How to distinguish between hot expansion steel pipe and seamless steel pipe

How to distinguish between hot expansion steel pipe and seamless steel pipe?

1. Appearance
Hot expansion steel pipe is a kind of finishing rolling process for welded pipe or seamless steel pipe with thick wall thickness, which is used to expand the pipe diameter by cross rolling or drawing method. In a short period of time, the steel pipe can be thickened to produce non-standard and special type seamless steel pipe. The pipe body of hot expansion steel pipe is red and there is lead powder in the inner diameter. If it is a heat expansion pipe made of welded pipe, you can see an extremely fine weld.

2. Instrument testing
By taking photos with infrared detector, it can be more clear to distinguish welded hot expansion steel pipe from seamless steel pipe.