淬火冷却介质流速对弧齿锥齿轮渗碳淬火热处理的影响

Influence of quenchant flow velocity on carburizing and quenching treatment of spiral bevel gear

使用流体动力学软件CFX求解淬火槽内淬火冷却介质流场分布,提出了考虑介质流速影响下弧齿锥齿轮不同表面换热系数的表征方法。建立基于多场耦合软件DEFORM-HT的扩散与相变模型,采用数值分析方法反馈介质流速对弧齿锥齿轮冷却特性的影响,给出了齿面、内/外圈和齿轮底面在不同介质流速下温度、马氏体体积分数、硬度及应力的演化规律。结果表明：介质入口流速越快,齿面冷却速率、马氏体体积分数及硬度越高;介质入口流速为1.5 m/s时,内/外圈冷却速率、马氏体体积分数及硬度达到极大值;介质入口流速为2.0 m/s时,齿轮底面冷却速率、马氏体体积分数及硬度达到极大值;介质入口流速对应力状态影响较小,流速越快的部位应力变化幅度及残余应力越大。

The flow field distribution of quenchant in quenching tank was solved by using fluid dynamics software CFX,and then the characterization method of different surfaces heat transfer coefficient of spiral bevel gear considering the effect of quenchant velocity was put forward. The diffusion and phase change model based on multi-field coupling software DEFORM-HT was established. The influence of quenchant velocity on the cooling characteristics of spiral bevel gears was studied by numerical analysis. The evolution laws of temperature,martensite volume fraction,hardness and stress of tooth surface,inner/outer ring and gear bottom surface under different quenchant velocities were obtained. The results show that the cooling rate,martensite volume fraction and hardness of the tooth surface increase with the increasing of the inlet quenchant flow velocity. When the inlet quenchant flow velocity is 1. 5 m/s,the cooling rate,martensite volume fraction and hardness of the inner/outer ring reach the maximum value. When the inlet quenchant flow velocity is 2. 0 m/s,the cooling rate,martensite volume fraction and hardness of the gear bottom reach the maximum value. The inlet quenchant flow velocity has little influence on the stress state of the spiral bevel gear,but the magnitude of stress variation and residual stress in the location with faster flow velocity are much larger.