The critical influence of La content on the microstructure-toughness relationship in the simulated coarse-grained heat-affected zone of high-strength low-alloy steels

2021 ◽  
Vol 118 (2) ◽  
pp. 212
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Hangyu Dong ◽  
Kaiming Wu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Fine Grained ◽  
Welding Thermal Cycle ◽  
Alloy Steels ◽  
High Fraction ◽  
The Impact

The present study was envisaged to investigate the role of La content on the particle, microstructure and toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels. Three steels with La content of 0.016 wt.%, 0.046 wt.% and 0.093 wt.% were prepared and simulated in a 100 kJ/cm heat input welding thermal cycle. Subsequently, the particle and microstructure of selected specimens were characterized and the impact absorb energy was measured at −20 °C. The results indicated that the La2O2S inclusions in 0.016 wt.%-La steel were gradually modified to LaS-LaP in 0.046 wt.%-La steel and to LaP in 0.093 wt.%-La steel. A higher fraction of acicular ferrite was obtained in the simulated CGHAZ of 0.016 wt.%-La steel, since the inclusion of La2O2S was more powerful to induce the formation of acicular ferrite. Furthermore, the fraction of M-A constituents in the simulated CGHAZ increased with increasing La content. The impact toughness in the simulated CGHAZ of 0.016 wt.%-La steel was the highest, owing to the high fraction of the fine-grained acicular ferrite and low fraction of M-A constituent.

Effect of Nb on Microstructure Evolution of Coarse-Grained Heat-Affected Zone with Large Heat Input Welding

2011 ◽  
Vol 284-286 ◽  
pp. 1174-1179 ◽  
Author(s):  
Xue Li Tao ◽  
Kai Ming Wu ◽  
Xiang Liang Wan
Keyword(s):  
Grain Boundary ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Acicular Ferrite ◽  
High Strength ◽  
Coarse Grained ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Grain Boundary Ferrite

The effect of Nb microalloying on microstructure transformation of coarse-grained heat-affected zone of high strength low alloy steels were investigated utilizing different heat input welding simulation. For the low-Nb steel, the microstructures of coarse-grained heat-affected zone mainly consisted of acicular ferrite, bainite and grain boundary ferrite for small heat input welding; the amount of acicular ferrite decreased whereas grain boundary ferrite, polygonal ferrite and pearlite increased with increasing heat input. In constrast, for the high-Nb steel, granular bainite was the dominant microstructure. The formation of granular bainitic microstructure was associated with the solid solution of Nb, which suppressed ferrite transformation and promoted the formation of granular bainite. The hardness of coarse-grained heat-affected zone increased with increasing Nb content, and decreased with decreasing heat input, which was attributed to the microstructural change.

scholarly journals Effect of Ce Content on Microstructure-Toughness Relationship in the Simulated Coarse-Grained Heat-Affected Zone of High-Strength Low-Alloy Steels

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2003
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Yong Wang ◽  
Xinbin Liu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Energy Levels ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Moderate Degree ◽  
Treated Steel ◽  
Alloy Steels ◽  
The Impact ◽  
Ce Content

The study aimed to identify a moderate degree of Ce addition to improve the toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels, based on the effect of the Ce content on particle characteristics, microstructure and impact toughness. Three steels with 0.012 wt.%, 0.050 wt.% and 0.086 wt.% Ce content were subjected to 100 kJ/cm heat input in their thermal welding cycles. The particles and microstructures in the simulated CGHAZ of each steel were characterized and the impact-absorbance energy levels were measured at −20 °C. The results indicated that Ce2O2S inclusion compounds were gradually modified to CexSy-CeP and CeP with the increasing of the Ce content. A higher fraction of acicular ferrite was formed in the 0.012 wt.%-Ce-treated steel due to the lower mismatch between Ce2O2S and α-Fe. Furthermore, a lower fraction of M-A constituent was obtained in the 0.012 wt.%-Ce-treated steel. As a result, superior toughness and a typical amount of ductile fracture were detected in the simulated CGHAZ of the 0.012 wt.%-Ce-treated steel. Compared with the 0.012 wt.%-Ce-treated steel, a smaller prior austenite grain was observed in the 0.086 wt.%-Ce-treated steel because of the segregation of CeP at the grain boundary. However, the larger size and density of CeP led to poor toughness in the CGHAZ of the 0.086 wt.%-Ce-treated steel.

Impact of Mo content on the microstructure– toughness relationship in the coarse-grained heat-affected zone of high-strength low-alloy steels

2021 ◽  
Vol 112 (2) ◽  
pp. 98-107
Author(s):  
Yuxin Cao ◽  
Xiangliang Wan ◽  
Feng Zhou ◽  
Yu Shen ◽  
Yu Liu ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
Prior Austenite ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Austenite Grain ◽  
Alloy Steels ◽  
Mo Content ◽  
Grain Boundary Pinning ◽  
Prior Austenite Grain

Abstract The present study elucidates the influence of Mo content on the microstructure – toughness relationship in the coarsegrained heat-affected zone of high-strength low-alloy steels. The low-Mo and high-Mo steels were subjected to 100 kJ cm–1 heat input welding thermal cycling. The results indicated that (Ti,Mo)-carbonitrides were formed in high-Mo steel, whereas (Ti,Nb)-carbonitrides were formed in low-Mo steel. The finer and dispersed precipitates in high-Mo steel refined the prior austenite grain in the coarse-grained heat-affected zone based on the grain boundary pinning effect. However, the smaller prior austenite grain and excessive Mo content induced the formation of an entirely bainitic microstructure in high-Mo steel. Furthermore, a higher fraction of martensite –austenite constituents was observed in high-Mo steel. These results could be responsible for the deterioration of the toughness in the coarse-grained heat-affected zone of high-Mo steel.

Toughness improvement by Zr addition in the simulated coarse-grained heat-affected zone of high-strength low-alloy steels

2017 ◽  
Vol 46 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Yu Liu ◽  
Guangqiang Li ◽  
Xiangliang Wan ◽  
Xianguang Zhang ◽  
Yu Shen ◽  
...  
Keyword(s):  
Heat Affected Zone ◽  
High Strength ◽  
Coarse Grained ◽  
Low Alloy Steels ◽  
Zr Addition ◽  
Alloy Steels ◽  
Toughness Improvement

TRI-MARK TM-811N2

Alloy Digest ◽  
1983 ◽  
Vol 32 (4) ◽  
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Heat Treating ◽  
Low Alloy Steels ◽  
Nickel Steel ◽  
Fine Grained ◽  
Subzero Temperatures ◽  
Steel Weld Metal ◽  
Alloy Steels ◽  
Welding Electrode

Abstract TRI-MARK TM-811N2 is a flux-cored welding electrode for all position semiautomatic arc welding. It is designed to weld 2-3% nickel steels for applications requiring good toughness at subzero temperatures; in addition, it is used to weld various other high-strength low-alloy steels and various fine-grained steels with low-temperature toughness. Tri-Mark TM-811N2 is used to deposit typically 2.35% nickel steel weld metal with good low-temperature impact properties. It is used for shipbuilding, oil rigs and similar structures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-389. Producer or source: Tri-Mark Inc..

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