304 stainless steel plate surface quality inspection method which has several?
304 stainless steel surface quality of pickling process mainly depends on the heat treatment, surface oxidation Pihou formation if heat treatment before a process, or organization is not uniform, with acid does not improve the surface smoothness and uniformity. Therefore, attention should be paid to heat treatment or surface cleaning prior to heat treatment.
Attachment of cold processing such as workpiece surface lubrication oil, must be fully skimmed in trichloroethylene degreasing agent, caustic soda solution and then with warm water washing, and then heat treatment. Stainless steel plate, if the surface of debris, especially organic matter or ash attached to the workpiece, heating, of course, will have an impact on the oxide skin. Stainless steel plate furnace atmosphere difference, furnace atmosphere in each part of the different, the formation of oxide skin will change, and this is also caused by uneven acid cleaning reasons. Therefore, when heating, the atmosphere in each part of the furnace must be the same. For this reason, the cycle of atmosphere must also be taken into account. Also, a heating workpiece with bench brick, asbestos, if contain water, when heated, water will evaporate, differences in direct contact with the water vapor and other parts of the atmosphere will produce, the formation of oxide of course is different. Therefore, objects that are in direct contact with the heating workpiece must be thoroughly dried before use. However, after drying, such as placed at room temperature, moisture in high conditions, the water will still condense on the surface of the workpiece. So, it's better to dry before use. If the local processing of stainless steel plate before heat treatment with oxide remaining, after heating with oxide remaining parts and parts without oxide, differences in composition and thickness of oxide skin will appear on the surface after pickling caused by uneven, so we should not only pay attention to the final heat treatment, but also to the full note that the middle heat treatment and pickling. There is a difference between the surface of stainless steel and the place where it is not touched.
If uneven surface oxide thickness of stainless steel plate, the surface of base metal thick smooth places and thin places following different degrees of surface and acid dissolved and oxidized surface oxide skin skin attachment site base metal by the acid erosion degree is different, so the steel plate surface is not uniform. Therefore, when the heat treatment is heated, the oxide scale must be uniformly formed. To achieve this, we must pay attention to the following problems: stainless steel plate in the heating oil if the workpiece surface, oil adhesion of oxide thickness parts and other parts of the oxide thickness and composition is different, and will produce carburizing.
