摘要
测定了中碳25Mn钢经温轧及退火处理后的拉伸性能及-196℃时的低温韧性,并对不同处理条件下的显微组织及冲击断口进行了观察,讨论了试验钢退火过程中的再结晶行为及其对力学性能的影响机制。结果表明:试验钢在550℃保温1 h后已经基本完成再结晶,再提高退火温度,再结晶组织逐渐粗化,导致奥氏体的稳定性变差,因此在变形过程中更易于发生马氏体相变,即相变诱导塑性(TRIP)机制逐渐增强,这虽然能够在一定程度上缓解裂纹形核与扩展过程中产生的应力集中,但马氏体的产生也会导致钢的韧性与塑性恶化。同时,结果也表明即便再结晶已经充分,细小的奥氏体晶粒中仍然存在一定量的高密度位错胞和层错,因此产生了比单一细晶强化更高的强度增量。
The tensile properties and low-temperature toughness at-196℃of medium carbon 25Mn steel after warm rolling and annealing treatment were measured,and the microstructure and impact fracture surface of the steel under different treatment conditions were observed.The recrystallization behavior of the experimental steel during annealing and its influence mechanism on mechanical properties were discussed.The results show that the experimental steel has basically completed recrystallization after annealing at 550℃for 1 h.By increasing the annealing temperature,the recrystallization structure gradually coarsens,leading to a decrease in the stability of austenite.Therefore,it is more prone to martensitic transformation during the deformation process,that is,the phase transformation induced plasticity(TRIP)mechanism gradually strengthens.Although this can alleviate the stress concentration generated during crack nucleation and propagation to a certain extent,the generation of martensite can also lead to a deterioration in the toughness and plasticity of the steel.At the same time,the results also indicate that even if the recrystallization is sufficient,there is still a certain amount of high-density dislocation cells and stacking faults in the fine austenite grains,resulting in a higher strength increment than fine grain strengthening.
作者
李敬
杨跃辉
张晓娟
苑少强
LI Jing;YANG Yue-hui;ZHANG Xiao-juan;YUAN Shao-qiang(Key Laboratory of Intelligent Equipment Digital Design and Process Simulation,Hebei Province,Tangshan University,Tangshan 063000,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2024年第1期131-137,共7页
Transactions of Materials and Heat Treatment
基金
河北省自然科学基金(E2019105101)。
关键词
高锰钢
温轧
再结晶
变形机制
high Mn steel
warm rolling
recrystallization
deformation mechanism
