Why do surface cracks appear in 304 stainless steel channel steel?

When we process 304 stainless steel channel steel, we sometimes find cracks on the surface. What is going on? What is the cause?

1. Reasons for cracks: there are ears in the rolled parts before the finished product; ears, flash, severe scratches, severe wear of the roller grooves caused by various processes in the rolling process; cleaning of billets with serious defects improper.

2. Reasons for cracks: During rolling, there are inclusions in the molten steel and the oxygen content is high, which produces oxides. They are not cleaned during the manufacturing process, resulting in cracks.

3. Reasons for cracks: The molten steel contains a large amount of gas. When the molten steel solidifies, the gas is discharged to form bubbles. The bubbles close to the outer layer of the billet become subcutaneous bubbles, which are vertically arranged in a honeycomb shape under the surface of the billet. Usually, the internal bubbles in the billet can be welded after being rolled. However, some subcutaneous bubbles are close to the surface. When heated, when the surface of the billet is oxidized or burned, the subcutaneous bubbles will be exposed, oxidized, and unable to be welded, thus making it impossible to weld. Cracks occur.