Heat resistance of stainless steel

Heat resistance means that stainless steel can still maintain its excellent physical and mechanical properties at high temperatures.
Influence of carbon: Carbon is strongly formed and stabilized in austenitic stainless steels. Elements that determine austenite and expand the austenite region. The ability of carbon to form austenite is about 30 times that of nickel, and carbon is an interstitial element that can significantly increase the strength of austenitic stainless steel through solid solution strengthening. Carbon can also improve the stress corrosion resistance of austenitic stainless steel in highly concentrated chloride (such as 42% MgCl2 boiling solution).
However, in austenitic stainless steel, carbon is often regarded as a harmful element, mainly because under some conditions (such as welding or heating at 450~850 ° C) in the corrosion resistance of stainless steel, carbon can interact with the carbon in the steel. Chromium forms high-chromium Cr23C6-type carbon compounds, which leads to the depletion of local chromium, which reduces the corrosion resistance of steel, especially the resistance to intergranular corrosion. therefore. Most of the newly developed chromium-nickel austenitic stainless steels since the 1960s are ultra-low carbon types with a carbon content of less than 0.03% or 0.02%. It can be known that as the carbon content decreases, the intergranular corrosion susceptibility of the steel decreases. When the carbon content is lower than 0.02% has the most obvious effect, and some experiments also pointed out that carbon also increases the pitting corrosion tendency of chromium austenitic stainless steel. Due to the harmful effect of carbon, not only should the carbon content be controlled as low as possible in the smelting process of austenitic stainless steel, but also in the subsequent hot, cold working and heat treatment processes, the surface of the stainless steel should be prevented from increasing carbon, and chromium carbides should be avoided. Precipitate.
As the stainless steel of the conveyor belt, the mechanical properties of the conveyor belt will decrease in a curve at high temperature, and slight deformation will occur to different degrees, which will lead to problems such as deviation and short life. Therefore, different maximum temperature standards will be set according to different industries. If the material is not corrosive, carbon steel strip with better heat resistance can be considered as the first choice.
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