我厂于1980年从鞍山锻压机械厂购置一台DHZ—1有轨操作机,其钳口夹紧缸的活塞结构如图1所示。该机试用不久,六个压板螺钉全部被齐头拉断,压垫也产生了变形。因是新购机械,所以生产厂派员修理,维修人员认为事故的原因是螺钉的强度不够、压垫太薄所致。因此就将螺钉材料由原来的35钢改为45钢调质,压垫由原来的8毫米加厚到10毫米。结果没用多久,6个强化后的螺钉又被拉断,加 I plant in 1980 from Anshan Forging Machinery Plant purchased a DHZ-1 rail operation machine, the jaw clamping cylinder piston structure shown in Figure 1. Shortly after the trial machine, the six plate screws are all pulled off, the pressure pad has also been deformed. Because of the new purchase of machinery, so the production plant to send staff to repair and maintenance staff that the cause of the accident is the strength of the screw is not enough pressure pad too thin. Therefore, the screw material from the original 35 steel to 45 steel quenched and tempered, pressure pad from the original 8 mm thick to 10 mm. Results useless how long, six enhanced screws have been pulled off, plus