基于临界损伤因子的40Cr伞齿轮锻造温度优化

Optimization of Forging Temperature of 40Cr Bevel Gear Based on Critical Damage Value

为获得40Cr材料韧性断裂的临界损伤因子,采用了模拟与试验拟合的方法,分别完成了动态压缩试验和一组高度方案下的模拟分析,获得了材料断裂时的高度压缩率,对所得一组损伤值求平均值确定了40Cr材料临界损伤因子为0.402。设计一组不同始锻温度的温成形方案,仿真分析获得齿轮锻件最大损伤值随始锻温度变化的规律曲线,与40Cr临界损伤因子做比较,发现了一个温度范围730～770℃,适合于温成形而不会出现开裂。仿真分析在室温下锻造的过程,发现最大损伤值高达1.19,可能有开裂,从而确定该规格伞齿轮冷精锻工艺是不可行的。

In order to obtain the critical damage value of 40Cr material, the method combining simulation results with test results was adopted, a dynamic compressing test and a simulation under different billet height were performed, the compressing ratio at the fracturing time was found, and the critical damage value 0.402 of 40Cr was conformed based on the mean of simulated damage values. A scheme of different original forging temperatures was designed and simulated, and the variation curves of maximal damage value of gear forging piece with the change of temperature was analyzed. By comparing with the critical damage value of 40Cr, a temperature range 730-770℃ which was applicable to warm forming was found. The simulation value of the maximal damage in cold forging was up to 1.19 under room temperature, at this time, this bevel gear was prone to fractures. Thus cold forging of this bevel gear was infeasible.