scholarly journals Heuristic Design of Advanced Martensitic Steels That Are Highly Resistant to Hydrogen Embrittlement by ε-Carbide

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 370
Author(s):  
Michio Shimotomai
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Absorption ◽  
Martensitic Steel ◽  
High Strength ◽  
Literature Survey ◽  
Martensitic Steels ◽  
Tempered Martensite ◽  
Grain Structures ◽  
Controlled Nucleation ◽  
Experimental Survey

Many advanced steels are based on tempered martensitic microstructures. Their mechanical strength is characterized by fine sub-grain structures with a high density of free dislocations and metallic carbides and/or nitrides. However, the strength for practical use has been limited mostly to below 1400 MPa, owing to delayed fractures that are caused by hydrogen. A literature survey suggests that ε-carbide in the tempered martensite is effective for strengthening. A preliminary experimental survey of the hydrogen absorption and hydrogen embrittlement of a tempered martensitic steel with ε-carbide precipitates suggested that the proper use of carbides in steels can promote a high resistance to hydrogen embrittlement. Based on the surveys, martensitic steels that are highly resistant to hydrogen embrittlement and that have high strength and toughness are proposed. The heuristic design of the steels includes alloying elements necessary to stabilize the ε-carbide and procedures to introduce inoculants for the controlled nucleation of ε-carbide.

scholarly journals Hydrogen Embrittlement and Diffusion in High Strength Low Alloyed Steels with Different Microstructures

2018 ◽  
Author(s):  
Marina Cabrini ◽  
Sergio Lorenzi ◽  
Diego Pesenti Bucella ◽  
Tommaso Pastore
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Tempered Martensite ◽  
Hsla Steels ◽  
And Diffusion ◽  
Embrittlement Resistance ◽  
Hydrogen Embrittlement Resistance

<span lang="EN-US">The paper deals with the effect of microstructure on the hydrogen diffusion in traditional ferritic-pearlitic HSLA steels and new high strength steels, with tempered martensite microstructures or banded ferritic-bainitic-martensitic microstructures. Diffusivity was correlated to the hydrogen embrittlement resistance of steels, evaluated by means of slow strain rate tests.</span>

scholarly journals Mitigation of hydrogen embrittlement in ultra-high strength lath martensitic steel via Ta microalloying

2021 ◽  
pp. 110090
Author(s):  
Shiqi Zhang ◽  
Dayang Xu ◽  
Feng Huang ◽  
Wenqiang Gao ◽  
Jifang Wan ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Martensitic Steel ◽  
High Strength

scholarly journals Hydrogen embrittlement properties of nitrogen added ultra-high-strength TRIP-aided martensitic steels evaluated by using conventional strain rate technique

2018 ◽  
Vol 15 ◽  
pp. 1581-1587 ◽  
Author(s):  
Tomohiko Hojo ◽  
Kiattada Chanvichitkul ◽  
Hiroyuki Waki ◽  
Fumihito Nishimura ◽  
Eiji Akiyama
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
High Strength ◽  
Martensitic Steels

Role of Mo/V carbides in hydrogen embrittlement of tempered martensitic steel

2015 ◽  
Vol 33 (6) ◽  
pp. 433-441 ◽  
Author(s):  
Junmo Lee ◽  
Taekyung Lee ◽  
Young Jin Kwon ◽  
Dong-Jun Mun ◽  
Jang-Yong Yoo ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Hydrogen Embrittlement ◽  
Beneficial Effect ◽  
Mechanical Performance ◽  
Martensitic Steel ◽  
Carbide Precipitation ◽  
Hydrogen Trapping ◽  
Martensitic Steels ◽  
Cr Addition

AbstractThe vulnerability of tempered martensitic steel to hydrogen embrittlement (HE) has attracted attention from a number of researchers. Although utilizing carbide precipitation is one of effective methods to improve HE resistance, few studies have focused on the effects of carbide characteristics, such as the chemical composition and morphology of carbide. This work clarifies the role of Mo carbide and V carbide in the HE behavior of tempered martensitic steels with four steels whose chemical composition was carefully controlled. The beneficial effect of carbides is discussed in terms of hydrogen trapping and fracture mode. The low amount of trapped hydrogen and undissolved carbide led to excellent HE resistance of Mo carbides compared to V carbides. In addition, the superior mechanical performance of Cr-Mo steel was also interpreted by the effect of Cr addition as well as Mo carbides.

