Study On Remanufacturing Technology Of Counterbalance Valves Core On Concrete Pump Truck

Remanufacturing is the advanced form of the use of renewable resources, is the emerging in the modern manufacturing industry, is conducive to saving energy and resources, reduce production costs and protect the environment, improve resource utilization, with an extremely important national strategic significance. The counterbalance valve in hydraulic system of concrete pump truck in the use process, often fails because of the cone surface of the valve core damage. Between the valve core conical surface and the valve sleeve line contact wear, lead to the valve sleeve and valve plug does not close, cause the inner leakage and pressure drop. Serious will cause the boom down, causing safety accidents. This paper takes the imported counterbalance valve failure of valve core cone wear as the research object, with the valve core of the remanufacturing repair as the research target. Use of different surface repair technology for remanufacturing counterbalance valve core, achieve batch production of remanufactured counterbalance valves. It provides a theoretical basis for counterbalance valves remanufacturing technology research, has broad application prospects and high value of engineering application. The main research work of this paper is as followed.Firstly, this paper introduces the status of construction machinery remanufacturing, and research status of surface engineering technology in construction machinery remanufacturing at home and abroad, pointed out the urgency of imported hydraulic counterbalance valve remanufacturing. Based on the analysis of structure and working principle of counterbalance valve in the concrete pump truck. Combined with the research for counterbalance valve that dismantling down from the scrapped concrete pump truck, found that the valve core cone wear is the main reason for the counterbalance valve failure. Meanwhile, testing the chemical elements composition and micro hardness of valve cone, it provides a theoretical basis for choose remanufacturing technology.Secondly, the valve core remanufactured. Tungsten inert gas arc welding technology, electrodeposition technology, laser cladding technology were used to repair the valve cone. And determine the appropriate process method and process parameters. After repairs are completed, take the machining or grinding process machined valve core cone, to achieve dimensional accuracy requirements.Then, testing and analysis appearance, microstructure, hardness of the valve core repair layer. A performance tests for remanufactured counterbalance valves, including maintain pressure test, life test and real vehicle test. The results of test prove that the remanufactured counterbalance valve achieved the using requirements, the service life up to the national standard, loaded on a remanufactured truck work stable and reliable.Finally, the multi-objective robust decision-making model is established considering the five decision objectives “Cost C, Quality Q, Time T, Resource R, Environment E”. Multi-objective decision-making and analysis for three repair techniques of counterbalance valve remanufacturing by using the model. The calculation results demonstrated that laser cladding is the optimal technology programs for counterbalance valve remanufacturing, providing a correct theoretical guidance for the enterprise.