论文部分内容阅读
本文通过对12CrMo钢经亚温淬火,200℃回火的试棒,在室温～-196℃范围内进行光滑拉伸、缺口拉伸、冲击性能试验.结果表明:(1)少于30%M的双相组织,当试验温度低于-140℃,σ_(0.2)增加速率大于σ_b,断裂强度S_K和塑性(δ,ψ_K)迅速下降,缺口强度σ_(bN)下降,缺口敏感度(σ_b/σ_(bN))>1,呈脆性解理断裂,断口处位错分布由室温的胞状亚结构转变为均匀分布的位错网络.(2)少于30%M的双相组织的试棒在光滑拉伸、缺口拉伸、冲击载荷下,都存在延性到脆性转变,转变温度分别为Tc_光低于-140℃,Tc 在-60℃附近,Tc_冲在-20℃.
In this paper, smooth tensile test, notched tensile test and impact test were carried out on 12CrMo steel with sub-tempered quenching and tempering at 200 ℃ in the temperature range of -196 ℃ .The results showed that: (1) less than 30% M , The fracture strength S_K and plasticity (δ, ψ_K) decreased rapidly and the notch strength σ_ (bN) decreased when the test temperature was lower than -140 ℃. The rate of increase of σ_ (0.2) (bN)> 1, showing a brittle cleavage fracture, dislocation dislocation distribution at room temperature from the cellular sub-structure into uniform dislocation network. (2) less than 30% M of the biphasic tissue test rod in the The results show that ductile to brittle transition exists under the condition of smooth drawing, notched drawing and impact loading. The transition temperature is respectively Tc_light below -140 ℃, Tc near -60 ℃ and Tc_ red at -20 ℃.