The effect of prestrain and bake hardening on the low-cycle fatigue properties of TRIP steel

• Published in: International journal of fatigue Vol. 30; no. 4; pp. 587 - 594
• Main Authors: Robertson, L.T., Hilditch, T.B., Hodgson, P.D.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-04-2008; Elsevier Science
• Subjects: Applied sciences; Cyclic softening; Exact sciences and technology; Fatigue; Low-cycle fatigue; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Prestrain; Strain-life; TRIP; TRIP; Cyclic softening; Prestrain; Strain-life; Low-cycle fatigue; Strain softening; Predeformation; Mechanical properties; Steel; Low cycle fatigue; Phase transformation; Hardening; Plasticity; Martensitic transformation
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2007.06.002

The scope of this study was to examine the effects of plane strain prestrain, induced via cold-rolling, and subsequent automotive paint bake hardening cycle on both tensile and fatigue properties of a hot rolled TRIP780 multiphase steel. Strain-life data has been generated for as-received (0% prestrain), 10% and 20% prestrained samples, in both baked and unbaked conditions. Cold rolling increased the number of strain reversals to failure at high cyclic strain amplitudes with no effect at low strain amplitudes. Bake hardening increased the number of reversals to failure at high cyclic strain amplitudes. The prestrained material exhibited partial cyclic softening, with some residual strength increase. The residual strength increase was attributed to the austenite to martensite transformation that occurred during the prestraining process.