This paper includes studies on the influence of grain refinement treatment with respect to the composition and structure of high zinc aluminium casting alloys on the changes of their tensile properties. The Al-20 wt.%...This paper includes studies on the influence of grain refinement treatment with respect to the composition and structure of high zinc aluminium casting alloys on the changes of their tensile properties. The Al-20 wt.%Zn alloy was inoculated with master alloys Al Ti5B1 and Al Ti3C0.15 to determine the impact of a variable titanium addition on the tensile properties of Al Zn20 alloy, and determine on this basis an optimal addition of Ti that would ensure the improvement of elongation of alloys cast in the sand mould, at the same time maintaining high tensile strength. Within the studies, light microscopy(LM) and strength tests were applied. Experimental results showed that the inoculation of high zinc aluminium alloy Al Zn20 with the master alloys Al Ti5B1 and Al Ti3C0.15 causes intensive structure refinement, while the intensity of reaction of both master alloys is comparable. The Al Ti3C0.15 master alloy addition, selected for further studies, introducing about 100 ppm Ti, enhances the tensile properties of the alloy; the elongation increases about 20% and tensile strength increases about 10% against the initial values(uninoculated alloy). Further increase of the Ti addition up to 500–600 ppm leads to the "overinoculation" effect that is accompanied by the decrease of elongation. Therefore,the Ti addition should be reduced to the level of about 100 ppm which ensures obtaining a set of optimal properties.展开更多
The fatigue properties of the newly developed wheel steel used for commercial vehicles were studied using push-pull axial loading fatigue tests with stress ratio R=-1. Q235B steel, which is conventionally applied to c...The fatigue properties of the newly developed wheel steel used for commercial vehicles were studied using push-pull axial loading fatigue tests with stress ratio R=-1. Q235B steel, which is conventionally applied to commercial vehicle wheels, was also analyzed for comparison. Although the chemical composition and microstructure （ferrite and pearlite） of newly developed wheel steel were similar to those of Q235B, the 107 cycles fatigue limit of the new wheel steel was 260 MPa, which is 24% higher than that of Q235B （210 MPa）. The improvement of the fatigue strength of the new wheel steel can be attributed to grain refinement. In order to investigate the effect of the decrease in thickness of the wheel steel on the fatigue property of the wheel, dynamic cornering fatigue tests were conducted on full scale wheels with the model of 8.25 × 22.5. The results indicated that the newly developed wheel steel had outstanding fatigue life even if the mass loss was 10% in comparison with Q235B.展开更多
基金financially supported by the European Union for the project Marie Curie TOK-DEV MTKD-CT-2006-042468
文摘This paper includes studies on the influence of grain refinement treatment with respect to the composition and structure of high zinc aluminium casting alloys on the changes of their tensile properties. The Al-20 wt.%Zn alloy was inoculated with master alloys Al Ti5B1 and Al Ti3C0.15 to determine the impact of a variable titanium addition on the tensile properties of Al Zn20 alloy, and determine on this basis an optimal addition of Ti that would ensure the improvement of elongation of alloys cast in the sand mould, at the same time maintaining high tensile strength. Within the studies, light microscopy(LM) and strength tests were applied. Experimental results showed that the inoculation of high zinc aluminium alloy Al Zn20 with the master alloys Al Ti5B1 and Al Ti3C0.15 causes intensive structure refinement, while the intensity of reaction of both master alloys is comparable. The Al Ti3C0.15 master alloy addition, selected for further studies, introducing about 100 ppm Ti, enhances the tensile properties of the alloy; the elongation increases about 20% and tensile strength increases about 10% against the initial values(uninoculated alloy). Further increase of the Ti addition up to 500–600 ppm leads to the "overinoculation" effect that is accompanied by the decrease of elongation. Therefore,the Ti addition should be reduced to the level of about 100 ppm which ensures obtaining a set of optimal properties.
基金Item Sponsored by National High Technology Research and Development Program of China(863)(2003AA33G010)
文摘The fatigue properties of the newly developed wheel steel used for commercial vehicles were studied using push-pull axial loading fatigue tests with stress ratio R=-1. Q235B steel, which is conventionally applied to commercial vehicle wheels, was also analyzed for comparison. Although the chemical composition and microstructure （ferrite and pearlite） of newly developed wheel steel were similar to those of Q235B, the 107 cycles fatigue limit of the new wheel steel was 260 MPa, which is 24% higher than that of Q235B （210 MPa）. The improvement of the fatigue strength of the new wheel steel can be attributed to grain refinement. In order to investigate the effect of the decrease in thickness of the wheel steel on the fatigue property of the wheel, dynamic cornering fatigue tests were conducted on full scale wheels with the model of 8.25 × 22.5. The results indicated that the newly developed wheel steel had outstanding fatigue life even if the mass loss was 10% in comparison with Q235B.
