer of zinc, steel surface must be very clean, rust, iron oxide, and this will reduce the adhesion properties of the coating, prevent binding of iron and zinc. Therefore, before plating steel surface preparation must be carried out. The process includes a general degreasing, washing, pickling, and then washing with water. Also included in the dry storage of galvanized, painted solvent.
The purpose is to remove grease clarinet skim the surface, dirt, steel pickling plant so as not to affect the results, degreasing can be achieved by burning or caustic, often caustic. Alkaline cleaning solution is an aqueous solution containing about 10-12% NaOH, the temperature is 70-80 ℃. Cleaning time is 8-10 minutes.
The purpose is to remove pickling steel surface oxide skin, the acid is generally used sulfuric acid and hydrochloric acid, sulfuric acid pickling effect depends on the temperature, the effect of hydrochloric acid depends on the concentration of H ions. The pickling solution is an aqueous solution of sulfuric acid containing 10-15% sulfuric acid at a temperature of 60-80 ℃, hydrochloric acid pickling solution containing 10-15% aqueous hydrochloric acid, at a temperature below 40 ℃, the pickling time is usually 30 minutes. The advantage of hydrochloric acid is that it can operate at room temperature, removing the oxide scale capability, less erosion of the base metal by absorption of the hydrogen gas and small in the possibility of contamination of the residue of carbon black, ferric oxide generated acid matter, dark angle, easy to remove, no effect on zinc from galvanized perspective, hydrochloric acid is more appropriate. However, the low sulfuric acid prices, easy regeneration, therefore, countries choose pickling solution under different circumstances, the United States and more with sulfuric acid, hydrochloric acid and West Germany, multi-purpose. Adding an appropriate amount of inhibitor in the acid, the acid can etch the surface of the pure steel decreases, so that the contact is reduced with hydrogen in the steel pipe. In addition, also reduce acid consumption and mist generated, the amount inhibitor is typically 0.1-0.5%. Usual amount inhibitor is generally 0.1-0.5%, commonly used inhibitor of water such as plastic.
The purpose is to remove grease clarinet skim the surface, dirt, steel pickling plant so as not to affect the results, degreasing can be achieved by burning or caustic, often caustic. Alkaline cleaning solution is an aqueous solution containing about 10-12% NaOH, the temperature is 70-80 ℃. Cleaning time is 8-10 minutes.
The purpose is to remove pickling steel surface oxide skin, the acid is generally used sulfuric acid and hydrochloric acid, sulfuric acid pickling effect depends on the temperature, the effect of hydrochloric acid depends on the concentration of H ions. The pickling solution is an aqueous solution of sulfuric acid containing 10-15% sulfuric acid at a temperature of 60-80 ℃, hydrochloric acid pickling solution containing 10-15% aqueous hydrochloric acid, at a temperature below 40 ℃, the pickling time is usually 30 minutes. The advantage of hydrochloric acid is that it can operate at room temperature, removing the oxide scale capability, less erosion of the base metal by absorption of the hydrogen gas and small in the possibility of contamination of the residue of carbon black, ferric oxide generated acid matter, dark angle, easy to remove, no effect on zinc from galvanized perspective, hydrochloric acid is more appropriate. However, the low sulfuric acid prices, easy regeneration, therefore, countries choose pickling solution under different circumstances, the United States and more with sulfuric acid, hydrochloric acid and West Germany, multi-purpose. Adding an appropriate amount of inhibitor in the acid, the acid can etch the surface of the pure steel decreases, so that the contact is reduced with hydrogen in the steel pipe. In addition, also reduce acid consumption and mist generated, the amount inhibitor is typically 0.1-0.5%. Usual amount inhibitor is generally 0.1-0.5%, commonly used inhibitor of water such as plastic.
Seamless steel tube for pipeline engineering welding techniques
Steel pipe transported to the site, firstly according to equipment and fittings position pipes, and in the field will be specific length of each pipe of measurement is good, mark the specific size and arrangement of the position, so that when the interface condemnation, the use of lower crane tube, down tube process be used in nylon lifting sling to pipe insulation protection.
