Spiral steel pipe used as transport oil, artificial gas, gas, water and some solid materials, pipes and so on. Steel pipe and solid steel bar, etc. compared to the amount of large quantities of pipes for transporting fluids. Flexural torsional strength, lighter weight, an economic cross-section steel, widely used in the construction of structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle frames and construction using steel scaffolding.
Lower carbon content, can reduce the problem of sulfide inclusions, spiral steel pipe for the specific requirements can effectively improve the weldability of steel; reduce the sulfur content in steel to improve the toughness of injection pipe and the arrestability beneficial. Improve crack resistance of steel, while reducing the sulfur content can enhance the quality of steel.
Phosphorus toughness steel strip and weldability of the steel are harmful elements other rare contrast, the spiral steel pipe P also has a strong influence rigid, reducing the phosphorus content can proceed directly weldability, because some hot-rolled steel phosphorus content with better. And an appropriate increase in titanium, vanadium, niobium content. Hot rolled steel strip chemical composition control is important is to reduce the carbon content of parathion. This spiral steel pipe to be qualified.
Wednesday, September 25, 2013
Spiral pipe stress analysis
Spiral pipe of the force is a very complicated situation. Spiral Pipe has affected transmission medium pressure, temperature effects were shed hoop stress generated axial stress; tube bearing capacity of the soil outside the pipe caused by different points along the length of the side asked the uniform settlement for bending sheet cows force; buried by soil pressure pipe above below the top soil by heavy, pipe weight, medium weight reaction force generated by such. Moreover, changes in the soil (plus landslide) external mechanical impact force, but also the pipe is compromised.
Spiral steel pipe inner force is clear. Calculation is simple. Spiral steel pipe outside force is not clear (large random factors), stress analysis is also more complicated. In recent years, although the next few pipeline workers in this area have been studied and published many articles, but still difficult as the design basis. The current practice is to pipe the force generated by the media for the design basis, and left a large degree of safety backup. In the safety in addition to considering the tube on the force generated by external causes, we should also consider the spiral steel pipe (including material and weld) that may arise outside the specified defects in the construction and handling, transportation, F Q, etc. Yim Sang to sodium pipe may damage (scratches, indenting, etc.). Degree of safety is based on the long-term practical experience to determine, issued
by the former Ministry of Petroleum Industry Pipeline design standards, due to internal pressure generated hoop stress control in the range of 0.72 yield limit due to the hoop stress and thermal stress generated when composed of axial stress over the yield limit stress control in 0.9 range. Security too large will result in an increase in capital base construction, low waste Road safety will spiral pipe accident increases. It should be noted that the incident is not caused due to the internal medium, or when the hoop stress occurs in overstressing old (because both have very low limit range), mostly due to an external force and the spiral steel pipe itself and the construction the deficiencies.
Spiral steel pipe inner force is clear. Calculation is simple. Spiral steel pipe outside force is not clear (large random factors), stress analysis is also more complicated. In recent years, although the next few pipeline workers in this area have been studied and published many articles, but still difficult as the design basis. The current practice is to pipe the force generated by the media for the design basis, and left a large degree of safety backup. In the safety in addition to considering the tube on the force generated by external causes, we should also consider the spiral steel pipe (including material and weld) that may arise outside the specified defects in the construction and handling, transportation, F Q, etc. Yim Sang to sodium pipe may damage (scratches, indenting, etc.). Degree of safety is based on the long-term practical experience to determine, issued
by the former Ministry of Petroleum Industry Pipeline design standards, due to internal pressure generated hoop stress control in the range of 0.72 yield limit due to the hoop stress and thermal stress generated when composed of axial stress over the yield limit stress control in 0.9 range. Security too large will result in an increase in capital base construction, low waste Road safety will spiral pipe accident increases. It should be noted that the incident is not caused due to the internal medium, or when the hoop stress occurs in overstressing old (because both have very low limit range), mostly due to an external force and the spiral steel pipe itself and the construction the deficiencies.
Instability spiral steel pipe expansion and crack arrest
Crack instability of disaster research and control. Pair of spiral steel long pipeline is very important. Pressure vessels and factory spiral piping network once the crack, all at once would have been destroyed, it is because the sake of these components is too short, so for them, mainly controlled study initiation and expansion of its instability research seems to crack arrest is pointless. Spiral steel pipe for long-distance pipeline situation is very different, although the initiation of long-distance pipelines for spiral pipe is also very important, a lot of people at home and abroad have done a lot of work, but more important is starting soon unstable propagation of crack after crack can get an early crack than to prevent long break, causing serious damage.
