An advanced simulation that considers the effect of wire vibrations was proposed for predicting accurately wear profiles of a die used in a wire-drawing process.The effect of wire vibrations,the changes in the wear pr...An advanced simulation that considers the effect of wire vibrations was proposed for predicting accurately wear profiles of a die used in a wire-drawing process.The effect of wire vibrations,the changes in the wear profiles,and the generation of ringing during die approach were investigated by this simulation.Wire vibrations occurring between the die and the drum are governed by a partial differential equation called the wave equation,which is a function of the wire length,tension,density,and initial wire velocity.The wire-drawing process was simulated by the commercial code Abaqus FEA,and the die wear profiles were predicted by Archard’s wear model.The predicted profiles were compared with measured profiles of a worn drawing die after producing 5 t of AISI 1010 wire;the die was made of tungsten carbide with a Brinell hardness of HB 682.The profiles predicted by considering the effect of wire vibrations are in good agreement with the experimental data,indicating that the advanced simulation can be used to accurately predict the die wear profiles when ringing is observed during die approach.展开更多
Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE we...Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% （mass fraction） RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2WSV. The large amount of coarse inclusions, （RE）2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.展开更多
The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wea...The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio （1.5-2.5） leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/carbon ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.展开更多
Wear resistance of several zirconia toughened ceramics in comparison with a metal-ceramic Co-WC has been studied in drawing wire field test. Result indicates that the harder the ceramic die, the longer the service lif...Wear resistance of several zirconia toughened ceramics in comparison with a metal-ceramic Co-WC has been studied in drawing wire field test. Result indicates that the harder the ceramic die, the longer the service life. Excellent wear resistance of ceramic die is obtained with a very high hardness (19 GPa). The service life is nearly three times that of Co-WC die. SEM observation on wear surfaces showed that material removal is mainly caused by plastic flow and ploughing process. But when the ceramic is composed of zirconia, alumina and some titanium carbide, micro-chipping and tribochemical reaction take place, and wear rate increases. Wear and friction induced martensite was detected by XRD. The T-M (tetragonal to monoclinic) phase transformation has a contribution to inhibiting microfracture.展开更多
基于热锻条件,使用销-盘摩擦设备对6061热锻铝合金和H13钢基自润滑模具材料进行了高温对磨实验,通过电子探针和能谱仪分析了不同工况下工件和模具的磨损机理。结果表明,随着载荷的增加,工件和模具之间的摩擦因数与磨损率先降低后升高;...基于热锻条件,使用销-盘摩擦设备对6061热锻铝合金和H13钢基自润滑模具材料进行了高温对磨实验,通过电子探针和能谱仪分析了不同工况下工件和模具的磨损机理。结果表明,随着载荷的增加,工件和模具之间的摩擦因数与磨损率先降低后升高;随着转速的增加,工件和模具之间的摩擦因数增大,磨损率呈倍数增加;当载荷为12 N、转速为100 r·min^(-1)时,工件和模具之间的摩擦因数最小,其值为0.416,磨损率仅为24.591 mm 3·N^(-1)·m^(-1);随着转速和载荷的增加,工件和模具之间的粘着磨损加重并且逐渐出现磨粒磨损和氧化磨损。展开更多
基金supported by the National Core Research Center (NCRC) program through the National Research Foundation of Korea funded by the Ministry of Education,Science and Technology (2010-0008-277)
文摘An advanced simulation that considers the effect of wire vibrations was proposed for predicting accurately wear profiles of a die used in a wire-drawing process.The effect of wire vibrations,the changes in the wear profiles,and the generation of ringing during die approach were investigated by this simulation.Wire vibrations occurring between the die and the drum are governed by a partial differential equation called the wave equation,which is a function of the wire length,tension,density,and initial wire velocity.The wire-drawing process was simulated by the commercial code Abaqus FEA,and the die wear profiles were predicted by Archard’s wear model.The predicted profiles were compared with measured profiles of a worn drawing die after producing 5 t of AISI 1010 wire;the die was made of tungsten carbide with a Brinell hardness of HB 682.The profiles predicted by considering the effect of wire vibrations are in good agreement with the experimental data,indicating that the advanced simulation can be used to accurately predict the die wear profiles when ringing is observed during die approach.
基金Project supported by the Itemof Early-TermKey Technology of Industrialization ,Plan Committee of China (1999317) 863project of China (2002AA331180)
文摘Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% （mass fraction） RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2WSV. The large amount of coarse inclusions, （RE）2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.
基金Item Sponsored by Early-Term Key Technology of Industrialization and Whole Set Equipment From Plan Committee of China(1999317) ,863 Project of China (2002AA331180) ,and Project of Key Lab of Universities in Jiangsu Province of China(Kjsmcx04004)
文摘The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio （1.5-2.5） leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/carbon ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.
文摘Wear resistance of several zirconia toughened ceramics in comparison with a metal-ceramic Co-WC has been studied in drawing wire field test. Result indicates that the harder the ceramic die, the longer the service life. Excellent wear resistance of ceramic die is obtained with a very high hardness (19 GPa). The service life is nearly three times that of Co-WC die. SEM observation on wear surfaces showed that material removal is mainly caused by plastic flow and ploughing process. But when the ceramic is composed of zirconia, alumina and some titanium carbide, micro-chipping and tribochemical reaction take place, and wear rate increases. Wear and friction induced martensite was detected by XRD. The T-M (tetragonal to monoclinic) phase transformation has a contribution to inhibiting microfracture.
文摘基于热锻条件,使用销-盘摩擦设备对6061热锻铝合金和H13钢基自润滑模具材料进行了高温对磨实验,通过电子探针和能谱仪分析了不同工况下工件和模具的磨损机理。结果表明,随着载荷的增加,工件和模具之间的摩擦因数与磨损率先降低后升高;随着转速的增加,工件和模具之间的摩擦因数增大,磨损率呈倍数增加;当载荷为12 N、转速为100 r·min^(-1)时,工件和模具之间的摩擦因数最小,其值为0.416,磨损率仅为24.591 mm 3·N^(-1)·m^(-1);随着转速和载荷的增加,工件和模具之间的粘着磨损加重并且逐渐出现磨粒磨损和氧化磨损。
