Heat treatment, microstructure and mechanical properties of a C-Mn-Al-P hot dip galvanizing TRIP steel
2016 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 674, 151-157 p.Article in journal (Refereed) Published
Heat treatments of a hot dip galvanizing TRIP (Transformation induced plasticity) steel with chemical composition 0.20C-1.50Mn-1.2Al-0.07P(mass%) were performed in a Gleeble 3500 laboratory equipment. The heat treatment process parameters were varied to investigate the effect of intercritical annealing temperature as well as isothermal bainitic transformation (IBT) temperature and time, on the microstructure and the mechanical properties. The microstructure was investigated using scanning electron microscopy, transmission electron microscopy and x-ray diffraction, while mechanical properties were evaluated by tensile testing. Furthermore, to generate a better understanding of the phase transformations during heat treatment, dilatometry trials were conducted. The desired microstructure containing ferrite, bainite, retained austenite and martensite was obtained after the heat treatments. It was further found that the IBT is critical in determining the mechanical properties of the steel, since it controls the fraction of bainite. With increasing bainite fraction, the fraction of retained austenite increases while the fraction of martensite decreases. The mechanical properties of the steel are excellent with a tensile strength above 780 MPa (expect in one case) and elongation above 22%.
Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 674, 151-157 p.
Hot Dip Galvanizing TRIP Steel, Mechanical Properties, Isothermal bainitic transformation, Microstructure, Heat treatment
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-193798DOI: 10.1016/j.msea.2016.07.119ISI: 000383292800019ScopusID: 2-s2.0-84982851934OAI: oai:DiVA.org:kth-193798DiVA: diva2:1039518
QC 201610242016-10-242016-10-112016-12-15Bibliographically approved