Effects of Ni additions on Graphitization in High carbon steel

고탄소강의 흑연화에 미치는 Ni첨가의 영향

  • Park, Young-Koo (Faculty of Advanced Materials Engineering & Institute of Advanced Materials Development Chonbuk National University) ;
  • Woo, Kee-Do (Faculty of Advanced Materials Engineering & Institute of Advanced Materials Development Chonbuk National University) ;
  • Jin, Young-Chul (Faculty of Advanced Materials Engineering & Institute of Advanced Materials Development Chonbuk National University) ;
  • Ryu, Jae-Hwa (POSCO Technical Lab.) ;
  • Park, Jong-Hyun (Royal Tungsten Carbide)
  • 박영구 (전북대학교 공과대학 신소재공학부, 신소재개발연구소) ;
  • 우기도 (전북대학교 공과대학 신소재공학부, 신소재개발연구소) ;
  • 진영철 (전북대학교 공과대학 신소재공학부, 신소재개발연구소) ;
  • 류재화 (포항종합제철 기술연구소 박판연구팀) ;
  • 박종현 (로얄초경)
  • Published : 1999.03.31

Abstract

Graphitization of cementite in high carbon steels at subcritical temperature is reported. We have studied about the effects of Ni in these steels on graphitization. The chemical compositions of the specimens were Fe-(0.54, 0.7)%-C-1.0%Si-0.1%Mn-(0.2~1.0)%Ni. After annealing at $650^{\circ}C$, $680^{\circ}C$ and $700^{\circ}C$ during various time the microstructures and hardness change were observed. In order to recover the initial hardness of high carbon steel, dissolution treatment of graphite was performed at $870^{\circ}C$. In case of 0.7%C steel, graphitization was accelerated rather 1.0%Ni addition steel than 0.2% and 0.54%Ni addition steels but the graphite is coarser. In case of 0.54%C-0.2%Ni steel, graphite particles were distributed relatively homogeniously and finely. Nickel addition promotes graphitization of these steels but makes graphite blocky.

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Acknowledgement

Supported by : 포항종합제철주식회사