The role of reverse temper embrittlement on some low and high temperature crack extension processes in low carbon, low alloy steels: A review

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.

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The Determination of Carbide Types in Thin-Film Specimens of Low Alloy Steels.

Microscopy and Microanalysis ◽

10.1017/s1431927600034231 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 348-349 ◽

Cited By ~ 1

Author(s):

A.J. Papworth ◽

M. Watanabe ◽

D.B. Williams

Keyword(s):

Auger Electron ◽

Temper Embrittlement ◽

Thermal Exposure ◽

Low Alloy Steels ◽

Austenite Grain ◽

Alloy Steels ◽

Electron Spectrometry ◽

Prior Austenite Grain

The introduction of “clean steels” was thought to have cured the problem of temper embrittlement in low alloy steels. However, even these steels exhibit temper embrittlement at services temperature above 400°C. Initial studies of temper embrittlement of clean steels used Auger electron spectrometry of fracture surfaces. The failure was found to occur along the prior austenite grain boundaries (PAGBs) where P segregation was found. It has been reported that the concentration of segregants changes along individual PAGB facets, as well as between the facets of different PAGBs. It was proposed that different elements segregate to different PAGBs, depending on their orientation. Differences in segregation along individual PAGBs were attributed to precipitation during thermal exposure, as identified by AEM. The cause of temper embrittlement is still unknown, as there are doubts about the role of precipitation. This implies that each PAGB may have a different chemistry.

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Role of Mn and Si in temper embrittlement of low alloy steels

Metallurgical Transactions A ◽

10.1007/bf03161846 ◽

1975 ◽

Vol 6 (11) ◽

pp. 2160-2161 ◽

Cited By ~ 25

Author(s):

A. Joshi ◽

P. W. Palmberg ◽

D. F. Stein

Keyword(s):

Temper Embrittlement ◽

Low Alloy Steels ◽

Alloy Steels

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The role of nanoscale strain-induced defects in the sharp increase of low-temperature toughness in low-carbon and low-alloy steels

Materials Science and Engineering A ◽

10.1016/j.msea.2019.138491 ◽

2019 ◽

Vol 768 ◽

pp. 138491 ◽

Cited By ~ 11

Author(s):

V.E. Panin ◽

L.S. Derevyagina ◽

S.V. Panin ◽

A.R. Shugurov ◽

A.I. Gordienko

Keyword(s):

Low Temperature ◽

Sharp Increase ◽

Low Alloy Steels ◽

Low Carbon ◽

Alloy Steels ◽

Low Temperature Toughness ◽

Induced Defects

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Mechanical and metallurgical considerations on the effects of ppb-level chloride on stress corrosion cracking of low alloy steels in high-temperature water

Corrosion Science ◽

10.1016/j.corsci.2020.109136 ◽

2021 ◽

Vol 179 ◽

pp. 109136

Author(s):

Xiaoyuan Lou ◽

Peter L. Andresen ◽

Jingfan Yang ◽

Rajeshwar Pathania ◽

Tiangan Lian ◽

...

Keyword(s):

High Temperature ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Corrosion Cracking ◽

Low Alloy Steels ◽

High Temperature Water ◽

Alloy Steels ◽

Temperature Water

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Effect of Carbide Content on Temper Embrittlement of 2.25Cr1Mo Steel

Volume 7: Operations, Applications and Components ◽

10.1115/pvp2016-63289 ◽

2016 ◽

Author(s):

Yian Wang ◽

Guoshan Xie ◽

Zheng Zhang ◽

Xiaolong Qian ◽

Yufeng Zhou ◽

...

Keyword(s):

High Temperature ◽

Pressure Vessel ◽

High Stress ◽

Temper Embrittlement ◽

Damage Mechanism ◽

Pressure Vessels ◽

Nondestructive Method ◽

Operating Conditions ◽

Low Alloy Steels ◽

Carbide Content

Temper embrittlement is a common damage mechanism of pressure vessels in the chemical and petrochemical industry serviced in high temperature, which results in the reduction of roughness due to metallurgical change in some low alloy steels. Pressure vessels that are temper embrittled may be susceptible to brittle fracture under certain operating conditions which cause high stress by thermal gradients, e.g., during start-up and shutdown. 2.25Cr1-Mo steel is widely used to make hydrogenation reactor due to its superior combination of high mechanical strength, good weldability, excellent high temperature hydrogen attack (HTHA) and oxidation-resistance. However, 2.25Cr-1Mo steel is particularly susceptible to temper embrittlement. In this paper, the effect of carbide on temper embrittlement of 2.25Cr-1Mo steel was investigated. Mechanical properties and the ductile-brittle transition temperature (DBTT) of 2.25Cr-1Mo steel were measured by tensile test and impact test. The tests were performed at two positions (base metal and weld metal) and three states (original, step cooling treated and in-service for a hundred thousand hours). The content and distribution of carbides were analyzed by scanning electron microscope (SEM). The content of Cr and Mo elements in carbide was measured by energy dispersive X-ray analysis (EDS). The results showed that the embrittlement could increase the strength and reduce the plasticity. Higher carbide contents appear to be responsible for the higher DBTT. The in-service 2.25Cr-1Mo steel showed the highest DBTT and carbide content, followed by step cooling treated 2.25Cr-1Mo steel, while the as-received 2.25Cr-1Mo steel has the minimum DBTT and carbide content. At the same time, the Cr and Mo contents in carbide increased with the increasing of DBTT. It is well known that the specimen analyzed by SEM is very small in size, sampling SEM specimen is convenient and nondestructive to pressure vessel. Therefore, the relationship between DBTT and the content of carbide offers a feasible nondestructive method for quantitative measuring the temper embrittlement of 2.25Cr-1Mo steel pressure vessel.

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