抄録
The purpose of this study is to investigate the tensile properties of super rapid tempering steel treated by high frequency induction heating method. In order to discuss the effect of tempering time on tensile properties, two types of specimens in which tempering time was different were prepared. Super rapid tempering specimen (IHT steel) was tempered for 0.35 sec by induction heating, and conventional tempering specimen (FT steel) was tempered for 3.6 Ksec by furnace tempering. While both of specimens were quenched by induction heating .These specimens were evaluated at room temperature. As a result, the both steel had almost same tensile strength. However the true stress of fracture of IHT steel was higher than that of FT steel. This result was explained by the reduction of area of IHT steel was higher than that of FT steel. The toughness of both specimens was also evaluated by the measuring area of nominal stress-nominal strain diagram. The toughness of IHT steel was 30% higher than that of FT steel. SEM observation suggested that the cementite particle of IHT steel was smaller and more finely dispersed compared to FT steel.
