The surface quality of stainless steel wire is influenced by its manufacturing processes, including heat treatment. Let’s delve into the origins of the relationship between surface quality and heat treatment:
Ss Wire Surface Quality and Heat Treatment
Heat treatment can improve the quality of the product. The surface quality of ss wire is mainly determined by the pickling process after heat treatment. This article will talk about the relationship between the surface quality of ss wire and heat treatment.
(1) If the thickness of the surface oxide scale of the ss wire is not uniform, the surface finish of the base metal under the thick place and the thin place is also different, and the dissolution of the surface oxide scale during pickling and the base metal at the attachment site of the oxide scale is acidified. The degree of erosion of the ss wire is different, so the surface of the ss wire is not uniform.
Therefore, during the heat treatment heating, it must be uniformly formed oxide scale, to achieve one, the following conditions are involved, and attention must be paid. 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 by the heavy oil burner during the initial combustion 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, bath workers should not directly touch stainless steel parts with their hands and do not stain the workpiece with new oil.
The surface of the workpiece, such as lubricating oil attached during cold working, must be fully degreased in 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 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 that is directly in contact with the flame of gas or oil and the place where it is not. Therefore, the treatment part must not directly touch the flame port during heating.
(4) If there is a residual oxide scale on the part of the treated part before heat treatment, there will be a difference in the thickness and composition of the oxide scale after heating, which will cause the surface to be uneven after pickling. Uniformity, so not only the final heat treatment but also 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 used, the roughness and fine scale on the surface will be different. For example, where the local defects are cleaned and where they are not cleaned, the conditions of oxide scale formation are different, which causes an uneven surface of the workpiece after pickling.
(6) The difference in furnace atmosphere The furnace atmosphere is different in various parts, and the formation of the oxide scale will also change. This is also the cause of unevenness after pickling. Therefore, when heating, the atmosphere of all parts in the furnace must be the same. For this reason, the circulation of the atmosphere must also be considered.