Hydrogen Embrittlement of Medium Mn Steels

Abstract

Recent research efforts to develop advanced–/ultrahigh–strength medium-Mn steels have led to the development of a variety of alloying concepts, thermo-mechanical processing routes, and microstructural variants for these steel grades. However, certain grades of advanced–/ultrahigh–strength steels (A/UHSS) are known to be highly susceptible to hydrogen embrittlement, due to their high strength levels. Hydrogen embrittlement characteristics of medium–Mn steels are less understood compared to other classes of A/UHSS, such as high Mn twinning–induced plasticity steel, because of the relatively short history of the development of this steel class and the complex nature of multiphase, fine-grained microstructures that are present in medium–Mn steels. The motivation of this paper is to review the current understanding of the hydrogen embrittlement characteristics of medium or intermediate Mn (4 to 15 wt pct) multiphase steels and to address various alloying and processing strategies that are available to enhance the hydrogen-resistance of these steel grades.

Recent Progress of Low and Medium-Carbon Advanced Martensitic Steels

“…It is well-known that metastable retained austenite can absorb a large amount of solute hydrogen in TBF, Q&P, CFB, and D-MMn steels [57,[106][107][108][109][110]. This results in a high delayed fracture strength in these steels because hydrogen concentration on the prior austenitic grain boundary is lowered.…”

“…Hojo et al [76] propose that the high hydrogen embrittlement resistance is caused by that (i) most of the solute hydrogen is trapped in the retained austenite with high mechanical stability, and resultantly, (ii) the initiation and propagation of voids and cracks at prior austenite grain, packet, block, and lath boundaries are suppressed. Many researchers are investigating the hydrogen embrittlement of D-MMn steels [57,111,112]. Unfortunately, there is not any research on the delayed fracture strength of M-MMn steel up to now.…”

“…Many researchers are investigating the hydrogen embrittlement of D-MMn steels [57,111,112]. Unfortunately, there is not any research on the delayed fracture strength of M-MMn steel up to now.…”

“…one-step and two-step quenched and partitioned (Q&P) steels [7][8][9]25,[34][35][36][37][38][39][40][41], carbidefree bainitic (CFB) steel [42][43][44][45][46][47][48][49], and duplex type medium manganese (D-MMn) steel [9,25,[50][51][52][53][54][55][56][57].…”

“…Metals 2021, 11, x FOR PEER REVIEW 2 (III). Third-generation AHSS (Type A): TRIP-aided bainitic ferrite (TBF) steel [9,10,29one-step and two-step quenched and partitioned (Q&P) steels [7][8][9]25,[34][35][36][37][38][39][40][41], bide-free bainitic (CFB) steel [42][43][44][45][46][47][48][49], and duplex type medium manganese (D-MM steel [9,25,[50][51][52][53][54][55][56][57]. (IV).…”