Repairing method of heavy-wear pick

Abstract

The invention discloses a repairing method of a heavy-wear pick. For the pick with the material of 35CrMnSiA and 42CrMo picks, the size is restored by a surfacing method; and then a laser cladding alloy wear-resistant layer is performed on the surface of a surfacing layer. 201Mn is used as a bottoming transition layer, and 200Mo is used as the "meat supplement" material. Argon tungsten-arc weldingis adopte to weld three layers. The results show that the surfacing layer is of good quality and no cracks are generated. The wear resistance test has found that the wear amount of a cladding layer prepared on the 35CrMnSiA and 42CrMo surfacing layers respectively has an average weight loss of 0.002g and 0.0024g per 100 reciprocations, the hardness reaches about 63HRC, and a micro-dendritic hardtissue is used as a skeleton to cooperate with a flexible phase to improve the wear resistance of the tissue. A three-dimensional morphology of a wear surface finds that slight ravines are on the surface without exfoliation or pitting.

Description

technical field [0001] The invention relates to the technical field of pick remanufacturing materials. Specifically, it is a method of repairing heavily worn picks. Background technique [0002] The pick is a key component of excavation equipment and is a vulnerable part. The pick is mainly affected by cyclical compressive stress, shear stress and impact load when working. At present, the domestic method of improving the wear resistance of new picks is to surfacing a layer of wear-resistant layer on the surface of new picks, and then adding appropriate heat treatment to improve the strength, hardness and wear resistance of picks. For heavily worn picks, it is necessary to The size must be completed first, and then laser cladding is carried out. For example, in the applicant's previous research "Comparative Study on the Performance of D212 Electrode Surfacing to Repair Mining Picks of Different Materials" [Thermal Processing Technology, Volume 45, Issue 1, January 2016], D...

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Problems solved by technology

However, with further research, the applicant found that D212 is a typical martensitic surfacing electrode, and the specific volume of martensite is larger than that of ferrite and austenite, so as the temperature decreases, austenite decomposes At the same time, accompanied by volume expansion, the phase transformation structure stress is formed, and the room temperature structure of the matrix is ​​not martensite, plus the thermal stress caused by different temperature changes, so the surfacing layer has the most cracks in the first layer, and Cracks that almost penetrate the surfacing layer, such as Figure 1a and Figure 1d , although the second and third layer structures are all martensite, there is no difference between the structures during the cooling process, but cracks are still produced under the influence of thermal stress, such as Figure 1b and Figure 1e , so it is not feasible to use D212 welding rod or single welding rod as size repair material

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