Optimization Of Flash-butt Welding Technology Parameters Of Band Saw Blade And Study Of Joint Performance

The flash-butt welding is a kind of high efficient welding methods.Because of its high degree of automation,excellent and stable welding quality,flash-butt welding technology has been widely used in various fields of industry.The welding of bandsaw blade also used this technology.However,our country’s research of flash-butt welding has lagged behind the developed countries.Therefore,flash-butt welding machine mostly rely on imports.This paper based on domestic automatic flash-butt welding machine,which was developed by a local company.After studying the working principle of automatic flash-butt welding machine,the author analyzes the way to control the welding process parameters in this welding machine,and let the setting values correspondence with the actual welding parameters.According to the principle of flash-butt welding,built a welding model in ANSYS.Then the numerical simulation of welding temperature field is obtained.The thermophysical properties of the material are considered in this model.Solved the problem of materials’ flash melting by using the birth-death element method.The process of contact resistance heat in welding were simulated by element entity layered loading.The variation law of temperature field is obtained by comparing different welding speeds,and this provides a theoretical reference for the optimization of the welding parameters.According to the simulation results and the data obtained from the literature,orthogonal test was designed to improve the welding parameters.Experiments are carried out to study the influence of welding parameters,such as flash speed,welding voltage,upsetting force and electric upsetting time.The subjective quality assessment and tensile strength of the welded joint was the evaluation index of each welding parameters.The optimal parameters combination of different specifications band saw has been obtained by tests.And the importance of each parameter to the welding quality is analyzed.After flash-butt welding,the joint has great strength but poor toughness.With the fact that the band saw is working under dynamic loads,this may leads to the fracture of the band saw.So the band saw blade need post-weld heat treatment to eliminate residual stress and improve the toughness.The single factor experiment was carried out on the holding temperature and holding time.Through the analysis of tensile test,hardness test and microstructure observation,the suitable process parameters of post-weld heat treatment are obtained.