The Research On Controlling Shape Technology Of Low Carbon Steel Based On MAG Wire And Arc Additive Manufacturing

MAG-WAAM(MAG Wire and Arc Additive Manufacturing,MAG-WAAM)technology has some advantages of lower production cost and higher forming efficiency,which is suitable for the rapid near net shaping of large size components,and it has a significant application prospect in the automotive and mold manufacturing field.Because of MAG-WAAM technology as a multi-parameter nonlinear coupling process,from the viewpoint of forming process characteristics,the influence of interlayer temperature,deposition current and travel speed on morphology quality and mechanical property was studied to determine the key factors controlling morphology quality and mechanical property,which was of great significance to the research on active control of morphology quality and mechanical property based on wire arc additive manufacturing technology..In this paper,the forming process characteristics of MAG-WAAM were studied,using wire H08Mn2SiA as raw material.Firstly,The influence of substrate temperature,deposition current and travel speed on weld morphology quality and section profile shape was studied.The results showed that substrate temperature had little influence on weld morphology quality and the fit result between weld section profile and arc shape was best.According to second-order response surface universal rotation combined experiment design method,the response surface relationship between effective wall width of single wall parts and interlayer temperature,deposition current,travel speed was established.It showed that interlayer temperature had little influence on effective wall width and the optimized interlayer temperature value was equal to 80 ?;both deposition current and travel speed had a significant influence on it.At last,deposition current and travel speed as input variables,the second-order response surface regression models of effective wall width and layer height were established and the reliability and accuracy of the regression models were verified by variance analysis and experimental methods.The influence of interlayer temperature,deposition current and travel speed on microstructure and mechanical property was studied,respectively.The microstructure had obvious characteristics of layer bands in the direction perpendicular to substrate.It mainly consisted of the coarsened polygonal ferrite in the interface between layer bands and a small amount of pearlite,a mixture of coarsened polygonal ferrite without undergoing recrystallization,fine polygonal ferrite and a small amount of granular pearlite undergoing recrystallization in the layer bands,the coarsened columnar pro-eutectoid ferrite,side-plate ferrite acicular ferrite and a small amount of pearlite in the top layer.The process parameters mentioned had little influence on microstructure characteristic.Under the condition that the interlayer temperature was 40??80??120?,respectively,there was no obvious change in microstructure.Keep interlayer temperature equal to 80 ?,with the increase of deposition current and travel speed,respectively,there was no obvious change in microstructure.In the horizontal and vertical direction,the ultimate strength and the yield strength had isotropic characteristic.The elongation in horizontal direction was larger than that in vertical direction,exhibiting anisotropy.Keep interlayer temperature equal to 80 ?,with the increase of deposition current and travel speed,respectively,there was no obvious change in mechanical property.The process parameters including interlayer temperature deposition current and travel speed,had little influence on mechanical property.During the forming process,from the point of view of controlling morphology quality,interlayer temperature should be set to 80 ?,the size of forming components mainly controlled by deposition current and travel speed.