Study On Induction Preheating Method Of Welding Wire In The Process Of Wire And Arc Additive Manufacturing

With the continuous progress of social development,higher requirements are put forward for the processing and manufacturing industry.Due to the characteristics of high efficiency and saving,Wire and Arc Additive Manufacturing(WAAM)is widely used in various fields.Due to the high heat input and low additive rate,the traditional WAAM has become a bottleneck restricting its development.In order to reduce the heat input and improve the efficiency of the additive,the method of induction preheating of welding wire is put forward.In this paper,the parameters of electromagnetic induction preheating are calculated,corrected by experiment and actual situation,purchased relevant equipment,built induction hot wire welding platform,explored the influence of different induction heating current on the preheating temperature of welding wire,and conducted a series of preheating experiments to explore the influence of induction heating current parameters on welding effect,which can provide reference for the process of induction heating wire.The main contents are as follows:First of all,according to the consulting data and empirical formula,the parameters of induction heating equipment are roughly calculated,including coil length,inner diameter,power frequency,etc.,and then the welding wire heating test is carried out in the induction equipment company.According to the heating effect,the coordination between induction coil and welding gun,and the actual efficiency of coil,the parameters of power supply and coil are adjusted and purchase heating equipment after meeting the use requirements.using the purchased heating equipment,the experiments of welding wire heating are carried out.It is found that the temperature of welding wire increases with the increase of induction heating current and decreases with the increase of wire feeding speed.Then,the integration of induction heating platform and welding platform is carried out.Firstly,the follow-up connection structure of coil and welding gun is designed according to the CMT welding platform,secondly,according to the size of coil and welding gun,the ceramic pipe with wire stiffness correction function and the protective cover with the function of preventing welding gas from escaping and welding slag splashing from damaging the coil are considered.Due to the insufficient load of the machine arm equipped with CMT,a synchronous operation platform based on MIG welding is designed,in which the coil is moved on the guide rail by the little truck,a connection device is made to fix the welding gun and the coil to realize the follow-up of the welding gun and the coil.The welding gun wire feeding switch and heating power switch are led out and connected to the same switch to realize the synchronous start and stop of welding machine wire feeding and coil heating.At last,the relevant experiments were carried out on the induction hot wire WAAM platform,and the changes of weld morphology,section size and heat affected zone(HAZ)depth under different induction heating current parameters were studied.It is found that with the increase of the induced current,the weld bead width increases and the residual height decreases,and the depth of the HAZ remains unchanged,but it is larger than that without induction heating.