消应力热处理对塑性变形后10CrNi5MoV钢性能与组织的影响

研究了10CrNi5MoV钢原始态试样、无塑性变形消应力热处理试样、塑性变形量为6.6%试样和塑性变形量为6.6%消应力热处理试样4种状态的组织与性能。结果表明,消应力热处理后,塑性变形量为6.6%试样较热处理前压缩屈服强度明显升高,包申格效应得到消除;试样的-20℃KV2、-84℃KV2较热处理前分别降低39 J、42 J,出现了脆化现象;消应力热处理后,塑性变形试样较热处理前金相组织和晶粒度未出现明显改变;消应力热处理后,塑性变形试样中生成了板条间条状碳化物,并发生了P、Ni等元素在晶界的偏聚;条状碳化物的出现、P等元素在晶界的偏聚是塑性变形试样经消应力热处理后脆化的原因。

Effect of Stress Relieving Heat Treatment on Microstructure and Properties of 10CrNi5MoV Steel after Plastic Deformation

The microstructures and properties of four different status of 10CrNi5 MoV steel including as-received sample, stress relieving heat treatment sample without plastic deformation, 6. 6% plastic deformation sample and stress relieving heat treatment sample with 6. 6% plastic deformation were investigated. The results indicated that after stress relieving heat treatment, the compressive yield strength of the 6. 6% plastic deformation sample increased significantly, meanwhile, the Bauschinger effect was eliminated. The impact absorbed energies at -20℃ and - 84℃ decreased by 39 J and 42 J, respectively, and embrittlement of the material occurred. The microstructures and grain sizes had no obvious differences before and after stress relieving heat treatment. It also found that strip-shaped carbide was formed between martensitic laths in the stress relieving heat treatment sample of plastic deformation and the segregation of phosphorus, nickel, carbon and other elements at grain boundaries happened ,which contributed to the embrittlement of the stress relieving sample with plastic deformation.