Application of Local Approach to Hydrogen Embrittlement Fracture Evaluation of High Strength Steels

2007 ◽  
Vol 539-543 ◽  
pp. 2155-2161 ◽  
Author(s):  
Shusaku Takagi ◽  
Satoshi Terasaki ◽  
Kaneaki Tsuzaki ◽  
Tadanobu Inoue ◽  
Fumiyoshi Minami
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Content ◽  
Fracture Property ◽  
Martensitic Steel ◽  
High Strength Steels ◽  
High Strength ◽  
New Method ◽  
Local Approach ◽  
Delayed Fracture ◽  
Ultra High Strength Steel

A new method for evaluating the hydrogen embrittlement (HE) susceptibility of ultra high strength steel was studied in order to propose a new method for assessing the delayed fracture property. The material used was 1400MPa tempered martensitic steel with the chemical composition 0.40C-0.24Si-0.81Mn-1.03Cr-0.16Mo(mass%). The local approach originally used for evaluating the brittle fracture property was applied to HE susceptibility assessment after modifying the method to include the effect of hydrogen content. Critical HE data used in the modified local approach was obtained by a stepwise test in which alternating processes of stress increase and stress holding were repeated until the specimen fractured. The specimen used in the stepwise test was 10 mm in diameter and the stress concentration factor was 4.9. Assessment of HE susceptibility for specimens with other dimensions entailed the use of a critical hydrogen content for failure, Hc, representing the maximum hydrogen content among the unfractured specimens in the HE test with constant loading. Matters to be noted for obtaining the material parameters are discussed.

Effect of Cooling Rate below Ms Temperature on Hydrogen Embrittlement of TRIP-Aided Martensitic Steels

2021 ◽  
Vol 1016 ◽  
pp. 654-659
Author(s):  
Naoya Kakefuda ◽  
Shintaro Aizawa ◽  
Ryo Sakata ◽  
Junya Kobayashi ◽  
Goroh Itoh ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Cooling Rate ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength ◽  
Martensitic Steels ◽  
The Matrix ◽  
Embrittlement Resistance ◽  
Hydrogen Embrittlement Resistance

Low alloy TRIP steel is expected to be applied to automobile bodies because of its high strength, high ductility, and excellent impact properties and press formability. It has been reported that the low alloy TRIP steel of hydrogen embrittlement resistance is improved by utilizing the hydrogen storage characteristics of highly stable retained austenite. Therefore, for the purpose of increasing the volume fraction of retained austenite, it was produced at various cooling rates below the martensite transformation start temperature. As a result, the volume fraction of retained austenite increased, and then the effect of hydrogen embrittlement decreased. The matrix phase and retained austenite is refined with decrees of the cooling rate. It is considered that the size and surface area of the retained austenite also affected the improvement of hydrogen embrittlement resistance.

scholarly journals Observations on the Relationship between Crystal Orientation and the Level of Auto-Tempering in an As-Quenched Martensitic Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1255 ◽  
Author(s):  
Shashank Ramesh Babu ◽  
Tuomo Nyyssönen ◽  
Matias Jaskari ◽  
Antti Järvenpää ◽  
Thomas Paul Davis ◽  
...  
Keyword(s):  
Room Temperature ◽  
Martensitic Steel ◽  
Low Carbon ◽  
Martensitic Steels ◽  
Tempered Martensite ◽  
Martensitic Microstructure ◽  
Austenite Grains ◽  
Variant Analysis ◽  
The Relationship ◽  
Electron Back Scattered Diffraction

Auto-tempering is a feature of the technologically important as-quenched low-carbon martensitic steels. The focus of this paper is on the morphology of the martensite and the orientation of the last forming untempered regions in relation to the earlier formed auto-tempered martensite in both small and large austenite grains. A low-carbon martensitic steel plate was austenitized for 24 h and quenched to room temperature. The resulting microstructure was characterized using electron microscopy and electron back scattered diffraction (EBSD) imaging. It was found that all the untempered regions in the martensitic microstructure were oriented with the plane normals {100} close to the thickness, or normal, direction of the plates. Variant analysis revealed that the untempered regions and the auto-tempered regions are part of the same packet.

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