How can stainless steel rounds occur? Is it a quality problem?
Cracks caused by inclusions in steel, cracks and steel surface of a certain angle, about 1 ~ 2.5mm, slightly decarburization on both sides, decarburization layer 0.10 ~ 0.15mm. There are inclusions on both sides of the crack and in the tail, and the ferrite band is formed
Cracks caused by surface folding, cracks and steel surface of 15 degrees to 75 degrees angle, about 1.5 ~ 3.5mm, tail vortex shape, slightly decarburization on both sides, decarburization layer 0.15 ~ 0.25mm, crack in the presence of oxide scales. Its macro shape is in the surface of the round steel along the rolling direction into a straight line or zigzag, continuous or intermittent appear in the partial or full length of steel. This shows that this is a folding process in the process of rolling steel. Main reasons of folding is finished before the workpiece with a handleonapot; secondly, in the process of rolling each pass from the handle, flash, serious scratch, damage, and roll ring groove wear etc., can make the product surface folding; in addition, such as the serious defect of blank, if cleaning may also be caused by improper finished folding. Therefore, the main measures to reduce or avoid folding appear: pass through reasonable design, accurate estimation of the spread, precisely adjust the position of roller groove, reduce or eliminate the finished product before rolling the handle, flash, scratches and other defects; the serious defects of the blank surface carefully cleaned.
By the skin bubbles, surface cracks and so on. Crack and steel surface vertical, about 0.8 ~ 1.5mm, no decarburization on both sides, this is caused by the bubble caused by the subcutaneous bubble. The molten steel contains a large amount of gas. When the liquid steel is solidified, the gas is discharged to form bubbles. The outer layer of the slab near the bubble called the subcutaneous bubbles, honeycomb shaped perpendicular to the surface of the billet, billet after rolling, the bubbles inside most welding. But if the subcutaneous bubbles near the slab surface is too close, while heating because of billet surface oxidation or burning of the bubble exposed, the bubble surface is oxidized, thus it is not possible to make the steel welding, surface cracks.