Dual control heating pipes, under normal circumstances can reduce 25% of project cost (using FRP do protective layer) and 10% (high-density polyethylene made protective layer) around. Pipe shall have a cross weld anywhere. When tack welding, weld all electrode positioning number (or grade) should be formally welding the same, but some fine electrode diameter optional. Positioning the welding current is selected from the weld becomes larger than the time of welding, is usually 10% -15% larger, in order to ensure penetration. For pipe welding, the weld should be smooth, uniform width, root penetration, no obvious defects and undercut bump phenomenon, should be above the pipe welds to strengthen the surface area of about 2 mm, welding the groove edge 2-3 mm. When the pipe and flange welding, pipe flanges should be inserted thirds, flange and pipe should be perpendicular to the axis of the two coincide.
a, horizontal pipe slope of not less than 0.3%.
b, should be checked before welding welding environment, welding installation equipment, welding materials, and dry cleaning, must comply with the specifications and requirements of welding operations.
c, welding pieces of double-sided welding, weld root should be cleaned and checked back, after cleaning up the defect before welding seam on the back. The provisions of gouging welds should be visually inspected after gouging before welding.
d, the wall of the pipe must fight more than 4mm groove before welding, bevel surface may not have dissection, cracks, damage processing, burrs and flame cutting slag and other defects. After coating should knock welding clean, weld should be rendered uniform scaly, without pores, slag, cracks, welding tumor and other phenomena, biting flesh length should be within specifications.
Dual control heating pipes, under normal circumstances can reduce 25% of project cost (using FRP do protective layer) and 10% (high-density polyethylene made protective layer) around. Pipe shall have a cross weld anywhere. When tack welding, weld all electrode positioning number (or grade) should be formally welding the same, but some fine electrode diameter optional. Positioning the welding current is selected from the weld becomes larger than the time of welding, is usually 10% -15% larger, in order to ensure penetration. For pipe welding, the weld should be smooth, uniform width, root penetration, no obvious defects and undercut bump phenomenon, should be above the pipe welds to strengthen the surface area of about 2 mm, welding the groove edge 2-3 mm. When the pipe and flange welding, pipe flanges should be inserted thirds, flange and pipe should be perpendicular to the axis of the two coincide.
a, horizontal pipe slope of not less than 0.3%.
b, should be checked before welding welding environment, welding installation equipment, welding materials, and dry cleaning, must comply with the specifications and requirements of welding operations.
c, welding pieces of double-sided welding, weld root should be cleaned and checked back, after cleaning up the defect before welding seam on the back. The provisions of gouging welds should be visually inspected after gouging before welding.
d, the wall of the pipe must fight more than 4mm groove before welding, bevel surface may not have dissection, cracks, damage processing, burrs and flame cutting slag and other defects. After coating should knock welding clean, weld should be rendered uniform scaly, without pores, slag, cracks, welding tumor and other phenomena, biting flesh length should be within specifications.
Thursday, October 16, 2014
The purpose of precision seamless steel tube heat treatment
Precision seamless steel tube as a product must have a certain performance to meet the needs of using conditions.There are two ways to improve the performance of the steel, it is adjusting the chemical composition of steel, which uses alloying method;The other is the combination of heat treatment and heat treatment and plastic deformation.In the field of modern industrial technology, heat treatment in the aspect of improving the performance of the steel is still dominant.
There are many types of precision seamless steel pipe, and formulate the corresponding standards, the use of steel seeds range, sometimes users according to their own conditions attached to increase demand.In the standard, as one of the terms of delivery performance indicators must meet specified requirements.The performance of precision seamless steel tube mainly refers to the mechanical properties, physical properties, performance and process capability, etc.And the heat treatment by heat, heat preservation and cooling to obtain certain steel microstructure and properties of the corresponding, in order to meet the product standard and the user's requirements.
Precision seamless steel tube heat treatment embodied in the following aspects: the purpose of homogenization for precision seamless steel tube group By heat treatment can eliminate the original precision seamless steel tube production of uneven performance of organization, to achieve the required uniform organization and physical properties;To eliminate the defects in production Such as cold drawn precision seamless steel tube processing production after hardening of 1.3 1.6 times higher strength, elongation rate was reduced by 30% - 35%, corresponding to cold working can pull off, so you need to intermediate annealing to eliminate internal stress;When hot rolled seamless precision seamless steel tube in the residual stress is bigger, affect the corrosion resistance, the fight against performance also need to eliminate the residual stress in heat treatment.
There are many types of precision seamless steel pipe, and formulate the corresponding standards, the use of steel seeds range, sometimes users according to their own conditions attached to increase demand.In the standard, as one of the terms of delivery performance indicators must meet specified requirements.The performance of precision seamless steel tube mainly refers to the mechanical properties, physical properties, performance and process capability, etc.And the heat treatment by heat, heat preservation and cooling to obtain certain steel microstructure and properties of the corresponding, in order to meet the product standard and the user's requirements.
