以检测发动机缸盖热疲劳性能为契机,自行研制开发缸盖热疲劳试验台架,制定缸盖热疲劳试验规范和试验参数,用感应加热的方式模拟发动机工作时气缸盖火力面的温度场,并按此温度场对气缸盖火力面进行加热、保温、冷却循环,直至出现裂纹,依据裂纹出现的循环次数、长度和形状判断缸盖的热疲劳寿命.试验裂纹产生的部位和失效形式与市场故障返回件一致.

随着气体渗氮技术的不断进步,尤其是氮势自动控制技术和深层快速渗氮技术的发展,使气体渗氮的质量越来越好,生产周期和成本也大幅降低,应用范围也越来越广.主要介绍了气体渗氮技术的最新进展和其在汽车零部件上的典型应用.

There are three sheet metal parts made by high srtrenth steel whitch were stamped. The cracks, major strain, thinning,and wrinkling of the parts were observed and measured. Also the stamping processess were caculated and simulated using simulation software PAMSTAMP. The caculated result was compared with the measured, and then the conclusion was drew that the accuracy of the simulation made by PAMSTAMP is 85 percent or more.

随着汽车用钢板迅速朝着高强度化和轻量化的方向发展,高强度钢板的应用日益广泛.随之而来的问题就是,钢板强度级别越高,成形越困难,回弹也越大,严重影响零件的精度和装配质量.为了解决高强度钢板成形性差的问题,避免开裂与起皱,更重要的是要保证零件尺寸和形状精度,迫切需要一种手段来优化工艺方案,从而获得合格的零件.随着有限元和塑性理论的不断完善以及计算机技术的迅猛发展,通过CAE方法优化工艺并预测回弹已成为可能.

本文通过试验测定了用不同牌号珠光体球铁产生的发动机曲轴在圆角未强化、氮化和圆角滚压等不同状态下的弯曲疲劳强度.结果表明,无论是否经过强化处理,材料牌号高的曲轴其弯曲疲劳强度并不优于材料牌号低的曲轴.据此,建议在曲轴的选材中优先采用铸态的QT700-2球墨铸铁.