What are the reasons for the discoloration of stainless steel screws?

Publish time: 27 Jul 21

We all know that stainless steel screws are the original color, and in most cases there is no need for surface treatment, unless it is requested by the customer. Some customers have asked before that stainless steel screws have changed color during use, red or black. Next, stainless steel screw manufacturers will come to talk to you about the reasons and solutions for this situation.

1. The discoloration of stainless steel is usually caused by the failure of cleaning after the screw is hardened. The cleaning fluid still remains on the surface of the stainless steel screw, so after a period of use, the cleaning fluid will react with it. The reaction causes discoloration of the surface of the stainless steel screw.

2. Surface discoloration and red rust after heat treatment of the phosphate film on the surface of the stainless steel screw. In order to imitate the discoloration of the screw, we will remove the phosphate film before the heat treatment. During the heat treatment process, we need to raise the problem appropriately. The fire in the mesh belt furnace area.

3. After the stainless steel screw is quenched, the water quenching medium remaining in the stainless steel screw will easily cause the rust imitation performance of the stainless steel screw to decrease and the phenomenon of blackening after a period of use. We need to check it from time to time during use. The data of the water quenching medium can imitate the blackening of the surface of the stainless steel screw.

4. In the process of stainless steel screw quenching, if the oil is too aging, it may also cause the screw to turn black. In the process of oil quenching, the temperature should generally be lowered, generally 50 degrees is more appropriate, so that the speed of oil aging can be guaranteed. Slow down.