Precision seamless steel tube heat treatment embodied in the following aspects: the purpose of homogenization for precision seamless steel tube group By heat treatment can eliminate the original precision seamless steel tube production of uneven performance of organization, to achieve the required uniform organization and physical properties;To eliminate the defects in production Such as cold drawn precision seamless steel tube processing production after hardening of 1.3 1.6 times higher strength, elongation rate was reduced by 30% - 35%, corresponding to cold working can pull off, so you need to intermediate annealing to eliminate internal stress;When hot rolled seamless precision seamless steel tube in the residual stress is bigger, affect the corrosion resistance, the fight against performance also need to eliminate the residual stress in heat treatment.
Spiral steel pipe heating process
In spiral steel pipe production process, the main processing was conducted under the thermal state, so the heating operation is very important to determine product quality process.
Heating operation lies in: the temperature of billet uniformly heated to suitable for processing due to punch a great influence on the quality, that is to say, the temperature of the perforation process is one of the important conditions affect the quality, so often to the perforation process of billet temperature control.Improper heating will be inside the tube billet surface or outer surface crack, folding and eccentric waste products.Blank hole temperature varies according to different materials.But mostly at about 1200 ℃, carbon and other alloying elements is large temperature is somewhat low.Heating operation the second key is to minimize the number of scale: especially in hot extrusion elbow, from the tool life and surface quality of extruded tube, more strict.Such as hot stove, according to their functions, divided into two kinds of furnace and furnace again;The former is used to heat the blank from room temperature to the processing temperature;The latter will be used in the processing process, then heated to the necessary processing temperature.There are many kinds of heating furnace, but the main use of annular furnace.This kind of furnace has annular furnace bottom, it can turn slowly, the diameter of the blank from the entrance along the bottom direction loading, turning a can be used at the exit of the heating and soaking to the specified temperature of a stove.Spiral steel pipe production process more slowly, but the factory use the spiral steel pipes are all conform to the specifications of the products.
Heating operation lies in: the temperature of billet uniformly heated to suitable for processing due to punch a great influence on the quality, that is to say, the temperature of the perforation process is one of the important conditions affect the quality, so often to the perforation process of billet temperature control.Improper heating will be inside the tube billet surface or outer surface crack, folding and eccentric waste products.Blank hole temperature varies according to different materials.But mostly at about 1200 ℃, carbon and other alloying elements is large temperature is somewhat low.Heating operation the second key is to minimize the number of scale: especially in hot extrusion elbow, from the tool life and surface quality of extruded tube, more strict.Such as hot stove, according to their functions, divided into two kinds of furnace and furnace again;The former is used to heat the blank from room temperature to the processing temperature;The latter will be used in the processing process, then heated to the necessary processing temperature.There are many kinds of heating furnace, but the main use of annular furnace.This kind of furnace has annular furnace bottom, it can turn slowly, the diameter of the blank from the entrance along the bottom direction loading, turning a can be used at the exit of the heating and soaking to the specified temperature of a stove.Spiral steel pipe production process more slowly, but the factory use the spiral steel pipes are all conform to the specifications of the products.
Carbon steel pipe cap
The circular (ring) carbon steel pipe cap stress and meridional stress at various points on the shell (axial) are changing, the vertex equals the hoop stress and axial stress, and stress on the equator.Carbon steel pipe cap under uniform internal pressure, axial stress of constant for the tensile stress (positive), an by a maximum point toward the equator gradually decreased to the minimum; hoop stress at the head transition zone will begin to appear compressive stress, continue to increase, if the length of axis ratio head transition zone on the edge of the compressive stress value will increase rapidly, the head is shallow, the higher the compressive stress values on the edge of the head, so will head length ratio limit within 2.6 is more reasonable.
Carbon steel pipe cap on QiuGuanXing head design, should pay attention to the cylinder connected to the pipe cap thickness should be not less than the thickness of the head, or should be set up to strengthen the period of transition between head and cylinder connections.Cylinder should strengthen the thickness of the section and the top thick, length should not be less than, the purpose is the cutting edgestress.
Carbon steel pipe cap on QiuGuanXing head design, should pay attention to the cylinder connected to the pipe cap thickness should be not less than the thickness of the head, or should be set up to strengthen the period of transition between head and cylinder connections.Cylinder should strengthen the thickness of the section and the top thick, length should not be less than, the purpose is the cutting edgestress.
