Why do these problems with stainless steel wire mesh?
Why do these problems with stainless steel mesh?
Causes the breakage of stainless steel wire mesh
Stainless steel wire mesh often breaks when used, and is analyzed by chemical composition analysis, metallographic examination, scanning electron microscopy and X-ray energy spectrum analysis. The results show that stress corrosion and pitting corrosion are the main causes of stainless steel wire mesh fracture. The corrosive medium is chloride ion in the humid atmosphere of the sea or various aqueous solutions are processed in chemical production. The broken wire mesh material is poor, its chemical composition does not meet the relevant technical conditions, the chromium and nickel content are low, and the high manganese content makes the corrosion resistance of 1Cr18Ni9 steel decrease, and more dispersed carbide particles appear in the microstructure. Ferrite greatly reduces the resistance of the wire to stress corrosion and pitting corrosion. The stainless steel wire fracture is mainly along the grain brittle fracture, and the steel wire artificial fracture is a normal fracture of the dimple, indicating that most stainless steel mesh is a stress corrosion fracture. The residual stress generated by wire mesh processing and the presence of stress corrosion sensitive medium are the main causes of stress corrosion cracking of steel wire.
Destroying stainless steel wire mesh passivation film will reduce corrosion resistance
Stainless steel wire mesh stainless steel has good corrosion resistance, high temperature oxidation resistance, good low temperature performance and excellent mechanical properties. Therefore, it is widely used in the screening and filtration under acid and alkali environmental conditions, chemical fillers, petroleum screens and other industries. Its main purpose is to prevent corrosion and rust. The corrosion resistance of stainless steel wire mesh 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 slag during the forming, assembly, welding, weld inspection, such as flaw detection, pressure test and construction marking of stainless steel equipment and components With spatters, etc., these materials 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 stainless steel stencil (including pitting, crevice corrosion), and even Causes 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. The surface of containers made of stainless steel wire mesh and composite steel plates with anti-corrosion requirements shall be pickled and passivated. This is for the filtration used in petrochemical industry because these devices are used for direct contact with corrosive media. Starting from the guarantee of corrosion resistance and corrosion resistance, it is necessary to provide pickling passivation. For other industries, such as not for corrosion protection purposes, only based on cleaning and aesthetic requirements, stainless steel materials do not require pickling passivation. However, the weld seam of the stainless steel equipment also needs to be pickled and passivated, and the stainless steel wire mesh passivation film is repaired to improve the rust resistance.