Tempering stress relaxation behavior and microstructure evolution of 300 M steel

Zheng, Wei Xing; Zhu, Jiajia; Yuan, Wei

doi:10.1016/j.matchar.2023.112688

Cited by 9 publications

(1 citation statement)

References 44 publications

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“…Since higher internal tensile stress leads to yielding at lower tensile strength applied externally, the tempering at 400 ℃ should relieve the internal stress more than that at 100 ℃, leading to YS raised with the increase of temperature from 100 ℃ to 400 ℃. However, the release of internal stress should not be the only factor that influence the YS of studied steel, because the tempering at 100 ℃ also released the internal stress in some extent [21] but only increased the YS by 20 MPa. A.J.…”

Section: Discussionmentioning

confidence: 99%

Influence of Tempering Temperature on Microstructures and Tensile Properties of a Cr–N Alloyed Medium-Mn Martensitic Steel

Wen

et al. 2024

ISIJ Int.

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In this paper, the influence of tempering temperatures on microstructures and tensile properties of a Cr-N alloyed medium Mn martensitic steel was studied. The microstructures formed after the tempering below 400 ℃ are composed of recovered martensite as the matrix, ultrafine retained austenite (RA) and carbonitrides. The tempering at 100 ℃ led to the best combination of 2080 MPa ultrahigh ultimate tensile strength (UTS) and 15% total elongation (TE), which is attributed to the prominent strain hardening capacity caused by both the gradually release of internal stress and the pronounced austenite-to-martensite transformation. The tempering at 400 ℃ resulted in the rapid increase of yield strength (YS) by ~500 MPa due to the relief of internal tensile stress and annihilation of dislocations and the best ductility because it produced the most stable RA grains with the highest C concentration for a sustainable austenite-to-martensite transformation over the large plastic straining. The further increase of temperature to 650 ℃ caused ferrite formed, which decrease both YS and strain hardening rate, leading to the lowest UTS. Moreover, it was found that higher N content increased YS but had little influence on both UTS and TE because it mainly contributed to enhanced precipitation of carbonitrides. It is then concluded that the strength and ductility of medium Mn martensitic steel could be increased by increasing the strain hardening capacity through tailoring both the internal stress in martensite and the mechanical stability of RA via a proper tempering treatment.

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Section: Discussionmentioning

confidence: 99%