基板强度对汽车用合金化热镀锌板摩擦因数的影响

Effects of Substrate Strength on Friction Coefficient of Galvannealed Auto Steel Sheets

采用平板滑动摩擦实验研究不同接触压力下合金化热镀锌钢板的摩擦因数。结果表明:在相同的变形条件下,低强度基板加工硬化较强烈;在相同接触压力下,镀锌板基板强度越高,摩擦因数越低;随着接触压力增大,低强度镀锌板摩擦因数由0.154降为0.136,高强度镀锌板摩擦因数由0.140降至0.135;随着接触压力的进一步增加,摩擦因数降低的趋势变缓。基于黏着理论深入分析了基板强度影响摩擦因数的原因,得出如下结论:摩擦因数主要由α值(总的实际接触面积中模具和镀层直接接触部分百分比)和基板表面显微硬度决定;基板强度是决定基板表面显微硬度和α值的主要因素;随着接触压力增大,不同的加工硬化率会使不同强度基板的表面显微硬度逐渐接近,致使α差异减小,最终使基板强度对镀锌板摩擦因数影响减弱。

Friction coefficient of galvannealed steel sheets under different contact pressure was studied by sliding test. The results show that, at the same deformation, the workhardening of the low strength substrate is stronger than that of highstrength substrate; the friction coefficient of the high strength substrate galvannealed steel sheets is lower at the same contact pressure. Moreover, the fric tion coefficient of lowstrength substrate galvanized steel sheets decreases from 0. 154 to 0. 136, and the friction coefficient of highstrength substrate galvanized steel sheets decreases from 0. 140 to 0. 135, when the contact pressure increases, but at the higher contact pressure, the decrease extent of friction coefficient is slow down. Furthermore, the effect of substrate strength on the friction coeffi cient using adhesion theory was investigated. The conclusions are as followings： friction coefficient is decided by a （mold and coating direct contact percentage of the total actual contact area） and substrate surface microhardness; a and substrate surface microhardness are mainly determined by substrate strength; the different substrate surface microhardness moves close to each other because of different workhardening as the contact pressure increases, contributing to a equality, and finally the effect of substrate strength on friction coefficient of galvannealed steel sheets would be low.