Surface and interior residual stress analysis of a deep-drawn 1180-MPa class ultra-high strength steel sheet with scratch marks

Microstructural Ductile Fracture Analysis of 1180-MPa Class Martensite-matrix Dual-phase Steel via <i>in situ</i> Tensile Test

“…is the cumulative slip and is expressed as follows: 𝛾 |𝛾 𝛼 |# (5) where t denotes time. In DP steels, it is challenging to classify and evaluate the properties of each phase for implementation in CP-FEA because the evaluation method is not well established e.g., 38), 39) .…”

“…High tensile steel sheets have been developed to achieve thinner components with high crash safety performance and are now widely used commercially 1) . However, the press formability of high tensile steel sheets is worse than that of mild steel sheets because of several issues such as shape fixability 2), 3) , damage on the die and workpiece surface 4), 5) , and high press forces 6), 7) . In particular, material fracture during press forming is a serious problem.…”

Hydrogen Embrittlement Property of a 1.5 GPa Dual-Phase Steel Evaluated Using U-bending Test: A Comparison with Tempered Martensitic Steel with Identical Tensile Strength

“…Therefore, the effects of residual stress and plastic strain must be considered when evaluating the hydrogen embrittlement properties of automobile steel components. In this regard, the deep-drawing test [10][11][12][13] , stretchforming test [14][15][16] , and U-bending test [17][18][19][20][21][22][23] coupled with hydrogen charging have been applied as practical evaluation methods.…”