Effect of Microstructure on Low-Temperature Impact Toughness of Multi-Pass Weld Metal of 1 GPa Class High Strength Steel

A new lower cost 600MPa TMCP steel with high strength,good low temperature impact toughness,low yield ratio and excellent weldability has been developed successfully by design of alloy composition and thermal mechanical control process technology, and the welding heat affected zone(HAZ) have been investigated. The systematic studies show that the new developed steels gather high strength, high low temperature toughness, good seismic performance(low yield ratio) and excellent weldability, and the base steels have a good match of strength and toughness. A large number of fine acicular ferrite in HAZ can ensure that the welding plate has high strength and good low temperature impact toughness. The comprehensive performance of steel can meet fully the high-technical requirements of large-scale engineering.

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Microstructure and Charpy Impact Toughness of a 2.25Cr-1Mo-0.25V Steel Weld Metal

Materials ◽

10.3390/ma13133013 ◽

2020 ◽

Vol 13 (13) ◽

pp. 3013 ◽

Cited By ~ 2

Author(s):

Kefan Wu ◽

Yingjie Yan ◽

Rui Cao ◽

Xinyu Li ◽

Yong Jiang ◽

...

Keyword(s):

Low Temperature ◽

Impact Toughness ◽

Weld Metal ◽

Power Plants ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Granular Bainite ◽

Confocal Laser ◽

Temperature Impact ◽

Low Temperature Impact Toughness

The demand for heat-resistant steel has increased owing to its utility in numerous devices that must withstand high steam pressures and high temperatures, such as turbine rotors and blades in ultra-supercritical power plants. It is inevitable to join heat-resistance steel part by welding method, so it is important to maintain the toughness of the weld metals. In this study, the microstructure, low-temperature impact toughness, and fracture surface of as-welded and post-weld heat treatment (PWHT) of 2.25Cr-1Mo-0.25V weld metal were investigated. The microstructures of the as-welded and PWHT specimens are granular bainite and ferrite, respectively. This work revealed the relationship between effective microstructure nearby crack initiation origin and low temperature impact toughness for both the as-welded and PWHT specimens. The evolution of the microstructure and prior austenite was then investigated using confocal laser scanning microscopy (CLSM) to observe the formation of coarse ferrite grain structures. A suggestion for enhancing the low-temperature toughness was provided based on the effect of adjusting Mn content and forming acicular ferrite.

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Interrelationships between yield strength, low-temperature impact toughness, and microstructure in low-carbon, copper-precipitation-strengthened, high-strength low-alloy plate steels

Materials Science and Engineering A ◽

10.1016/j.msea.2017.11.022 ◽

2018 ◽

Vol 711 ◽

pp. 424-433 ◽

Cited By ~ 10

Author(s):

S.W. Thompson

Keyword(s):

Low Temperature ◽

Impact Toughness ◽

Yield Strength ◽

High Strength ◽

Low Carbon ◽

Alloy Plate ◽

Copper Precipitation ◽

Temperature Impact ◽

Low Temperature Impact Toughness ◽

Plate Steels

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Effect of Microstructural Factors on Room- and Low-Temperature Impact Toughness of Hypoeutectoid Steels with Ferrite-Pearlite Structure

Korean Journal of Materials Research ◽

10.3740/mrsk.2015.25.11.583 ◽

2015 ◽

Vol 25 (11) ◽

pp. 583-589

Author(s):

Seung-Yong Lee ◽

Sang-Woo Jeong ◽

Byoungchul Hwang

Keyword(s):

Low Temperature ◽

Impact Toughness ◽

Temperature Impact ◽

Low Temperature Impact Toughness

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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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.937.61 ◽

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.

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