Spiral steel pipe is a kind of product formed by welding technology, so in the production process for the welding process is very strict. (1) Raw materials are strip coil, welding wire and flux. Strict physical and chemical tests must be carried out before being put into operation. (2) The joint

Spiral steel pipes should be subjected to mechanical performance test, flattening test and flaring test before leaving the factory, and must meet the requirements of the standard. The quality inspection methods of straight seam steel pipes are as follows:1. Judging from the surface, that is, in appe