Thermal fatigue behavior of hard chromium electroplated steel in three different crack intensities of high contraction(HC), medium contraction (MC) and low contraction (LC) was studied. Maximum and minimum temperature...Thermal fatigue behavior of hard chromium electroplated steel in three different crack intensities of high contraction(HC), medium contraction (MC) and low contraction (LC) was studied. Maximum and minimum temperaturesduring thermal cycle were 800 and 100℃, respectively. The topography and cross sections of the samples exposedto 50, 100 and 200 thermal cycles were studied. The thermal fatigue behavior was analyzed using the data obtainedfrom surface roughness, crack networks and stress induced during cycles. Although the as-coated sample with LCchromium contained no crack, it appeared to have a high crack density after only 50 cycles. The crack depth andwidth in cyclically oxidized LC coating were much less than those in MC and HC coatings. It was concluded that theLC coating protected the substrate from having cracks or subsurface oxidation during thermal fatigue. The cracksin the HC and MC coatings increased in density as well as in depth by thermal cycles. Moreover, the opening of thecracks to the substrate resulted in sub-surface oxidation.展开更多
文摘Thermal fatigue behavior of hard chromium electroplated steel in three different crack intensities of high contraction(HC), medium contraction (MC) and low contraction (LC) was studied. Maximum and minimum temperaturesduring thermal cycle were 800 and 100℃, respectively. The topography and cross sections of the samples exposedto 50, 100 and 200 thermal cycles were studied. The thermal fatigue behavior was analyzed using the data obtainedfrom surface roughness, crack networks and stress induced during cycles. Although the as-coated sample with LCchromium contained no crack, it appeared to have a high crack density after only 50 cycles. The crack depth andwidth in cyclically oxidized LC coating were much less than those in MC and HC coatings. It was concluded that theLC coating protected the substrate from having cracks or subsurface oxidation during thermal fatigue. The cracksin the HC and MC coatings increased in density as well as in depth by thermal cycles. Moreover, the opening of thecracks to the substrate resulted in sub-surface oxidation.
