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Differences between high chromium ball and medium chromium ball, low chromium ball and forged steel ball Release time：2020-10-21　　　　 Views

　　High chromium ball, medium chromium ball, low chromium ball and forged steel ball are several kinds of wear-resistant steel ball commonly used in grinding industry, and also several kinds of wear-resistant steel ball produced by Shandong elite. Many people may only know that they are different, but they cannot distinguish the specific differences. The difference between these steel balls is introduced. Different quality indexes of high chromium ball: chromium content (> 10.0%) and carbon content (> 1.80% - 3.20%) are called high chromium balls. According to the national standard, the hardness of high chromium sphere must be above 58, and the impact value AK (> 3.0j / 2). In order to achieve the hardness of high chromium sphere, high temperature quenching and tempering must be adopted (at present, quenching is available in China). Oil quenching and air quenching, such as hardness test (HRC) less than 54, prove that the steel ball is not quenched. Quality index of medium chromium ball: chromium content 3.0% - 7.0%, carbon content 1.80% - 3.20% is called medium chromium ball, impact value AK (> 2.0j / 2), hardness of chromium ball in national standard must be greater than 47, to ensure the quality of chromium ball, high temperature, high hardness. Tempering treatment (relieving casting stress) is adopted, such as steel ball table. The dark red surface indicates that the product has been tempered at high temperature. If the surface of the ball is still metal, the product is not tempered at high temperature. The quality index of low chromium ball: 0.5% - 2.5% chromium content, 1.80% - 3.20% carbon content is called low chromium ball. The national standard requires that the hardness (HRC) of low chromium ball must be greater than 45, and the impact value AK should be greater than 1.5j/2. In order to ensure the quality of low chromium ball, high temperature tempering treatment (to eliminate casting stress) should be adopted, such as steel ball. Deep red on the surface indicates that the product has been tempered at high temperature. For example, the surface of a steel ball is still metallic, indicating that the product has not been tempered at high temperatures. Quality index of forged steel ball: chromium content is 0.1% ~ 0.5% (forged steel ball generally does not contain chromium), carbon content is less than 1.0%, steel ball is forged by high temperature. Although the surface hardness of some forged steel balls can reach 56 or more (the hardened layer is only about 15 feet), the hardenability and hardenability of forged steel balls are poor. Generally speaking, the hardness is only above 30 degrees. Under normal conditions, water quenched forged steel balls are often used.

　　Different wear resistance

　　Wear resistance comparison: after quenching treatment, the wear resistance from high to low is: high chromium ball, medium chromium ball, low chromium ball, forged steel ball.

　　Different production processes

　　High chromium ball, medium chromium ball and low chromium ball belong to casting steel ball, which is made by melting raw materials at high temperature and casting with steel mold.

　　The steel ball is forged with air hammer and die.