一、前言汽车薄壁铸铁件,常常因工艺、操作、搬运或焊补不当而引起裂纹。若裂纹发生于重要受力部位或热疲劳负荷区,则可能导致铸件断裂损坏。因此,汽车生产和使用者均把铸件裂纹视为致命缺陷。据悉、国外某公司曾因气缸体裂纹赔偿数千台发动机、造成上亿美元直接的经济损失。检验铸件粗糙表面上的微细裂纹、历来 First, the preface Automotive thin-walled cast iron parts, often due to process, handling, handling or welding caused by improper cracks. Cracks that occur at critical points of stress or thermal fatigue loading may result in fracture damage to the castings. As a result, casting cracks are considered fatally flawed by car producers and users alike. It is reported that a foreign company had thousands of engines due to cylinder block crack compensation, resulting in hundreds of millions of dollars in direct economic losses. Inspection of fine cracks on the rough surface of castings, traditionally