合金元素钒对重轨钢氢脆敏感性的影响

EFFECT OF ALLOYING ELEMENT VANADIUM ON HYDROGEN EMBRITTLEMENT SUSCEPTIBILITY FOR RAIL STEEL

不含钒重轨钢(DB钢)产生氢鼓泡和氢致塑性损失的临界可扩散氢浓度分别为0.7×10^(-4)％和0.09×10^(-4)％:而对含钒的PD_3钢,其相应值为2.2×10^(-4)％及0.26×10(-4)％。钒提高了产生氢损伤的临界氢浓度,从而降低了重轨钢的氢脆敏感性。两种钢的氢致塑性损失I_δ与可扩散氢浓度Co的倒数呈直线关系,即I_δ=100-9/Co(DB钢)及I_δ=105-27/Co(PD3钢)。这表明合金元素钒能降低氢致塑性损失。

The threshold hydrogen concentrations for hydrogen blistering and hydrogen-induced elongation loss were 0.7×10-1% and 0.09× 10-4% for DB steel without vanadium; as well as 2.2×10-4% and 0.26×10-4% for PD3 steel containing vanadium, respectively. Obviously, vanadium increase the threshold hydrogen concentration, resulting in decrease in hydrogen embrittlement susceptibility. The main cause for the effect was that alloying element vanadium and carbon combined to form VC, which was irreversible hydrogen trap. The energy for VC was 82.3kJ/mol and its density was 3.36×1021/cm3. The hydrogen-induced elongation loss Iδ decreased linearly with the reciprocal of the diffusible hydrogen concentration C0 for both the steels, i. e. Iδ = 100-9/C0, for DB steel and Iδ = 105-27/C0 for PD3 steel. This showed that vanadium could decrease the elongation loss.