The Microstructure And Chemical Composition Affecting The Mechanical Properties Of High, Medium And Low Chromium Cast Balls

The grinding body is a kind of wear-resistant material. As the name implies, the grinding body is a medium used to pulverize, crush and grind materials. Depending on the material properties, the requirements for the performance of the grinding body are also different. First of all, as the abrasive body, it must be abrasion resistant, which is an indicator of rigidity. Secondly, the contact surface of the abrasive body must be hard. Studies have shown that the surface hardness of the grinding body must be equal to or greater than 80% of the material hardness in order to have a good grinding effect and wear resistance at the same time. It is not difficult to understand that the higher the surface hardness of the abrasive body, the stronger the ability to resist material anti-embedding. In this case, as long as the force exerted on the grinding body is large enough, the effect of crushing the material can be achieved. Then, what determines the hardness of the grinding body? The main factor that determines the strength and hardness of metal wear-resistant materials is its internal structure. There are two factors that affect the internal structure of metal wear-resistant materials: the heat treatment process and the chemical composition of the material. Next, we discuss the influence of the microstructure and chemical composition of high, medium and low chromium cast balls on their mechanical properties.

So what is high school low chromium cast ball? Wear-resistant castings with martensite as the matrix and a large number of special carbides are the unique performance characteristics of high chromium cast balls. The high-strength, high-hardness martensite matrix can well resist the planing and peeling of hard materials, and prevent the carbides with higher hardness from being broken and lost in isolation. They are organically combined like reinforced concrete and support each other, which is the best combination of wear-resistant materials. Medium chromium cast balls are generally not quenched due to chemical composition, so the microstructure after as-cast annealing is pearlite, but more than half of the microstructure is pearlite with lower hardness, so the hardness of the product is relatively low. In use, especially under the working conditions of a ball mill with abrasive wear, the low-hardness pearlite is first worn under the action of abrasive scouring and gouging, exposing the high-hardness carbide structure. It is well known that the carbide structure is not only hard but also fragile. Under the protection and support of the matrix, it can resist the planing and splitting of larger materials, prevent the loss of larger particles, and thus play a role in wear resistance. When the matrix is worn, the hard and brittle carbides are easily lost due to the impact fracture after the material is exposed, which accelerates the loss of the material and causes the ball's anti-wear performance to decrease. Like the medium chromium balls, the low chromium balls are also used under as-cast annealing conditions, and the matrix structure is pearlite and carbide. Different from the medium chromium ball, the low chromium ball contains less medium-strong carbide elements, so the carbide formed in the low chromium ball is cementite. The wear resistance mechanism of the low chromium ball is similar to that of the medium chromium ball in use, but due to the relatively low content of special carbides in the low chromium ball, the friction and wear resistance between the cast ball and the cast ball and the liner is much lower than that of the high chromium ball Ball and low chromium ball, so its wear resistance is also the worst among high, medium and low chromium cast balls.

Analyze the chemical composition and microstructure characteristics of high, medium and low chromium cast balls. According to the wear resistance mechanism of each brand and the actual industrial and mining conditions of the ball mill, comprehensive analysis of the cost performance of the ball mill using the ball is a reference for us to purchase the ball.