Effect of quenching rate on hardness and microstructure of hot-stamped steel

Nishibata, Toshinobu; Kojima, Narumi

doi:10.1016/j.jallcom.2011.12.154

Cited by 64 publications

(32 citation statements)

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“…High Mn contents also influence the martensitic start temperature M s , as shown by the calculations depicted in Figure . The M s temperature of steel 22MnB5 was calculated to be 387 °C, which is in agreement with the values reported in the literature (375–420 °C) . All included alloying elements lead to a decrease in the M s temperature.…”

Section: Resultssupporting

confidence: 88%

Mn‐Alloyed High‐Strength Steels with a Reduced Austenitization Temperature: Thermodynamic Calculations and Experimental Investigations

Windmann

Opitz²,

Klein

et al. 2018

steel research int.

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High-strength steels (e.g., 1.5528-22MnB5), processed by direct press-hardening, are widely used for security-relevant structures in automotive bodyworks. In this study, the austenitization temperature A C3 of the steel 22MnB5 (approx. 840 C) is decreased to enable a reduction in the heattreatment temperature. Thermodynamic calculations using the CALPHAD method are used to assess the effect of alloying elements on the α-γ transformation temperatures. On this account, 22MnB5 steel is alloyed with 6 to 9.5 mass% manganese, which decreases the α-γ transformation temperature to 744 C. Simultaneously, the martensite finish temperature decreases below room temperature, which is accompanied by the presence of retained austenite after hardening. Furthermore, e-martensite is formed. High Mn-alloyed steel 22MnB5 (9.5 mass% Mn, A C3 ¼ 744 C) possesses a high strength of R m ¼ 1618 MPa, similar to the initial material 22MnB5. Elongation -to-fracture decreases to A 5 ¼ 3.5% due to the formation of e-martensite. The material strength of the steel alloyed with 6 mass% manganese (A C3 ¼ 808 C) strongly increases to R m ¼ 1975 MPa as a result of α-martensite and solidsolution strengthening by the element manganese. This steel possesses a higher elongation-to-fracture of A 5 ¼ 7%.

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Section: Resultssupporting

confidence: 88%

Mn‐Alloyed High‐Strength Steels with a Reduced Austenitization Temperature: Thermodynamic Calculations and Experimental Investigations

Windmann

Opitz²,

Klein

et al. 2018

steel research int.

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“…In reality, the total shape strain of martensite variants might be varied due to the different combination and volume fraction, leading to a locally inhomogeneous dislocation density and contributing to the large scatter of nanohardness distribution in lath martensite. Moreover, sample 1 may contain the fresh and tempered martensite as the initially transformed martensite may suffer from auto-tempering due to high temperature [24]. It is noted that the martensite after ferrite transformation may be lower than the original one (420°C) as the austenite may be slightly carbon enriched.…”

mentioning

confidence: 99%

On the nanoindentation behaviour of complex ferritic phases

Zhu

Huang

2014

Philosophical Magazine Letters

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“…For this reason, useful correlations can be developed that directly relate the microhardness of an alloy to cooling rate. shows such relationships between hardness and cooling rates for collected data on steels [61][62][63][64][65][66], aluminum alloys [67][68][69][70][71] and nickel alloys [72][73][74][75][76] in which plates or bars are cooled at controllable rates. The logarithmic scale on the horizontal axis shows that the cooling rates cover multiple orders of magnitudes.…”

Section: Cooling Ratesmentioning

confidence: 99%

“…Figure 4. Hardness data as a function of reported cooling rates for (a) steels [61][62][63][64][65][66], (b) aluminum alloys [67][68][69][70][71] and (c) nickel alloys [72][73][74][75][76] in which no post-processing heat treatment was used. Hardness variations as a function of location within a DED-L single pass, multilayer build of IN718 [81] showing (a) a longitudinal cross section (X-Z plane), (b) a transverse cross section (Y-Z plane), and (c) a horizontal cross section (X-Y plane) where X is the travel direction, Y is the track width direction, and Z is the build direction.…”

Section: (D)mentioning

confidence: 99%

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The Hardness of Additively Manufactured Alloys

DebRoy¹,

Zuback²

2018

Preprint

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The rapidly evolving field of additive manufacturing requires a periodic assessment of the progress made in understanding the properties of metallic components. Although extensive research has been undertaken by many investigators, the data on properties such as hardness from individual publications are often fragmented. When these published data are critically reviewed, several important insights that cannot be obtained from individual papers become apparent. We examine the role of cooling rate, microstructure, alloy composition, and post process heat treatment on the hardness of additively manufactured components. Hardness data for steels and aluminum alloys processed by additive manufacturing and welding are compared to understand the relative roles of manufacturing processes. Furthermore, the findings are useful to determine if a target hardness is easily attainable either by adjusting AM process variables or through appropriate alloy selection.

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Effect of quenching rate on hardness and microstructure of hot-stamped steel

Cited by 64 publications

References 1 publication

Mn‐Alloyed High‐Strength Steels with a Reduced Austenitization Temperature: Thermodynamic Calculations and Experimental Investigations

Mn‐Alloyed High‐Strength Steels with a Reduced Austenitization Temperature: Thermodynamic Calculations and Experimental Investigations

On the nanoindentation behaviour of complex ferritic phases

The Hardness of Additively Manufactured Alloys

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