Fracture toughness of high-alloy austenitic-martensitic TRIP steels after Q&amp;P processing

Eckner, Ralf; Krüger, Lutz; Ullrich, C.; Wendler, Marco; Volkova, Olena

doi:10.1007/s10704-018-0332-5

Cited by 18 publications

(4 citation statements)

References 36 publications

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“…Eckner et al [ 32 ] reported the fracture toughness ( K JC ) of Q&P processed Fe–14Cr–3Ni–3Mn–0.4Si–0.11N–0.15C (all wt%) steel. Their study demonstrated a higher K JC value in the Q&P condition (≈108 MPa√m) than in the as‐quenched condition (88 MPa√m).…”

Section: Introductionmentioning

confidence: 99%

Stress Intensity Range Dependent Slowing Down of Fatigue Crack Growth under Strain‐Induced Martensitic Transformation of Film‐Like Retained Austenite

Kumar,

Ghosh,

Pallaspuro

et al. 2024

steel research int.

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A clear understanding of strain‐induced martensitic transformation of filmy retained austenite (RA) near stable cracks is required. Literature shows RA transformation during fatigue crack growth (FCG) in steels containing blocky but not film‐like RA, as the latter is known to resist strain‐induced phase transformation. This work investigates the transformation in 0.2% C steel processed by direct quenching and partitioning (DQP) containing filmy and a small vol% of blocky RA and compares it with RA‐free direct quenched (DQ) steel. While the DQ steel is lath‐martensitic, DQP steel has 8.5 vol% film‐like RA evenly distributed between martensite laths. The experimental FCG rates are comparable for both steels in the low regime but increasingly differing in the Paris regime, the Paris law exponent being lower for DQP (n = 2.1) compared to DQ (n = 2.5), confirming that resistance to FCG is dependent on the stress intensity range (). Moreover, RA content near crack surface decreases during crack growth from 7.5 vol% at of 25 MPa√m to 2.3 vol% at of 54 MPa√m. Results show that higher the stress intensity range in steels with film‐like RA, the higher the degree of RA transformation and more suppression of FCG rate.

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Section: Introductionmentioning

confidence: 99%

Stress Intensity Range Dependent Slowing Down of Fatigue Crack Growth under Strain‐Induced Martensitic Transformation of Film‐Like Retained Austenite

Kumar,

Ghosh,

Pallaspuro

et al. 2024

steel research int.

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“…In subsequent years, the principle of transformation toughening was effectively implemented to develop a series of steels known as transformation-induced plasticity (TRIP) steels [2,3]. These steels contain martensite and islands of metastable retained austenite, which undergoes strain-induced transformation to martensite near advancing cracks [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], improving the mechanical properties [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The austeniteto-martensite transformation involves volume expansion which, constrained by the surrounding martensitic matrix, induces compressive stresses and reduces the stress intensity factor at the crack tip, thereby increasing the ductility and fracture toughness [5][6][7][8][9][10][11][12][13][14]…”

Section: Introductionmentioning

confidence: 99%

“…In subsequent years, the principle of transformation toughening was effectively implemented to develop a series of steels known as transformation-induced plasticity (TRIP) steels [2,3]. These steels contain martensite and islands of metastable retained austenite, which undergoes strain-induced transformation to martensite near advancing cracks [4–23], improving the mechanical properties [9–22]. The austenite-to-martensite transformation involves volume expansion which, constrained by the surrounding martensitic matrix, induces compressive stresses and reduces the stress intensity factor at the crack tip, thereby increasing the ductility and fracture toughness [5–22].…”

Section: Introductionmentioning

confidence: 99%

“…These steels contain martensite and islands of metastable retained austenite, which undergoes strain-induced transformation to martensite near advancing cracks [4–23], improving the mechanical properties [9–22]. The austenite-to-martensite transformation involves volume expansion which, constrained by the surrounding martensitic matrix, induces compressive stresses and reduces the stress intensity factor at the crack tip, thereby increasing the ductility and fracture toughness [5–22]. Apart from the compressive stresses generated due to the volume expansion, the shear component of the martensitic transformation plays an important role in transformation toughening by delaying the shear instability and enhancing fracture toughness [23].…”

Section: Introductionmentioning

confidence: 99%

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Micromechanics-based understanding of the stability of film-like austenite in steels

Kumar,

Bhandakkar,

Mishra

et al. 2023

Materials Science and Technology

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Based on the carbon content and processing technique, the austenite morphology in steels can be either film-like or blocky. Experiments have shown that a film-like morphology of austenite shows a higher resistance to strain-induced martensitic transformation than its blocky counterpart. In the present work, using aspect ratio to distinguish austenite morphology, a micromechanical model is developed to show that the presence of an unfavourable stress field discourages the austenite to martensite transformation in film-like morphology, thereby lending its stable nature compared to the blocky version.

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The Effect of Bake Hardening on Quenched and Partitioned AISI 420 Stainless Steel

Raami,

Wendler,

Volkova

et al. 2024

steel research int.

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Bake hardening (BH) is a static strain aging phenomenon, where the yield strength of steel increases during industrial paint baking. In this study, the effect of standard BH treatment on the mechanical properties of a quenched and partitioned (Q&P) AISI 420 stainless steel is investigated. The parameters for the Q&P treatment are selected based on numerical simulations, dilatometry, X‐ray diffraction, and tensile tests, and the results are compared to conventional quenching and tempering (Q&T) treatment. It is shown that, in comparison with Q&T, Q&P can slightly increase the strength of the steel without sacrificing elongation. Heat‐treated samples are then subjected to a paint baking treatment with and without prestrain. It is indicated that the mechanical properties of the heat‐treated steel are not affected by paint baking without prestrain, whereas after a 2% prestrain the yield strength is drastically increased up to 1800 MPa, resulting in BH index exceeding 100 MPa. However, this increase in yield strength is instantly followed by necking and reduced post‐uniform elongation. The results suggest that the effect of industrial paint baking is a considerable practical aspect in the design of Q&P components if the steel is subjected to deformation before painting.

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Fracture toughness of high-alloy austenitic-martensitic TRIP steels after Q&P processing

Cited by 18 publications

References 36 publications

Stress Intensity Range Dependent Slowing Down of Fatigue Crack Growth under Strain‐Induced Martensitic Transformation of Film‐Like Retained Austenite

Stress Intensity Range Dependent Slowing Down of Fatigue Crack Growth under Strain‐Induced Martensitic Transformation of Film‐Like Retained Austenite

Micromechanics-based understanding of the stability of film-like austenite in steels

The Effect of Bake Hardening on Quenched and Partitioned AISI 420 Stainless Steel

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