Other influencing factors of stainless steel corrosion

Weld splash
Welding spatter has a lot to do with the welding process. For example: GTAM (gas shielded tungsten arc welding) or TIG (inert gas shielded tungsten welding) no splash. However, the use of GMAW (gas shielded metal arc welding) and FCAW (arc welding with flux core) two welding processes will cause a lot of spatter if the welding parameters are used improperly. When this happens, the parameters must be adjusted. If you want to solve the problem of welding spatter, each side of the joint should be coated with anti-splash agent before welding, which can eliminate the adhesion of the splash. After welding, this anti-splash agent and various spatter can be easily cleaned off without damaging the surface or causing minor damage.
Welding processes using flux include manual welding, arc welding with flux core and submerged arc welding. These welding processes will leave small particles of flux on the surface, which cannot be removed by ordinary cleaning methods. This particle will be the corrosion source of crevice corrosion and must be removed by mechanical cleaning methods.
Weld defect
Welding defects such as edge biting, incomplete penetration, dense porosity and cracks not only reduce the fastness of the joint, but also become a corrosion source of gap corrosion. To improve this result, they also entrain solid particles during cleaning operations. These defects can be repaired by re-welding or re-welding after grinding.
Oils and greases
Organic substances such as oil, grease and even finger prints can become a source of local corrosion. Because these substances can act as barriers, they can affect the chemical and electrochemical cleaning effect, and must be thoroughly removed. The ASTM A380 has a simple WATERBREAK test to detect organic contaminants. To test, water is poured from the top of a vertical surface, separating along the organic material as it flows down. Fluxes and/or acid chemical cleaners remove oil stains and grease.
Residual adhesive
When the tape and protective paper are removed, a part of the adhesive always remains on the stainless steel surface. If the adhesive is not hard, it can be removed with organic flux. However, when exposed to light or air, the adhesive hardens, forming a corrosion source of gap corrosion. Mechanical cleaning with fine abrasives is then required.
Pen impression
The effects of these contaminants are similar to those of oils and greases. It is recommended to wash with a clean brush and clean water or alkaline cleaning agent, but you can also use high-pressure water or steam rinse. Stainless steel with a predominantly ferritic structure in use. Chromium content in 11%~30%, with body centered cubic crystal structure. This kind of steel generally does not contain nickel, and sometimes contains a small amount of Mo, Ti, Nb and other elements, this kind of steel has a large thermal conductivity, small expansion coefficient, good oxidation resistance, excellent stress corrosion and other characteristics, and is used to manufacture parts resistant to atmospheric, water vapor, water and oxidizing acid corrosion. This kind of steel has the disadvantages of poor plasticity, plasticity and corrosion resistance after welding, which limits its application. The application of off-furnace refining technology (AOD or VOD) can greatly reduce the gap elements such as carbon and nitrogen, so that this kind of steel is widely used.