Material properties and stress-strain curves for titanium-clad bimetallic steels

Titanium-clad (TC) bimetallic steel plate is a composite steel plate manufactured by metallurgically bonding a titanium cladding layer to a base structural carbon steel plate commonly through hot-rolling process. Such advanced bimetallic product takes advantages of the weldability, formability, thermal conductivity and good mechanical properties of structural carbon steel and the excellent corrosion and impact resistance of titanium in a symbiotic fashion, so it possesses structural performance, environmental and economic benefits compared with pure structural carbon steel and titanium. TC bimetallic steels have been applied wisely in many engineering structures, but their research studies in engineering application in the open literature are still very limited. The aim of this paper is to present an experimental study for investigating the material properties and stress-strain curves of TC bimetallic steels. A series of experimental tests including tensile coupon tests, bend tests, Charpy impact tests and hardness tests on the TC bimetallic steel specimens are undertaken and reported. Their basic mechanical properties and stress-strain curves are obtained. The influence of the clad ratio that is defined as the ratio of the thickness of cladding layer to the total plate thickness on the stress-strain curves are studied. Through the interpretation of the collected experimental data and supplementary finite element analysis data of tensile coupon tests, a three-stage model for predicting the stress-strain curves of the TC bimetallic steels over full range of tensile strain are developed. The proposed model is defined by using the four basic parameters including three basic Ramberg-Osgood parameters and an exponent parameter, together with some additional parameters that can be expressed in terms of these basic parameters. The predictive expressions for the basic and additional parameters are also proposed in this study. The accuracy of the proposed model is demonstrated by comparing its predictions with the experimental stress-strain curves of the TC bimetallic steels with various clad ratios. (C) 2019 Elsevier Ltd. All rights reserved.