汽车用590MPa级别双相钢氢致延迟开裂行为的研究

Research on Hydrogen Induced Delayed Cracking Behavior of 590 MPa Grade Dual Phase Steel for Automotive

采用电化学充氢、慢拉伸试验、TDS分析以及SEM等方法对汽车用590 MPa级别双相钢(DP590)的氢致延迟开裂行为进行研究。结果表明,DP590的氢扩散系数为9.31×10-7cm^2/s。随着充氢电流密度从0 m A/cm^2增加到8 m A/cm^2,试样内部氢含量从0.98×10^(-6)增加到1.76×10^(-6),伸长率从28.64%降低到25.40%。另外,抗拉强度变化不明显。断裂方式为韧性断裂。综上表明,随氢含量增加,DP590氢脆敏感性增加,但整体氢脆敏感性较低。

The hydrogen induced delayed cracking behavior of 590MPa grade dual phase steel for automotive was studied by electrochemical hydrogen charging, slow tensile test, TDS analysis and scanning electron microscope. The results show that the hydrogen diffusion coefficient of DP590 is 9.31 ×10.7 em2/s. The hydrogen concentration in the samples increases from 0.98×10-6 to 1.76×10-6, and the elongation decreases from 28.64 % to 25.40 % when charging hydrogen current density increases from 0 to 8 mA/cm2, but the tensile strength does not change significantly. The fracture mode is ductile fracture. In summary, the hydrogen induced cracking sensitivity of DP590 increases with hydrogen content increasing, but the overall hydrogen induced cracking sensitivity is lower.