Stainless steel quality inspection process

Qualified or unqualified stainless steelshould be determined by inspection, and the quality inspection is divided into seven steps.

1. If oil is attached to the surface of the work piece when the stainless steel plate is heated, the thickness of the oxide scale at the oil-attached part will be different from the thickness and composition of the oxide scale on 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. Therefore, the operator should not directly touch the stainless steel parts with his hands, and do not stain the workpiece with new oil.

2. 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, then cleaned with warm water, and then heat treated.

3. If there are impurities on the surface of stainless steel, especially when organic matter or ash adheres to the workpiece, heating will certainly affect the oxide scale.

4. The difference of the atmosphere in the stainless steel 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.

5. Objects that are in direct contact with the heated workpiece must be fully dried before they can be used. However, if placed at room temperature after drying, moisture will still condense on the surface of the workpiece under high humidity. Therefore, it is best to dry before use.

There is residual oxide scale before, and after heating, there will be differences in the thickness and composition of the oxide scale, which will cause the surface to be uneven after pickling, so not only pay attention to the final heat treatment, And also pay full attention to intermediate heat treatment and pickling.

There are differences in the scale produced. Therefore, the treatment part must not directly touch the flame port during heating.