Seam or not would be an important factor to recognize the seamless and ERW steel pipe. For the last one, we have to concern about the cold crack as this has determined function for the quality of this kind of tube.

Joints of welded steel tube, cooling to a lower temperature, are generated by the welded cracking. Thus, we should figure out the technological parameters for guaranteeing the high quality of welded steel pipe. In general, we will call it cold cracking, which includes delayed cracking, thermal stress cracking and lamellar tearing. And if you want to judge the types of cold crack, there is the reference for it: boundary cracks, under-bead cracks and root cracks.