Requirements of Oil Well Casing Pipe Standard for Weld Deviation

　　The welding deviation of Oil Well Casing Pipe means that the welding position deviates from the welding center line. When oil well casing pipe welding, the welding angle deviates from the welding junction and is not welded along the weld.

　　In each standard, the welding deviation of API 5CT 8 Inch Oil Well Casing Pipe weld is also specified:

　　1.Oil well casing pipe for low pressure fluid transmission pipeline, which is not specified in SY / t5037-2012 standard.

　　2. Technical conditions for delivery of steel pipes for oil and natural gas industry - Part 1: class a steel pipe GB / t9711-2011 PSL1 standard stipulates that as long as the non-destructive test proves that the weld is fully penetrated and fully fused, the welding deviation cannot be used as the rejection basis for oil well casing pipe.

　　3. Technical delivery conditions for oil and natural gas industrial transmission steel pipe part 2: steel pipe of class B GB / t9711-2011 PSL2 standard stipulates that the welding deviation shall not exceed 3mm when t ≤ 10, and 4mm when t > 10.

　　4. According to API Spec 5L, as long as the non-destructive inspection proves that the weld is fully penetrated and fused, the welding deviation cannot be used as the basis for rejection of oil well casing pipe.