Effect of Rapid Hardening on the Mechanical Behavior Ferritic Fe-C-（X） Alloys
作者单位：School of Physics and Materials Engineering Monash University Victoria 3800 School of Physics and Materials Engineering Monash University Victoria 3800 School of Physics and Materials Engineering Monash University Victoria 3800 Australian Key Centre for Microscopy and Microanalysis The University of Sydney NSW 2006.
会议名称：《The Fourth International Conference on Physical and Numerical Simulation of Materials (ICPNS’2004)》
会议日期：2004年
学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化]
关 键 词：Heat treatment Rapid hardening Shear punch testing.
摘 要：正Low carbon ferritic steels have been researched extensively in the 1950 and 1960’s for ambient temperature structural applications. Elements such as vanadium （V）, molybdenum （Mo）, and manganese （Mn） are strong carbide formers and the precipitation of such carbides is known to strongly affect the properties of *** work aims to develop a new approach for strengthening ferrite associated with the early stages of age-hardening. The ageing behavior of four low carbon （- 0.01 wt %） ferritic steels with and without the additions of Mn, Mo and V was studied. The alloys were solution heat treated in the fully austenitic （γ） region at 1050°C for Fe-C and Fe-C-Mn and at about 1285°C for Fe-C-V and Fe-C-Mo quenched into water to produce a completely ferritic （α） matrix, then held at 700 -730℃for ferrite saturation, and subsequently aged at 550℃to facilitate substantial strengthening through precipitation hardening. Two peaks were observed on the age-hardening curve: the initial rise at 30 sec of ageing at 550℃and then a peak hardness where hardness values corresponded to approximately six times that of the as quenched values for the Fe-Cr-Mo and Fe-Cr-V steels and three times for Fe-C and Fe-C-Mn steels. The ratio between the peak hardenss values and the rapid hardness values was-3:1.A minituarised technique - shear punch testing was employed to investigate the mechanical performance of these alloys at various ageing times of significance. A technique of shear punch testing allows to utilize small amounts of material and then to correlate the results to ultimate tensile strength （UTS） and yield strength. In this study the variation of UTS, yield strength and elongation was found to be consistent in all four steels in the early stages of precipitation-hardening. An optimum combination of strength and ductility was achieved at the initial rapid-hardening stage and not at peak hardness ageing time.