Tuesday, October 14, 2014
Carbon steel seamless steel tube concrete classification
Carbon steel seamless steel pipe concrete classification and application
1, general carbon seamless pipe
General carbon content 0.25% or less steel is low carbon steel, mild steel annealing organization for ferrite and a small amount of pearlite, its low strength and hardness, plasticity and toughness is good, easy to drawing, stamping, extrusion, forging and welding, including 20 cr steel used more widely.The steel has the certain strength, after the steel quenching tempering at low temperature has good comprehensive mechanical properties, good low temperature impact toughness, temper brittleness is not obvious.
USES: in the machinery manufacturing is suitable for making welding structure, and by forging, hot stamping and machining parts are not affected by high stress, corrosion in the steam turbine and boiler manufacturing for more than medium work of pipes, flanges, header, and various kinds of fasteners;Applies to the manufacture of automobiles, tractors and general machinery manufacturing small and medium-sized carburizing and carbonitriding parts, such as car hand brake shoe, passive gear lever fork shaft, transmission speed, transmission and tractor on the camshaft, hanging balancer shaft, balancer, inner and outer bushing, etc.;In medium and heavy machinery industry, such as forging or suppression of rod, shackle, leverage, sleeve, fixture, etc.
2, low carbon steel seamless steel tube
The carbon content of mild steel carburizing: in more than 0.15% of low carbon steel after carburizing and quenching and low temperature tempering treatment, surface requirement for high hardness, good wear resistance shaft, shaft sleeve, sprocket, and some parts, such as plastic mold.Low carbon steel after carburizing and quenching and low temperature tempering treatment for surface for high carbon martensite, the core of low carbon martensite organization, so as to ensure that the surface has high hardness, high wear resistance and core has good strength and toughness.Hand for the production brake shoe, fork lever shaft, transmission speed, transmission driven gear and the tractor on the camshaft, hanging balancer shaft, balancer, inner and outer sleeve, sleeve, fixture, etc.
3, medium carbon steel seamless steel tube
Medium carbon steel, carbon is 0.25% ~ 0.25% of the carbon steel, 30, 35, 40, 45, 50, 55 brand belongs to the medium carbon steel, because of the content of pearlite in the steel, before its strength and hardness is improved, the hardness after quenching can increase significantly.Among them, with the most typical of 45 steel.45 steel is the carbon quenched and tempered high strength steel, has a certain plasticity and toughness, good cutting performance, the quenched and tempered treatment can obtain good comprehensive mechanical properties, low hardenability.Used in the manufacture of high strength requirement, the toughness of medium parts.Usually in conditioning or using normalized condition.In order to make the steel has the necessary toughness and eliminate the residual stress, should be after the steel quenching tempering sorbite.
1, general carbon seamless pipe
General carbon content 0.25% or less steel is low carbon steel, mild steel annealing organization for ferrite and a small amount of pearlite, its low strength and hardness, plasticity and toughness is good, easy to drawing, stamping, extrusion, forging and welding, including 20 cr steel used more widely.The steel has the certain strength, after the steel quenching tempering at low temperature has good comprehensive mechanical properties, good low temperature impact toughness, temper brittleness is not obvious.
USES: in the machinery manufacturing is suitable for making welding structure, and by forging, hot stamping and machining parts are not affected by high stress, corrosion in the steam turbine and boiler manufacturing for more than medium work of pipes, flanges, header, and various kinds of fasteners;Applies to the manufacture of automobiles, tractors and general machinery manufacturing small and medium-sized carburizing and carbonitriding parts, such as car hand brake shoe, passive gear lever fork shaft, transmission speed, transmission and tractor on the camshaft, hanging balancer shaft, balancer, inner and outer bushing, etc.;In medium and heavy machinery industry, such as forging or suppression of rod, shackle, leverage, sleeve, fixture, etc.
2, low carbon steel seamless steel tube
The carbon content of mild steel carburizing: in more than 0.15% of low carbon steel after carburizing and quenching and low temperature tempering treatment, surface requirement for high hardness, good wear resistance shaft, shaft sleeve, sprocket, and some parts, such as plastic mold.Low carbon steel after carburizing and quenching and low temperature tempering treatment for surface for high carbon martensite, the core of low carbon martensite organization, so as to ensure that the surface has high hardness, high wear resistance and core has good strength and toughness.Hand for the production brake shoe, fork lever shaft, transmission speed, transmission driven gear and the tractor on the camshaft, hanging balancer shaft, balancer, inner and outer sleeve, sleeve, fixture, etc.