Initiation of the word, in the spiral steel pipe is a long-distance large diameter pipe and spiral steel pipe weld defects, including transport and construction process of the surface damage caused (such as indentations and scratches, etc.) in the pressure test procedure after a period of steady expansion, or in the operating process due to stress corrosion and fatigue fracture propagation (due to pressure fluctuations) and other reasons, the formation - "after the expansion phase stability, resulting in leakage through
cracks in terms of the medium for compression container to control the initiation, is to make the entire life process defects will not reach the critical crack length, the unstable growth will not happen for long-distance pipeline, it is very difficult to do that in fact the current domestic were done outside, this is because spiral pipe some up to hundreds of kilometers and even dry I kilometers long welds, weld too, plus the construction and damage caused during transport, so that string machine undetected surge addition long pipeline is buried, and often is continuously conveyed, in fact, can not be checked throughout the period, due to "leak-before-crack" criteria and regular
observation of the defect etc. Diao; possible so that we can only focus on the spiral pipe crack instability on the crack arrest.
Initiation of the word, in the spiral steel pipe is a long-distance large diameter pipe and spiral steel pipe weld defects, including transport and construction process of the surface damage caused (such as indentations and scratches, etc.) in the pressure test procedure after a period of steady expansion, or in the operating process due to stress corrosion and fatigue fracture propagation (due to pressure fluctuations) and other reasons, the formation - "after the expansion phase stability, resulting in leakage through
cracks in terms of the medium for compression container to control the initiation, is to make the entire life process defects will not reach the critical crack length, the unstable growth will not happen for long-distance pipeline, it is very difficult to do that in fact the current domestic were done outside, this is because spiral pipe some up to hundreds of kilometers and even dry I kilometers long welds, weld too, plus the construction and damage caused during transport, so that string machine undetected surge addition long pipeline is buried, and often is continuously conveyed, in fact, can not be checked throughout the period, due to "leak-before-crack" criteria and regular
observation of the defect etc. Diao; possible so that we can only focus on the spiral pipe crack instability on the crack arrest.
The use of seamless steel pipe
In recent years, in factories, stadiums and other framework from the roofs of buildings, beams, room and pillar of steel tube has been adopted steel pipe because of the tube bending ability. with the development of steel production in the construction, more and more use of steel structure, daily utensils, furniture, water supply and drainage, gas, heating and ventilation, transport and agricultural equipment manufacturing, underground resources such as coal, oil, natural gas development, defense and aerospace used guns, artillery, rockets, missiles, etc. are inseparable from the pipe, so the pipe on the national economy development and people's living standards have a close relationship.
Seamless technical standards is fully seamless performance characteristics, correct and reasonable economic use of seamless services. In the technical standards set forth in the diameter, wall thickness and tolerances, pipe length, bending, end elliptical degrees, delivery weight, markings generally specified range, lists must meet the technical requirements and mechanical properties , process performance, test items and test methods, inspection rules. For some special-purpose seamless pay special attention to some of the requirements specified in the standard requirements. Therefore, the use of seamless process both to understand the user's requirements, but also to meet the technical standards of seamless carbon steel tube.
Seamless technical standards is fully seamless performance characteristics, correct and reasonable economic use of seamless services. In the technical standards set forth in the diameter, wall thickness and tolerances, pipe length, bending, end elliptical degrees, delivery weight, markings generally specified range, lists must meet the technical requirements and mechanical properties , process performance, test items and test methods, inspection rules. For some special-purpose seamless pay special attention to some of the requirements specified in the standard requirements. Therefore, the use of seamless process both to understand the user's requirements, but also to meet the technical standards of seamless carbon steel tube.
Sunday, September 22, 2013
Seamless structural steel heat treatment technology
Seamless steel pipe for structural workpiece in the heating and cooling process, because the central portion of the cooling surface and the speed and time of inconsistencies, the formation temperature, volume expansion and contraction can lead to uneven stress, the thermal stress. Under the effect of thermal stress, because the surface temperature is below the core part begins, shrinkage core portion by the central portion is greater than the tension, when the end of cooling, since the volume shrinkage of the cooling core section last leaving the surface pressure can not freely central portion tension. That is, in the final thermal stress under the action of the workpiece surface pressure while the heart of tension. This phenomenon is cooled rate, material composition and heat treatment process and other factors.
When cooled, the faster, the higher the carbon content and the alloy composition, the cooling process under thermal stress generated in the non-uniform plastic deformation larger, the final form of the residual stress it gets. The other hand, during the heat treatment of steel changes in the organization that the austenite to martensite transition, will be accompanied by an increase in specific volume due to the volume expansion of the workpiece, the workpiece successively all parts of the phase change, resulting in inconsistent grown produce tissue volume stress. The final result of the stress variation is the surface tensile stress, the center of compressive stress, the thermal stress is just the opposite. The size of the stress in the workpiece martensite transformation zone cooling rate, shape, chemical composition and other factors.
