【摘要】 对比研究了B对Ti添加和Ti、Nb复合添加的冷轧IF钢板经电阻焊接前后的显微组织和疲劳性能的影响·结果表明 ,B可以细化这两种IF钢的退火组织和焊接热影响区组织 ,改善晶界结合强度 ,提高焊接疲劳强度·疲劳断口分析结果表明 ,IF钢焊后表现为沿晶断裂特征 ,B可使IF钢断裂特征得以改善 ,由沿晶断裂转变成穿晶断裂更多还原

【Abstract】 Effect of boron on spot welding fatigue of cold rolled Ti bearing and Ti Nb bearing Interstitial Atom Free(IF) sheet steels was investigated through the heat effected zone(HAZ) microstructure examination, fatigue tests and fracture surface analysis. It was found that the boron addition is effective to improve the spot welding fatigue resistance of the steels. The fracture surface analysis reveals the evidence to clarify the effects of boron on grain refining and cohesion improvement of grain boundaries. The fracture mode is transited from intergranular form to the transgranular one due to boron addition,which is in good agreement with the fatigue test results.更多还原