一种含N低Ni经济型双相不锈钢的抗氢脆性能的研究

Study on the Hydrogen Embrittlement Resistance of an N-contained Low-Ni Lean Duplex Stainless Steel

设计了一种新型低Ni经济型双相不锈钢,通过金相显微镜、X射线衍射仪和扫描电子显微镜对不同固溶温度处理后的试样进行表征,通过常规拉伸实验得到综合力学性能最佳的热处理温度点,并通过电化学预充氢后的慢应变速率拉伸实验探究了其氢脆敏感性能。实验表明,随着温度的升高,奥氏体体积分数明显下降,铁素体体积分数升高,氢在双相不锈钢中的扩散能力提高。在1050℃下固溶处理5 min后水淬的经济型双相不锈钢(lean duplex stainless steel,LDSS)综合性能最佳,其屈服强度和抗拉强度分别为744.7 MPa和807.7 MPa,总伸长率为62%,并且该材料在不同温度都具有优异的加工硬化性能。通过对1050℃热处理后的试样进行不同电流密度和时间的预充氢处理,发现其氢脆敏感性能受充氢时间影响大于充氢电流,氢原子主要在塑性变形阶段降低材料抗拉强度和伸长率,对屈服强度影响较小。

A new type of low-Ni economical duplex stainless steel was designed.The samples treated at different solution temperatures were characterized by optical microscope,X-ray diffractometer and scanning electron microscope.The heat treatment temperature for the best comprehensive mechanical properties was obtained by conventional tensile test.The hydrogen embrittlement sensitivity was investigated by slow strain rate tensile test after electrochemical hydrogen pre-charging.The results show that with the increase of temperature,the volume fraction of austenite decreases obviously,the volume fraction of ferrite increases,and the diffusion ability of hydrogen in duplex stainless steel increases.After solution treatment at 1050°C for 5 min,the comprehensive properties of water quenched lean duplex stainless steel(LDSS)are the best.The yield strength and tensile strength are 744.7 MPa and 807.7 MPa respectively,the total elongation is 62%,and the material show excellent work hardening ability at different temperature.Through the hydrogen pre-charging treatment on the 1050°C heat-treated samples at different current density and time,it is found that the effect of hydrogen charging time on hydrogen embrittlement sensitivity was greater than that of hydrogen charging current.The hydrogen atom mainly reduces the tensile strength and elongation of the material in the plastic deformation stage,but shows little effect on the yield strength.