When cooled, the faster, the higher the carbon content and the alloy composition, the cooling process under thermal stress generated in the non-uniform plastic deformation larger, the final form of the residual stress it gets. The other hand, during the heat treatment of steel changes in the organization that the austenite to martensite transition, will be accompanied by an increase in specific volume due to the volume expansion of the workpiece, the workpiece successively all parts of the phase change, resulting in inconsistent grown produce tissue volume stress. The final result of the stress variation is the surface tensile stress, the center of compressive stress, the thermal stress is just the opposite. The size of the stress in the workpiece martensite transformation zone cooling rate, shape, chemical composition and other factors.
Friday, September 20, 2013
Methods to improve the wear resistance of stainless steel seamless pipe
To compensate not wear soft stainless steel, the friction coefficient of weakness, commonly used to improve the stainless steel plated with the drive shaft parts of the surface hardness and self-lubricating properties. Stainless steel is a surface easily passivated metal must be removed before the plating surface passivation film, stainless steel through to the oil, dipping, activation, and the pre-nickel plating processes, obtained chromium, zinc, copper, tin, precious metals, and other coatings. Studies show that the stainless steel base metal turbine, using the periodic inverted earth chrome plating, coating thickness of about 013mm, coating a metal matrix phase and a rare earth salt particles composed of a second phase, the hardness can reach 900 ~ 1000Hv, abrasion resistance of the coating the base material 25 to 28 times, than the original product life of stainless seamless steel pipe 2 to 6 times higher.
Thermal spraying is the use of certain heat the coating material is heated to a molten or semi-molten state, and by means of high velocity gas stream and the flame to be atomized and to promote the atomized spray particles to the substrate surface, depositing as having a function of the coating. Thermal spraying can provide surface wear and corrosion resistance, high temperature coating. Coating material usually present between the substrate and the combination of three ways: mechanical bonding, physical bonding, and a metallurgical bond. With the low pressure plasma spraying, high-energy, high velocity plasma spraying, HVOF technology, to further improve the performance of the coating. Porosity can be reduced to 015% to 1%; coating and the substrate bonding strength can reach 70 ~ 140MPa. Studies show that using HVOF (HVOF) and plasma spray technology (ASP) technology, respectively, in 0Cr13Ni5Mo prepared on stainless steel substrate iron-based amorphous alloy coating and iron. Based amorphous and nanocrystalline coatings studied two coating at room temperature friction and wear characteristics, the results showed that the two spraying iron-based coatings are prepared with high hardness and low porosity, dense and showed a typical layered structure, improve the coating wear layer.
Thermal spraying is the use of certain heat the coating material is heated to a molten or semi-molten state, and by means of high velocity gas stream and the flame to be atomized and to promote the atomized spray particles to the substrate surface, depositing as having a function of the coating. Thermal spraying can provide surface wear and corrosion resistance, high temperature coating. Coating material usually present between the substrate and the combination of three ways: mechanical bonding, physical bonding, and a metallurgical bond. With the low pressure plasma spraying, high-energy, high velocity plasma spraying, HVOF technology, to further improve the performance of the coating. Porosity can be reduced to 015% to 1%; coating and the substrate bonding strength can reach 70 ~ 140MPa. Studies show that using HVOF (HVOF) and plasma spray technology (ASP) technology, respectively, in 0Cr13Ni5Mo prepared on stainless steel substrate iron-based amorphous alloy coating and iron. Based amorphous and nanocrystalline coatings studied two coating at room temperature friction and wear characteristics, the results showed that the two spraying iron-based coatings are prepared with high hardness and low porosity, dense and showed a typical layered structure, improve the coating wear layer.
Application of electro-galvanized steel sheet
Household appliances used in the production of traditional steel, electro-galvanized steel mainly. In recent years, with galvanized steel mechanical properties and surface quality continues to improve, with electro-galvanized steel sheet compared to its low production costs, strong corrosion resistance and environmental pollution, etc. become increasingly prominent, and thus with its alternative plating zinc steel appliances at home and abroad has become a major trend in the manufacturing industry. However, from the use of electric appliances with galvanized sheet steel to hot galvanized plate is not a simple substitution process. Among them, how to choose the right materials, it is worth studying.
Appliances with a selection of hot dip galvanized steel mainly related to material grades, coating the surface structure and surface treatment and so on. Appliance parts with specific conditions of use and quality requirements for a reasonable selection, to ensure the quality of home appliances under the premise of reducing material costs, and increase overall competitiveness.
Steel appliances generally stamping with a soft steel, its mechanical properties in accordance with national standards, European standards, the Japanese standard, American standard, etc. to be divided, different standards corresponding to different grades of series. According to the material in the course of processing the degree of deformation, usually steel appliances by stamping level is divided into general use, stamping purposes, uses and ultra deep drawing ( special ) deep drawing uses. Overall, the appliance sheet metal parts stamping difficulty is not too large, but there is a big difference between different parts, so the parts should be based on the deformation mode, deformation characteristics and quality requirements of a reasonable selection of materials. Sheet metal parts stamping appliance that may arise in the main problem is cracking , wrinkling and springback. Because steel stamping defects but also with mold conditions related parts stamping process, a reasonable selection should also consider the user's own mold factors and process factors.
