View Full-text

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


(논문)연구논문

한국주조공학회지 (13권5호 432-440)

Effects of the Alloying Elements and Special Heat Treatment on the Multi-phase (Ferrite-Bainite-Martensite), Strength and Toughness in Ductile Cast Iron

구상흑연주철(球狀黑鉛鑄鐵)의 혼합조직(混合組織) 및 강인성(强靭性)에 미치는 합금원소(合金元素)와 특수열처리(特殊熱處理)의 영향(影響)

Sug-Won Kim, Eui-Kweon Lee, Jae-Hwan Sim

Chonbuk National University

Abstract

Ductile cast iron has a good ductility and toughness than those of gray cast iron, because the shape of graphite is spheroidal. Also, it has been reported that, additional strengthening and toughening of the ductile cast iron can be obtainded from the proper combination of matrix structures by the heat treatment and addition of alloying elements. In this study the effect of special heat treatment and addition of alloying elements(Ni, Mo) on the multi-phase(ferrite- bainite-martensite) structures, strength and toughness of ductile cast iron were studied systematically. In water quenching from 770℃, the martensite volume(%) increased, but the ferrite volume(%) decreased with increment of Ni content. In as cast, pearlite volume(%) and hardness increased with increment of Mo and Ni contents. And with the increment of the destabilization austempering holding time, the bainite volume(%) increased but the martensite volume(%) decreased. As destabilization austempering holding time is same, bainite volume(%) decreased, martensite increased with the increment of Ni and Mo contents. The hardness and tensile strength decreased, but impact energy increased with the decrease of Ni and Mo contents, and increment of holding time of destabilization austempering treatment.

Keywords