压力和氧化作用对热冲压界面换热系数的影响

发布时间：2019-04-11 21:03

【摘要】：针对热冲压过程中钢板容易氧化的特点,测定了不同保温时间下板料氧化皮厚度的变化情况,利用自制实验装置测量热冲压板料和模具的温度,运用有限元软件模拟热冲压板料与模具之间的热交换过程,并结合最小二乘法求解压力1~10 MPa和氧化皮厚度9~135μm条件下的等效换热系数,分析了板料的氧化作用和压力及其交互作用对换热系数的影响.结果表明:换热系数随着板料氧化皮厚度的增加而逐渐减小,且其降幅逐渐趋缓;随着压力增加,换热系数增大,且与压力保持幂函数的增长关系;压力增加将导致氧化皮破裂,使其氧化作用对换热的阻碍效果逐渐减弱,而换热系数对压力的敏感性随着氧化皮厚度的增加而增强.同时,将氧化皮厚度、压力和换热系数进行整体拟合,得到了换热系数随氧化皮厚度和压力变化的关系式.
[Abstract]:According to the characteristic of easy oxidation of steel sheet in hot stamping process, the change of oxide scale thickness of sheet metal under different holding time was measured, and the temperature of hot stamping plate and die was measured by self-made experimental device. The heat transfer process between hot stamping sheet and die is simulated by finite element software, and the equivalent heat transfer coefficient under pressure 1 / 10 MPa and oxide thickness 9 ~ 135 渭 m is calculated by least square method. The influence of oxidation pressure and interaction of sheet metal on heat transfer coefficient was analyzed. The results show that the heat transfer coefficient decreases gradually with the increase of the thickness of sheet metal oxide, and the decrease of heat transfer coefficient decreases gradually with the increase of pressure, and the heat transfer coefficient increases with the increase of pressure and maintains the relation of power function with the increase of pressure. Increasing the pressure will lead to the rupture of the oxide scale, which will weaken the effect of the oxidation on the heat transfer, and the sensitivity of the heat transfer coefficient to the pressure will increase with the increase of the thickness of the oxide scale. At the same time, the thickness, pressure and heat transfer coefficient of the oxide scale are fitted, and the relationship between the heat transfer coefficient and the thickness and pressure of the oxide scale is obtained.
【作者单位】：重庆大学材料科学与工程学院;
【基金】：中央高校科研业务费专项基金(CDJZR13130082)资助
【分类号】：TG306

【参考文献】