Improvement of Impact Toughness of the Welding Heat-Affected Zone in High-Strength Low-Alloy Steels through Ca Deoxidation

2021 ◽  
Author(s):  
Yinhui Zhang ◽  
Jian Yang ◽  
Dekun Liu ◽  
Xiaoqian Pan ◽  
Longyun Xu
Keyword(s):  
Impact Toughness ◽  
Heat Affected Zone ◽  
High Strength ◽  
Low Alloy Steels ◽  
Alloy Steels

Microstructures and Properties of HAZ of JB800 Bainite Steel

2014 ◽  
Vol 670-671 ◽  
pp. 65-69
Author(s):  
Jun Sheng Sun ◽  
Hong Quan Wang
Keyword(s):  
Impact Toughness ◽  
Lower Cost ◽  
Welding Process ◽  
High Strength ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Test Results ◽  
Bainite Steel ◽  
Alloy Steels ◽  
Allotriomorphic Ferrite

JB800 steel has grain boundary allotriomorphic ferrite and granular bainite (FGBA/BG), and it is a kind of high strength low alloy steels, which has simple produce procedure, lower cost and excelled property. The law of microstructure transformation in CGHAZ, hardness, and impact toughness in HAZ of JB800 steel were studied by means of thermal simulation. The test results show that under the general condition of welding process (t8/5=5~50s), microstructure of CGHAZ is composed of mixture microstructure of Martensite and Bainite and with the increase of cooling rate, the content of Martensite will decrease, but that of Bainite will increase; when t8/5 is 20s, CGHAZ zone have better impact toughness, which is composed of 95% Martensite and 5% Bainite. Therefore t8/5 should be controlled at about 20s to get better impact toughness.

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 Hot Work on Hardness and Impact Toughness of Heat Treated Low Alloy Steels

2014 ◽  
Vol 1082 ◽  
pp. 197-201
Author(s):  
Mahmoud M. Tash ◽  
Saleh A. Alkahtani ◽  
Khaled A. Abuhasel
Keyword(s):  
Impact Toughness ◽  
Hot Forging ◽  
Weight Ratio ◽  
High Strength ◽  
Extensive Study ◽  
Low Alloy Steels ◽  
Alloying Additions ◽  
Heat Treated ◽  
Alloy Steels ◽  
Effect Of Hot Rolling

The present study was undertaken to investigate the effect of hot work reduction ratio on the hardness and impact toughness of different grades of low alloy steels. The effect of hot rolling and hot forging with different reduction ratios on the hardness and impact toughness properties will be studied. An extensive study will be carried out to investigate the effect of alloying additions and TMT parameters on the hardness and impact toughness of heat-treated low alloy steels. An understanding of the combined effect of TMT and heat treatment on the hardness and impact toughness of the low alloy steels would help in selecting conditions required to achieve optimum mechanical properties and alloy high strength to weight ratio.

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.

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