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Material Application of Chromium Molybdenum Steel Valves


Material Application of Chromium Molybdenum Steel Valves

Chromium molybdenum steel valve is the most commonly used type of valve in power plants, and its difference lies in the fact that other valves are made of chromium molybdenum steel material. For valves made of chromium molybdenum steel material, everyone is still not familiar with it, so I will briefly introduce it here< br /> CrMo steel is a low alloy heat-resistant steel with good mechanical properties and hydrogen resistance at room and high temperatures. The main alloying elements in steel include molybdenum, chromium, vanadium, silicon, boron, etc< br /> Molybdenum is a very important alloy element in hot strength steel, which significantly improves the thermal strength performance of steel, maintains sufficient strength at high temperatures, and can refine grains to prevent the tendency of steel to overheat. However, steel containing only molybdenum will accumulate into graphite and precipitate at high temperatures for a long time, leading to deterioration of performance. To eliminate this tendency, the element chromium is often added simultaneously to the steel. Adding chromium to steel can also improve its thermal strength, high-temperature oxidation resistance, and corrosion resistance. This is because chromium can form a dense and highly adhesive oxide film on the surface of steel, thereby preventing internal metal from further oxidation or corrosion. The higher the chromium content in steel, the denser the oxide film, and the better its oxidation and corrosion resistance< br /> The carbon content of low alloy heat-resistant steel is below 0.20%, and the structure is mainly composed of pearlite and a small amount of ferrite. Most of them are delivered for use in the normalized state. After welding, it should be tempered at a temperature at least 100 higher than the usage temperature< br /> The commonly used chromium molybdenum steels in China include 30CrMo (500 ℃), 35CrMo (525 ℃), 15CrMo (550 ℃), 12Cr2Mo1 (575 ℃), 1Cr5Mo (600 ℃), etc. Note: The temperature in parentheses refers to the upper limit of the usage temperature< br /> This type of steel is most commonly used in the design of power plant valves, especially 15CrMo, 12Cr2Mo1, and 1Cr5Mo