Acid pickling treatment process of stainless steel

Abstract

The invention discloses a stainless steel pickling treatment process, comprising the following steps: (1) configuring materials: by weight percentage, 20-22% of nitric acid, 5-7% of hydrofluoric acid, and the rest is water; (2) Dosing: Mix and stir the configuration materials according to the above mass ratio; (3) Loose oxide film: Soak the stainless steel to be treated in sulfuric acid with a volume concentration of 10-15% at a temperature of 800°C for 20-25 minutes; (4) Remove Oxide film: Soak the stainless steel to be treated in the above solution, treat it at room temperature for 10 to 15 minutes, take it out, then rinse the surface with water, and finally rinse and neutralize it with lye, clean it and dry it. The stainless steel pickling treatment process provided by the invention is controlled by strict process parameters, can remove scale quickly and efficiently, has little corrosion to the substrate, has high corrosion inhibition rate, and has no acid mist during the cleaning operation process.

Description

technical field [0001] The invention relates to a stainless steel surface treatment process, in particular to a stainless steel pickling treatment process. Background technique [0002] The stainless steel pickling passivation process is to remove a layer of oxide scale and other metal compounds on the surface of stainless steel after pickling, rolling or other processing processes. The surface chromium is precipitated to form a layer of chromium oxide, which has a strong passivation ability and can prevent it from reacting with other substances, so as to achieve the purpose of stainless steel. The corrosion resistance of stainless steel is mainly due to the fact that the surface is covered with a very thin and dense passivation film, which is isolated from the corrosive medium and is the basic barrier for stainless steel protection. Stainless steel workpieces will form an oxide film when placed in the air, but the protection of this film is not perfect. Usually, it needs ...

AI Technical Summary

Problems solved by technology

In the prior art, when stainless steel pipe fittings are pickled and passivated, the process is complicated and there are many steps. The ratio of pickling and passivation solution is often determined by each manufacturer according to its own materials and production experience. The determined ratio is different. Stable, the use effect is not ideal, there are shortcomings such as incomplete removal of oxides on the surface of the pipe fittings after pickling, insufficient passivation film formation, poor finish, etc.