Influences Of Laser Constraining Arc On Surface Quality Of Low Alloy And High Strength Steel Components Manufactured By Wire And Arc Welding Additive Manufacturing Technology

Wire and Arc additive manufacturing technology was a kind of manufacturing technology which was based on the three-dimensional model of a part and used arc as the heat source to melt the wire material and obtain the component by means of layer-by-layer accumulation.Its fast forming speed made it suitable for high efficiency and low cost near net forming of large and complex components.However,the high surface roughness of forming parts was an urgent problem to be solved.The effect of laser on the arc shape and size under different process parameters was studied.The influence of laser on the stability of molten pool,the topography of accumulation layer and the surface roughness of components were also analyzed.(1)Laser could constrain the stability of arc.The high speed camera system was used to observe the change of the shape before and after the laser acted on the arc,and the image processing software was used to measure the size of the arc and analyze the change of the size of arc under different process parameters.In the case of small specification parameter(I=90A),the optimal distance between laser and wire end arcs was 1mm,in the case of medium specification parameter(I=130A),the optimal distance between laser arcs was 2mm,and in the case of large specification(I=170A),the optimal distance between laser arcs was 3mm.(2)Laser could improve the stability of the molten pool,reduce the fluctuation of the size of the molten pool,and make the formation morphology of the deposited layer more neat.The melting pool and arc were observed by high-speed camera system,the size of melting pool and arc at the same time were measured by image processing software,and the contour of deposited layer was measured by three-dimensional measurement system.Compared with the effect of MAG,under different specification parameters,the size fluctuation of arc was reduced due to the constraint effect of laser on arc,the size of corresponding molten pool was more stable,and the uniformity of deposited layer was improved.In addition,it was verified that the arc was closely related to the forming morphology of the molten pool and the deposited layer.The larger the arc size fluctuation was,the larger the pool size fluctuation would be,and the more uneven the accumulation layer would be.On the contrary,the more stable the arc was,the more stable the pool size was,the more neat the accumulation layer was,and the better the forming morphology was.(3)After the laser was applied to the arc,the surface roughness of the arc additive manufacturing component decreased and the surface quality was close to that of the sand mold casting.Compared with the MAG effect,when specification parameters were small(I=90A),the part's surface roughness Ra value reduced from 150.178?m to 53.521?m.When specification parameter were moderate(I=130A),the part's Ra value reduced from 71.328?m to 41.498?m.When specification parameters were big(I=170A),the part's Ra value reduced from 110.163?m to 82.352?m.The surface roughness of metal components manufactured by laser-restrained arc additive was close to that of sand mold casting.