我公司的一台QTZ63塔吊回转大齿圈折断了2颗齿,断裂在分度圆下近齿根处,齿的模数为12。修理时没有更换新齿轮,而采用电焊堆焊方法修复了断齿,不仅停修的时间短,而且修复的成本也低。具体做法如下。一、焊条选用该齿圈的材质为中碳铸钢,经调质处理,硬度为HB 220,按照堆焊层应 A QTZ63 crane’s rotating large ring gear of our company broke 2 teeth and fractured near the tooth root at the index circle. The module of the tooth was 12. The new gears were not replaced during repairs, and the broken teeth were repaired using the weld overlay method. This not only shortened the maintenance time but also reduced the cost of repairs. The specific approach is as follows. First, the material of the ring gear is selected from medium carbon cast steel. After quenched and tempered, the hardness is HB 220.