To determine the root cause of a bare-spot defect in a hot-dip galvanized boron-added steel sheet,we performed metallurgical characterizations using time-of-flight secondary ion mass spectrometry(ToF-SIMS)in addition ...To determine the root cause of a bare-spot defect in a hot-dip galvanized boron-added steel sheet,we performed metallurgical characterizations using time-of-flight secondary ion mass spectrometry(ToF-SIMS)in addition to glow discharge optical emission spectrometry,field-emission scanning electron microscopy(FE-SEM),and energy dispersive spectroscopy.Mn and B enrichments on the steel surface in the bare-spot area were detected through various methods.FE-SEM revealed external oxide nodules and zinc droplets,which indicated poor wettability.ToF-SIMS further revealed considerably more detailed lateral and depth distributions of Mn,B,and Al.The formation of external Mn-B compound oxides on the steel surface prior to hot dipping,which substantially deteriorated the wettability and prevented the formation of a Fe_(2)Al_(5)inhibition layer,resulted in the formation of a bare-spot defect.ToF-SIMS mapping of Al ion proved that a slight reaction still occurred between the dissolved Al in the molten zinc bath and steel substrate,although no evident Fe_(2)Al_(5)inhibition layer formed in the bare-spot area.展开更多
采用Al Si5铝合金焊丝,冷金属过渡方法对6061铝合金和裸钢板进行了搭接点塞焊试验,运用正交试验法优化工艺参数,分析了接头的界面结构特征及其性能.结果表明,采用上述方法成功实现了铝和裸钢板的连接,点焊接头成形美观、性能良好;工艺...采用Al Si5铝合金焊丝,冷金属过渡方法对6061铝合金和裸钢板进行了搭接点塞焊试验,运用正交试验法优化工艺参数,分析了接头的界面结构特征及其性能.结果表明,采用上述方法成功实现了铝和裸钢板的连接,点焊接头成形美观、性能良好;工艺参数显著性顺序为裸钢板孔径大小、点焊时间、送丝速度;接头为典型的点熔钎焊接头,由钎焊结合区和熔焊结合区组成;接头上的缺陷主要是气孔;接头的最大抗拉剪载荷可达4 k N以上,断裂方式为撕裂型断裂.展开更多
文摘To determine the root cause of a bare-spot defect in a hot-dip galvanized boron-added steel sheet,we performed metallurgical characterizations using time-of-flight secondary ion mass spectrometry(ToF-SIMS)in addition to glow discharge optical emission spectrometry,field-emission scanning electron microscopy(FE-SEM),and energy dispersive spectroscopy.Mn and B enrichments on the steel surface in the bare-spot area were detected through various methods.FE-SEM revealed external oxide nodules and zinc droplets,which indicated poor wettability.ToF-SIMS further revealed considerably more detailed lateral and depth distributions of Mn,B,and Al.The formation of external Mn-B compound oxides on the steel surface prior to hot dipping,which substantially deteriorated the wettability and prevented the formation of a Fe_(2)Al_(5)inhibition layer,resulted in the formation of a bare-spot defect.ToF-SIMS mapping of Al ion proved that a slight reaction still occurred between the dissolved Al in the molten zinc bath and steel substrate,although no evident Fe_(2)Al_(5)inhibition layer formed in the bare-spot area.
文摘采用Al Si5铝合金焊丝,冷金属过渡方法对6061铝合金和裸钢板进行了搭接点塞焊试验,运用正交试验法优化工艺参数,分析了接头的界面结构特征及其性能.结果表明,采用上述方法成功实现了铝和裸钢板的连接,点焊接头成形美观、性能良好;工艺参数显著性顺序为裸钢板孔径大小、点焊时间、送丝速度;接头为典型的点熔钎焊接头,由钎焊结合区和熔焊结合区组成;接头上的缺陷主要是气孔;接头的最大抗拉剪载荷可达4 k N以上,断裂方式为撕裂型断裂.
