How to distinguish the quality of 316 stainless steel channel?

The quality of the surface of 316 stainless steel channel 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 structure is uneven, pickling cannot improve the surface finish and uniformity. Therefore, full attention should be paid to the heating of heat treatment or the surface cleaning before heat treatment.

If the surface oxide scale thickness of stainless steel channel steel is uneven, the surface finish of the base metal under the thick and thin areas is also different. In addition, the dissolution of the surface oxide scale during pickling is different from the degree of acid erosion of the base metal at the oxide scale attachment site, so the surface of the steel plate is uneven. Therefore, during heat treatment heating, the oxide scale must be formed evenly.

To achieve this requirement, the following issues must be noted:
(1) If the surface of the stainless steel channel steel is attached to oil during heating, the oxide scale thickness and composition of the oil-attached area are different from those of other parts, and carburization will occur.
(2) If there are impurities on the surface of the stainless steel channel steel, especially when organic matter or ash is attached to the workpiece, heating will certainly affect the oxide scale.
(3) Differences in the atmosphere in the furnace of stainless steel channel steel. The atmosphere in the furnace is different in different parts, and the formation of oxide scale will also change, which is also the reason for the unevenness after pickling. Therefore, when heating, the atmosphere in each part of the furnace must be the same. For this reason, the circulation of the atmosphere must also be considered.
(4) If there is residual oxide scale on the treated part of the stainless steel channel steel before heat treatment, there will be differences in the thickness and composition of the oxide scale between the parts with residual oxide scale and the parts without oxide scale after heating, causing uneven surface after pickling. Therefore, not only should we pay attention to the final heat treatment, but also pay full attention to the intermediate heat treatment and pickling.
(5) There is a difference in the oxide scale produced on the stainless steel surface that is directly contacted by the gas or oil flame and the parts that are not in contact. Therefore, when heating, the treated parts must not be directly in contact with the flame mouth.
(6) The influence of different surface finish of stainless steel channel steel.