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Effect of Two-Step High Temperature Treatment on Phase Transformation and Microstructure of V-Bearing Bainitic Steel. METALS 2022. [DOI: 10.3390/met12060983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effects of VC precipitation on phase transformation, microstructure, and mechanical properties were studied by controlling two-step isothermal treatment, i.e., austenization followed by intercritical transformation. The results show that the bainite transformation time of 950 °C–860 °C treatment and 950 °C–848 °C treatment is shorter than that of 950 °C single-step treatment. This is related to the isothermal ferrite transformation in the intercritical transformation range. The formation of ferrite nuclei increases the density of medium temperature bainite nucleation sites and decrease the bainite nucleation activation energy. At the same time, a large number of VC particles are precipitated. The additional VC particles provide numbers of preferential nucleation sites. The toughness of the specimen treated at 950~870 °C is improved, which is related to the large proportion of high angle grain boundaries. High angle grain boundaries can hinder crack propagation or change the direction of crack propagation. The specimen treated at 950 °C–848 °C exhibits large proportion of low angle grain boundaries, which is beneficial for the strength improvement.
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Effects of Quenching and Tempering Heat Treatment Processing on the Microstructure and Properties of High-Strength Hull Steel. METALS 2022. [DOI: 10.3390/met12060914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The construction of heavy polar icebreakers is usually done with special hull steels, which require comprehensive properties such as good low-temperature toughness, high strength, and superior fatigue resistance. Reasonable and satisfactory heat treatments should be investigated and applied to acquire the required high strength and superior low-temperature toughness, since this is deemed an effective approach to ameliorate the combined properties of high-strength hull steels. Regarding this, the present study specifically explores the effects of different laboratory-based quenching (850 to 930 °C) and tempering (580 to 660 °C) heat treatments on the final low-temperature toughness of the high-strength hull steels. The low-temperature toughness is eventually improved without significantly sacrificing the strength. The results show that a favourable combination of properties can be obtained in the specimens under 900 °C quenching and 660 °C tempering processes. Additionality, the specimens tempered at 620 °C present the highest hardness, owing to the higher percentage of tempered martensite. Detailed mechanisms of the enhanced properties of the typical specimens subjected to the corresponding quenching and tempering processing are analysed and explicated.
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Kalwa G, Schnabel E, Schwaab P. Grain structure of bainitic and martensitic steels. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/srin.198600755] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Gerhard Kalwa
- Mannesmann Forschungsinstitut GmbH; Duisburg-Huckingen
| | | | - Paul Schwaab
- Mannesmann Forschungsinstitut GmbH; Duisburg-Huckingen
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Reuben RL, Baker TN. Mechanical properties and microstructure of lovv-carbon-4% manganese steels. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/030716984803274909] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Bowen P, Knott JF. Cleavage fracture of A 533 B pressure vessel steel in martensitic condition. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/030634584790420131] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Scruby CB, Jones C, Titchmarsh JM, Wadley HNG. Relationship between microstructure and acoustic emission in Mn-Mo-Ni A533B steel. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/030634581790426750] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Wallin K, Saario T, Törrönen K. Statistical model for carbide induced brittle fracture in steel. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/030634584790420384] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Curry DA. Influence of hydrostatic tension on cleavage fracture of bainitic pressure vessel steel. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/030634582790427532] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Curry DA. Influence of microstructure on yield stress and cleavage fracture stress at −196°C of SA 508 Class 2 pressure vessel steel. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/030634584790420276] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Edmonds DV, Cochrane RC. Structure-property relationships in bainitic steels. ACTA ACUST UNITED AC 1990. [DOI: 10.1007/bf02672567] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Beremin FM, Pineau A, Mudry F, Devaux JC, D’Escatha Y, Ledermann P. A local criterion for cleavage fracture of a nuclear pressure vessel steel. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/bf02663302] [Citation(s) in RCA: 844] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Naylor JP. The influence of the lath morphology on the yield stress and transition temperature of martensitic- bainitic steels. ACTA ACUST UNITED AC 1979. [DOI: 10.1007/bf02658305] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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