Effect of Heat Treatment Technique on the Low Temperature Impact Toughness of Steel EQ70 for Offshore Structure

2017 ◽  
Vol 36 (8) ◽  
pp. 825-830 ◽  
Author(s):  
Su-Fen Tao ◽  
Yun-Jin Xia ◽  
Fu-Ming Wang ◽  
Jie Li ◽  
Ding-Dong Fan
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Impact Toughness ◽  
Treatment Technique ◽  
Offshore Structure ◽  
Treatment Techniques ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness ◽  
The Impact ◽  
Quenching And Tempering

AbstractCircle quenching and tempering (CQ&T), intercritical quenching and tempering (IQ&T) and regular quenching and tempering (Q&T) were used to study the influence of heat treatment techniques on the low temperature impact toughness of steel EQ70 for offshore structure. The steels with 2.10 wt. % Ni (steel A) and 1.47 wt. % Ni (steel B) were chosen to analyze the effect of Ni content on the low temperature impact toughness of steel EQ70 for offshore structure. The fracture morphologies were examined by using a scanning electron microscope (SEM, JSM-6480LV), and microstructures etched by 4 vol. % nitric acid were observed on a type 9XB-PC optical microscope. The results show that the impact toughness of steel A is higher than that of steel B at the same test temperature and heat treatment technique. For steel B, the energy absorbed is, in descending order, CQ&T, Q&T and IQ&T, while for steel A, that is CQ&T, IQ&T and Q&T. The effects of heat treatment on the low temperature impact toughness are different for steels A and B, the absorbed energy changes more obviously for steel A. The results can be significant references for actual heat treatment techniques in steel plant.

Retained Austenite Control and Extra-Cryogenic Impact Toughness of Fe-3.0%Mn Low Carbon Steel

2020 ◽  
Vol 993 ◽  
pp. 520-525
Author(s):  
Xiang Tao Deng ◽  
Xiao Lin Li ◽  
Long Huang ◽  
Zhao Dong Wang
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Low Temperature ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Uniform Elongation ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Low Temperature Impact Toughness ◽  
The Impact

The control of the retained austenite in Fe-3.0%Mn Low carbon steel by a three-step intercritical heat treatment and the low-temperature impact toughness evolution during the process were analyzed in the present study. The results indicated that the microstructure consisted intercritical ferrite, martensite/bainite and retained austenite. The distribution of carbon and manganese could improve the stability of the austenite located at the grain boundaries of prior austenite and lath boundaries of martensite. For the TRIP effect of the austenite, the excellent plasticity and low temperature toughness was obtained. The impact toughness could reach 200 J (impact energy) at －80 °C during the three-step heat treatment, and the uniform elongation could exceed at 16%.

Effect of Welding Processes with High Heat Input on the Microstructure and Toughness of Coarse-Grained Heat-Affected Zone of a High-Strength High-Toughness Steel

2018 ◽  
Vol 937 ◽  
pp. 61-67
Author(s):  
Yu Jie Li ◽  
Jin Wei Lei ◽  
Xuan Wei Lei ◽  
Oleksandr Hress ◽  
Kai Ming Wu
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Heat Input ◽  
High Strength ◽  
High Heat ◽  
Coarse Grained ◽  
Low Temperature Impact Toughness ◽  
The Impact ◽  
Welding Processes

Utilizing submerged arc welding under heat input 50 kJ/cm on 60 mm thick marine engineering structure plate F550, the effect of preheating and post welding heat treatment on the microstructure and impact toughness of coarse-grained heat-affected zone (CGHAZ) has been investigated. The original microstructure of the steel plate is tempered martensite. The yield and tensile strength is 610 and 660 MPa, respectively. The impact absorbed energy at low temperature (-60 °C) at transverse direction reaches about 230~270 J. Welding results show that the preheating at 100 °C did not have obvious influence on the microstructure and toughness; whereas the tempering at 600 °C for 2.5 h after welding could significantly reduce the amount of M-A components in the coarse-grained heat-affected zone and thus improved the low temperature impact toughness.

Low temperature impact toughness of high strength structural steel

2018 ◽  
Vol 132 ◽  
pp. 410-420 ◽  
Author(s):  
Lewei Tong ◽  
Lichao Niu ◽  
Shuang Jing ◽  
Liwen Ai ◽  
Xiao-Ling Zhao
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Structural Steel ◽  
High Strength ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness

Low temperature impact toughness of structural steel welds with different welding processes

2015 ◽  
Vol 19 (5) ◽  
pp. 1431-1437 ◽  
Author(s):  
Hyun-Seop Shin ◽  
Ki-Tae Park ◽  
Chin-Hyung Lee ◽  
Kyong-Ho Chang ◽  
Vuong Nguyen Van Do
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Structural Steel ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness ◽  
Steel Welds ◽  
Welding Processes

scholarly journals EFFECTS OF Q&P PROCESS PARAMETERS ON PROPERTIES OF 42SiCr STEEL

2018 ◽  
Vol 24 (2) ◽  
pp. 126
Author(s):  
Kateřina Rubešová ◽  
Ivan Vorel ◽  
Hana Jirková ◽  
Štěpán Jeníček
Keyword(s):  
Heat Treatment ◽  
Ultimate Strength ◽  
Retained Austenite ◽  
High Strength ◽  
Carbon Diffusion ◽  
Salt Bath ◽  
Treatment Techniques ◽  
Microstructure Effects ◽  
The Impact ◽  
Quenching And Tempering

<p class="AMSmaintext"><span lang="EN-GB">The requirement for high strength and good ductility poses problems in today’s advanced steels. This problem can be tackled by appropriate heat treatment which produces suitable microstructures. By this means, ultimate strengths of about 2000 MPa and elongations of more than 10% can be obtained. One of such advanced heat treatment techniques is the Q&amp;P (Quenching and Partitioning) process. It produces a mixture of martensite and retained austenite, where the latter is an important agent in raising the ductility of steel. </span></p><p class="AMSmaintext"><span lang="EN-GB">In this experiment, a low-alloy steel with 0.41% carbon and manganese, silicon and chromium was used. An air furnace and a salt bath were employed for heat treatment and quenching, respectively. In order to obtain the best ultimate strength and elongation levels, partitioning temperatures of 250°C and 300°C were applied. Partitioning involves carbon diffusion from super-saturated martensite into retained austenite, and tempering of hardening microstructure. Effects of the quenching temperatures of 200°C and 150°C were studied as well. To map the impact of the Q&amp;P process on mechanical properties, an additional schedule with conventional quenching and tempering was carried out. Upon optimization of the parameters, the process produced martensite with a small amount of bainite and retained austenite. The ultimate strength was between 1930 and 2080 MPa and the elongation levels were from 9 to 16%.</span></p><p class="AMSmaintext"><span lang="EN-GB"> </span></p>

Effect of Vanadium and Boron on Microstructure and Low Temperature Impact Toughness of Bainitic Steels

2021 ◽  
Vol 31 (3) ◽  
pp. 139-149
Author(s):  
Yuanjiu Huang ◽  
◽  
Hun Lee ◽  
Sung Kyu Cho ◽  
Jun Seok Seo ◽  
...  
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Bainitic Steels ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness
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