Cold drawn steel surface crack

Cold drawn steel is a common machine material. Ordinary cold drawn steel, cold drawn round steel, cold drawn flat steel, cold drawn six angle rod and so on, are usually stainless steel, carbon steel, free cutting steel, bearing steel. Cold drawn steel processing has the characteristics of high dimensional accuracy and smooth surface. In actual production, this advantage is only suitable for hot rolled materials compared with other bright materials such as peeling or polishing materials, because the surface cracks appear to be more likely to be at a disadvantage. Cold drawn steel bars are usually shallow, and throwing 20 to 50 can be eliminated. It is a slight crack.


From the billet production process, the occurrence of steel cracks is closely related to the following three factors.


(1) the wrapping of a ladle. Inclusions in molten steel and high oxygen content in steel lead to incomplete cleaning and cracking.


(2) surface folds. The steel is folded during rolling, causing the steel surface to appear linear or serrated cracks along the rolling direction.


3. Subcutaneous bubbles. There are some subcutaneous bubbles near the surface. When heated, the surface of the billet is oxidized or burned, and the subsurface bubbles will be exposed and oxidized, which can not be welded and cause cracks.