Thursday, December 18, 2014

Cold straightening of seamless steel pipe

Let the processed seamless steel pipe products have a smaller tortuosity relied on the mechanical straightening machine to complete. So in order to eliminate the seamless steel pipe turns, all seamless steel pipe must undergo cold straightening.
Seamless steel pipe tortuous is caused by the improper adjustment, residual stress of rolling and inequality of the cooling section and length along the tube. Thus, you can not get straight pipe directly from the mill, only through straightening, the steel pipe tortuosity can meet the conditions of the rule.
The fundamental principle of straightening is to make the seamless steel pipe elastoplastic tortuous, changing from large tortuosity to small tortuosity, and therefore within the steel straightening machine will definitely suffer repeated setbacks. The repeat tortuous degree of the steel pipe is mainly determined by adjusting the straightening machines.
There are many factors affecting the straightening quality, such as the tortuosity of original tube, pipe dimensions and material type alignment models, adjusting parameters and so on.

Straight seam steel pipe and spiral steel pipe

Process quality overall performance of straight seam steel pipe is better than spiral steel pipe. At present, the domestic production of straight seam steel pipe are: nominal diameter DN400 and below the high-frequency ERW steel pipe, nominal diameter DN400 above for LSAW steel pipe. For LSAW steel pipe, according to different molding process, a total five different ways of UOE, JCOE, HME, RBE and PFP, the former two are the most common. Because UOE forming welded steel pipe production line is with high molding equipment technology content, high production efficiency, molding process is relatively simple, good shape, and a small welding stress after forming ; and because of the overall expansion of production used in hydraulic diameter steel pipe can effectively eliminate stress, improve the pipe strength and dimensional accuracy, so the quality is better than JCOE forming welded steel pipe.

45 # seamless steel pipe

45 # seamless steel pipe
45 # seamless steel pipe is one of the steel materials. A high-quality carbon structural steel.
A lot of mold production company will use it as the mold steel.
45 # seamless steel pipe refers to the carbon content of such material, probably about 450. Such material, compared to the other high quality carbon steel, are more common.
45 Steel: the average carbon content of 0.42-0.50%, the average silicon content of 0.17-0.37%, the average manganese content of 0.50-0.80%, the average sulfur content of <= 0.035%, the average phosphorus content <= 0.035% , the average chromium content <= 0.25%, with an average nickel content of <= 0.2545 steel. About 0.45% carbon content.
Recommended heat treatment temperature
45 # seamless steel normalizing: 850
45 # seamless steel pipe quenching: 840
45 # seamless steel tempering: 600
45 # seamless steel tensile strength: not less than 600Mpa
45 # seamless steel pipe yield strength: not less than 355Mpa
45 # seamless steel pipe elongation: 10%
45 # seamless steel pipe shrinkage: 40%
45 # seamless steel pipe Impact Energy: 39J
45 # seamless steel pipe steel delivery status hardness: no more than
45 # seamless steel pipe is not heat-treated: 229HBS
45 # seamless steel annealed steel: 197HBS
45 # seamless steel pipe Application examples:
For parts of the impeller pump compresso,r manufacturing gears, rack, sprockets, shaft, keys, pins, steam turbine.
Model 45 #
45 # seamless steel pipe products specifications φ: 756MM; wall thickness: below 100MM.

Wednesday, December 17, 2014

Main materials of line pipe

The line pipe includes seamless steel pipe and welded steel pipe two type, the pipe ends have flat end, threaded end and socket end; coupled essentials for welding ends, coupling connection, socket connection and so on.

Materials mainly are: 10 #, 20 #, 35 #, 45 #, 16Mn (Q345), 27SiMn, 40Cr, 15CrMoG, 35CrMo, 12Cr1MoVG, 10CrMo910, T91 (Steel Institute 102), A335P11, A335P12, A335P22, A335P91, A213T11, A213T12, SA106B, SA106C, A333GR.1, A333GR.6, ST45.8-III, J55, K55, N80, L80, P110, X40-70, L245, L360, DZ40, DZ50, R80, YB235-70,12Cr2MoWVTiB etc. .

