基于响应面法发动机连杆热锻模具磨损失效分析

Analysis on wear failure of hot forging die for engine connecting rod based on response surface method

以发动机连杆作为研究对象,有效预测连杆终锻上模磨损最严重区域和使用寿命。基于Archard修正磨损模型,采用滑移速度﹑表面温度和表面压强作为评定终锻上模磨损量的依据,预测上模磨损最严重位置,对磨损最严重区域,选取上模材料初始硬度、摩擦因数、上模预热温度和下压速度进行单因素和多因素离散试验,以优化磨损量;对连杆进行20次模拟,并对磨损量结果进行曲线拟合,预测连杆终锻上模的使用寿命。模拟结果表明,上模P2点区域为磨损最严重位置,该区域优化后的最优磨损量为0.9615×10^(-6) mm,对应的最优参数组合为:预热温度为200℃、初始硬度为58 HRC、摩擦因数为0.3和下压速度为55 mm·s^(-1)。试验表明,模型预测和实际磨损量数值基本相同,回归模型的预测数值可信度极高,该模型终锻上模寿命为87298次。研究结果有助于降低试模成本,提高连杆模具的研发成功率。

For the engine connecting rod,the most severely worn area and the service life of final forging upper die for connecting rod were effectively predicted,and based on the Archard modified wear model,the slip speed,surface temperature and surface pressure were used as the basis for evaluating the wear of final forging upper die.Then,the most severely worn position of the upper die was predicted,and the wear amount in the most severely worn area was optimized by single-factor and multi-factor discrete tests choosing the initial hardness of upper die material,the friction coefficient,the preheating temperature of upper die and the down pressure speed.Furthermore,twenty simulations were performed on the connecting rod,and the result of wear amount was curve-fitted to predict the service life of the final forging upper die for connecting rod.The simulation results show that the P2 point area in the upper die is the location of the most severely worn area.After optimization of this area,the optimal wear amount is 0.9615×10^(-6) mm,and the corresponding optimal parameter combi-nation is the preheating temperature of 200℃,the initial hardness of 58 HRC,the friction coefficient of 0.3 and the down pressure speed of 55 mm·s^(-1).In addition,the model prediction values and the actual wear amounts are basically the same,the prediction value of the regression model is extremely reliable,and the life of the final forging upper die for the model is 87298 times.Thus,the result helps to re-duce the cost of trial die and increase the successful rate of development for connecting rod die.