Tensile and Charpy Impact Properties of High-Strength Bainitic Steels Fabricated by Controlled Rolling Process

Abstract Three steels were designed based on HSLA-100 with additional levels of Mn, Ni, Cr and Cu. The steels were prepared by controlled rolling and tempered at temperatures in range of 550–700°C. The continuous cooling time curves were shifted to longer times and lower temperatures with the increased tendency for the formation of martensite at lower cooling rates. The microstructures revealed that controlled rolling results in austenite with uniform fine grain structure. The steel with the highest amount of Mn showed the greatest strength after tempering at 750 °C. The top strength was attributed to the formation of Cu-rich particles. The steel with 1.03 wt.% Mn, tempered at 650 °C exhibited the best Charpy impact toughness at –85°C. On the other hand, the steel that contained 2.11 wt.% Mn and tempered at 700 °C showed the highest yield strength of 1 097.5 MPa (∼159 ksi) and an impact toughness of 41.6 J at –85°C.

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Effects of Cooling Conditions on Microstructure, Tensile Properties, and Charpy Impact Toughness of Low-Carbon High-Strength Bainitic Steels

Metallurgical and Materials Transactions A ◽

10.1007/s11661-012-1372-5 ◽

2012 ◽

Vol 44 (1) ◽

pp. 294-302 ◽

Cited By ~ 19

Author(s):

Hyo Kyung Sung ◽

Sang Yong Shin ◽

Byoungchul Hwang ◽

Chang Gil Lee ◽

Sunghak Lee

Keyword(s):

Impact Toughness ◽

Tensile Properties ◽

Charpy Impact ◽

High Strength ◽

Low Carbon ◽

Charpy Impact Toughness ◽

Cooling Conditions ◽

Bainitic Steels

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The Influence of Ultra Fast Cooling Processing on Tensile and Charpy Impact Properties of Low-Carbon High-Strength Steel

DEStech Transactions on Engineering and Technology Research ◽

10.12783/dtetr/icace2018/25512 ◽

2018 ◽

Author(s):

Lisong Zhang ◽

Zhuang Li ◽

Wei Lv ◽

Xijun Cui ◽

Qi Zhou

Keyword(s):

High Strength Steel ◽

Charpy Impact ◽

High Strength ◽

Low Carbon ◽

Impact Properties ◽

Ultra Fast Cooling ◽

Fast Cooling

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Effect of Rolling Process on Impact Toughness in High Strength Low Carbon Bainitic Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.816.743 ◽

2015 ◽

Vol 816 ◽

pp. 743-749 ◽

Cited By ~ 1

Author(s):

Xiao Long Yang ◽

Xiao Dong Tan ◽

Yun Bo Xu ◽

Zhi Ping Hu ◽

Yong Mei Yu ◽

...

Keyword(s):

Impact Toughness ◽

Ductile Fracture ◽

Cleavage Fracture ◽

Charpy Impact ◽

High Strength ◽

Rolling Process ◽

Bainitic Steel ◽

Low Carbon ◽

Austenite Recrystallization ◽

The Impact

Based on TMCP and UFC technology, the microstructures and impact toughness of low carbon bainitic steel were studied in this paper. The bainite morphology and fracture surfaces of Charpy impact specimens were observed by SEM, and mechanical properties of bainitic steel were measured by tensile and impact test. The results showed that the yield and tensile strengths of steel were 804MPa and 1015MPa, and elongation was 15.7% when the rolling was finished in the austenite recrystallization region. The steel rolled below Tnr temperature obtained tht yield strength of 930 MPa, tensile strength of 1090 MPa and elongation of 16.2%. However, the impact toughness was deteriorated in the steel rolled above Tnr temperature while the excellent impact toughness existed in the steel rolled below Tnr temperature. The impact toughness of steel rolled below Tnr temperature was 140J at-60°C, while the impact toughness of 15J at the same temperature was obtained for the steel rolled above Tnr temperature. The large cleavage fracture region on the fracture surface occured with the decrease of tested temperature in the steel rolled above Tnr temperature and inevitably reduced the impact toughness, while the main ductile fracture existed in the steel rolled below Tnr temperature at the same temperature. The rolling process of steel can strongly affect impact toughness of low carbon bainitic steel. Hence, the different rolling processes can adjust the occurrence of cleavage fracture and ductile fracture in order to improve the impact toughness.

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Influence of thermomechanical processing and heat treatments on tensile and Charpy impact properties of B and Cu bearing high-strength low-alloy steels

Materials Science and Engineering A ◽

10.1016/j.msea.2010.03.106 ◽

2010 ◽

Vol 527 (16-17) ◽

pp. 4341-4346 ◽

Cited By ~ 40

Author(s):

Byoungchul Hwang ◽

Chang Gil Lee

Keyword(s):

Thermomechanical Processing ◽

Charpy Impact ◽

High Strength ◽

Heat Treatments ◽

Low Alloy Steels ◽

Impact Properties ◽

Alloy Steels

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Study on rolling process and heat treatment of high strength ship plate steel EH40

Metallurgical and Materials Engineering ◽

10.30544/372 ◽

2018 ◽

Vol 24 (3) ◽

pp. 199-208 ◽

Cited By ~ 1

Author(s):

Chunquan Liu ◽

Qichun Peng ◽

Zhengliang Xue

Keyword(s):

Heating Temperature ◽

Control Process ◽

Charpy Impact ◽

High Strength ◽

Charpy Impact Test ◽

Rolling Process ◽

Rolling Temperature ◽

Plate Steel ◽

Laminar Cooling ◽

Time Deformation

Means of a tensile test studied the mechanical properties and microstructure of the experimental steel plate under different rolling processes, Charpy impact test, optical microscopy and scanning electron microscopy (SEM). The results show that the optimum thermomechanical control process (TMCP) is a heating temperature of 1200 °C, the best rolling temperature of 1180 °C. The thickness of the ship plate steel was rolled from 170 mm to 40 mm in the recrystallization zone by multi-channel time deformation, and then the thickness was decreased from 40 mm to 15mm in the non-recrystallization zone, the temperature waiting for a range 980 °C ~ 920 °C, the finish rolling temperature of 830 °C. After rolling and being cooled rapidly by laminar cooling, the cooling rate is about 12 °C/s and the final target temperature of 600 °C, which maintains the best state of steels. All data of the experimental steels have accelerated the international level, high-strength ship plate EH40 has been successfully trialed and met the practical requirements, all of these provide a solid foundation for further scientific research.

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