Effect of Composition System on Microstructure and Properties of 1000-MPa Grade Cold Rolled DPSteel

• Published in: Materials science forum Vol. 993; pp. 534 - 540
• Main Authors: Zhao, Dong Liang, Zhao, Xiao Long
• Format: Journal Article
• Language: English
• Published: Pfaffikon Trans Tech Publications Ltd 01.05.2020
• Subjects: Alloy systems; Cold rolling; Composition effects; Continuous annealing; Dual phase steels; Duplex stainless steels; Hot rolling; Martensite; Microstructure; Pickling; Simulated annealing; Steel; Thermal simulation; Thermal simulators; Cold Rolled DPSteel; Performance; Component; Microstructure
• ISSN: 0255-5476; 1662-9752; 1662-9752
• DOI: 10.4028/www.scientific.net/MSF.993.534

1000 MPa grade cold-rolled duplex steel with 5 component systems was trial-produced in the laboratory. After hot rolling, pickling and cold rolling, the test steel was simulated continuous annealing on Gleeble-3800 thermal simulator. The microstructure and properties of 5 kinds of experimental steels after simulated annealing were analyzed. The results show that C and Mn elements are the basic alloy systems of all duplex steels. In the case of low Si element, the C element content of the 1000 MPa grade dual phase steel should be 0.15 % or higher, and the Mn element content should be higher than 1.8 %. Si element increased to the A3 point, while the amount of austenite was less in the two-phase region during annealing, and the volume fractionof martensiteafter the rapid cooling is insufficient; Nb element is a high-efficiency fine-grain strengthening element, which greatly improvedthe uniformity of the steel species. The fine-grained martensite islands have enhance the tempering stability of martensite and thereby to reduce the adverse strength effect from over-aging temperature.