柴油机铝活塞镶铸铁耐磨圈结合层的缺陷分析

Defects Analysis of the Compound Zone of Cast-in Iron Ring Inlaid Aluminum Alloy Piston for Diesel Engine

采用宏观观察、金相检验和能谱分析等方法分析了铝活塞镶铸铁耐磨圈结合层的缺陷原因并提出了相应的解决措施。结果表明,镶圈活塞结合层包含Al-Fe结合界面、扩散层、过渡层和渗铝层与活塞本体结合界面,缺陷主要表现为镶圈表面存在氧化物、气孔、渗铝不充分,Al-Fe结合区粘结层开裂,以及渗铝层与活塞本体结合界面存在氧化夹杂和渣、气孔等。缺陷类型与渗铝及活塞铸造工艺控制有密切关系。

The common casting-defects of wear-resistant cast iron ring inlaid in aluminum alloy piston from a company were analyzed by means of macroscopic examination,metallographic,scanning electron microscopy（SEM）and energy spectrum analysis（EDX）,and the countermeasures of different defect forms were put forward.The results show that the compound zone between iron ring and aluminum piston is composed of Al-Fe interface,diffusion layer,transition layer and fusing interface between infiltration layer and piston body.The dominant defects in the aluminum alloy piston include air holes,aluminization,cracks in the Al-Fe zone as well as oxide inclusions and slag blowholes,gas holes in interface between aluminizing melt and piston body,which were closely related to the process of iron ring aluminizing and aluminum piston casting.