Application of high chromium wear-resistant cast iron hammer and liner in metal crusher
Hammer metal crusher, hammer and liner are the most easily worn parts. These parts are mainly made of high manganese steel (ZGMn13). The hardness HB180~220 of high manganese steel after water treatment is characterized by work hardening of working surface under the action of large extrusion force or large impact load. The hardness of surface hardening from HB200 to HB500 can have good wear resistance. Under working conditions, the potential wear resistance of high manganese steel can not be brought into full play because it does not cause enough work hardening of high manganese steel parts. It will be worn out like low hardness materials, thus shortening the service life of the parts. This not only increases the overhaul cost of the equipment, but also decreases the operation rate of the equipment and increases the service life of the parts. Labor intensity of workers.
1. Selection of hammer head and lining plate materials from the analysis of the crusher’s working conditions, using high chromium wear-resistant cast iron hammer head and lining plate should choose 15Cr2Mo1Cu high chromium wear-resistant cast iron. The cast iron has high hardness and good toughness.
1. The choice of carbon content should be considered from the wear resistance and impact toughness of hammer head and liner. The hammer metal crusher is a kind of impact machine. The wear of hammer head and liner is chiseling type. Therefore, the hammer head and liner require both wear resistance and enough toughness. Therefore, the choice of carbon must be properly matched with wear resistance and toughness. Carbides with excessive carbon content are more and thicker, but their toughness is lower. Carbides with excessive carbon content distribute in network along grain boundaries, which is disadvantageous to toughness and wear resistance. Therefore, the carbon content is determined to be 2.6% ~ 3.0%.
2. Selection of silicon content Silicon in cast iron is the element to promote graphitization, so the silicon content in white cast iron should not be too high. Although high carbon content in high chromium wear-resistant cast iron can not form pitting structure, it will have an adverse effect on permeability. Cavitation infiltration is easy to produce sorbite structure, and sorbite structure affects the wear resistance of high chromium cast iron. At the same time, the excessive amount of silicon will make the brittleness trend increase. Therefore, the silicon content in high chromium wear resistant cast iron is controlled at no more than 0.8%.
3. The determination of manganese content is not only an effective and inexpensive stable austenite element, but also a weak carbide forming element. In high chromium wear-resistant cast iron, manganese is chosen as alloy element, mainly because it is beneficial to increase permeability (especially when steel and copper are used together), so the manganese content is controlled in 0.5% ~ 1.0%.
4. Determination of chromium molybdenum copper alloy elements chromium is one of the main alloying elements in high chromium wear resistant cast iron. Chromium is a strong carbide forming element. After adding chromium, free graphite can be prevented, complete whitening can be guaranteed, and carbide can be transformed from ordinary cementite (Fe3C) to alloy cementite, thus significantly improving the microhardness of carbide and wear resistance. The addition of chromium is also conducive to the improvement of permeability. Therefore, the chromium content of hammers and lining plates should be controlled at 14%~16%. Molybdenum can significantly improve the permeability of alloy cast iron. In order to make the thicker cast iron permeable without pearlite, it is necessary to add appropriate molybdenum into white cast iron. It can also ensure the uniformity of cast iron section and improve the toughness. The addition of copper can further improve the permeability and thus reduce the molybdenum content.