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
The surface treatment technology of hot aluminum-zinc steel plate and UV curing technology may be effectively combined in the present research. According to different light curing mechanisms, different formulations fr...The surface treatment technology of hot aluminum-zinc steel plate and UV curing technology may be effectively combined in the present research. According to different light curing mechanisms, different formulations from UV curing surface treatment agents can be applied to the surface treatment of hot aluminum-zinc steel plate, mainly including 3-ethyl-3-benzoxy-methyl oxacyclobutane (TCM 104) and 3,4-epoxy-cyclohexylformic acid -3',4'-epoxy-cyclohexyl methyl ester (UVR 6110) as active diluents, high molecular weight polyfunctional oxacyclobutane as oligomer, triaryl sulfonium salt as a cationic photoinitiator, and an anthracene compound as a sensitizer. 385 nm LED lamp used as a radiation resource, the effects of the proportion of active diluent, the type and amount of photoinitiator, the amount of sensitizer, the curing temperature, and the amount of nano-SiO<sub>2</sub> on the photocuring rate were investigated by photoper-scanning differential calorimetry (Photo-DSC). The experimental results show that the system has the fastest photocuring rate under the conditions of 8:2 ratio of TCM 104 to UVR 6110, 2.5% photoinitiator, 0.6% sensitizer, 0.2% nano-SiO<sub>2</sub> additive, and 80˚C curing temperature. Based on addition of the appropriate number of various additives, the cationic photocuring surface treatment solution was prepared and further coated on the hot-dip galvalume steel plates. After curing, the passivation films were characterized by neutral salt spray test (NSST), Fourier transform infrared spectroscopy (FT-IR), electrochemical testing and other methods. The results show that the formulations could be cured at an energy of 150 mJ/cm<sup>2</sup>, and the overall performance of the passivation film could meet with the requirements of the downstream users.展开更多
Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refi...Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refiner plates is of significance to the wood industry. It may affect refining quality, production efficiency, and power consumption. In this paper, the abrasion resistance of the refiner plate made of different materials, the stainless steels and high chromium cast irons, were tested and compared. The results showed that abrasion resistance of refiner plate made of high chromium cast irons was better than that of the stainless steel materials. Although the two kinds of materials have the same compositions, their abrasion resistances have ap-parent difference. The main reason is that the material microstructures have very important effects on their performance. The refiner plates made of developed high chromium cast irons don抰 demand the complex heat treatment. This can simplify the producing process, save the cost of production, decrease labor strength, and increase the production efficiency.展开更多
Hot deformation behavior of a novel Ni-Cr-Mo-B heavy plate steel was studied by hot compression tests,which were conducted on a Gleeble-3800thermo-mechanical simulator corresponding to the temperature range of850-1 15...Hot deformation behavior of a novel Ni-Cr-Mo-B heavy plate steel was studied by hot compression tests,which were conducted on a Gleeble-3800thermo-mechanical simulator corresponding to the temperature range of850-1 150℃ with the strain rates of 0.01-10s-1 and the true strain of 0.8.The results suggest that the majority of flow curves exhibit a typical dynamic recrystallization（DRX）behavior with an apparent single peak stress followed by agradual fall towards a steady-state stress.Important characteristic parameters of flow behavior as critical stress/strain for initiation of DRX and peak and steady-state stress/strain were derived from curves of strain hardening rate versus stress and stress versus strain,respectively.Material constants of the investigated steel were determined based on Arrhenius-type constitutive equation,and then the peak stress was predicted by the equation with the hot deformation activation energy of 379 139J/mol,and the predicted values agree well with the experimental values.Furthermore,the effect of Zener-Hollomon parameter on the characteristic points of flow curves was studied using the power law relation,and the ratio of critical stress and strain to peak stress and strain were found to be 0.91and0.46,respectively.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.
文摘The surface treatment technology of hot aluminum-zinc steel plate and UV curing technology may be effectively combined in the present research. According to different light curing mechanisms, different formulations from UV curing surface treatment agents can be applied to the surface treatment of hot aluminum-zinc steel plate, mainly including 3-ethyl-3-benzoxy-methyl oxacyclobutane (TCM 104) and 3,4-epoxy-cyclohexylformic acid -3',4'-epoxy-cyclohexyl methyl ester (UVR 6110) as active diluents, high molecular weight polyfunctional oxacyclobutane as oligomer, triaryl sulfonium salt as a cationic photoinitiator, and an anthracene compound as a sensitizer. 385 nm LED lamp used as a radiation resource, the effects of the proportion of active diluent, the type and amount of photoinitiator, the amount of sensitizer, the curing temperature, and the amount of nano-SiO<sub>2</sub> on the photocuring rate were investigated by photoper-scanning differential calorimetry (Photo-DSC). The experimental results show that the system has the fastest photocuring rate under the conditions of 8:2 ratio of TCM 104 to UVR 6110, 2.5% photoinitiator, 0.6% sensitizer, 0.2% nano-SiO<sub>2</sub> additive, and 80˚C curing temperature. Based on addition of the appropriate number of various additives, the cationic photocuring surface treatment solution was prepared and further coated on the hot-dip galvalume steel plates. After curing, the passivation films were characterized by neutral salt spray test (NSST), Fourier transform infrared spectroscopy (FT-IR), electrochemical testing and other methods. The results show that the formulations could be cured at an energy of 150 mJ/cm<sup>2</sup>, and the overall performance of the passivation film could meet with the requirements of the downstream users.
文摘Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refiner plates is of significance to the wood industry. It may affect refining quality, production efficiency, and power consumption. In this paper, the abrasion resistance of the refiner plate made of different materials, the stainless steels and high chromium cast irons, were tested and compared. The results showed that abrasion resistance of refiner plate made of high chromium cast irons was better than that of the stainless steel materials. Although the two kinds of materials have the same compositions, their abrasion resistances have ap-parent difference. The main reason is that the material microstructures have very important effects on their performance. The refiner plates made of developed high chromium cast irons don抰 demand the complex heat treatment. This can simplify the producing process, save the cost of production, decrease labor strength, and increase the production efficiency.
基金Sponsored by National Natural Science Foundation of China(51071019,51371030)National High Technology Research and Development Program of China(2013AA031601)National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2011BAE25B01)
文摘Hot deformation behavior of a novel Ni-Cr-Mo-B heavy plate steel was studied by hot compression tests,which were conducted on a Gleeble-3800thermo-mechanical simulator corresponding to the temperature range of850-1 150℃ with the strain rates of 0.01-10s-1 and the true strain of 0.8.The results suggest that the majority of flow curves exhibit a typical dynamic recrystallization（DRX）behavior with an apparent single peak stress followed by agradual fall towards a steady-state stress.Important characteristic parameters of flow behavior as critical stress/strain for initiation of DRX and peak and steady-state stress/strain were derived from curves of strain hardening rate versus stress and stress versus strain,respectively.Material constants of the investigated steel were determined based on Arrhenius-type constitutive equation,and then the peak stress was predicted by the equation with the hot deformation activation energy of 379 139J/mol,and the predicted values agree well with the experimental values.Furthermore,the effect of Zener-Hollomon parameter on the characteristic points of flow curves was studied using the power law relation,and the ratio of critical stress and strain to peak stress and strain were found to be 0.91and0.46,respectively.
