Heat treatment can improve the quality of the product. The quality of the surface of stainless steel wire is mainly determined by the pickling process after heat treatment. This paper talks about the relationship between the surface quality of stainless steel wire and heat treatment.
1. If the thickness of the surface of the stainless steel wire is not uniform, the surface of the base metal under the thick place and the thin place is also different. The surface oxide of the surface oxide and the oxide metal is acidified when it is pickled. The degree of erosion is different, so the surface of the stainless steel wire is not uniform. Therefore, in the heat treatment heating, it is necessary to uniformly form the scale. To achieve one, the following conditions are involved, and attention should be paid:
If oil adheres to the surface of the workpiece during heating, the thickness of the scale at the oil adhering portion and the thickness and composition of the oxide scale in other portions are different, and carburization occurs. The portion of the subcutaneous matrix metal that is carburized will be severely attacked by acid. When the heavy oil burner is initially burned, the oil droplets sprayed on the workpiece have a great influence. The fingerprint of the operator is also affected when it is attached to the workpiece. Therefore, the operator should not directly touch the stainless steel parts by hand, do not let the workpiece stain the surface of the new oil workpiece. If there is lubricating oil attached during cold working, it must be fully degreased in the trichloroethylene degreaser and caustic soda solution. Wash with warm water and then heat treatment.
2. If there is debris on the surface of the workpiece, especially when organic matter or ash adheres to the workpiece, heating will of course have an effect on the scale.
3. The surface of the stainless steel that is in direct contact with the flame of gas or oil is different from the scale produced by the place where it is not in contact. Therefore, it is necessary to make the treatment member not directly contact the flame port when heating.
4. If the local part of the treatment part has residual scale before heat treatment, there is a portion where the scale remains and the part without the scale after heating, and the thickness and composition difference of the scale may occur, causing uneven surface after pickling. , so not only pay attention to the final heat treatment, but also pay attention to the intermediate heat treatment and pickling.
5. The influence of different surface finishes, if the surface finish is different, even if it is heated, the scale on the surface is rough and the scale is not the same. For example, in a place where a local defect is cleaned and a place where it is not cleaned, the condition of forming a scale is different, so that the surface of the workpiece after pickling is uneven.
6. The difference in the atmosphere in the furnace, the atmosphere in the furnace is different in each part, and the formation of the scale will also change, which is also the cause of unevenness after pickling. Therefore, the atmosphere of each part of the furnace must be the same when heated. To this end, the cycle of the atmosphere must also be considered.