APISPEC5L-2000 line pipe steel is a pipeline specification prepared and published by the American Petroleum Institute, common used throughout the world. This kind of critical steel material: B, X42, X56, X65, X70 and other steel grade.

Oil casing importing

Oil casing import
(1)oil casing main importing countries are: Germany, Japan, Romania, the Czech Republic, Italy, Britain, Austria, Switzerland, the United States, Argentina, Singapore also. Standard reference import more American Petroleum Institute Standard API5A, 5AX, 5AC. Steel grade is H-40, J-55, N-80, P-110, C-75, C-95 and the like. The main specifications for 139.77.72R-2,177.89.19R-2,244.58.94R-2,244.510.03R-2,244.511.05R-2 and so on.
(2)API predetermined length in three ways: i.e., R-1 is 4.88 ~ 7.62m, R-2 is 7.62 ~ 10.36m, R-3 is 10.36m to longer.   
(3)some of the imported goods marked with LTC words, that is the filaments buckle sleeve.
(4)The casing pipe imported from Japan in addition to using API standards, there are a small part implementation of the Japanese factory standards (such as Nippon Steel, Sumitomo, Kawasaki, etc.), steel grades are the NC-55E, NC-80E, NC-L80, NC-80HE and so on.
(5) In the case of claims, there have been black buckle, threaded injury, tube folding buckle down and threaded standoff ultra-poor, ultra poor coupling J value the appearance of defects and brittle casing, yield strength and low intrinsic quality problems.

Tuesday, December 16, 2014

Width, material, temperature and magnet requirements for welded steel pipe

Welded steel pipe strip width, material, temperature and magnet requirements
1 the width of the steel belt and tolerance range are carried out according to the requirements of GB/T3091-2001, cutting edges strip should be adopted in principle.
2 the material of steel belt (weldability), according to the request of GB700.
3 welding temperature: 1350-1380℃, the high frequency furnace frequency: 200-400 KHZ, under the condition of the high frequency equipment must have built-in frequency, frequency of high frequency welding changes with the welded steel pipe diameter and wall thickness.
4 bar (impedance) requirements

NPS Bar OD        NPS Bar OD
1/2" Ф13×140 2" Ф35×200
3/4" Ф18×140 3" Ф30×200×4
1" Ф22×140 4" Ф30×200×7
1 1/4" Ф30×200 5" Ф32×200×7
1 1/2" Ф32×200 6" Ф35×200×7

5 water cooling control.
Induction coil, the magnet, and adjacent squeezing roller device generated large heat due to the high frequency effect, which must strengthen the water flow to cooling, after cooling temperature shall below 400℃. Output transformer and induction coil device also should be passed into the circulating cooling water, and ensure the long-term circulating water outlet water in the running process.
6 high frequency electric resistance welded steel pipe appearance judgment:
6.1 when do normal welding operation, look from the squeezing roller center along the direction of equipment operation should be from coarse to fine, from deep to dark red metal extrusion line.
6.2 by scraping scar device, the burr of the steel pipe can not have split ends.
6.3 by scraping scar, the weld of the steel pipe surface should be a continuous blue strip, line width of 1 -- 3 mm.
6.4 weld reinforcement inside the steel pipe should be full and uniform.

Thermal expansion seamless steel pipe and straight seam steel pipe

Thermal expansion seamless steel pipe and straight seam steel pipe production technology
In terms of the technology processes, the thermal expansion seamless steel pipe and straight seam steel pipe production are almost the same. The large thermal expansion seamless steel pipe is generally using seamless steel pipe of finished, semi-finished seamless steel pipe or seamless steel blanks for secondary processing. On the expansion machine equipment, medium frequency heating the finished seamless steel pipe, semi-finished seamless steel pipe or seamless steel blank, select the appropriate processing of finished steel according to the required specifications, with a suitable mold expand from a small pipe to a bigger one and from coarse to fine. The difference between flaring straight seam steel pipe and thermal expansion seamless steel pipe lies in the the choice of the mother pipe - straight seam or seamless.