Experimental Investigation of Hydrogen Embrittlement of 65Mn Steel with Small Punch Testing Method
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摘要: 采用小压杆方法对核电厂中常用的高强度弹簧钢65Mn的氢脆特性进行实验研究。对试样采用阴极电解充氢方法,实验采用不同的电解电流(1、4、10、20 mA),经过氢在金属中吸附、扩散、聚集和起裂导致材料的氢脆。采用小压杆实验方法对充氢后的试样进行压入实验,结果表明随着充氢电流强度的提高,试样的最大载荷降低,强度降低;试样的压入吸收功、临界断裂应力和临界断裂应变降低,表明材料的韧性降低。从试样的断裂表面发现,随着充氢电流强度的提高,试样宏观断裂表面从韧性断裂转变到典型的脆性断裂,微观表面特征从韧窝转变到沿晶解离断裂。通过理论分析表明,电流密度升高,试样中氢的浓度升高,氢脆较为严重。Abstract: The hydrogen embrittlement of the 65Mn used as the high strength spring material in Nuclear Power Plant is investigated with small punch testing method.During cathode hydrogen charging with the cur-rent density of 1mA,4mA,10mA and 20mA,the hydrogen atom is absorbed,diffused,segregated in the metal which causing the initiation of the brittle cracks.The specimens are punched after charging with small punch testing method.It is found that the maximum loading level,the total energy,the critical fracture strain and fracture stress reduce with the increment of the current density which means the strength and toughness re-duce.The macro fracture surface changes from the ductile fracture to the typical brittle fracture and the micro fracture properties change from the ductile voids to the intergranular brittle fracture.The hydrogen concentrations in the metal were analyzed with theoretical model.It was found with the increment of the current density,the hydrogen concentration increases.
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Key words:
- Hydrogen embrittlement /
- 65Mn Steel /
- Small punch method /
- Damage mechanism
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