The Necessity Of Pickling Passivation Of Stainless Steel Wire Mesh
Austenitic stainless steel wire mesh has good corrosion resistance, high temperature oxidation resistance, good low temperature performance and excellent mechanical and processing properties. 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 incomplete or defective, the stainless steel will still be corroded. The pickling passivation treatment is usually carried out in the engineering, so that the corrosion resistance potential of the stainless steel is exerted more. Surface oil, rust, non-metallic dirt, low melting point metal contaminants, paint, welding in the process of forming, assembling, welding, weld inspection (such as flaw detection, pressure test) and construction marking of stainless steel equipment and components Slag and spatter, etc., which affect the surface quality of stainless steel equipment and components, destroy the oxide film on the surface, reduce the overall corrosion resistance and local corrosion resistance of steel (including pitting, crevice corrosion), and even lead to Stress corrosion cracking.
Stainless steel wire mesh surface cleaning, pickling and passivation, in addition to maximizing corrosion resistance, it also prevents product contamination and aesthetics. In GBl50-1998 "Steel Pressure Vessels", "the surface of containers made of stainless steel and composite steel plates with anti-corrosion requirements shall be pickled and passivated". This regulation is for pressure vessels used in petrochemical industry. Because these equipments are used to directly contact corrosive media, it is necessary to initiate pickling passivation from the perspective of ensuring corrosion and corrosion resistance. For other industrial sectors, if not for corrosion protection purposes, only based on cleaning and aesthetic requirements, stainless steel materials do not require pickling passivation. However, the weld bead of stainless steel equipment also needs to be pickled and passivated. For nuclear engineering, certain chemical equipment and other strict requirements, in addition to pickling and passivation, high-purity medium should be used for final fine cleaning or finishing treatment such as mechanical, chemical and electrolytic polishing.
Hope this article can help you better understand the reason why the stainless steel wire mesh is to be pickled and passivated.
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