Experimental Research On Laser Cladding Repaired Of 45 Steel Gear

Laser cladding repair technology is widely used in the fields of aviation,shipbuilding because its thermal deformation of repaired parts is small and the repaired tissue is small and compact,and it is easy to form dense metallurgical bonding with the substrate.The laser cladding repair technology which saves economic cost and has broad prospects of development is used to recover the geometrical size and mechanical properties of the collar parts.The laser cladding repair technology can realize the forming and remanufacturing of metal parts.45 steel is characterized by good mechanical properties,low quenching and low price,which is used to make high strength moving parts such as turbine impeller,compressor piston,gear,rack and worm.However,in the long-term production practice,the bad conditions such as wear and corrosion often results in the failure of parts causing great economic losses.Laser cladding repair and remanufacturing technology not only conforms to the concept of green manufacturing,but also saves the economic cost,so it is of great significance to study the laser cladding repaired of 45 steel.In this paper,the method of experiment and theoretical analysis was used to study the single channel cladding repair,multi-channel multi-layer cladding repair and different scanning paths.The method of equal area was used to model multiple lap joints and the optimal theoretical lift with multi-layer accumulation.In this paper,the typical damaged parts were repaired by reverse engineering,and the mechanical properties of the repaired parts were tested and analyzedThe specific research contents of this paper are as follows:(1)The background and significance of laser remanufacturing were introduced and the research status at home and abroad was analyzed.Besides,the difficulties and research direction of laser cladding repair are presented and finally the research content of this paper were put forward.(2)The matching of substrate and repaired powder materials has an important influence on the quality of repair products.Therefore,the Theoretical analysis was carried out for the matching of substrate and repaired powder materials to determine the selection principle of repaired material.The rapid solidification mechanism of laser remanufacturing and the interaction between laser and material were introduced.In this paper,we model the multi-channel single-layer cladding model and single channel multi-layer accumulation model for laser deposition to determine the theoretical multichannel scanning spacing and theoretical z-axis lifting.Finally,the simulation of the process of single channel multi-layer laser deposition is simulated by means of finite element analysis.(3)45 steel was selected as the substrate,and the repaired material H13 steel was used.In order to successfully complete the research and analysis of the experiment,software and hardware system of the experiment were constructed in detail,The orthogonal experiment of single channel laser cladding was designed based on the single-channel preexperiment to obtain optimum parameters such as laser power,scanning speed,rotary speed and to obtain the geometric parameters such as melting width and the melting height.Based on the multi-channel single-layer cladding model experiment the optimal overlap ratio and optimal scanning path were explored.According to the single channel multi-layer theory model,the optimal z-axis lifting volume and the optimal layer accumulation mode were determined.(4)The typical 45 steel broken gears was repaired.3D scanner was used to obtain point cloud data of damaged parts without contact measurement after the best repair parameters were obtained.The point cloud data was processed by reverse-engineering software Geomagic to obtain 3D data model of damaged parts.The Boolean operation of 3D data model of damaged parts that obtained by reverse engineering was carried out with the original model to obtain defect model.The defect model was leaded into Robotart to compile the trajectories of the robot layer by layer and the trajectories of the robot were simulated to verify the correction of trajectories.Finally,the damaged 45 steel gear were used as substrate and the defect model was printed according to trajectories that were compiled to realize the repair of typical parts.(5)The test of hardness test,tensile test,friction wear and other mechanical properties were carried out to analyze whether the performance can meet the requirements and whether the repaired technology was meaningful after typical parts were repaired.