The cutter manufacturer will explain to you the reasons for the failure of the excavator cutter

The cutter manufacturer will explain to you the reasons for the failure of the excavator cutter
1. Quality issues with hard alloy heads. The hard alloy heads contain graphite impurities, uneven grain distribution, and cracks exist in some hard alloys. Under the action of impact loads, the cutting edge is in a high stress state. When encountering hard coal and rock, brittle cracking occurs when the high-pressure stress exceeds the strength of the hard alloy. If the content of Co element in hard alloy is insufficient, resulting in insufficient toughness, the hard alloy cutting edge is also prone to brittle cracking under impact load.
2. The residual stress of brazing is high, and the cutting teeth are mostly made of copper zinc brazing material, with a welding temperature of over 920 degrees Celsius. There is a significant difference in the coefficient of expansion between hard alloy, brazing material, and matrix metal. When cooled, the three materials have different degrees of shrinkage, with copper having a larger shrinkage, followed by matrix metal, and hard alloy having a smaller shrinkage. This inevitably leads to significant tensile stress between hard alloy and brazing material, as well as between brazing material and matrix metal, resulting in a decrease in the strength of the weld seam. During cutting, the hard alloy head is subjected to strong impact loads, leading to brittle cracking.
1. Abrasive wear. Some alloy elements in the alloy do not meet the requirements, contain graphite impurities, uneven grain distribution, multiple pores, and uneven structure, which are the main reasons for the wear of hard alloy heads; The unstable quality and performance of tooth material and improper control of heat treatment process are the reasons for tooth wear.
2. Wear caused by low red hardness. Red hardness refers to the ability of prop materials to maintain high hardness at high temperatures. In theory, the manufacturer of rotary excavator cutting teeth can maintain high hardness of hard alloy at high temperatures of 800-1000 ℃, but due to some practical problems in the production of hard alloy, the red hardness of the cutting teeth is relatively low. When cutting coal and rock, the surface temperature of the cutting edge can reach 600-800 ℃, and its hardness decreases by about 50%. The softening of the material accelerates the wear of the cutting edge. Due to welding and shape design reasons, the alloy head fell off.