Process Research Of Inertia Radial Friction Welding T2 Copper-40Cr Steel

This paper aimed to research T2 copper rings and 40 Cr steel bars inertia radial friction welding,using ten different groups of parameters.The welded joints were analyzed by macroscopic and microscopic analysis,spectrum analysis,microhardness test and shear test to study dissimilar metal inertia radial friction welding process,microstructure and mechanism.Main results are listed below:(1)Analyze the macroscopic and microscopic deformation of the welded joints.According to deformation of copper rings,flash,seals and interface,four groups welded joints were defined as good welds.(2)Focus on microstructure of inertia radial friction welded joints.Grains on copper side were elongated axially and compressed radically.The microstructure of copper side would be separated three zones both radically and axially: fine grain zone,thermal mechanical affected zone and mechanical affected zone.Grain size of thermal mechanical affected zone is the largest.When rotating speed is low,grain size of fine grain zone is larger than mechanical affected zone’s;when rotating speed is high,grain size of fine grain zone is smaller than mechanical affected zone’s.And microstructure of steel side would be separated as bright zone,thermal affected zone and base metal.The width of bright zone would grow wide with the speed growing and the width would get larger with pressure growing.There are little martensite and sorbite in the bright zone.And pearlite and ferrite were found both in thermal affected zone and base metal.Grain sizes on both sides would get larger at first and become smaller later with speed increasing.And when the weld speeds are same,grain size with high pressure would be smaller than the other one.(3)Microhardness of inertia radial friction welded joints reached the top at the interface.And then it dropped quickly on the copper side and dropped slowly on the steel side.(4)In shear tests of inertia radial friction welded joints,the largest strength is 182.8MPa,which is far more large than any other welding technologies.In en groups,shear strength of four groups are equal to or larger than shear strength of T2 copper.According to results of macroscopic and microscopic deformation,maximum speed 4500 rpm with forging pressure 8MPa,maximum speed 4800 rpm with forging pressure 6MPa and maximum speed 4800 rpm with forging pressure 8MPa produced qualified welded joints.