The Effection Of Laser Cladding Layer’ Stress Field Under The High-frequency Forging

The laser cladding is the advanced technology which formed on the substratesurface and having the matrix of mutual fusion and a completely differentcomposition and properties of alloy cladding layer. However, because of the lasercladding process of the effective of the laser heat input, it will inevitably lead to thegeneration of residual stress in the specimen, and the presence of residual stress wouldadversely affect the specimen’s the mechanical properties and service life. Therefore,how to eliminate the residual stress and prevent the field of cladding layer crackingwhich is a very important subject. Micro-forging is an effective method to eliminatethe residual stress of laser cladding, it can not only effectively reduce the residualstress of cladding layers, but also even form the compressive stress zone in the dealingwith metal surface and a certain depth, and then change the state of the stress ofcladding layer.In this paper the main content of the study:1. Firstly, based on the ANSYS’s APDL language established a2dimension ofthe finite element numerical analysis model of laser cladding before micro-forging. Inthe analysis process, making use of the loop*do-*enddo variety, and setting the timestep to achieve the movement of the Gaussian heat source, compared the numericalresults of the model’s temperature field with the experimental results. And alsoestablished a3dimension of finite element numerical analysis model of laser cladding,the analysis of the powder to join through the element birth and death technique,obtained the cladding layer’s temperature distribution and the point of the claddinglayer’s temperature change over time relationship by analyzing.2. Based on the analysis results of temperature field, with the thermalelastic-plastic analysis of single-channel and multi-channel laser cladding process.With the order of the coupling method, namely using ANSYS ldread command from RTH file read temperature field calculation results, and as their body load adding tothe structural analysis model. The analysis obtained single-channel changes of thelongitudinal and transverse residual stress along the vertical depth, as well as itsdeformation curve. And also obtained a multi-channel degree of warpage, as well asthe variation of the cladding layer thermal stress with cladding time.3. Based on the micro-forging experiments, establishing an impact-contactnumerical analysis model. Analysis drawn perpendicular to the loading and unloadingof the cladding layer of the role of micro-forging, longitudinal and transverse stresswith vertical depth change relations. Then based on the residual stress analysis ofsingle-layer and single-channel, obtains the role of micro-forgingcladding layer’slongitudinal and transverse comprehensive residual stress of vertical curve withvertical depth. At the same time, this paper probes into the forging effects from theamount of plastic deformation and forging-head is not the same as the diameter, andobtain the relation curve of the longitudinal residual stress with vertical depth.4. Experimental study on different forming the thickness of the lasercladding,under the different temperature, measured the condition of different formingthickness warpage deformation, to theoretical analysis providing the validate basis.And, based on laser cladding forming the warpage of the different levels of thickness,the establishment of a mathematical model obtained deflection and yield strength ofthe relationship. At the same time, the establishment of a cantilever beam modelcalculated forming the thickness of the formed parts of the surface residual stressvalues, further validate the finite element numerical analysis model. And use of themathematical model to calculate the forging forming the thickness of the formingsurface residual stress values.