After the crane leaves the factory, there is generally a running in period of about 60 hours, which is stipulated according to the technical characteristics of the crane at the initial stage of use. Running in period is an important factor to ensure the normal operation of crane, reduce the failure rate and extend its service life.

I. characteristics of running in period:

1. Fast wear

Due to the influence of processing, assembly and adjustment of new machine parts, the conflict surface is rough, the contact area of the cooperation surface is small, and the pressure bearing condition of the surface is uneven. During the running process of the machine, the height of the parts' surface collides with each other. The worn metal debris, as abrasives, continues to participate in the conflict, which accelerates the wear of the parts' cooperative surface. Therefore, the wear of parts (especially the appearance of cooperation) formed in the running in period is simple, and the wear rate is fast. At this time, if overload work, may lead to damage, early failure.

2. Poor lubrication

Because the cooperation gap of newly installed parts is small, and because of installation and other reasons, it is difficult to ensure the uniformity of cooperation gap, and smooth oil (grease) is not easy to form a uniform oil film on the surface of conflict to prevent wear. Then the smooth efficiency is reduced to form the early abnormal wear of the parts. When it is severe, it will form a scene of scratch or occlusion on the surface of fine cooperation, resulting in the occurrence of failure.

3. Looseness

There are several errors in the shape and cooperation scale of newly processed and installed parts. In the early stage of application, due to the impact, vibration and other alternating loads, as well as the influence of heating, deformation and other factors, coupled with the factors such as excessive wear and tear, the originally fastened parts simply loosen.

4. Leakage

Because of the looseness and oscillation of the machine parts and the influence of the heat of the machine, the sealing surface and the pipe joints of the machine will show leakage; some defects such as forging and processing are hard to be found during the assembly and commissioning, but because of the vibration and impact effect in the working process, this kind of defect will be exposed, showing as oil (water) leakage. Therefore, the running in period presents a simple leakage phenomenon.

5. Many mistakes in operation