Chemical pipelines are used to transport various corrosive media such as acids, alkalis, salts and organic solvents for a long time. Therefore, the corrosion resistance of the materials is extremely demanding. The 347 stainless steel pipe, with its unique composition design, demonstrates excellent comprehensive corrosion resistance in various chemical corrosion environments.
The anti-intergranular corrosion performance is the most prominent advantage of 347 stainless steel pipes. During the manufacturing process of chemical pipelines, a large amount of welding is involved. After ordinary stainless steel pipes are welded, chromium carbides tend to precipitate in the heat-affected zone, forming a chromium-poor area, which subsequently leads to intergranular corrosion. 347 stainless steel pipes, due to the addition of niobium stabilizing elements, form carbides of niobium and carbon preferentially, effectively inhibiting the formation of chromium carbides. Even without undergoing solution treatment after welding, the pipelines can still maintain excellent anti-intergranular corrosion ability, and are particularly suitable for on-site installation scenarios in large chemical plants where post-weld heat treatment cannot be carried out.
In terms of antioxidant performance, the 347 stainless steel tube exhibits stability in high-temperature chemical media. With a chromium content ranging from 17.0% to 19.0%, it can form a dense chromium oxide passivation film on the surface, effectively preventing the contact between corrosive media and the substrate. Even at high temperatures ranging from 400°C to 800°C, this passivation film can still maintain good integrity, and its antioxidant capacity is superior to that of ordinary 304 stainless steel tubes.
In terms of uniform corrosion resistance, 347 stainless steel pipes have good tolerance to various chemical media. They perform well in oxidizing acids such as nitric acid and phosphoric acid, and also possess certain corrosion resistance in organic acids such as acetic acid and formic acid. It should be noted that in strong reducing acids like hydrochloric acid and dilute sulfuric acid, the corrosion resistance of 347 stainless steel pipes is limited. When selecting materials, it is necessary to evaluate based on specific medium conditions.
In terms of stress corrosion cracking, the austenitic structure of 347 stainless steel tubes makes them highly susceptible to chloride stress corrosion. Therefore, they should be used with caution in high-temperature environments containing chloride ions and under tensile stress.
Jiangsu Cunrui Metal Products Co., Ltd. Specialized in supplying 347 stainless steel pipes specifically for chemical pipelines. The products strictly follow the ASTM A312 standard. The specifications are complete, and material certificates and technical selection support can be provided.
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