Necessity of pickling and passivation of stainless steel wire mesh

Austenitic stainless steel wire has good corrosion resistance, high temperature oxidation resistance, good low temperature performance and excellent mechanical and additive R energy. Therefore, it is widely used in chemical, petroleum, power, nuclear engineering, aerospace, marine, pharmaceutical, light industry, textile and other sectors. Its main purpose is to prevent corrosion and rust. The corrosion resistance of stainless steel mainly depends on the surface passivation film, if the film is not complete or defective, stainless steel wire mesh will still be corroded. In engineering, acid pickling and passivation are usually used to make the corrosion potential of stainless steel more effective. In the process of forming, assembling, welding, weld inspection (such as flaw detection, pressure test) and construction marking of stainless steel equipment and components, surface grease, rust, non-metallic dirt, low melting point metal contaminants, paints, welding slag and splashes are brought about, which affect the surface quality of stainless steel wire mesh equipment and components. The oxidation film on the surface of the steel is destroyed, and the overall corrosion resistance and local corrosion resistance (including pitting corrosion and crevice corrosion) of the steel are reduced, even leading to stress corrosion cracking.

The surface cleaning, pickling and passivation of stainless steel wire mesh can not only maximize the corrosion resistance, but also prevent product pollution and obtain beautiful appearance. According to GBl50-1998 Steel Pressure Vessels, the surface of vessels made of stainless steel and clad steel plates with anticorrosion requirements shall be pickled and passivated. This regulation is for pressure vessels used in petrochemical industry, because these equipment is used in direct contact with corrosive media occasions, starting from guaranteeing corrosion resistance, pickling passivation is necessary. For other industrial sectors, if not for anticorrosion purposes, only based on cleanliness and aesthetic requirements, and the use of stainless steel judgment without pickling passivation. But the weld of stainless steel equipment needs to be pickled and passivated. Strict requirements for nuclear engineering, some chemical plants and other uses require that, in addition to pickling and passivation, high-purity media be used for final fine cleaning or finishing such as mechanical, chemical and electrolytic polishing.