Investigation of hot deformation characteristics of AISI4340 steel using processing map
Uniaxial compression tests at various temperatures from 850℃ to 1200℃ and strain rates between 0.01 s-1 and 10 s-1 were carried out in order to determine hot working characteristic of the AISI 4340 steel.The plastic stress-strain responses at high temperatures of the steel were provided.Constitutive relationship between the flow stresses and the Zener-Hollomon parameters was primarily established by means of a hyperbolic sine function for the entire range of the investigated conditions.Afterwards,the power dissipation map and instability map were developed on the basis of the Dynamic Materials Model (DMM).The variation of efficiency of the power dissipation calculated as a function of strain rate sensitivity represented material behaviors according to the microstructure evolution.The peak efficiency indicated an optimum proccssing window for hot working.In this study,processing map was obtained by a superimposition of the power dissipation and the instability criterion.The domains of temperature and strain rate,in which material flow stability occurred,were determined.For the AISI 4340 steel,the processing maps exhibited a distinct domain with its peak efficiency at about 1050-1200℃ and 0.01-0.1 s-1,in which the peak efficiencies of about 40-50% were shown for different strains.In combination with microstmcture observations after hot deformation,dynamic recrystallization zone could be identified in the processing map at a certain strain.
AISI4340 Hot deformation Processing maps Dynamic recrystallization
Apichat Sanrutsadakorn Vitoon Uthaisangsuk Surasak Suranuntchai Borpit Thossatheppitak
Department of Tool and Materials Engineering Department of Mechanical Engineering,Faculty of Engineering, King Mongkuts University of Technology
国际会议
北京
英文
301-306
2012-12-16（万方平台首次上网日期，不代表论文的发表时间）