3, medium carbon steel seamless steel tube
Medium carbon steel, carbon is 0.25% ~ 0.25% of the carbon steel, 30, 35, 40, 45, 50, 55 brand belongs to the medium carbon steel, because of the content of pearlite in the steel, before its strength and hardness is improved, the hardness after quenching can increase significantly.Among them, with the most typical of 45 steel.45 steel is the carbon quenched and tempered high strength steel, has a certain plasticity and toughness, good cutting performance, the quenched and tempered treatment can obtain good comprehensive mechanical properties, low hardenability.Used in the manufacture of high strength requirement, the toughness of medium parts.Usually in conditioning or using normalized condition.In order to make the steel has the necessary toughness and eliminate the residual stress, should be after the steel quenching tempering sorbite.
Cold drawn seamless steel tube hot dip galvanizing production process
Galvanized cold drawn seamless steel tube with strong corrosion resistance and strength, stiffness, widely used in gas, heat and water transport pipeline.Technological process is: the clarinet, alkaline cleaning, washing, pickling, rinse, leaching agent, drying, hot dip galvanized - - within the outer wind - air cooling, water cooling, passivation, water rinse, inspection, weighing, warehousing.
Disposal process before plating
1) some cold drawn seamless steel tube appearance have oil, require alkaline cleaning.
2) use hydrochloric acid pickling to remove the oxide skin cold drawn seamless steel tube appearance.
3) to get rid of cold drawn seamless steel tube appearance of residual acid and iron salts, need to rinse twice cold drawn seamless steel tube.
4) flux function to remove all impurities from cold drawn seamless steel tube appearance, ensure clean touch, cold drawn seamless steel tube and liquid zinc constitute outstanding coating.
5) to avoid cold drawn seamless steel tube immersed in zinc pot blasting appearance, need to paint on the flux cold drawn seamless steel tubes for drying, drying temperature in 120-200 ℃, time of no less than 150 s.
Hot dip galvanizing process
1) the temperature of molten zinc in zinc pot strict control in 450 + 5 ℃.
2) drying treatment of cold drawn seamless steel tube through the chain by the root out of baking furnace, furnace roller, and then transported to the galvanizing furnace, rolling into the galvanized machine from three leaching zinc in a spiral.
3) three spiral phase is different, make the cold drawn seamless steel tube on the spiral into a skewed, with screw rotation, cold drawn seamless steel tube side moves down a skew Angle, and then into the liquid zinc, and continue to move down.
4) cold drawn seamless steel tube active fell on the slippery course of zinc pot, organized by ejecting the dial to the lateral, again by machine liquid zinc is put forward.
5) cold drawn seamless steel tube to magnetic roller roller surface, absorb and move to drag out on the table.
Disposal after plating process
1) cold drawn seamless steel tube through the outer ring, there is a row of holes on it, by compressed air blowing cold drawn seamless steel tube residual liquid zinc, shiny appearance.
2) under the satisfactory production rhythm, drop drag out speed, can control the amount of zinc, zinc consumption.
3) blow can get rid of cold drawn seamless steel tube in the rest of the liquid zinc appearance, make bright appearance, was get rid of the zinc liquid zinc powder, be retrieved.
4) water tank temperature control at 80 ℃, cooling water pump to the cooling tower for cooling cycle after use.
5) water back out of the water tank, fell on the inspection on the bench, after the inspection will finish tube into the waste basket, the finished tube into the output table.
6) transport in the finished product through the loops of passivation liquid spray blow pipe, the pipe surface passivation, after blowing outside ring, use compressed air to blow out the rest of the passivation solution.
7) delivery by laying in steam heating pipe line of drying stages, after dried, for printing packaging.
Disposal process before plating
1) some cold drawn seamless steel tube appearance have oil, require alkaline cleaning.
2) use hydrochloric acid pickling to remove the oxide skin cold drawn seamless steel tube appearance.
3) to get rid of cold drawn seamless steel tube appearance of residual acid and iron salts, need to rinse twice cold drawn seamless steel tube.
4) flux function to remove all impurities from cold drawn seamless steel tube appearance, ensure clean touch, cold drawn seamless steel tube and liquid zinc constitute outstanding coating.
