The effect of heat treatment on the surface quality of stainless steel

The surface of stainless steel is not uniform. When heat treatment is heated, it must be uniformly formed oxide scale. To achieve consistency, the quality of stainless steel surface is mainly determined by the pickling process after heat treatment, and full attention should be paid to the heating of heat treatment or before heat treatment. Surface cleaning.

1. If oil adheres to the surface of the workpiece during heating, the thickness of the oxide scale at the oil-attached part is different from the thickness and composition of the oxide scale of other parts, and carburization will occur. The carburized part of the base metal under the oxide skin will be severely corroded by acid. The oil droplets sprayed out when the heavy oil burner burns at the beginning will have a great influence if it adheres to the workpiece. The fingerprint of the operator may also be affected when it is attached to the workpiece. Therefore, do not touch the stainless steel parts directly with your hands, and do not stain the workpiece with new oil. If there is lubricating oil attached to the surface of the workpiece during cold working, it must be fully degreased in trichloroethylene degreasing agent and caustic soda solution before cleaning with warm water. Then heat treatment.

2. If there is debris on the surface of the workpiece, when organic matter or dust adheres to the workpiece, heating will certainly affect the oxide scale.

3. There is a difference between the scale of the stainless steel surface directly contacted by the gas or oil flame and the place where it is not. Therefore, the treatment part must not directly touch the flame port during heating.

4. If there is residual oxide scale on the part of the treated part before heat treatment, there will be differences in the thickness and composition of the oxide scale after heating, and the surface will be uneven after pickling. , So not only pay attention to the subsequent heat treatment, but also pay full attention to the intermediate heat treatment and pickling.

5. The effect of different surface finishes. If the surface finishes are different, even if the same heating is applied, the scales on the rough and fine surfaces will be different. For example, where local defects have been cleaned and where they have not been cleaned, the conditions of oxide scale formation are different, which causes uneven surface of the workpiece after pickling.

6. The difference of the atmosphere in the furnace: the atmosphere in the furnace is different in various parts, and the formation of oxide scale will also change, which is also the cause of unevenness after pickling. Therefore, when heating, the atmosphere of all parts in the furnace must be the same. Therefore, the circulation of the atmosphere must also be considered.