Abstract:
Rolling mill rolls are subjected to thermal fatigue cracking and mass removal during operation. Work rolls for hot-strip mills are composite components made of an outer shell of cast wear-resistant material. Alloys of the Fe-C-X system, where X represents Cr and/or W and/or Mo and/or V and/or Nb, strongly predominate as the shell material, their microstructure features being tempered martensite with secondary carbides and eutectic carbides. Previous work has shown that thermal fatigue cracking behavior of V-bearing alloys is mainly governed by the “continuity/mean free distance” ratio of the eutectic carbides: the higher the “C/D” ratio, the higher the crack propagation rate. In the present work, the effect of the volume fraction and distribution of the eutectic carbides on thermal fatigue of Nb-bearing alloys was investigated. It was observed that the “C/D” ratio of the Nb-rich MC eutectic carbides is the key parameter for thermal cracking behavior also in this case.
Reference:
BOCCALINI JR., Mário; FARINA, Paula Fernanda da Silva. Thermal fatigue of Nb-bearing alloys for hot rolling mill rolls. In: INTERNAIONAL TOOLONG CONFERENCE – TOOL, 9., 2012, Loeben. Proceedings… 8p.
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https://escriba.ipt.br/pdf_restrito/171178.pdf
Rolling mill rolls are subjected to thermal fatigue cracking and mass removal during operation. Work rolls for hot-strip mills are composite components made of an outer shell of cast wear-resistant material. Alloys of the Fe-C-X system, where X represents Cr and/or W and/or Mo and/or V and/or Nb, strongly predominate as the shell material, their microstructure features being tempered martensite with secondary carbides and eutectic carbides. Previous work has shown that thermal fatigue cracking behavior of V-bearing alloys is mainly governed by the “continuity/mean free distance” ratio of the eutectic carbides: the higher the “C/D” ratio, the higher the crack propagation rate. In the present work, the effect of the volume fraction and distribution of the eutectic carbides on thermal fatigue of Nb-bearing alloys was investigated. It was observed that the “C/D” ratio of the Nb-rich MC eutectic carbides is the key parameter for thermal cracking behavior also in this case.
Reference:
BOCCALINI JR., Mário; FARINA, Paula Fernanda da Silva. Thermal fatigue of Nb-bearing alloys for hot rolling mill rolls. In: INTERNAIONAL TOOLONG CONFERENCE – TOOL, 9., 2012, Loeben. Proceedings… 8p.
Log into BiblioInfo Biblioteca-DAIT/IPT to access the text in PDF. Document is password protected, ask Customer Service/Library-DAIT/IPT:
https://escriba.ipt.br/pdf_restrito/171178.pdf
