Weld cold cracking in the heat affected zone of medium, high carbon low alloy steels

1989 ◽  
Vol 3 (3) ◽  
pp. 233-237
Author(s):  
F Matsuda ◽  
H Nakagawa ◽  
Hwa Soon Park
Keyword(s):  
Heat Affected Zone ◽  
Cold Cracking ◽  
Low Alloy Steels ◽  
High Carbon ◽  
Alloy Steels

Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review

2017 ◽  
Vol 36 (4) ◽  
pp. 309-325 ◽  
Author(s):  
Wangzhong Mu ◽  
Pär Göran Jönsson ◽  
Keiji Nakajima
Keyword(s):  
Heat Affected Zone ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Intragranular Ferrite ◽  
Metallic Inclusions ◽  
Theoretical Investigations ◽  
Alloy Steels ◽  
Institute Of Technology ◽  
Future Work

AbstractIntragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063–1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

Fast Fracture Evaluation of Steam Generator Channel Heads Considering High Carbon Macro-Segregation

2020 ◽  
Author(s):  
Kaikai Shi ◽  
Yixiong Zhang ◽  
Yu Yang ◽  
Bin Zheng ◽  
Hai Xie ◽  
...  
Keyword(s):  
Stress Intensity Factor ◽  
Transition Temperature ◽  
Stress Intensity ◽  
Carbon Content ◽  
Steam Generator ◽  
Low Alloy Steels ◽  
High Carbon ◽  
Fracture Failure ◽  
Alloy Steels ◽  
Fast Fracture

Abstract The Fracture evaluation is important in the structural integrity analysis of nuclear equipment which is subjected to the effects of neutron irradiation. The increment of ductile and brittle transition temperature is mainly due to the neutron irradiation, thermal ageing and strain ageing. In addition to above these factors, the high carbon macro-segregation of low-alloy steels also increases the risk of fast fracture failure as the carbon positive macro-segregation will lead to the increasing transition temperature of low-alloy steels. In this work, a relationship between the carbon content and the increment of transition temperature is developed and is used to the fast fracture failure analysis of the highest carbon content region in steam generator channel head. Results show that ratio between the calculated stress intensity factor considering safety coefficient suggested by ASME design code and the critical stress intensity factor is less than one, which indicates a safe design for the highest carbon content region in steam generator channel head.

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.

High Carbon Steel Microcracking Control During Hardening

1984 ◽  
Vol 106 (3) ◽  
pp. 253-256 ◽  
Author(s):  
J. Lyman
Keyword(s):  
Carbon Steel ◽  
High Carbon Steel ◽  
Low Alloy Steels ◽  
Austenitizing Temperature ◽  
High Carbon ◽  
Tempering Temperature ◽  
Aisi 52100 ◽  
Alloy Steels ◽  
Short Time

When high carbon, low alloy steels, such as AISI 52100, are conventionally quenched or marquenched from an austenitizing temperature that dissolves all of the carbon in the austenite, many of the martensite crystals in the quenched microstructure are fractured or microcracked. This paper describes a process in which a limited amount of martensite is formed by quenching the steel to a temperature between the Ms temperature and conventional quench temperatures. This martensite is then tempered for a short time to toughen it before again cooling the steel to complete the formation of martensite from austenite. When the limited amount of martensite formed, and intermediately tempered, and the martensite formed on cooling from the intermediate tempering temperature are appropriately balanced by the processing, micro-cracking is essentially avoided. The process can be done in equipment and with procedures commonly used commercially.

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