Active Control of the Residual stress in Inconel718 Grinding Assisted by the Strengthen Induction Heating

Abstract

Abstract：Nickel-based superalloy Inconel 718 possesses high strength and corrosion resistance, which is widely applied in aviation industry, especially the high temperature components of gas turbine engines. However, the final forming grinding process often forms a large residual tensile stress on the surface of the parts, which is detrimental to the fatigue strength and life of the parts. A combined grinding process based on the principle of the thermal gradient adjustment in grinding zone is studied, which could adjust the residual stress distribution on the surface of Inconel718 parts actively. In the combined grinding process, the heat source is embedded into the sub-surface of the workpiece by induction heating equipments well controlled, which can adjust the residual stress by the active control of the temperature gradient. The results show that the smaller surface residual tensile stress and even compressive stress distribution can be obtained by reasonably adjusting the parameters of the induction heating and grinding process. This study can reduce the extra shot peening process during the current production in order to obtain the compressive residual stress on the surface, and realize the on-line active control of the grinding residual stress. Furthermore, the combined grinding technology can be extended to the other materials and machining processes, such as cutting, milling, etc. Key words：nickel-based superalloy；grinding residual stress；induction heating；metal powder bonded magnetic flux concentrator (MPB-MFC)；active control * * 国家自然科学基金(U1430116)、太原理工大学校基金(2016QN08)和太原 理工大学引进人才(tyut-rc201554a)资助项目。20170301 收到初稿， 20171012 收到修改稿