The need for plating appliance parts, use glossy plate, so as to achieve the effect of the light after plating. Appliances are mostly bare plate with ( interior parts ) and painted or foil used ( exterior parts ), you should use matte steel, coating and is conducive to enhancing the binding force between the plates. Meanwhile, the matte side of the beneficial effect of lubricating oil, in order to improve the ability of the material forming. Hot dip galvanized steel in accordance with zinc coating structure, zinc solution to add other elements can be divided into ordinary circumstances hot galvanized plate, zinc alloy of plates, zinc-aluminum alloy coated sheet, aluminum-zinc alloy coated sheet. Different kinds of steel sheets having different characteristics, such as zinc alloy plate weldability, zinc-aluminum alloy plate stamping performance, aluminum-zinc alloy sheet and strong corrosion resistance. At present, the major users of domestic appliances using ordinary galvanized steel (GI), small parts using galvanized (GL) and zinc alloy plate (GA). Ordinary hot- dip galvanized sheet surface state can be divided according to their normal spangle boards, finishing spangle boards, panels and small spangle spangle board, different states steel surface quality, corrosion resistance and paint different results. Zinc galvanized steel sheet thick layer of welded parts prone to injury electrodes, welding is not strong or welding wear phenomenon. Meanwhile, in order to ensure steel within a certain period does not produce red rust on the thickness of the zinc layer has certain requirements.
Galvanized sheet in order to prevent the transport and storage process produces white rust, galvanized sheet surface passivation generally require treatment or oiled. Chromate passivation previously widely used approach has better anti- white rust function, but can not meet the requirements of the EU directive RoHs. Currently, some domestic steel companies successfully developed passivation board can fully meet the EU requirements, to enhance the quality of home appliances to make a contribution. According to user needs, galvanized sheet surface can be thin organic coating, such as fingerprint resistant coating film, anti-fingerprint film helps prevent the production and transportation process residual fingerprints, perspiration and other issues affecting the appearance and surface quality. Plate in order to increase the lubricity of the stamping process, the steel sheet surface to reduce friction and damage the steel sheet can be self- lubricated.
Appliances with a selection of hot dip galvanized steel mainly related to material grades, coating the surface structure and surface treatment and so on. Appliance parts with specific conditions of use and quality requirements for a reasonable selection, to ensure the quality of home appliances under the premise of reducing material costs, and increase overall competitiveness.
Steel appliances generally stamping with a soft steel, its mechanical properties in accordance with national standards, European standards, the Japanese standard, American standard, etc. to be divided, different standards corresponding to different grades of series. According to the material in the course of processing the degree of deformation, usually steel appliances by stamping level is divided into general use, stamping purposes, uses and ultra deep drawing ( special ) deep drawing uses. Overall, the appliance sheet metal parts stamping difficulty is not too large, but there is a big difference between different parts, so the parts should be based on the deformation mode, deformation characteristics and quality requirements of a reasonable selection of materials. Sheet metal parts stamping appliance that may arise in the main problem is cracking , wrinkling and springback. Because steel stamping defects but also with mold conditions related parts stamping process, a reasonable selection should also consider the user's own mold factors and process factors.
The need for plating appliance parts, use glossy plate, so as to achieve the effect of the light after plating. Appliances are mostly bare plate with ( interior parts ) and painted or foil used ( exterior parts ), you should use matte steel, coating and is conducive to enhancing the binding force between the plates. Meanwhile, the matte side of the beneficial effect of lubricating oil, in order to improve the ability of the material forming. Hot dip galvanized steel in accordance with zinc coating structure, zinc solution to add other elements can be divided into ordinary circumstances hot galvanized plate, zinc alloy of plates, zinc-aluminum alloy coated sheet, aluminum-zinc alloy coated sheet. Different kinds of steel sheets having different characteristics, such as zinc alloy plate weldability, zinc-aluminum alloy plate stamping performance, aluminum-zinc alloy sheet and strong corrosion resistance. At present, the major users of domestic appliances using ordinary galvanized steel (GI), small parts using galvanized (GL) and zinc alloy plate (GA). Ordinary hot- dip galvanized sheet surface state can be divided according to their normal spangle boards, finishing spangle boards, panels and small spangle spangle board, different states steel surface quality, corrosion resistance and paint different results. Zinc galvanized steel sheet thick layer of welded parts prone to injury electrodes, welding is not strong or welding wear phenomenon. Meanwhile, in order to ensure steel within a certain period does not produce red rust on the thickness of the zinc layer has certain requirements.
