Technological Peculiarities of Chemical Heat Treatment of Alloyed Steel Gears

Gears made of various steels are chemical heat treatment for greater strength. The strength of cylindrical and bevel (hypoid) gears is evaluated by contact and bending strength of their teeth. The strength of alloyed steel gears greatly depends on the chemical heat treatment applied. The achieved values of the strength of alloy steel gears largely depend on the applied chemical and thermal treatment. The best performance in cylindrical and bevel (hypoid) gears of alloyed, low-carbon steels by contact and bending strength of the teeth is obtained by chemical heat treatment, including carburizing and hardening. To reduce the deformation of the teeth and the base surfaces of vacuum carburizing processes with alternating short cycles of saturation and diffusion followed by hardening with inert gas—nitrogen or helium under pressure. The paper analyzes the conditions of vacuum carburizing with subsequent pressurized-gas quenching. Vacuum carburizing and high-pressure gas hardening systems with a capacity of 100–200 kg/h should be used in mass and large-scale production in the machining production line, ensuring the continuity of the process. It presents the results of experimental studies of how the necks and the rims of hypoid wheel shafts are affected.