M415空气锤是50年代从苏联引进的设备。缸体材质为灰D铸铁。缸体曾先后两次出现裂纹，两次进行修补，均在使用一个月后再次出现裂纹。该设备缸体的第三次开裂是在前两次裂纹补焊焊缝基础上再次开裂，裂纹加宽、加长，并且裂纹周围母材组织疏松，呈许多分枝裂纹状，外侧裂纹深约 M415 air hammer is imported from the Soviet Union in the 50’s equipment. Cylinder material is gray D cast iron. The cylinder has cracked twice in succession and repaired twice, all of which were cracked again after one month of use. The third crack of the equipment cylinder body was cracked again on the basis of the first two crack weld repairs, the crack widened and lengthened, and the parent material structure around the crack was loose with many branch cracks and the depth of lateral crack was about