5) to avoid cold drawn seamless steel tube immersed in zinc pot blasting appearance, need to paint on the flux cold drawn seamless steel tubes for drying, drying temperature in 120-200 ℃, time of no less than 150 s.
Hot dip galvanizing process
1) the temperature of molten zinc in zinc pot strict control in 450 + 5 ℃.
2) drying treatment of cold drawn seamless steel tube through the chain by the root out of baking furnace, furnace roller, and then transported to the galvanizing furnace, rolling into the galvanized machine from three leaching zinc in a spiral.
3) three spiral phase is different, make the cold drawn seamless steel tube on the spiral into a skewed, with screw rotation, cold drawn seamless steel tube side moves down a skew Angle, and then into the liquid zinc, and continue to move down.
4) cold drawn seamless steel tube active fell on the slippery course of zinc pot, organized by ejecting the dial to the lateral, again by machine liquid zinc is put forward.
5) cold drawn seamless steel tube to magnetic roller roller surface, absorb and move to drag out on the table.
Disposal after plating process
1) cold drawn seamless steel tube through the outer ring, there is a row of holes on it, by compressed air blowing cold drawn seamless steel tube residual liquid zinc, shiny appearance.
2) under the satisfactory production rhythm, drop drag out speed, can control the amount of zinc, zinc consumption.
3) blow can get rid of cold drawn seamless steel tube in the rest of the liquid zinc appearance, make bright appearance, was get rid of the zinc liquid zinc powder, be retrieved.
4) water tank temperature control at 80 ℃, cooling water pump to the cooling tower for cooling cycle after use.
5) water back out of the water tank, fell on the inspection on the bench, after the inspection will finish tube into the waste basket, the finished tube into the output table.
6) transport in the finished product through the loops of passivation liquid spray blow pipe, the pipe surface passivation, after blowing outside ring, use compressed air to blow out the rest of the passivation solution.
7) delivery by laying in steam heating pipe line of drying stages, after dried, for printing packaging.
Cold drawn seamless steel tube
So-called cold drawn, that is, without heating for seamless steel tube and cold drawing machine long pull, the advantage is not under the high temperature, the disadvantage is that residual stress is larger, and not pull out too long cold drawing can improve the toughness and tensile strength to get good mechanical properties.Cold dial the seamless steel tube in addition to general steel tube, low medium pressure boiler pipe, high pressure boiler tube, alloy steel, stainless steel pipe, oil cracking pipe, steel pipe, other include carbon thin wall steel tube, alloy thin wall steel pipes, thin-walled stainless steel tube, steel tube.Cold rolled to heat treatment state delivery.
Cold drawing (rolling) seamless steel tube production and processing process: the round tube billet - heat - punch to heading, annealing and pickling to apply oil (copper), multi-channel time cold drawing (cold rolled) to the tube billet - heat treatment - straightening, hydrostatic test (NDT) - tag to put in storage.
Difference between cold drawing and cold drawn seamless steel pipe:
Cold drawing and cold drawn seamless steel tube of cold working in two different ways, the two are not a concept.Cold drawn in applying pull the ends of the seamless steel tube material, make the seamless steel tube material produces tensile deformation method;One end of the cold drawing refers to the material pulling force, make the seamless steel tube material method, is pulled through a die opening and mold the diameter of the aperture to the material.
Cold drawing processing makes the material in addition to the tensile deformation and extrusion deformation, cold drawing process will make the special cold drawing machine.Manufactured by cold drawing of seamless steel tube material than the cold-drawn processing performance better.
Cold drawing (rolling) seamless steel tube production and processing process: the round tube billet - heat - punch to heading, annealing and pickling to apply oil (copper), multi-channel time cold drawing (cold rolled) to the tube billet - heat treatment - straightening, hydrostatic test (NDT) - tag to put in storage.
Difference between cold drawing and cold drawn seamless steel pipe:
Cold drawing and cold drawn seamless steel tube of cold working in two different ways, the two are not a concept.Cold drawn in applying pull the ends of the seamless steel tube material, make the seamless steel tube material produces tensile deformation method;One end of the cold drawing refers to the material pulling force, make the seamless steel tube material method, is pulled through a die opening and mold the diameter of the aperture to the material.
Cold drawing processing makes the material in addition to the tensile deformation and extrusion deformation, cold drawing process will make the special cold drawing machine.Manufactured by cold drawing of seamless steel tube material than the cold-drawn processing performance better.
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