Heat resistance refers to the high temperature of stainless steel can still maintain its excellent physical and mechanical properties.
Effect of Carbon: Carbon is strongly formed and stabilized in austenitic stainless steels. Austenite and expand the austenitic region of the element. Carbon is capable of forming austenite about 30 times that of nickel. Carbon is a kind of interstitial element, which can significantly improve the strength of austenitic stainless steel by solid solution strengthening. Carbon also enhances the stress-corrosion-resistant properties of austenitic stainless steels in highly concentrated chlorides such as 42% MgCl2 boiling solution.
However, in austenitic stainless steels, carbon is often considered to be a harmful element, mainly due to corrosion in the use of stainless steel in some conditions (such as welding or by 450 ~ 850 ℃ heating), carbon and steel in the Chromium to form a high chromium Cr23C6 type carbon compounds leading to local chromium depletion, the corrosion resistance of steel, especially the resistance to intergranular corrosion performance. therefore. Since the 1960s, the newly developed chrome-nickel austenitic stainless steel is mostly carbon content of less than 0.03% or 0.02% ultra-low carbon type, we can know that with the carbon content decreased, the intergranular corrosion susceptibility of steel lower when the carbon content 0.02% to have the most obvious results, some experimental pearl also pointed out that carbon will increase the chrome austenitic stainless steel point pitting tendency. Due to the deleterious effects of carbon, not only should the carbon content be minimized as required in the smelting of austenitic stainless steels, but also in the subsequent heat, cold working and heat treatment processes. Carbide precipitation.