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研究了直接双相区热处理工艺的保温时间和回火时间对9Ni钢组织性能的影响。结果表明:在相同回火条件下,保温时间为40 min时低温韧性最好,少于Quenching+Lamellarizing+Tempering(QLT)工艺中双相区保温所需时间;保温时间为20 min时,强度增加但低温韧性降低;保温时间过长(60 min)会导致组织粗化、低温韧性差,延长回火时间低温冲击功也基本不变。保温时间为40 min时,随着回火时间的增加,回转奥氏体增加,抗裂纹扩展能力增强,低温冲击功增加,但强度降低,这主要归因于回转奥氏体在板条束间的析出和对马氏体中C及其它有害元素的净化作用。
The effects of holding time and tempering time on the microstructure and properties of 9Ni steel were studied. The results showed that under the same tempering condition, the low temperature toughness was the best when the holding time was 40 min, less than the time required for the dual phase insulation in the Quenching + Lamellarizing + Tempering (QLT) process. When the holding time was 20 min, the strength increased But the low temperature toughness decreased; too long holding time (60 min) will lead to the organization of coarse, low temperature toughness is poor, extend the tempering time low temperature impact energy is basically the same. When the holding time is 40 min, as the tempering time increases, the austenite increases, the crack propagation resistance increases, the impact energy at low temperature increases, but the strength decreases, which is mainly due to the fact that the austenite in the slab bundle Precipitation and decontamination of C and other harmful elements in the martensite.