Galvanized sheet in order to prevent the transport and storage process produces white rust, galvanized sheet surface passivation generally require treatment or oiled. Chromate passivation previously widely used approach has better anti- white rust function, but can not meet the requirements of the EU directive RoHs. Currently, some domestic steel companies successfully developed passivation board can fully meet the EU requirements, to enhance the quality of home appliances to make a contribution. According to user needs, galvanized sheet surface can be thin organic coating, such as fingerprint resistant coating film, anti-fingerprint film helps prevent the production and transportation process residual fingerprints, perspiration and other issues affecting the appearance and surface quality. Plate in order to increase the lubricity of the stamping process, the steel sheet surface to reduce friction and damage the steel sheet can be self- lubricated.
Monday, September 16, 2013
Spiral pipe causes a fracture
Spiral steel brittle fracture and component usage temperature. The study found that people when the temperature drops below a certain temperature, the material will be brittle transition state, the impact absorbed energy decreased, a phenomenon known as cold brittleness, high strength metal materials, low stress occurring in brittle fracture process, the material structure is far from homogeneous and isotropic. Tissues have cracks, there will be inclusions, porosity and other defects, which are a material can be seen in the micro-cracks. Therefore, the design also according to the operating temperature to select members with appropriate cold brittle transition temperature of the material.
The above formula, the excitation frequency of the excitation circuit capacitance, inductance is inversely proportional to the square root, or the voltage and current proportional to the square, as long as the change in the circuit capacitance, inductance, or voltage and current can change the size of the excitation frequency, so as to achieve control of welding temperature. For low carbon steel, welding temperature control in the 1250 ~ 1460 ℃, can meet the pipe wall thickness 3 ~ 5mm penetration requirements. In addition, the soldering temperature can be achieved by adjusting the welding speed.
Spiral steel pipe drawing, due to the presence of hot tube defects such as cracks, or high-precision drawing after the tank is made, in the course of the fracture occurred, almost no plastic deformation occurs, in general are brittle fracture. Brittle fracture is caused by a variety of reasons. Such as: precipitates on the grain boundaries, regardless of the intensity ratio of the matrix strength strong or weak, are all causes cracks; grain boundary segregation of inclusions also cause fracture; addition, even in far less than the yield limit of the cross-variable loads, can also cause fatigue fracture phenomena.
The above formula, the excitation frequency of the excitation circuit capacitance, inductance is inversely proportional to the square root, or the voltage and current proportional to the square, as long as the change in the circuit capacitance, inductance, or voltage and current can change the size of the excitation frequency, so as to achieve control of welding temperature. For low carbon steel, welding temperature control in the 1250 ~ 1460 ℃, can meet the pipe wall thickness 3 ~ 5mm penetration requirements. In addition, the soldering temperature can be achieved by adjusting the welding speed.
Spiral steel pipe drawing, due to the presence of hot tube defects such as cracks, or high-precision drawing after the tank is made, in the course of the fracture occurred, almost no plastic deformation occurs, in general are brittle fracture. Brittle fracture is caused by a variety of reasons. Such as: precipitates on the grain boundaries, regardless of the intensity ratio of the matrix strength strong or weak, are all causes cracks; grain boundary segregation of inclusions also cause fracture; addition, even in far less than the yield limit of the cross-variable loads, can also cause fatigue fracture phenomena.
Straight seam steel pipe rupture causes
After a period of time, a lot of straight seam steel pipe fracture happens, in general, all data is assumed to be uniform isotropic continuous analysis according to this method is safe design, breakage sometimes unexpected accidents. As hot-rolled tube defects such as cracks or high-precision cold drawn tube is made after the tank, cold drawn seamless when. Breakage occurs during use, almost no plastic deformation occurs, in general are brittle fracture.
Longitudinal fracture, hydraulic (pneumatic) parts used in the design of mechanical properties, but also with members of brittle fracture with temperature. Brittle fracture caused by a variety of reasons, such as: precipitates on the grain boundaries, regardless of the intensity ratio of the matrix strength strong or weak, are all causes cracks; grain boundary segregation of inclusions also cause fracture; addition, even in far less than the yield limit alternating loads can also cause fatigue fracture phenomena.
Longitudinal fracture, hydraulic (pneumatic) parts used in the design of mechanical properties, but also with members of brittle fracture with temperature. Brittle fracture caused by a variety of reasons, such as: precipitates on the grain boundaries, regardless of the intensity ratio of the matrix strength strong or weak, are all causes cracks; grain boundary segregation of inclusions also cause fracture; addition, even in far less than the yield limit alternating loads can also cause fatigue fracture phenomena.
Precision light pipe characteristics
Precision light pipe welded butt joints before welding primer tube and the cavity should be filled with argon gas to perform TIG welding. In certain particular at low temperatures, the operation of fingerprint adhesion ranking officials will also impact the workpiece. Do not make the workpiece gets new oil. Wear clean gloves must operate. If the surface of the lubricating oil during cold adhesion must trichlorethylene degreasing agents, caustic soda solution and then with warm water to fully defatted.
