The quality of the appearance of 304 stainless steel is mainly determined by the pickling process after heat treatment. If the surface oxide scale formed by the previous heat treatment process is thick or the arrangement is uneven, pickling does not improve the surface finish and uniformity. Therefore, it is necessary to pay full attention to the heat treatment or the appearance of the heat treatment before finishing.
If the thickness of the outer scale of the stainless steel plate is uneven, the surface finish of the base metal under the thick ground and the thin ground is also different. When the surface is pickled, the dissolution of the outer scale and the degree of corrosion of the base metal at the site where the scale is attached by the acid Different, so the appearance of the steel plate is uneven. Therefore, during heat treatment and heating, it is necessary to make the scale uniform.
To meet this requirement, it is necessary to pay attention to the following problems. If the stainless steel plate deposits oil on the surface of the workpiece during heating, the thickness of the scale at the oil adhesion part is different from the thickness and composition of the other parts, and carburization will occur. The carburized part of the base metal under the oxide scale will be severely corroded by acid. The oil droplets ejected when the heavy oil burner begins to burn, if attached to the workpiece, will have a great influence.
Operator's fingerprint will also affect when attached to the workpiece. Therefore, the operator should not directly touch the stainless steel parts with his hands, and do not make the work pieces get new oil stains. It is necessary to wear clean gloves. If there is lubricating oil adhering to the workpiece during cold working, it is necessary to fully degrease in trichloroethylene degreasing agent and caustic soda solution, wash with warm water, and then heat-treat.
