1500 MPa级高强度钢42CrMoVNb的氢吸附行为

来源期刊：金属学报2011年第4期

论文作者：李阳 张永健 惠卫军 王毛球 董瀚

文章页码：423 - 428

关键词：42CrMoVNb高强度钢； 氢陷阱； 热分析； 碳化物； 热处理

Key words：42CrMoVNb high strength steel； hydrogen trap； thermal desorption analysis； carbide； heat treatment

摘    要：采用阴极充H和H热分析等实验方法,研究了新开发的1500MPa级高强度钢42CrMoVNb在不同奥氏体化温度淬火和不同温度回火后的H吸附行为,并与常用钢42CrMo进行了对比.结果表明,在淬火态及不同温度回火处理后,42CrMoVNb钢充H试样的H逸出曲线峰值温度θ_P^在200-250℃之间.回火温度从200℃升高到500℃时,充H试样的H含量缓慢增加;当回火温度升高到500℃以上时,充H试样的H含量急剧增加,并且在600℃附近达到最高值6.6×10^-6左右,该H含量约为淬火态时的5倍;继续提高回火温度,则H含量又急剧下降.在不同奥氏体化温度(850-1100℃)加热淬火,经400℃回火时,没有细小弥散的(V,X)C碳化物析出,因而充H试样的H含量随奥氏体化温度升高的变化不明显;而在有细小(V,X)C析出的峰值温度600℃回火时,H含量则随奥氏体化温度的升高而明显增加.这表明,细小弥散的(V,X)C碳化物可作为H陷阱而吸附大量的H.通过改变升温速率测定(V,X)C析出相的H陷阱激活能E_a=28.7kJ/mol.

Abstract: Hydrogen absorption behaviors of a newly developed 1500 MPa-grade high strength steel 42CrMoVNb at different austenitizing temperatures and tempering temperatures were studied using cathodic charging and hydrogen thermal desorption analysis,which were also compared with commercial structural steel 42CrMo.The results show that the hydrogen escape peak temperatures (θ_p) in hydrogen evolution curves of hydrogen charged 42CrMoVNb specimens are between 200℃to 300℃both at as-quenched condition and as-tempered condition.The absorbed hydrogen content of 42CrMoVNb specimen increases slowly with increasing tempering temperature up to 500℃.When the tempering temperature exceeded 500℃,the absorbed hydrogen content increases sharply and reaches its peak,6.6×10^-6,for the specimen tempered at 600℃,which is 5 times as much as that of the as-quenched specimen.Thereafter the absorbed hydrogen content declines sharply as the tempering temperature was gone up sequentially.When the specimen was tempered at 400℃,the absorbed hydrogen content decreases slightly with austenitizing temperature increasing,and in the microstructure no fine dispersed(V,X)C carbide precipitated,while when the specimen was tempered at 600℃, the absorbed hydrogen content increases sharply with austenitizing temperature increasing,and more fine dispersed (V,X)C precipitated.These results indicate that fine dispersed (V,X)C precipitate could be regarded as a strong hydrogen trap,and the trap activation energy,E_a,is equal to about 28.7 kJ/mol,which was obtained by change heating rate.