Effects Of Electropulsing On The Microstructure And Mechanical Properties Of The Boron Steel

With the development of science and technology, the cars that have light weight, lowcost, high performance are becoming the main direction of people demands, so we putforward higher requirements on the materials and production processes of automobileparts. Hot stamping technology with its features of light weight, high strength is far betterthan the traditional stamping technology. For its advantages, hot stamping is becomingeffective way to deal with a series of problems and it is more and more widely used in thefuture, while the deficiency of traditional heating methods has been revealed with thedevelopment of hot stamping.This paper mainly studied on the microstructure and mechanical properties of hotstamping B1500HS boron steel by electropulsing heating and traditional heating, andanalyzed the change of physical fields during heat processing.By using high-energy electropulsing with high-strength B1500HS boron steel, weexplore the influence of microstructure, mechanical properties, hardness and surfaceoxidation of the high-strength boron steel, and obtained some conclusions as follow:Under the optimal parameters condition, martensite microstructure of the quenchedsamples that were heated by electropulsing was finer than the specimen were heated bytraditional furnace. For this result, we hold the view that rapid heating of electropulsingtreatments can improve the austenite nucleation rate, and can inhibit the austenite gainsfrom growing up, and finally, we obtained the fine martensite microstructure.The mechanical properties of quenched boron steel had obviously improved byelectropulsing heating. The tensile strength of samples was about1660MPa, and theelongation increased by7%, at the same time, the samples was maintaining the highhardness. The high strength and toughness of the samples were determined by plasticityeffect that was generated by eletropulsing heating. Eletroplusing heating can effectivelyimprove the comprehensive mechanical properties of materials and vehicle safety coefficient.By electropulsing treatments, the surface oxidation of samples was few, and theoxidation weight was obviously less than that is heated by furnace heating. Theprocessing of transient heating and rapid pressure by eletropulsing heating determined thesamples can transient stay in the air, so it can decrease the surface oxidation, improvedthe utilization rate of energy, and effectively ensure the workpiece dimensional accuracy,reduce the materials waste of oxidation, and the most important thing is it can conductiveto energy conservation and environmental protection.Finite element simulation analysis method was used to study the temperature andcurrent density distribution of the inner materials in the processing of eletropulsing. Finiteelement simulation results showed that due to the shape of samples were rules, byeletropulsing treatment, the overall current distribution of samples were uniformity, andonly existed the current density gradient distribution in the edges of samples. The resultsof the temperature field numerical simulation showed that the temperature in the middleof samples were higher than the ends of samples, and with increasing heating time, thistemperature gradient was getting larger. The forming effective area in the middle ofsamples was in a state of high temperature, so we can make full use of the heat energy.In this paper, we used experiments and simulation to study the influence ofmicrostructure and mechanical properties of high-strength boron steel by eletropulsingtreatment, and aimed at providing some guidance in practical production processing. webelieve that eletropulsing technology will be more and more widely applied in the field ofhot stamping.