| The bulb-flat steel is a structure steel specially for shipbuilding.It usually performed as the keels and stiffeners,various constructions can be formed when connected with ship plate steel.It is essential to have great performance of bulb-flat steel due to its vital role in the structure of a ship.The shape characterization of bulb-flat steel lead to uneven temperature,microstructure and properties distribution after rolling,and then heat treatment is essential to reduce the section heterogeneity.Quenching and tempering is one heat treatment process to produce high-strength and high-toughness bulb-flat steel.and induction hardening and tempering is favored for the fast heating speed,short residence time in high temperature zone and high utilization rate of energy.The effect of induction heating on the microstructure and properties of 16#bulb-flat steel has been intensively studied by simulation with ABAQUS software and experiment investigation.Through simulation,the number of coils,preheating current density,heating current density,insulation distance and moving speed during the heating process all influence the temperature field distribution of the section of bulb-flat steel.The section temperature uniformity of bulb-flat steel can be achieved by using two coils,increasing the preheating current density,appropriately extending the insulation distance and slowing down the moving speed,and the accuracy of the calculated results has been verified.Meanwhile,by varying the heat treatment conditions during industrial production based on the simulation results,the effect of quenching temperature,tempering temperature and tempering time on the microstructure and properties of 16# single bulb-flat steel are investigated.Finally,the best heat treatment condition for 16#single bulb-flat steel with better section uniformity is obtained: induction heating at980℃ and tempering at 670℃ for 2h. |
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