Cold crack, one of most important steps for ERW steel pipe producing, plays an essential role for quality of welded steel pipe. Then how to control the technical steps to decrease the shortage of cold crack?

There are two main aspects for this: the role of hydrogen and quenching effect.

The role of hydrogen: Temperature control would be important for welding steel pipe production process. Some of the hydrogen atoms are in the compound of the state of the precipitation of hydrogen resolution, and large amount of hydrogen will be dissolved in the metal bath. As the bath temperature dropped, the solubility of hydrogen in the metal drastically reduced. However, quickly cooling of the weld pool, the hydrogen too late to escape and remains in the weld metal.

Quenching effect: Near the weld seam zone or cold cracks formed on the metal phase transition process and the mechanical properties of rapidly changing and complex stress state. Cold cracking occurs mainly in medium carbon steel, high carbon steel and high strength steel. The main features of this type of steel is easy to quenching.