三元磷酸盐体系无机预润滑试剂的研发及其在改善热镀锌汽车板成形方面的应用（英文）

Development of Ternary Phosphate-based Inorganic Dry Pre-lubricant Reagent and Its Applicatuion in Improving Forming Properties of Galvannealed Autosheets

目的旨在合成一种用于改善热镀锌汽车板材料成形性能的无机预润滑试剂,以期降低热镀锌板表面摩擦系数,进而减少冲压过程中开裂等缺陷的发生。方法以磷酸、金属硝酸盐等为主要试剂合成机预润滑试剂,在热镀锌汽车板材料表面得到均匀、连续的无机预润滑薄膜。采用扫面电子显微镜、辉光光谱仪等手段对材料表面所形成的无机预润滑薄膜的基本形貌、厚度等进行表征。采用平板摩擦、深冲实验对材料涂覆预润滑膜后的表面摩擦系数及冲压性能进行分析。同时,根据汽车板材料认证特点,对无机预润滑处理后的热镀锌汽车板材料的焊接/胶接、涂装性能进行分析。结果采用辊涂法在热镀锌汽车板材料表面可形成厚度为50～60 nm连续、均匀的薄膜。较之普通热镀锌材料,上述表面涂覆无机预润滑薄膜后的热镀锌材料表面摩擦系数可有效下降13%。,且伴随板面温度升高,无机预润滑热镀锌材料表面摩擦系数的下降愈发明显;同时,无机预润滑处理热镀锌材料的焊接性能(包括焊接窗口、焊接寿命)符合同等厚度汽车板材料的认证需求。涂覆无机预润滑薄膜热镀锌板表面与汽车结构胶具有良好的兼容性;此外,汽车主机厂挂片实验结果证实,现有的脱脂工艺可将材料表面无机预润滑膜彻底脱除,所得磷化膜厚度、晶粒大小与普通热镀锌板无异。结论当前所研发的无机预润滑试剂在热镀锌板表面形成薄膜,在不影响材料其他各项性能的前提下,可有效降低材料摩擦系数,为减少冲压缺陷的发生提供保证。

The work aims to synthesize an inorganic pre-lubricant reagent for improving the formability of the galvannealed steel sheets,so as to reduce the friction coefficient on the surface of galvannealed steel sheets and decrease the defects during stamping.Phosphoric acid and metallic nitrate were used as the main materials to prepare the inorganic pre-lubricant reagent and then a uniform and continuous inorganic pre-lubricant film was obtained on the galvannealed steel sheet.The basic morphology and thickness of such film formed on the material was characterized by SEM and GDS.The surface friction coefficient and stamping properties of materials coated with inorganic pre-lubricant film were analyzed by plate friction test and deep drawing test.Meanwhile,the welding/cementing and coating properties of galvannealed steel sheet coated with inorganic pre-lubricant film were analyzed according to certification features of steel sheet.A uniform and continuous inorganic film could be formed on the surface of the galvannealed steel sheet by roller coating method and the thickness of such inorganic film was 50~60 nm.The surface frictional coefficient of such pre-lubricant film coated galvannealed steel sheet was 13%lower than that of the plain galvannealed steel sheet,and such decrease of surface frictional coefficient became more obvious with the increasing surface temperature of the sheet.Moreover,such pre-lubricant film coated galvannealed steel sheet also showed well spot weldability(including welding window and welding service life)that met the certification requirements of the steel sheet with the same thickness and had good compatibility with typical automotive structural adhesives.At last,automotive OEM showed that such inorganic dry pre-lubricant film on the galvannealed steel sheet could be completely removed under the present degreasing process and the thickness and grain size of obtained phosphating film was the same as that of ordinary galvannealed sheet.The currently developed inorganic pre-lubricant reagent can form a film on the galvannealed sheet and can effectively reduce the material friction coefficient and provide guarantee for reduction of stamping defects without affecting other properties of materials.