The bucket teeth of an open-pit excavator fail early due to severe wear and tear. In view of these bucket teeth, the failure forms and causes of bucket teeth surface of the excavator are analyzed, and improvement measures are put forward.
The bucket teeth of excavators with different failure modes are subjected to different degrees of wear and impact in service under different working conditions, which results in different degrees and forms of failure. The bucket teeth of the excavator will fail after only 3 days (about 36 hours) under normal working conditions, which is not suitable for both economic and operational purposes.
From the macro photos of the failure parts, it can be seen that the front working surface of bucket teeth of excavator has obvious plough groove scratches, a small amount of plastic deformation at the tip and no cracks. The front working face (the contact surface with the ground) is the thinnest, about 4 mm, and the back working face is about 8 mm.
Through analysis and discussion, we can draw a conclusion that:
(1) Force analysis excavator bucket teeth face contact with the excavated object, in a complete excavation process in different stages of the stress situation is different. When the tooth tip first contacts the surface of the material, the bucket tip is strongly impacted because of its faster speed. If the yield strength of bucket teeth of excavator is low, plastic deformation will occur at the tip. With the increase of excavation depth, the force of bucket teeth will change. When the bucket teeth cut the material, the bucket teeth move relative to the material, which produces a large positive extrusion force on the surface, thus generating a large friction between the bucket teeth working face and the material.
If the material is hard rock, concrete and so on, the friction force will be great. The repeated action of this process results in different degrees of surface wear on the bucket teeth working face of excavators, which leads to deep furrows. The composition of bucket teeth of excavator affects the service life of bucket teeth. Of course, the selection of bucket teeth is more prudent.
(2) The process analysis takes two samples from the front and back working faces respectively, and grinds them flat for hardness testing. It is found that the hardness of the same sample varies greatly, and the preliminary judgment is that the material is not uniform. After grinding, polishing and corrosion of the bucket teeth of excavators, it was found that there were obvious boundaries on the short pieces, but the locations of the boundaries were different.
It is suggested that proper normalization should be carried out after casting to improve the structure and properties and service life of the castings. After reasonable heat treatment of castings, the service life of bucket teeth of excavator is nearly doubled under the same working conditions.
Huangzuan Machinery established in 2008, is a specialized manufacturer of bucket teeth, bucket adaptor and side cutter which is used Caterpillar, Komatsu, Hyundai, Daewoo, Kobelco, Hensley, Liugong, Hitachi, XCMG, XGMA, Volvo, Esco, JCB .etc.
With production facilities covering an area of 18136 square meters and staff of 100, our annual processing capability equals approximately 12,000 metric tons. we currently have the technology of lost wax casting, precoated sand casting, resin sand casting, have the advanced instrument such as spectromaxx, Brinell hardness tester, universal testing machine, metalloscope.