Yuming Fu

Pulse Discharge Strengthening of 16Mn Welded Joint and Mechanical Performance

The way of pulse discharge strengthening is introduced, and the electromagnetic heat pulse discharge method can increase the strength and toughness of welded joints. 16Mn low alloy steel welded joints are used in the ZL-2 super pulse current generator, and the test of pulse discharge strengthening is carried out. And the mechanical performance comparison test of welded joint is finished. On the universal tensile machine, tensile strength test before and after strengthening has been done. On the S-4800 scanning electron microscope, micro-fracture morphology is analyzed. The results show that electromagnetic heat strengthening test is carried out based on the appropriate discharge parameters. In the junction of weld and base metal near the heat affected zone of the fracture, there is a white layer organization. It appears to improve the mechanical performance of welded joint, and enhance strength and toughness of welded joints.

The Influences of Alternating Magnetic Field to the Microstructure and Mechanical Property of Diamond Agglomerations

By numerical and experimental methods, heat alternating magnetic treatment of diamond agglomerations were researched, the microstructure and mechanical properties before and after treatment were also analysed comparatively. The numerical analysis shows: the alternating magnetic field stress is bound to make solid-state microstructure change, this intensified magnetic shock can broke dendrites and tangles organization within the organization and enables organization uniform, dense. The experiments indicate: After heat alternating magnetic treatment, the HRB hardness of test pieces matrix is improved 4.34, impact toughness enhanced more than 25%, matrix organization became uniformity and density. Results revealed that alternating magnetic treatment can be an effective method for improving the performance of the diamond agglomeration.

The Analysis of Aluminum Alloy Microstructure Changes in Strong Alternating Magnetic Field

The change of aluminum alloy microstructure before and after strong alternating magnetic treatment in the aluminum alloy LY12 after the thermal plastic figuration is studied in experimental ways using strong alternating magnetic field generator.By comparing microstructure before and after strong alternating magnetic treatment, the changes of microstructure component organization is analyzed to make further analysis of the organizational factors that leads to aluminum alloy LY12 microstructure’s refinement after thermal plastic figuration caused by alternating magnetic field.

Self-Protection of Flux-Cored Wire Surfacing is Applied to the Enhancement of Chute Lining Board

Self-protection of flux-cored wire surfacing is a new way to improve mechanical parts surface properties, and can improve mechanical equipment in the harsh condition of wear-resisting, corrosion resistant, high temperature resistant and oxidation resistance abilities. This paper based on this technology, research on its reinforcement in the roof without bells chute board, first analyzes the board of chute working conditions, stress and aggrandizement requirements, and using ANSYS simulated the displacement field and the equivalent stress field during the impact process, to explain failure modes, Then from the view of experiment to research the effect of molybdenum and niobium self-protection of flux-core wire, the hard facing layer microstructure analysis show that hard facing layer can obviously increase the matrix micro hardness and impact toughness, The microstructure of Niobium surfacing layer is more delicate than molybdenum surfacing layer, impact toughness is higher and more suitable for strengthening chute lining board.

Crack arrest in metal component with double spatial cracks using electromagnetic heating

The temperature field around a crack tip is simulated for the case when crack arrest is proceeding in a test piece with prepared spatial cracks using pulse current discharge, the thermal-electrical coupling analysis method is applied numerically, and the results are verified experimentally. The numerical simulation and experiment results show that the deposit joint can be formed around the crack tip, and the radius of curvature around the crack tip increases remarkably instantly after pulse current discharged.