Oxidation of cold rolled steel plate

Continuous casting, heating furnace, hot rolling, cold rolling annealing, packaging and transportation processes all involve oxidation problems

The role of oxide scale on the surface of steel plates
Black leather steel to improve corrosion resistance
  
During the hot rolling process, by adjusting relevant parameters, a layer of iron oxide scale composed of Fe3O4 is generated on the surface of the product. This kind of iron oxide scale is black, has good plasticity, adhesion, thin thickness and tight bonding with the matrix. It will not peel or crack due to cold stamping and cold forming during deep processing. At the same time, this kind of iron oxide scale plays a lubricating role between the tool and the workpiece, and deforms with the matrix during deep processing, so there is no need to remove the iron oxide scale through pickling.

The dangers of steel oxidation (1)
Significantly increases oxidation burning loss, 1%~5%, reducing the yield of finished products

The dangers of steel oxidation (2)
Some steel types are seriously oxidized in the heating rate furnace, which affects the life of the heating furnace, hot rolling edge cracks, depletion of surface alloy elements, and difficulty in descaling, affecting the surface quality of the product. The dangers of steel oxidation (3)
Improper control of secondary oxidation behavior will cause hot-rolled plates to easily rust.
The thicker the oxide scale, the more difficult it will be to pickle.

The dangers of steel oxidation (4)
Annealing of cold-rolled steel plates produces oxidation color difference, which affects the appearance and indirectly affects the corrosion resistance. The dangers of steel oxidation (5)
The oxidation of steel during packaging and transportation will cause corrosion, produce rust spots, affect appearance and even performance, and cause quality objections.

Oxidation color defects during annealing of cold rolled plates
¢Oxidation color is a surface quality defect produced when cold-rolled strip steel is annealed in a bell furnace. It will cause uneven color effects when sprayed by users.
¢Mainly occurs in bell annealing furnaces
¢Including red oxidation color and white oxidation color