Anaylisis Of Crack Arrest And Mechaniclal Properity With Half-Embedding Crack Using Electromagnetic Heating Effect

Crack is familiar in machine parts and project component's. Many disastrous accidents are caused by the surface crack or the penetration fracture. Therefore, the research on how to prevent the crack expansion in metal material, has a significant theoretical and practical value.Crack arrest by electromagnetic heating is a relatively new technology for stopping internal crack propagation in metal components. Crack arrest by electromagnetic heating has the obviously advantage of carrying out conveniently and taking effect rapidly. This article researches on the theoretical analysis, numerical simulation, experimental surveys of crack arrest by the electromagnetic heating based on the introduction of half-imbedded metal structures with crack. The results can provide the theoretical basis for solving practical problems. The main work can be outlined as follows:(1)The space theoretical model was set up using the method of complex variable function, and the temperature field and the stress field were gave in the style of calculating examples in the instant time of crack arrest.(2)The electrical, thermal and mechanical fields are coupled in the process of the calculations. The evolution process of current-temperature-stress is simulated by numerical analysis. It is the first time to use MARC finite element software to calculate temperature field and thermal stress field in the metal component with a space half-embedding crack when the electromagnetic heating technology was carried out.(3)Crack arrest online experimental study about 45 steel and Cr12 metal electromagnetic components was done using the self-made ZL-2 Super-pulse current discharge device. Experiment discovered that on some extend stress ,the crack was not craze at the moment of the current is switched on. Through metallographic analysis of microstructure around the crack-tip intensity, show the white layer matrix micro-organizational structure whose toughness and hardness were higher, clarifying the microcosmic essence.(4)Tension, impulsion and torsion experiments were carried out after crack arrest, and the mechanical properties were also studied before and after the crack arrest.The three aspects of the theoretical calculation, experimental analysis and numerical simulation mutually validate that electromagnetic heating technology can realize crack arrest in the metal component with a space half-embedding crack and it is a novel and feasibly method.