轧制工艺对Q&P钢组织及力学性能的影响

doi:10.13251/j.issn.0254-6051.2025.04.026

摘要/Abstract

摘要： 采用相同成分和厚度的C-Si-Mn钢热轧板和冷轧板进行临界区奥氏体化,然后分别进行直接水淬和淬火-配分(Q&P)处理,利用SEM、EBSD、TEM、拉伸试验机等研究不同试样的组织及力学性能。结果表明,直接水淬试样的组织主要为铁素体和马氏体,其中冷轧板组织形态以块状为主,热轧板以板条状为主。经过Q&P处理后,冷轧Q&P钢和热轧Q&P钢的残留奥氏体含量显著升高,主要形态分别为块状和板条状。相较于冷轧Q&P钢,热轧Q&P钢残留奥氏体体积分数和残留奥氏体碳含量更高,且尺寸较小。相较于直接水淬试样,Q&P处理后试样的强度降低,但塑性和强塑积明显更高。热轧Q&P钢表现出比冷轧Q&P钢更佳的塑性和强塑积,其获得最佳塑性主要归因于较高含量的残留奥氏体以及残留奥氏体更高的机械稳定性,这能显著扩展TRIP效应区间。因此,相比直接淬火工艺,采用Q&P工艺能显著提高钢的延伸率和强塑积,采用初始组织为马氏体+铁素体的热轧板进行Q&P处理可得到比初始组织为珠光体+铁素体的冷轧板更好的强塑性。

关键词: 轧制工艺, Q&P钢, 残留奥氏体含量, 残留奥氏体稳定性, 强塑性

Abstract: Hot-rolled and cold-rolled C-Si-Mn sheets with the same composition and thickness were subjected to intercritical austenitization, followed by direct water quenching and quenching and partitioning (Q&P) treatment, respectively. The microstructure and mechanical properties of direct water quenched and Q&P treated sheets were investigated by means of SEM, EBSD, TEM, tensile testing machines. The results show that the microstructure of the directly water quenched sheets mainly consists of ferrite and martensite. The microstructure the cold-rolled sheets after direct water quenching is mainly blocky and the hot-rolled sheets is mainly lath-like. After Q&P treatment, the retained austenite content of the sheets significantly increases, and the main morphology of retained austenite in the cold-rolled Q&P steel and hot-rolled Q&P steel are blocky and lathy, respectively. The volume fraction and carbon content of retained austenite in the hot-rolled sheet after Q&P treatment are higher and smaller in size compared to the cold-rolled sheet. The sheets after Q&P treatment exhibit lower strength but significantly higher ductility and product of strength and elongation (PSE) compared to the direct water quenched sheets, and the hot-rolled Q&P sheet shows better ductility and PSE than the cold-rolled Q&P sheet. The excellent plasticity of the hot-rolled sheet after Q&P treatment is mainly attributed to the higher content and the higher mechanical stability of retained austenite, which significantly extends the TRIP effect region. Therefore, compared with the direct water quenching, the Q&P treatment can significantly improve the elongation and PSE of the steel, and using hot-rolled sheet with initial microstructure of martensite+ferrite for Q&P treatment can obtain better PSE than the cold-rolled sheet with initial microstructure of pearlite+ferrite.

Key words: rolling process, Q&P steel, content of retained austenite, stability of retained austenite, strength and plasticity

中图分类号:

TG142.1

张梦岚, 许德明, 张定坤, 邓秋阳, 方琳华, 游诗琪, 邓思洋. 轧制工艺对Q&P钢组织及力学性能的影响[J]. 金属热处理, 2025, 50(4): 180-187.

Zhang Menglan, Xu Deming, Zhang Dingkun, Deng Qiuyang, Fang Linhua, You Shiqi, Deng Siyang. Effect of rolling process on microstructure and mechanical properties of Q&P steel[J]. Heat Treatment of Metals, 2025, 50(4): 180-187.

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