Structure–mechanical property relationship in a high strength low carbon alloy steel processed by two-step intercritical annealing and intercritical tempering
Structure–mechanical property relationship in a high strength low carbon alloy steel processed by two-step intercritical annealing and intercritical tempering
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DOI：
10.1016/j.msea.2014.03.107
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发表时间：
2014-06
期刊：
影响因子：
6.4
通讯作者：
W. Zhou;X. L. Wang;P.K.C. Venkatsurya;Hui Guo;C. Shang;R. Misra
中科院分区：
文献类型：
--
作者：
W. Zhou;X. L. Wang;P.K.C. Venkatsurya;Hui Guo;C. Shang;R. Misra
研究了两步间温退火和间温回火热处理后退火和回火温度对低碳合金钢显微组织和力学性能的影响。一般来说，加工后的钢的显微组织包括两相板条状铁素体、贝氏体/马氏体板条和针状残余奥氏体。较低的相间退火温度导致相间铁素体含量较低，晶粒尺寸较细，因此强度较高。另一方面，临界回火温度显着影响残余奥氏体含量和析出。在略高于Ac1温度的温度下获得了高含量的残余奥氏体，并且残余奥氏体含量随着回火温度的升高而降低。这种行为归因于Mn和Ni的富集与反转奥氏体分数之间的竞争。获得了尺寸约为 2-6 nm 的细碳化铌沉淀物和尺寸范围约为 10-30 nm 的铜沉淀物。获得约 30 GPa% 的拉伸强度和伸长率乘积的最佳相间退火和回火温度分别为 780 °C 和 660 °C，残余奥氏体体积分数为约 29%。
The influence of annealing and tempering temperature on the microstructure and mechanical properties was investigated in a low carbon alloy steel that was processed by a two-step intercritical annealing and intercritical tempering heat treatment. In general, the microstructure of the processed steel comprises intercritical lath-like ferrite, bainitic/martensitic lath and acicular-type retained austenite. The lower intercritical annealing temperature resulted in lower fraction of intercritical ferrite with finer grain size and consequently higher strength. On the other hand, the intercritical tempering temperature significantly influenced retained austenite content and precipitation. High fraction of retained austenite was obtained at a temperature slightly above Ac1temperature and retained austenite content decreased with increase in tempering temperature. This behavior is attributed to the competition between the enrichment of Mn and Ni and the fraction of reversed austenite. Fine niobium carbide precipitates of size ~2–6 nm and copper precipitates of size range ~10–30 nm were obtained. The optimal intercritical annealing and tempering temperatures to obtain the product of tensile strength and elongation % of ~30 GPa% were 780 °C and 660 °C, respectively and the volume fraction of retained austenite was ~29%.