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Microstructure and Properties of Nanoduplex Bainite–Austenite Steel for Ultra‐High‐Strength Plates
Author(s) -
Garbarz Bogdan,
Burian Wojciech
Publication year - 2014
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201300453
Subject(s) - bainite , materials science , microstructure , austenite , ultimate tensile strength , continuous cooling transformation , scanning electron microscope , metallurgy , transmission electron microscopy , elongation , tensile testing , composite material , nanotechnology
Basing on experimentally determined continuous cooling transformation (CCT) and time–temperature–transformation (TTT) diagrams, examination of microstructure by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD) techniques and measurements of mechanical properties an optimized chemical composition of a nanostructured bainite–austenite steel intended for production of plates is proposed. The optimized composition enables to manufacture ultra‐high‐strength plates up to 15 mm in thickness at relatively low cost of alloying elements and with characteristics facilitating industrial production. Experimental flat bars manufactured in semi‐industrial conditions of the developed steel containing 0.56% C, 2.00% Mn, 1.76% Si, 1.29% Cr, and 0.76% Mo after transformation at 225°C for 60–72 h show good combination of mechanical properties: ultimate tensile strength over 1.9 GPa, yield strength in the range of 1.3–1.4 GPa, total elongation about 15% and hardness at the level of 600 HV.