Heat resistance refers to the high temperature of stainless steel can still maintain its excellent physical and mechanical properties.
Carbon impact: carbon is strongly formed and stable in austenitic stainless steel.The austenite and the expansion of the austenite.The ability of carbon to form austenite is about 30 times that of nickel. Carbon is a interstitial element.Carbon also improves the stress and corrosion resistance of austenitic stainless steel in highly concentrated chloride (eg. 42%MgCl2 boiling solution).
But, in the austenitic stainless steel, carbon is often seen as the harmful elements, this is mainly due to the corrosion of stainless steel used in some conditions, such as welding or heating by 450 ~ 850 ℃), carbon steel with chromium in forming high chromium Cr23C6 type carbon compounds which can lead to local chromium depletion, make steel corrosion resistance especially resistant to intergranular corrosion performance degradation.So.Since the 60 s of the development of new cr-ni austenitic stainless steel is mostly carbon content less than 0.03% or 0.02% of the ultra-low carbon type, you can know as the carbon content is reduced, the steel intergranular corrosion sensitivity is reduced, when carbon content less than 0.02% is one of the most obvious effect, some experiments also pointed out that the carbon will also increase the chromium austenitic stainless steel corrosion tendency.Due to the harmful effect of carbon, not only in the smelting process of austenitic stainless steel should be controlled as low as possible carbon content as required, but also in the subsequent heat, cold processing and heat treatment processes to prevent the surface of stainless steel carbon, to avoid chromium carbide precipitation.