重型起重机的旋转机构采用转盘滚轮式支承装置(如图1所示),使用五、六年之后,发现旋转环形轨道表面出现不同程度的磨损凹陷,局部还有龟裂剥落,深达2～3mm,严重影响了旋转机构的正常运行。为此需要对上、下环形轨道进行修复。从图1中可以看到,这种起重机的上、下环形轨道是分别焊接在转盘及大针轮上的。我们曾经沿用老的工艺对环形轨道进行修理,即把起重臂、机房等起 Rotating mechanism of the heavy crane adopts the wheel-type roller bearing device (as shown in Fig. 1). After five or six years of use, it is found that there are different degrees of wear and tear on the surface of the rotating ring track, , Seriously affecting the normal operation of the rotating mechanism. To do this, we need to repair the upper and lower ring tracks. Can be seen from Figure 1, the crane’s upper and lower annular track were welded to the turntable and a large wheel. We have used the old craft to repair the circular orbit, that is, from the boom, engine room, etc.