Carbide evolution for a quenched and tempered Dievar steel. Issue 7 (3rd May 2023)

• Record Type: Journal Article
• Authors: Xie, Yixin; Si, Shanshan; Ju, Yulin; Luo, Rui; Zhou, Lei; Cheng, Xiaonong
• Is Part Of: Materials science and technology. Volume 39:Issue 7(2023)
• Page Start: 815
• Page End: 827
• Publication Date: 2023-05-03
• Subjects: Dievar steel -- secondary alloy carbides -- carbide coarsening -- hardness evolution -- secondary hardening; Materials science -- Periodicals; Microstructure -- Periodicals; Metallurgy -- Periodicals; 620.1105
• DOI: 10.1080/02670836.2022.2142746
• Languages: English
• ISSNs: 0267-0836

Abstract

Abstract : Carbide precipitation, coarsening and hardness variations have been investigated for a quenched and tempered Dievar steel by SEM, TEM, STEM, HRTEM, XRD and Rockwell hardness testing. The carbide precipitation sequence has been ascertained as: M8 C7 + bainitic/auto-tempered carbides → M8 C7 + M2 C + M7 C3 → M8 C7 + M7 C3 +M23 C6 → M8 C7 + M7 C3 + M23 C6 + M6 C. Boundary carbides coarsen obviously faster than matrix ones. Hardness variations originating from the carbide evolution have been qualified. A fine-dispersion of M2 C carbides leads to a high hardness tempered at 550°C, whereas the hardness drops drastically for tempering at 600/650°C predominately due to the dissolution of unstable M2 C and the coarsening of carbides.