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The effect of loading rate on the strength and toughness of fine‐grained structural steels
Author(s) -
Kussmaul Karl,
Dernier Thomas
Publication year - 1992
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199201758
Subject(s) - fracture toughness , materials science , toughness , composite material , ultimate tensile strength , brittleness , strain rate , deformation (meteorology) , tensile testing , fracture mechanics , stress (linguistics) , linguistics , philosophy
The effect of loading rate on the strength and deformation characteristics of tensile tested smoothed round bar specimens and on linear‐elastic and elastic‐plastic fracture toughness values was investigated. Test materials were a high toughness melt of the fine‐grained structural steel 20 MnMoNi 5 5 and two model materials of reduced toughness. The strain rate was varied between ∊̇ = 10 −3 and 10 3 s −1 in the tensile tests, the loading rate between K̇ = 1 and 2 · 10 6 MPam 1/2 s −1 in the fracture toughness tests. The true‐stress true‐strain curve is shifted to higher stresses with increasing strain rate. A reduction of the deformation characteristics was only observed in cases of extremely reduced toughness. However, no brittle fracture at nominal stresses below yield was found in the tensile tests with smoothed specimens. Contrary to that all fracture mechanics tests showed a reduction of the crack initiation toughness with increasing loading rate K̇ .