304 stainless steel pipe will turn black? 2020-09-07 Today, some friends asked why the 304 stainless steel pipe products they used at home turned black. It turns out that the stainless steel pipes will turn black. Today, the editor specially sorted out some reasons and treatment methods on how to deal with the blackening of stainless steel pipes. . In fact, stainless steel pipe products of stainless steel pipe manufacturers are generally speaking, products made from good 304 stainless steel pipes will not have this situation. If stainless steel pipe products have blackened and darkened during long-term use, this is because The stainless steel tube produces a layer of oxide film under the action of air. The main function of this layer of oxide film is to prevent the metal in the stainless steel from being oxidized. This layer of oxide film does not need to be wiped off specially, and it does not damage the pipe material. Stainless steel of different materials Because there are some differences in the element content of the tube, the color of the oxidized film will also be different, but all have no effect on the tube. In this case, no other treatment is needed. If you feel that it is not beautiful to use, you can go to a stainless steel pipe processing center to do a polishing treatment, and it can be easily solved. If the stainless steel pipe is welded, the inner and outer surfaces of the stainless steel pipe become black and yellow. This is because the welding gas is not pure enough or the back is oxidized at high temperature. Use the following three methods to avoid such things from happening. 1. Increase the purity of the argon used in the welding of stainless steel pipes to pure argon. From the outer surface of the stainless steel pipe, pure argon is significantly brighter than ordinary argon welding. 2. The backside should be protected by argon gas. The important stainless steel pipe should be backside protected after welding. Otherwise, high temperature oxidation will cause the welding layer passing through the backside to oxidize and produce defects. Polishing the backside weld is the same as slag, so protect It can effectively prevent back oxidation in the future. 3. You can apply a back protection agent on the back, which can save argon protection. Just apply a thickness of about 1 mm. Then when the front is soldered, a thin film is formed on the back to form a protective layer. Stainless steel pipe manufacturer Stainless steel pipe 304 If you have found that the weld marks of stainless steel pipes are black, you can use pickling passivation paste to clean it, which is to use acid to corrode the black oxide layer on the surface, and then rinse it with clean water. Therefore, in order to avoid this blackening of 304 stainless steel pipes, it is recommended to choose a quality-guaranteed stainless steel pipe manufacturer, which can bring unnecessary trouble to our lives.