The role of ausforming in the stability of retained austenite in a medium-C carbide-free bainitic steel

Zorgani, Muftah; García‐Mateo, C.; Jahazi, Mohammad

doi:10.1016/j.jmrt.2020.05.062

Cited by 18 publications

(8 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During further rapid cooling below the martensite start temperature, the deformed austenite transformed into martensite. Due to the effect of deformation in austenite and the very high cooling rate, martensite is formed with very fine martensite blocks and a large amount of retained austenite [31][32][33][34][35][36][37]. Other researchers [38,39] have also reported that the ratio of martensite to austenite depends a lot on laser power, scan speed, hatching pitch, and layer thickness.…”

Section: Resultsmentioning

confidence: 99%

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

Trinh,

Nguyen,

Pham

et al. 2023

Acta Metall Slovaca

View full text Add to dashboard Cite

AISI H13 steel samples were additively manufactured using a laser powder bed fusion (LPBF) system. The effect of annealing tem-perature, quenching & tempering, and nitriding were determined. The microstructure and properties of the samples were investigated using optical microscopy, scanning electron microscopy, electron backscattered diffraction, electron probe micro-analysis, X-ray diffraction, roughness measurement, and a hardness tester. The results show that the as-built AISI H13 steel sample had a roughness on the surface and pores inside. The microstructure consisted of martensite and retained austenite. The average hardness was 460 HV, and the porosity was 0.086 %. The annealing process helped homogenize the microstructure, increase the density, and reduce the porosity and hardness of the LPBF-manufactured sample. The quenching process helped increase the hardness of the steel to the maximum of 787 HV, then the tempering process reduced the hardness to 572 HV. Heat treatment and nitriding processes tended to increase the martensite block size, reduce the retained austenitic content, and precipitate the V-Mo-rich carbide in the LPBF-manufactured AISI H13 steel. After nitriding was conducted, the nitriding case depth was 87 um, and the surface hardness increased up to higher than 1020 HV due to the formation of CrN and Fe3-4N.

show abstract

Section: Resultsmentioning

confidence: 99%

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

Trinh,

Nguyen,

Pham

et al. 2023

Acta Metall Slovaca

View full text Add to dashboard Cite

show abstract

“…It is considered that the maintaining of strain hardening in the early stage (strain below 0.02) may be contributed, on the one hand by multiplication of dislocation in PF during tensile deformation, and on the other hand by the deformation induced martensitic transformation from blocky retained austenite, which is not stable enough against deformation. [ 25,26 ] As strain further increases, less stable retained austenite was left for 860 °C austenitizing, resulting in sharper decreasing of strain hardening rate. As the strain is above 0.045, the contribution of retained austenite is negligible due to its higher stabilization and the steady decreasing of strain hardening rate is considered to result from the increasing loss rate of dislocation density caused by dynamic recovery.…”

Section: Resultsmentioning

confidence: 99%

The Role of Microstructural Constituents on Strength–Ductility–Local Formability of a Transformation‐Induced‐Plasticity‐Aided Bainitic Steel

Tang

Lan

et al. 2020

steel research int.

View full text Add to dashboard Cite

The microstructural evolution for varied austenitizing temperature is investigated in a transformation‐induced‐plasticity (TRIP)‐aided bainitic steel. Special attention is given to the effect of microstructural constituents on mechanical properties and local formabilities (stretch flangeability and bendability). With the decreasing of austenitizing temperature, proeutectoid ferrite is formed due to the refinement of prior austenite grain size, which yields the increased amount of large blocky martensite/austenite (M/A) constituents. The existence of ferrite and the TRIP effect provided by blocky retained austenite contributes to the higher strain hardening rate in the early stage of deformation as well as the more gradual decreasing of the strain hardening rate, leading to higher uniform elongation (UEL) for decreased austenitizing temperature. Whereas, the post uniform elongation (PEL) shows the opposite trend. Both hole expansion ratio (HER) and bending ratio (BR) have a linear relationship with PEL as well as yield ratio (YR). Replacing the multiphase microstructure with uniform bainitic microstructure would increase the balance of strength and local formability, in which the role of PEL is consistent with YR.

show abstract

“…Reference source not found.c, and further details on the selection of the conditions can be found in ref. [31]. Specimens were heated at 10 °Cs -1 to a temperature of 980 °C, where they were held for 5 min under vacuum.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…of the steel were determined to be 470±10 and 310±5 o C, respectively, and the bay between ferrite/pearlite and bainite (F/P-B) delimited between 500-600 ºC [31].…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…Deformation temperatures (Tdef) prior to isothermal transformation at 325 °C (TIso) were selected as follows: i) Tdef > BS at 600 °C; ii) BS > Tdef > TIso at 400 ºC; and iii) Tdef = TIso at 325 °C. The deformation step was selected to be less than 10 s to avoid possible bainite transformation during the deformation process [31]. The deformed samples were cooled down to TIso = 325 °C at a cooling rate of 20 °C/s and then held for 30 min to allow the bainitic transformation to finish.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

Effects of ausforming temperature on carbide-free bainite transformation and its correlation to the transformation plasticity strain in a medium C- Si-rich steel

Zorgani

García‐Mateo²,

Jahazi

2021

Materials Characterization

Self Cite

View full text Add to dashboard Cite

The role of ausforming in the stability of retained austenite in a medium-C carbide-free bainitic steel

Cited by 18 publications

References 38 publications

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

The Role of Microstructural Constituents on Strength–Ductility–Local Formability of a Transformation‐Induced‐Plasticity‐Aided Bainitic Steel

Effects of ausforming temperature on carbide-free bainite transformation and its correlation to the transformation plasticity strain in a medium C- Si-rich steel

Contact Info

Product

Resources

About