Carbon steel pipe internal defects are generated in the carbon steel smelting defect smelting and casting processes, such as segregation, non-metallic inclusions, porosity, shrinkage, and cracks.

Segregation

Segregation is the uneven distribution of chemical composition in the steel, in particular harmful elements such as sulfur, phosphorus enrichment in the ingot.

Non-metallic inclusions

Non-metallic inclusions refer to non-metallic inclusions in steel containing impurities such as sulfides and oxides.

Stomata

Stomata refer to iron and carbon monoxide gas effect generated in the pouring can not fully escape and stay in the tiny pores in the ingot.

Shrinkage

Shrinkage is due to the liquid steel ingot mold from outside to inside, the volume contraction during solidification bottom-up, because the level drops, the final solidification of liquid steel parts can not be added to form.

Crack

Solidification of liquid steel in the order due to different causes stress, tension cracks may appear larger parts.