Gear carburizing and quenching technology

　　XNUMX. Gear material selection

　　Gears are usually based on the performance requirements of the workpiece to decide what material to choose and what process to use to meet this requirement.mostgearThe reason why the carburizing and quenching heat treatment process is adopted is that when the driving gear transmits power to the driven gear when the gear is moving, the transmitted torque changes the direction of movement and the speed ratio changes to change the movement speed.

　　XNUMX. Gear noise control

　　In the process of cyclic impact friction vibration, the two tooth surfaces intersect and slip, so the contact area is subject to alternating contact pressure stress, and the tooth root is subject to alternating bending stress. In addition, the gear is subject to additional dynamic loads.Such service conditions determine the performance of the gear. The tooth surface must have high wear resistance and high contact fatigue limit, and the tooth root must have high bending strength and sufficient impact toughness. Accordingly, material selection needs to be proposed. Reasonable requirements, and through appropriate heat treatment modification technology to meet the corresponding requirements, at the same time the precision gear must have high transmission accuracy and produce the lowest NVH noise.

　　Three, gear processing accuracy requirements

　　It also puts forward very high requirements for machining accuracy and heat treatment deformation control.Only low-speed and light-duty gears for less important occasions can be made of medium-carbon steel or medium-carbon alloy steel materials for quenching and tempering or normalizing and surface hardening, or plastic gears for applications where the force is small. High-speed and heavy-duty gears need to be made of carburized steel. To meet the final use requirements, use quenching and tempering or normalizing as preliminary heat treatment. After gear processing, the carburizing quenching and tempering process is used as the final heat treatment to ensure that the performance requirements are met. If necessary, the tooth profile needs to be finished after heat treatment to make the tooth surface have High hardness can wear resistance and high contact fatigue strength, while the tooth root core has enough toughness to resist impact.The surface hardness, effective hardened layer, surface carbon concentration and carbon concentration and hardness distribution of the carburized layer of the workpiece after carburizing and quenching, core hardness, metallographic structure, tensile strength, bending strength, impact toughness and other heat treatment performance requirements are not in this article Discussion, this article summarizes the existing main research methods of heat treatment deformation theory analysis.