Technical Application of Thermal Spray Technology in Sliding Bearing Manufacturing

       Thermal spraying technology is a method and technology that uses a heat source to heat the sprayed material to a molten or semi-molten state, sprays it onto the pretreated substrate surface at a certain speed, and forms a coating through the deposition of tiny particles, thereby endowing the substrate surface with special functions and technologies. , is an important part of surface engineering technology. Using different coating materials and different process methods, functional coatings such as wear-reducing and wear-resistant, corrosion-resistant, high-temperature oxidation resistance, thermal barrier, electromagnetic shielding and receiving, insulation can be prepared on the surface of the substrate.



The more commonly used thermal spraying methods include flame spraying, arc spraying, and plasma spraying. The coating materials include metals, metal alloys, ceramics, cermets, plastics and other composite materials. Thermal spraying methods and technologies have been widely used in various fields of the national economy such as aerospace, metallurgy, energy, military equipment, petrochemicals, machinery manufacturing, transportation, and bioengineering.



At present, various functional coatings made by thermal spraying technology are mostly used for the protection, strengthening and repair of parts, and there are few reports on the direct use of thermal spraying technology to make parts. This paper introduces a method and process of manufacturing sliding bearings by thermal spraying. Due to the special process method, it can also be used as an exploration of the combination of thermal spraying technology and material accumulation process to make special parts.



1. Manufacturing method of conventional sliding bearing



Sliding bearings are commonly used mechanical parts, consisting of a rotating journal and a fixed bearing seat, and the inner surface of the bearing seat in contact with the journal is called a bearing bush or bearing bush. Since the shaft often bears a certain load and transmits motion and power during use, the commonly used materials are various steel and cast iron, which are relatively wear-resistant; the commonly used materials for bearing bushes or bearing linings are bearing alloys, bronze, aluminum-based alloys, zinc Base alloys, etc., among which bearing alloys (mainly alloys of tin, lead, antimony or other metals) are due to their good wear resistance, high plasticity, good running-in performance, good thermal conductivity, good adhesion resistance and adsorption to oil. Well, it is used more under heavy load and high speed, but the bearing alloy has less strength and is more expensive. Generally, centrifugal casting is used to cast it on the working surface of steel, iron and other bearing housings to form the working surface of sliding bearings.



2. Process method of manufacturing sliding bearing lining by thermal spraying technology



At present, there are many materials and literatures introducing the repair of sliding bearings by thermal spraying technology. The German Volkswagen Company also has an invention patent for making wear-resistant aluminum bronze coating on the inner hole of the connecting rod of an internal combustion engine by plasma spraying. However, due to the limitation of the existing thermal spraying equipment and operation methods, various functional coatings prepared by thermal spraying technology are mostly limited to the outer surface of the part and the surface of the larger inner hole. Construction is difficult, if the surface of the part cavity is special, it cannot be constructed.