Steel for high-strength bolts The chemical composition requirements of steel for high-strength bolts are as follows: Carbon is the most important element affecting the plastic deformation of steel. The higher the carbon content, the higher the strength of the steel and the lower the plasticity. The higher the carbon content, the lower the quenching heating temperature, the higher the hardenability, and the higher the tendency of cracking and deformation. Manganese can reduce the harmfulness of sulfur to steel.17Cr2Ni2Mo Steel Gear Vacuum Carburizing As a permanent element in steel, the increase of manganese can increase the tensile strength and yield strength of steel, and increase the hardenability. Among the alloy steels, CrMo and CrMoV are more suitable for high-strength fasteners used under complex conditions.Classification and selection of vacuum carburizing process In order to control the bolt strength and guaranteed stress within the qualified range, on the basis of increasing the lower limit of hardness, the following five aspects should be paid more attention to during tempering. Differences in materials, furnace types, upsetting (differences between red punching and cold heading), thread differences (difference between full teeth and half teeth, the total effective cross-sectional area of full teeth is small.MANUAL FEED SADDLE MOVING SURFACE GRINDER 618A/818A The bearing tensile strength is low, the tempering temperature deviation is 5-10°C and the difference between the medium (the difference between water quenching and oil quenching). 3. Operation points of mesh belt furnace High-strength fasteners have large production volume and low price, and the threaded part is relatively fine and precise. Therefore, mesh belt furnace is especially suitable for heat treatment of small and medium-sized fasteners, with high degree of automation and good heat treatment quality. .M71 AUTOMATIC WHEEL HEAD MOVING SURFACE GRINDER MACHINE