Study On Additive Remanufacturing Process Of Centrifugal Pump Impeller By Laser Cladding

Centrifugal pump is a widely used general machinery in the industrial field.Due to the complex,changeable and harsh service conditions,the impeller of its core functional components often has different forms of failure.Carrying out the remanufacturing of centrifugal pump impeller can restore its size and performance and prolong the service life of the product.Laser cladding is a kind of additive remanufacturing technology which can realize damage repair and surface modification.It has the advantages of good metallurgical bonding,small heat affected zone and low dilution rate.It is widely used in mining machinery remanufacturing,mold remanufacturing and other fields.In this paper,supported by the National Natural Science Foundation of China（51775071）and the Chongqing Technology Innovation and Application Demonstration（Industrial Key R＆D）project（cstc2018jscx-msyb X0334）,the additive remanufacturing process of centrifugal pump impeller by laser cladding was studied.Firstly,the main failure modes of centrifugal pump impellers were analyzed,and the whole process from remanufacturing to re-service of failed centrifugal pump impellers was comprehensively analyzed.The qualitative and quantitative analysis of centrifugal pump impeller was carried out from three aspects of technical feasibility,economic feasibility and re-service performance prediction.The corresponding evaluation index system was established,and the remanufacturing evaluation method of centrifugal pump impeller for re-service performance was formed,which was provided decision-making basis for the remanufacturing of centrifugal pump impeller.Secondly,with 20Cr13 steel used for centrifugal pump impeller as the substrate and M2 alloy powder as the cladding material,single-pass single-factor experiment and multipass central composite experiment of laser cladding were carried out to analyze the influence of laser power,scanning speed,powder feeding,overlapping rate and other laser cladding process parameters on the quality characteristics of cladding layer dilution rate,width and surface smoothness.The quality characteristics of cladding layer was used as the optimization objective,the process parameters was used as the optimization variables,the response surface approximate mathematical model between the process parameters of laser cladding and the quality characteristics of cladding layer was constructed.The particle swarm optimization algorithm was used to solve the optimization problem to obtain the optimal combination of process parameters.The optimization method of laser cladding process parameters based on the response surface method and particle swarm optimization algorithm was formed,which was helpful to improve the quality of cladding layer of the remanufactured centrifugal pump impeller.Finally,according to the failure characteristics of the centrifugal pump impeller,the laser cladding process design of the centrifugal pump impeller was carried out,and the centrifugal pump impeller was additively remanufactured based on the optimized process parameters;the microstructure and mechanical properties of the remanufactured centrifugal pump impeller were analyzed,including penetrant inspection,microstructure,phase analysis and microhardness,wear resistance,corrosion resistance testing,to verify the re-service performance of remanufactured centrifugal pump impellers.