The martensitic advanced high-strength steels (MS-AHSS) are used to create fuel-efficient, crashworthy cars. Hydrogen embrittlement (HE) is an issue with high-strength steels; thus, the interaction of hydrogen with MS-AHSS needs to be studied. There are only a few published works on the HE of MS-AHSS. The current literature indicates that the HE susceptibility of MS-AHSS is affected by (i) the strength of the steel, (ii) the applied strain rate, (iii) the concentration of hydrogen, (iv) microstructure, (v) tempering, (vi) residual stress, (vii) fabrication route, (viii) inclusions, (ix) metallic coatings, and (x) specific precipitates. Some of the unresolved issues include (i) the correlation of laboratory results to service performance, (ii) establishing the conditions or factors that lead to a certain HE response, (iii) studying the effect of stress rate on HE, and (iv) a comprehensive understanding of hydrogen trapping in MS-AHSS.

A review of hydrogen embrittlement of martensitic advanced high-strength steels

Effects of grain size and dislocation density on the susceptibility to high-pressure hydrogen environment embrittlement of high-strength low-alloy steels

Effects of grain size on hydrogen embrittlement in a Fe-22Mn-0.6C TWIP steel

Evaluation of hydrogen induced cracking behavior of API X70 pipeline steel at different heat treatments

Dependence of hydrogen-induced lattice defects and hydrogen embrittlement of cold-drawn pearlitic steels on hydrogen trap state, temperature, strain rate and hydrogen content

The effect of grain size on the susceptibility of high-strength low alloy steels to hydrogen environment embrittlement in a 45 MPa gaseous hydrogen atmosphere was examined in term of the hydrogen content penetrating the specimen during the deformation. Notch tensile tests were performed in a 45 MPa hydrogen environment using specimens with different prior austenite grain size numbers varying from 2.5 to 5.4. The hydrogen content was measured by thermal desorption analysis with a quadrupole mass spectrometer before and after the tensile test. The fracture stress of the notch tensile test increased with increasing grain size number; this showed that grain refinement was effective in reducing the susceptibility of the specimens to hydrogen environment embrittlement in a high-pressure hydrogen atmosphere. The addition of nickel did not affect the fracture stress. A remarkable increase in the content of diffusive hydrogen was observed after the notch tensile test. Assuming that part of the diffusive hydrogen desorbed from grain boundaries, it can be inferred that grain refinement can reduce the mass of hydrogen in the unit grain boundary area, and the susceptibility to high-pressure hydrogen environment embrittlement. [doi:10.2320/matertrans.M2009241]

Effects of Grain Size on Hydrogen Environment Embrittlement of High Strength Low Alloy Steel in 45 MPa Gaseous Hydrogen

Absorption of hydrogen in a high-strength nickel–chromium–molybdenum steel during tensile deformation in 0.5 MPa gaseous hydrogen was examined using a thermal desorption analysis method. The tensile strength of the specimen was varied in the range from 1214 to 947 MPa by heat treatment. The dislocation density of the specimens was measured by X-ray diffractometry after tensile testing in a hydrogen atmosphere. The hydrogen content absorbed during tensile deformation increased with increasing tensile strain in proportional elastic range until just before yielding. The yield stress was defined as 0.2% proof stress in this work. At the same tensile strains, the hydrogen content of lower-strength specimens was larger than that of higher-strength specimens. The dislocation density gradually decreased until just before yielding, corresponding to the proportional increase of hydrogen content to the tensile strain. This implies that the hydrogen absorption behavior during tensile deformation in gaseous hydrogen is related to the motion of mobile dislocations initially contained in the specimens. The activation energy for desorption of hydrogen absorbed during tensile deformation did not depend on the strength of the steel. This indicates that the trap sites of hydrogen atoms created through the tensile deformation were the same regardless of the strength levels.

Absorption of Hydrogen in High-strength Low -alloy Steel during Tensile Deformation in Gaseous Hydrogen

An object of the present invention is to provide at a low cost a low-alloy steel having a high strength and excellent high-pressure hydrogen environment embrittlement resistance characteristics under a high-pressure hydrogen environment. The invention is a high-strength low-alloy steel having high-pressure hydrogen environment embrittlement resistance characteristics, which has a composition comprising C: 0.10 to 0.20% by mass, Si: 0.10 to 0.40% by mass, Mn: 0.50 to 1.20% by mass, Ni: 0.75 to 1.75% by mass, Cr: 0.20 to 0.80% by mass, Cu: 0.10 to 0.50% by mass, Mo: 0.10 to 1.00% by mass, V: 0.01 to 0.10% by mass, B: 0.0005 to 0.005% by mass and N: 0.01% by mass or less, and further comprising one or two of Nb: 0.01 to 0.10% by mass and Ti: 0.005 to 0.050% by mass, with the balance consisting of Fe and unavoidable impurities.

High-strength low-alloy steel excellent in high-pressure hydrogen environment embrittlement resistance characteristics and method for producing the same

Effects of grain size on hydrogen environment embrittlement of high strength low alloy steel in 45 MPa gaseous hydrogen

Using information about the position, orientation, and shape of a crack appeared in a judged material and information about the structure of the judged material as parameters, the stress intensity factor KI of the crack is found. Based on the stress intensity factor KI, hydrogen embrittlement cracking of the judged material is judged. The crack growth rate and possibility of brittle fracture can be judged by comparing the stress intensity factor KI with the critical stress intensity factor KIH for crack initiation or the critical stress intensity factor KIC-H for brittle fracture about the temper embrittled steel which absorbs approximately 2.0 ppm hydrogen.

Yoru Wada

Papers

Effects of Grain Size on Hydrogen Environment Embrittlement of High Strength Low Alloy Steel in 45 MPa Gaseous Hydrogen

Absorption of Hydrogen in High-strength Low -alloy Steel during Tensile Deformation in Gaseous Hydrogen

High-strength low-alloy steel excellent in high-pressure hydrogen environment embrittlement resistance characteristics and method for producing the same

Effects of grain size on hydrogen environment embrittlement of high strength low alloy steel in 45 MPa gaseous hydrogen

Method of judging hydrogen embrittlement cracking of material used in high-temperature, high-pressure hydrogen environment