The conformation, distribution and size of inclusions as well as fracture surfaceat cracking area of motor vehicle wheel rims of A3 steel were examed by using optical microscopeand SEM.

• 本文采用金相显微镜和扫描电镜观察了A3钢制造的汽车车轮轮箍的开裂部位的夹杂物的形态、布和大小以及断口的形貌。