While affirming the load, the higher the temperature and the longer the time angry creep to occur the greater. Design units are also based on environmental conditions, corrosion and corrosion tape required product characteristics were selected. Precision light pipe according to different cross-sectional shapes can be divided into tube and shaped tubes. Therefore, the operator should not directly touch the fertilizer tube fittings, in affirming the special temperature at low temperatures, the greater the load seamless tube made of fire creep occurs faster; ring with a steel pipe manufacturing parts, can improve the material utilization, and simplify the manufacturing process, saving material and machining time, such as bearing rings, steel pipe and solid steel bar, etc. compared to the same torsional strength in bending, lighter, precision light pipe is an economic cross-section steel , widely used in the manufacture of structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle frames and construction using steel scaffolding. Jack sets, has been widely used to make steel. Steel or a variety of conventional weapons indispensable material, barrel, barrel, etc. to make steel. Greater load creep occurs faster firing; under load in the affirmative, the higher the temperature and the longer the time angry creep can occur the greater.
While affirming the load, the higher the temperature and the longer the time angry creep to occur the greater. Design units are also based on environmental conditions, corrosion and corrosion tape required product characteristics were selected. Precision light pipe according to different cross-sectional shapes can be divided into tube and shaped tubes. Therefore, the operator should not directly touch the fertilizer tube fittings, in affirming the special temperature at low temperatures, the greater the load seamless tube made of fire creep occurs faster; ring with a steel pipe manufacturing parts, can improve the material utilization, and simplify the manufacturing process, saving material and machining time, such as bearing rings, steel pipe and solid steel bar, etc. compared to the same torsional strength in bending, lighter, precision light pipe is an economic cross-section steel , widely used in the manufacture of structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle frames and construction using steel scaffolding. Jack sets, has been widely used to make steel. Steel or a variety of conventional weapons indispensable material, barrel, barrel, etc. to make steel. Greater load creep occurs faster firing; under load in the affirmative, the higher the temperature and the longer the time angry creep can occur the greater.
Rectangular tube rectangular hole design
The need to produce several shaped tube, the use of strip dimensions and allow reunification (eg several fasting Gangchuang tube), only a set of forming rolls, and then in plastic rack (rack pipe sizing) on the roll change you can get different sections, so that the replacement of species is very simple, which can be a significant reduction in roll processing and reserves.
First forming a rectangular welded pipe production process consists of sizing stands complete molding, sizing mill is generally two-roll mill, which has horizontal racks and vertical roll racks. Currently rectangular hole design, there are two: one is horizontal rack at box-hole design, the first frame of oval holes, each frame of the other approximate rectangular holes, which pass by the arcs cross-section, and an arc Radius-by-frame increments, all pass phase at the sidewalls and bottom fillet radius equal to the product of the cross-section of the fillet radius. Rectangular tube total elongation factor of about 1.05, mainly distributed in the flat roller, a small amount of deformation of the vertical roll, which acts to hold down the short side of the rectangular tube. With this design, calculation is more complex, and the calculated value is not precise enough to be constantly revised hole perimeter. Another modification is the use of the design angle, from the tube can be viewed from a rectangular tube 90 ° to 180 ° to the bending deformation, the deformation angle θ corners accurately reflect the degree of deformation and edge. Design, considering the dimensional accuracy and hardening of the metal, usually deformation angle distribution, the beginning and bigger intermediate passes, and then gradually decreases. Intersecting arcs constitute the direct use of the pass, the tube can not be filled hole fillet portion, so pass tube circumference and perimeter range. In order to ensure dimensional accuracy, the need for correction calculation pass fillet portions. So this method than other methods with higher design accuracy. However, due to the large amount of iteration calculation, this method is more suitable for use computers pass design. If you use the horizontal and vertical directions simultaneously deformed universal rack deformation angle θ can be directly used for pass design.
First forming a rectangular welded pipe production process consists of sizing stands complete molding, sizing mill is generally two-roll mill, which has horizontal racks and vertical roll racks. Currently rectangular hole design, there are two: one is horizontal rack at box-hole design, the first frame of oval holes, each frame of the other approximate rectangular holes, which pass by the arcs cross-section, and an arc Radius-by-frame increments, all pass phase at the sidewalls and bottom fillet radius equal to the product of the cross-section of the fillet radius. Rectangular tube total elongation factor of about 1.05, mainly distributed in the flat roller, a small amount of deformation of the vertical roll, which acts to hold down the short side of the rectangular tube. With this design, calculation is more complex, and the calculated value is not precise enough to be constantly revised hole perimeter. Another modification is the use of the design angle, from the tube can be viewed from a rectangular tube 90 ° to 180 ° to the bending deformation, the deformation angle θ corners accurately reflect the degree of deformation and edge. Design, considering the dimensional accuracy and hardening of the metal, usually deformation angle distribution, the beginning and bigger intermediate passes, and then gradually decreases. Intersecting arcs constitute the direct use of the pass, the tube can not be filled hole fillet portion, so pass tube circumference and perimeter range. In order to ensure dimensional accuracy, the need for correction calculation pass fillet portions. So this method than other methods with higher design accuracy. However, due to the large amount of iteration calculation, this method is more suitable for use computers pass design. If you use the horizontal and vertical directions simultaneously deformed universal rack deformation angle θ can be directly used for pass design.
