What is the reason for the blue color of stainless steel vacuum annealing?
When vacuum annealing stainless steel, if the process is not up to standard, it is easy to cause the product to turn blue after heat treatment. The following briefly introduces the reasons and solutions for this problem:
Stainless steel, the color is bright when vacuum quenched, and the color after vacuum tempering is white and bright. But when tempering, the color turns blue or purple. If it is 2 series, 3 series, 4 series, stainless steel, you can check the vacuum Furnace tightness. Or the purity of the cooling gas. If these two indicators are not qualified, then the part will change color to blue. If these two indicators are qualified, then the part will definitely not change color. If the cooling gas is not pure, it is recommended that you can Cooled with liquid nitrogen. The purity is 99.999%. The pressure rise rate after the oven is <0.3 Pa/hour. In this way, the color of the product after annealing will not turn blue.