ERW pipe technical requirements

ERW pipe technical requirements

Technical requirements For oil and gas transport For low pressure fluid conveying
Material Gr.b Gr.b
Pipe body diameter D508mm, ±0.75%; D≥508mm, ±0.75% D≤168.3, ±1.0%; 168.3D≤508,±0.75%; 
Wall thickness D508mm,+15.0%,-12.5%; D≥508mm, +17.5%,-10% ±12.5%
Bending ≤0.2% ≤0.2%
Ovality D≥508mm≤±1% ≤±0.75%
Bevel ≤1.59mm ≤5mm
Hydrostatic testing 100% 100%
Nondestructive testing 100% non-destructive weld inspection Ultrasonic flaw detection is 100%

ERW pipe weld contour shape

According to API SPEC 5L standards, most domestic production plant during SAW pipe weld tensile test, usually retain the weld reinforcement, direct tensile test from the test rarely broken welds situation. The main reason can be attributed to the presence of the weld reinforcement. SAW pipe, said more than high or strengthen high, in the objective to increase the thickness of the weld area, and enhance the structural strength of the weld, the strength of the weld area (the overall structural strength) than the strength of the base metal parts.

Reference SAW pipe weld Strengthening beneficial role in the ERW pipe welding Weld intends to squeeze thick, in the vicinity of the weld to form a thickness greater than the thickness of the base material, extending to the reinforcing layer weld heat-affected zone, then within the welding burr formation completely evenness, forming wavy smooth transition region to improve the structural strength of the weld area between the base metal and steel welds. Meanwhile, since the thickness of pipe welds have a greater tolerance, even scraping system instability due to internal glitch, resulting in some degree of scratch groove welds, it will not cause a serious decrease weld strength. In addition, the weld and base metal smooth transition, ultrasonic testing of the weld does not cause false positive rate increases.

Scrape the inside welds very smooth burr, weld and base metal transition very smooth. Usually a steel pipe wall thickness is 11.9mm, a thickness range of extrusion welds typically range from about 25mm to either side of each weld, the weld portion after the removal of burr than other parts of the base material thickness of about 10%. Smaller thickness of the pipe, squeeze thick range may be reduced, but the proportion of weld thicker parts of the general control 10% of the base material thickness.

Post time: Oct-29-2019