通过细化初始组织提高汽车用双相钢的强塑性

doi:10.13251/j.issn.0254-6051.2025.12.007

摘要/Abstract

摘要： 设计了具有高淬透性的低碳DP钢,在热轧和冷轧后获得了初始组织为全贝氏体的DP钢(B-DP),对比分析了其与初始组织为铁素体+贝氏体的DP钢(FB-DP)在临界区淬火后的组织与力学性能。结果表明,B-DP钢比FB-DP钢的晶粒更细,铁素体和马氏体的平均晶粒尺寸分别为2.1和1.9 μm,这使得B-DP钢相比FB-DP钢具有更高的屈服强度、抗拉强度、断裂总延伸率和断裂应变,分别为677 MPa、984 MPa、17.7%和0.46。细晶强化和高加工硬化能力是B-DP钢高抗拉强度的主要原因。此外,细化晶粒不仅提高均匀延伸率,还抑制了两相界面开裂和马氏体断裂,有利于B-DP钢获得优异的断裂总延伸率和断裂应变。

关键词: 双相钢, 初始组织, 细化晶粒, 微观结构, 力学性能

Abstract: A low-carbon DP steel with high hardenability was designed to obtain a full bainite microstructure after hot rolling and cold rolling. The microstructure and mechanical properties of the DP steels with initial microstructure of full bainite (B-DP) and ferrite+bainite (FB-DP) after intercritical quenching were compared and analyzed. The results show that compared with FB-DP steel, the B-DP steel shows a finer grain size with an average ferrite grain size of 2.1 μm and an average martensite grain size of 1.9 μm, which results in higher yield strength, ultimate tensile strength, total elongation and fracture strain, that is 677 MPa, 984 MPa, 17.7% and 0.46, respectively. Fine grain strengthening and high work-hardening ability are responsible for higher ultimate tensile strength of the B-DP steel. In addition, grain refinement not only improves uniform elongation, but also suppresses the interphase crack between ferrite and martensite and martensite fracture initiation and development, which substantially improves the total elongation and fracture strain of the B-DP steel.

Key words: dual phase steel, initial microstructure, grain refinement, microstructure, mechanical properties

中图分类号:

TG142.1

万娜娜, 周细林. 通过细化初始组织提高汽车用双相钢的强塑性[J]. 金属热处理, 2025, 50(12): 41-47.

Wan Nana, Zhou Xilin. Improvement of strength and ductility of dual-phase steel for automobiles by refining initial microstructure[J]. Heat Treatment of Metals, 2025, 50(12): 41-47.

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