Thursday, September 12, 2013
Steel casing is buried technology
Steel casing (steel jacket) embedded technology is a waterproof, leakproof, impermeability, compressive and fully enclosed laying of new technology, is burying technology used in areas with high water table, a large-break. It is composed of the transmission medium pipe, seamless carbon steel pipe and steel pipe and anticorrosion coat jacket filled with fine steel wool between the combination can also be used graphite, calcium silicate tiles shell filled with polyurethane foam and composite.
One is by the transmission medium steel pipe, steel pipe and anticorrosion coat jacket filled with fine steel wool between the combination can also be used graphite, calcium silicate tiles shell filled with polyurethane foam and composite. Steel casing (steel jacket) embedded technology is a waterproof, leakproof, impermeability, compressive and fully enclosed laying of new technology, is burying technology used in areas with high water table, a large-break. Protective tube buried pipe water tight primary problem is the reliability, in addition to have a good mechanical strength, high strength steel casing as welded connections, the waterproof reliability is very high sealing performance, in addition, its high temperature performance is other outer protection tube can not be compared. In areas with high groundwater level, in order to ensure groundwater does not affect the normal operation of the steam buried pipe, outer protective layer is preferably made of sturdy, sealed steel casing.
One is by the transmission medium steel pipe, steel pipe and anticorrosion coat jacket filled with fine steel wool between the combination can also be used graphite, calcium silicate tiles shell filled with polyurethane foam and composite. Steel casing (steel jacket) embedded technology is a waterproof, leakproof, impermeability, compressive and fully enclosed laying of new technology, is burying technology used in areas with high water table, a large-break. Protective tube buried pipe water tight primary problem is the reliability, in addition to have a good mechanical strength, high strength steel casing as welded connections, the waterproof reliability is very high sealing performance, in addition, its high temperature performance is other outer protection tube can not be compared. In areas with high groundwater level, in order to ensure groundwater does not affect the normal operation of the steam buried pipe, outer protective layer is preferably made of sturdy, sealed steel casing.
Wednesday, September 11, 2013
Spiral welded pipe measures to prevent electrochemical corrosion
To prevent scratches and pollutants generated during construction under the state attached to stainless steel foil construction. (SSAW), but with time the residual liquid paste period of use in accordance with foil construction should be carried out after removing the surface film washing and use special stainless steel cleaning tool with the general public in order to prevent iron adhesion tools should be cleaned. It should be taken not to have strong magnetic and stone luxury corrosive cleaning stainless steel surfaces come into contact with drugs if the contact should be immediately washed. After the construction of the building application neutral detergent and water, dried attached to the surface of cement, ash until the matter.
TIG welded stainless steel pipe generally used two kinds of TIG arc welding or required for the protection of argon welding operation, which is simple and good quality. Arc welding should be used the same type of stainless steel electrode stainless steel electrode welding current according to manufacturer's recommended current supply and demand can also be negotiated. After welding the weld preferably be polished surface quality of the pipe so that all the same conditions if the surface can also be passivated to enhance the corrosion resistance of the weld. Spiral pipe production line of high-quality engineering, installation pipeline is the most basic requirement of the port tube flush.
Spiral welded pipe Handle with care when transporting the oil to avoid and prohibit non-violent impact collision with sharp objects and throw, throw, roll, drag; pipe should be placed to avoid bending the average weight of water. Stainless steel piping to be connected with galvanized steel pipe need to be scratching their heads with retractable teeth, add copper fittings transition to avoid electrochemical corrosion. Use of the environment as far as possible dry.
TIG welded stainless steel pipe generally used two kinds of TIG arc welding or required for the protection of argon welding operation, which is simple and good quality. Arc welding should be used the same type of stainless steel electrode stainless steel electrode welding current according to manufacturer's recommended current supply and demand can also be negotiated. After welding the weld preferably be polished surface quality of the pipe so that all the same conditions if the surface can also be passivated to enhance the corrosion resistance of the weld. Spiral pipe production line of high-quality engineering, installation pipeline is the most basic requirement of the port tube flush.
Spiral welded pipe Handle with care when transporting the oil to avoid and prohibit non-violent impact collision with sharp objects and throw, throw, roll, drag; pipe should be placed to avoid bending the average weight of water. Stainless steel piping to be connected with galvanized steel pipe need to be scratching their heads with retractable teeth, add copper fittings transition to avoid electrochemical corrosion. Use of the environment as far as possible dry.
