Chromium Cast Iron Grinding Balls Organizations And Performance

In this paper, chromium in chromium cast iron in the role of anti-wear based on the design of the three kinds of diameterΦ110mm, chromium content of chromium in different anti-wear cast iron ball; using metallographic techniques, electron microscopy, TEM techniques, X-ray diffraction and other analytical techniques, through materials, macro-hardness, micro-hardness, toughness and wear performance of comparison and analysis of the different chromium content of the material properties; and through two different means of improving the heat resistance of high chromium grinding cast iron and properties, analysis of the material after heat treatment changes in the organization and performance, and two different heat treatment process to discuss the impact of the material and concluded.The results show that:under the three kinds of chromium cast iron eutectic are ledeburite organizations, low, medium chromium cast iron eutectic relatively thick, high-chromium cast iron eutectic is relatively small.With the increase in the amount of chromium, three types of chromium cast iron carbide experienced by the M3C to the M7C3 process of transforming. Low-chromium cast iron carbide types are M3C mainly carbide showed honeycomb-like and reticular distribution.Midium-chromium cast iron carbides types are M3C and M7C3 mixture of carbide significantly increased the number of low-chromium cast iron, and many more needle-like distribution. And the high chromium cast iron carbide types are the high-hardness carbides M7C3 mainly macro-hardness of the material, austenite transformation products and carbide micro-hardness than low, medium and high-chromium, MyC3-type carbides hexagonal rod-shaped and lath was distributed in the matrix, a continuous level greatly reduced. Under the high chromium cast iron was significantly higher than the hardness of low, medium chromium cast iron, the surface hardness value reached 53HRC, the same time, three kinds of chromium cast iron impact toughness values of low, no more than 4.73 J/cm2.On this basis, this program of research designed two kinds of heat treatment heat treatment process for high-chromium cast iron morphology. Studies have shown that:the amount of chromium of about 15% of the high chromium cast iron using conventional heat treatment process, when the quenching temperature is 850℃, tempering temperature is 350℃, high chromium cast iron best performance of the organization get to martensite as a Lord matrix organization, mainly M7C3 carbide type of content-based and more, showing off the block, the distribution strip. Its surface hardness value can be achieved 60HRC, the impact toughness to 6.3J/cm2; when using the austempering heat treatment, through the austempering heat treatment process can be high chromium cast iron under the martensite and acicular bainite matrix-based organization, Under the Bayesian approach the hardness of martensite, while the toughness is superior to martensite, allowing high-chromium cast iron to obtain better impact toughness. At 320℃isothermal quenching 1.5h, get the best matrix, the hardness value reached 63HRC, the impact toughness value reached 8.4 J/cm2. By comparison, found that isothermal quenching process can effectively improve the material and properties, can obtain better impact toughness of the material.Through the impact of high chromium cast iron fracture surface and wear surface morphology observation analysis showed that the fracture of high chromium cast iron are brittle fracture, wear, abrasive wear mechanism dominated. Austempering treatment, the high chromium cast iron is superior to normal wear and tear samples after heat treatment specimens, with good wear resistance.