对采用粉末锻造技术生产出的一款Fe-C-Cu汽车发动机连杆(H16)进行了微观组织分析及力学性能测试, 并研究了影响其疲劳性能的因素. 结果表明: H16粉锻连杆密度大于7.80 g/cm³, 接近全致密, 微观组织无氧化穿透或氧化物网络, 脱碳层厚度在70 mm以内, 微观组织在不同区域呈各向异性. 利用升降法得到H16粉锻连杆毛坯在不同存活率下的疲劳极限. 结果表明, 其疲劳性能及抗拉强度、屈服强度等力学性能超越钢锻连杆, 并且不低于国外同类粉锻连杆产品. 此外, 还发现连杆的弯曲度对疲劳寿命影响较大, 而表面喷丸情况及其微观组织特性对疲劳裂纹萌生的位置有一定影响.

Powder-forged (P/F) connecting rods have been widely used due to their advantages of high strength, less machining, light weight, and consistency etc.. Currently, P/F connecting rods were only supplied by GKN in Britain and Metaldyne in US in commercial quantities. In this work, the microstructure and mechanical properties of the P/F Fe-C-Cu automobile engine connecting rods (H16) were designed and manufactured domestically, and the factors affecting the fatigue performance were systematically analyzed. The Measured results indicate that the density of the connecting rod is greater than 7.80 g/cm³. Microstructure observation showed that there were no oxide penetrations or network near or at rod surface and the surface decarburization layer is thinner than 70 mm. Anisotropy at different locations inside the P/F connecting rod was revealed. Furthermore, the bending of connecting rods was found to affect the fatigue performance significantly. The microstructure and the surface shot-peening condition had certain influence on the sites of fatigue crack initiation. Most importantly, the fatigue strength of H16 P/F connecting rod was found to be superior to that of the wrought steel-forged connecting rod (C70), and similar to that of P/F connecting rods designed and manufactured by entities.