Monday, September 9, 2013
Tension reducing the difference between steel pipe and Longitudinal Process
Different processes have formed a production quality differences, reducing tension in welded steel pipe also stopped a straight seam welded pipe Friends of the process is not stopped: online eliminate internal and external burrs. The existence glitch affects tube fluid - flow, glitches obstruct the normal activities of the fluid, resulting whirlpool. Based on principles of fluid dynamics, weld some pressure must increase, the average discontinuity of the Friends of the pipe safety factor is also greatly reduced, stretch reducing pipe processing technology to fully reflect on the existence of the risk of glitches, stop burr elimination, making it an average wall thickness, seamless appearance with no difference.
Resolution of the weld quality is directly YHI pipe quality, but also where the biggest difference between pipe and seamless. Friends of straight seam welded pipe at high frequency welding or submerged arc welding, the carbon can not be set straight seam eliminate the weld interface in conjunction with the parent only, and not a complete blend of one, could not stand the test of time and pressure. Tension Reducing heat welded steel pipe in the pipe even after high temperature of about 800 degrees after heating, the overall annealing, after this series of processes, the weld performance close to the parent organization, well done seamlessly from seam to transition. So from this point of view, hot stretch reducing pipe joints from having also completed a seamless transition, of course, the distinction between the two is not only limited to the above two points, but enough to clarify YHI straight seam welded pipe and tension reducing pipe there are still significant differences. Longitudinal bedrock on the latter has ceased online eliminate burrs inside and outside, the overall heating type variable and a series of new technologies disposal, so that it has been a qualitative leap in the high-pressure areas can be commonly applied, straight seam Friends fat pipe used in low pressure environment of ordinary water gas walks or for steel construction.
Resolution of the weld quality is directly YHI pipe quality, but also where the biggest difference between pipe and seamless. Friends of straight seam welded pipe at high frequency welding or submerged arc welding, the carbon can not be set straight seam eliminate the weld interface in conjunction with the parent only, and not a complete blend of one, could not stand the test of time and pressure. Tension Reducing heat welded steel pipe in the pipe even after high temperature of about 800 degrees after heating, the overall annealing, after this series of processes, the weld performance close to the parent organization, well done seamlessly from seam to transition. So from this point of view, hot stretch reducing pipe joints from having also completed a seamless transition, of course, the distinction between the two is not only limited to the above two points, but enough to clarify YHI straight seam welded pipe and tension reducing pipe there are still significant differences. Longitudinal bedrock on the latter has ceased online eliminate burrs inside and outside, the overall heating type variable and a series of new technologies disposal, so that it has been a qualitative leap in the high-pressure areas can be commonly applied, straight seam Friends fat pipe used in low pressure environment of ordinary water gas walks or for steel construction.
ERW carbon steel pipe hardness testing
Hardness is the assessment of mechanical properties of metallic materials most commonly used indicators. The hardness of the material to resist another real ability to push harder material. Hardness testing was to evaluate the mechanical properties of metals fastest, most economical and simplest test methods. The main purpose of hardness testing is to measure the suitability of materials, or materials for the use of the particular purpose for hardening or softening effect. For the test materials, the hardness represents a certain pressure force of the head and the reflected test the flexibility, ductility, strength, toughness and wear resistance and other physical quantity of the overall performance. As can be reflected through the ERW carbon steel pipe hardness test on a different chemical composition, structure and properties of the heat treatment process conditions vary, it is widely used in ERW carbon steel pipe hardness testing performance testing, monitoring heat treatment process quality and new materials research.
There are two types of ERW carbon steel pipe hardness testing test methods. One is a static test method, test force is applied such methods are slow and no shocks. Determination of hardness mainly on the depth of the indentation, the indentation or indentations gravure projection area size of the area. Static test methods include Brinell, Rockwell, Vickers, Knoop, Vickers, pasteurized and so on. Including cloth, Luo, Victoria three test methods are the most widely used, they are the main ERW carbon steel pipe hardness testing test methods. Here Rockwell hardness test is the most widely used, it is widely used for product testing, according to statistics, the current application of the 70% hardness Rockwell hardness. Another test method is a dynamic test method, test force is applied such methods are dynamic and impact resistance. This includes Shaw and Leeb hardness test method. Dynamic test method is mainly used for large-scale, non-removable workpiece hardness testing.
There are two types of ERW carbon steel pipe hardness testing test methods. One is a static test method, test force is applied such methods are slow and no shocks. Determination of hardness mainly on the depth of the indentation, the indentation or indentations gravure projection area size of the area. Static test methods include Brinell, Rockwell, Vickers, Knoop, Vickers, pasteurized and so on. Including cloth, Luo, Victoria three test methods are the most widely used, they are the main ERW carbon steel pipe hardness testing test methods. Here Rockwell hardness test is the most widely used, it is widely used for product testing, according to statistics, the current application of the 70% hardness Rockwell hardness. Another test method is a dynamic test method, test force is applied such methods are dynamic and impact resistance. This includes Shaw and Leeb hardness test method. Dynamic test method is mainly used for large-scale, non-removable workpiece hardness testing.
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