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pISSN : 1598-706X / eISSN : 2288-8381


(논문)연구논문

한국주조공학회지 (35권1호 1-7)

Mechanical Properties of Austempered Fe-2.0wt.%Si-0.3wt.%Mn Steel with various Carbon Contents

탄소함량 변화에 따른 오스템퍼드 Fe-2.0wt.%Si-0.3wt.%Mn 강의 기계적 성질

Jong-Gyu Ha, Sang-Yun Shin, Do-Hoon Lee and Byung-Joon Ye†

Depatment of Metallurgical Engineering Graduate School of Kyungpook National University,

DOI : http://dx.doi.org/10.7777/jkfs.2015.35.1.001

Abstract

In this study, we investigated the effect of carbon on mechanical properties with different austempering conditions of high carbon(0.7~1.3wt.%C)-2.0wt.%Si steels. The specimens were austenitized at 850, 925 and 1020oC, and austempered at 260, 320 and 380oC for the various period of time from 3 min to 300 min. After heat treatment, the evolution of stage I and stage II was identified with optical microscope, XRD and hardness test. When the austempering temperature was 260oC, the microstructure consisted of the lower ausferrite while the upper ausferrite micro-structure was formed at 380oC. As the austempering temperature increases from 260 to 380oC, the tensile strength decreases and elongation increases. In addition, when carbon content increases, tensile strength and elongation decrease.

Keywords

Casting, Retained austenite, Carbon contents, Austempering, Austempered ductile cast iron, Heat treatment, Ausferrite