Huang Sheng, Li Zhiying, Yang Hui, Zeng Zeyun, Shi Yingjie, Li Changrong
College of Materials and Metallurgy, Guizhou University, Guiyang, 550025, China.
Guizhou Provincial Key Laboratory of Metallurgical Engineering and Process Energy Saving, Guiyang, 550025, China.
Sci Rep. 2025 Mar 23;15(1):10005. doi: 10.1038/s41598-025-95103-w.
This study investigates the effects of microalloying elements vanadium (V) and niobium (Nb), along with varying isothermal transformation temperatures, on the microstructural evolution and mechanical properties of SWRH82B high-carbon pearlitic steel. Comprehensive microstructural characterization was conducted using optical microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results show that the addition of V alone or in combination with V and Nb refines the lamellar spacing, pearlite clusters and pearlite ball clusters. Compared with the matrix steel, the lamellar spacing was refined by 46% at lower isothermal transitions; the dimensions of pearlite clusters and pearlite globule clusters were reduced by up to 43% and 31%.The additions of V and Nb significantly increased the microhardness, tensile strength, and yield strength of the steels. The tensile and yield strengths increased by 272 MPa and 178 MPa to 1172 MPa and 657 MPa, respectively. This increase in strength was dominated by the precipitation strengthening of VC and NbC particles and the fine grain strengthening effect. The impact toughness of pearlite steels increases with the refinement of the microstructure, which is attributed to the increase in fracture initiation energy and fracture extension energy. The increase in fracture initiation energy is greater than the extension energy under the same isothermal conditions. The fracture mode is a mixture of deconvoluted and ductile fracture. This research provides a scientific foundation for optimizing the manufacturing process of SWRH82B steel and offers significant insights into the study and application of other microalloyed high-strength steels.
本研究调查了微合金元素钒（V）和铌（Nb）以及不同的等温转变温度对SWRH82B高碳珠光体钢的组织演变和力学性能的影响。使用光学显微镜、扫描电子显微镜（SEM）、电子背散射衍射（EBSD）和透射电子显微镜（TEM）进行了全面的微观结构表征。结果表明，单独添加V或V与Nb组合添加可细化片层间距、珠光体团簇和珠光体球团簇。与基体钢相比，在较低的等温转变温度下，片层间距细化了46%；珠光体团簇和珠光体球团簇的尺寸分别减小了43%和31%。V和Nb的添加显著提高了钢的显微硬度、抗拉强度和屈服强度。抗拉强度和屈服强度分别提高了272MPa和178MPa，达到1172MPa和657MPa。强度的增加主要归因于VC和NbC颗粒的析出强化和细晶强化效应。珠光体钢的冲击韧性随着组织的细化而增加，这归因于裂纹萌生能量和裂纹扩展能量的增加。在相同等温条件下，裂纹萌生能量的增加大于扩展能量。断裂模式为解理断裂和韧性断裂的混合。本研究为优化SWRH82B钢的制造工艺提供了科学依据，并为其他微合金高强度钢的研究和应用提供了重要见解。
