By using a reformed laboratory rolling mill,hot wear test under near service conditions has been carried out to examine the wear mechanisms of high chromium iron roll.Each time after being rolled up to a given cycle,t...By using a reformed laboratory rolling mill,hot wear test under near service conditions has been carried out to examine the wear mechanisms of high chromium iron roll.Each time after being rolled up to a given cycle,the worn morphology of roll surface was examined under SEM and occasionally by AES.Based on rolling conditions and lasting of in-service time,various wear characteristics have been identified distinctly.It involves abrasive wear and oxidation wear for matrix phase,fatigue wear,polishing wear and grain pull-out wear for carbides,smear adhesive wear,chemical wear,and in extreme case,plasticity-dominated wear.At the same time,wear type is also discussed compatibly in terms of abrasive wear,fatigue wear,as well as chemical wear according to conventional classification.And only in an extreme situation,i.e.rolling without cooling water,adhesive wear may partially be involved.At anytime under specified conditions,there are always several wear mechanisms occurring simultaneously,but usually only one of them can be identified as the dominant mode.And finally a wear mechanism figure can be depicted to qualitatively describe the relationship among them.展开更多
This study developed a new technology for preparing high-chromium cast iron(HCCI)/low-carbon steel(LCS)wear-resistant composite plates by hot rolling at a 1050°C and a rolling speed of 0.2 m/s.The effects of diff...This study developed a new technology for preparing high-chromium cast iron(HCCI)/low-carbon steel(LCS)wear-resistant composite plates by hot rolling at a 1050°C and a rolling speed of 0.2 m/s.The effects of different rolling reductions(30%,45%,and 60%)on the microstructure(interface and HCCI layer)and mechanical properties(bonding strength,hardness,and wear resistance)of the composite plate were studied.SEM images showed that when the reduction was increased,no impurities and interlayers were found between the microscopic interfaces after hot rolling,and the bonding interface exhibited a wave-like shape.EDS analysis showed that the Cr element diffusion between two metals after hot rolling was promoted when the reduction was increased,thereby improving the bonding quality under the same rolling temperature and rolling speed.Experiments showed that due to the stress release effect of the LCS of the cladded layer,the macro-slab shape after hot rolling performed well,and the brittle HCCI layer underwent thermoplastic deformation without cracking.Moreover,the increase of rolling reduction improved the bonding quality.As the rolling reduction was increased,the volume fraction of Cr-carbides in the HCCI layer also increased,resulting in an increase of hardness and wear-resistance.展开更多
文摘By using a reformed laboratory rolling mill,hot wear test under near service conditions has been carried out to examine the wear mechanisms of high chromium iron roll.Each time after being rolled up to a given cycle,the worn morphology of roll surface was examined under SEM and occasionally by AES.Based on rolling conditions and lasting of in-service time,various wear characteristics have been identified distinctly.It involves abrasive wear and oxidation wear for matrix phase,fatigue wear,polishing wear and grain pull-out wear for carbides,smear adhesive wear,chemical wear,and in extreme case,plasticity-dominated wear.At the same time,wear type is also discussed compatibly in terms of abrasive wear,fatigue wear,as well as chemical wear according to conventional classification.And only in an extreme situation,i.e.rolling without cooling water,adhesive wear may partially be involved.At anytime under specified conditions,there are always several wear mechanisms occurring simultaneously,but usually only one of them can be identified as the dominant mode.And finally a wear mechanism figure can be depicted to qualitatively describe the relationship among them.
文摘This study developed a new technology for preparing high-chromium cast iron(HCCI)/low-carbon steel(LCS)wear-resistant composite plates by hot rolling at a 1050°C and a rolling speed of 0.2 m/s.The effects of different rolling reductions(30%,45%,and 60%)on the microstructure(interface and HCCI layer)and mechanical properties(bonding strength,hardness,and wear resistance)of the composite plate were studied.SEM images showed that when the reduction was increased,no impurities and interlayers were found between the microscopic interfaces after hot rolling,and the bonding interface exhibited a wave-like shape.EDS analysis showed that the Cr element diffusion between two metals after hot rolling was promoted when the reduction was increased,thereby improving the bonding quality under the same rolling temperature and rolling speed.Experiments showed that due to the stress release effect of the LCS of the cladded layer,the macro-slab shape after hot rolling performed well,and the brittle HCCI layer underwent thermoplastic deformation without cracking.Moreover,the increase of rolling reduction improved the bonding quality.As the rolling reduction was increased,the volume fraction of Cr-carbides in the HCCI layer also increased,resulting in an increase of hardness and wear-resistance.
