Study On Microstructure Andproperities Of GH4169 Superalloy Butt-Cover Plate

As the key structural material of spacecraft and aerial craft , high-temperature alloy has been applied to aviation and astronavigation industry, specially to the body of airplane and the engine which demanded high strength and heat resistance. The joint of high temperature alloy has been an important technique during the application of high temperature alloy .It is not in aviation and astronavigation industry but also in automobile industry that some structure need to weld before forming .The laser welding has many merits that the other welding don't have. So it's of great meaning to study the microstructure and properties of high temperature alloy laser welded butt-cover plate and to solve the problem of butt-cover's plastic forming. GH4169 high temperature alloy laser welded butt-cover plate will been taken as a example, used the forecasting and analysis of XRD, SEM, optical microscope to study the base and weld joint's microstructure of GH4169 high temperature alloy laser welded butt-cover plate in this article. The base and weld joint's mechanical properties of GH4169 high temperature alloy laser welded butt-cover plate will be studied through high temperature tensile test and micro-hardness test.The mechanical properties of the GH4169 high temperature alloy laser welded butt-cover plate's base and weld joint have been studied by high temperature tensile test. The temperature is 950 0C and the initial strain rate is 2.67×10-4 s-1.Two welded processing parameters have been employed, parameter of the first time is that, frequency:16 Hz, power:1500 W, pulse width:2 ms, welding speed:120 mm/min, the second time is , frequency:16 Hz, power:2000 W, pulse width:2 ms, welding speed:900 mm/min. The results show that the elongation of GH4169 high temperature alloy laser welded butt-cover plate parallel to rolling direction was higher than that of the direction which was perpendicular to rolling direction; The weld joint's elongation of the first time welding is better than the second time, but the base's elongation is bad; The weld joint's elongation of heat treating is better than that of no heat treating, but the base's elongation is bad has also been found.The micro-hardness analysis of the GH4169 high temperature alloy laser welded butt-cover plate's base and weld joint has been made. The results show that, the micro-hardness of base and weld joint is gradual increasing along with the first time welding, the second time welding and the heat treating. A possible microstructure cause of GH4169 high temperature alloy laser welded butt-cover plate's base and weld joint's property has been obtained by analysis of the base and weld joint's microstructure through XRD, SEM, optical microscope.