DSAW steel pipe, namely Double Submerged Arc Welded steel pipe is different from ERW. As ERW steel pipe means Electric Resistance Welded Pipes. Today, we would make an detailed analysis for them.

We would like to talk them from five categories, which are segregation, non-metallic inclusions, stomata, shrinkage and crack.

First of all, segregation means the uneven distribution of the chemical composition for the steel pipes. For ERW and DSAW steel pipe, they would include different chemical characters made by different content of sulfur, phosphorus enrichment and so on.

Secondly, for non-metallic, it would be explained for steel containing impurities such as sulfides and oxides.

Thirdly, stomata says the iron and carbon monoxide gas effect for the whole steel tubes once they are generated in the pouring can not fully escape and stay in the tiny pores in the ingot.

For the next different categories, we would talk in next essay, see you then.