The Influence of Microstructural Features and Mechanical Properties on the Cold Formability of Ferritic Steel Sheets

In the present study, the formability of cold rolled and annealed steel sheets having carbon equivalent values in the range of 0.028 to 0.098 wt% were investigated. The steel sheet having the lowest carbon equivalent was a titanium-stabilized interstitial free steel, which established the highest strain hardening exponent, anisotropy coefficient and higher Forming Limit Diagram (FLD). Since plain strain intercept (FLD₀) is the most critical strain limit on the FLD, the empirical equations were derived between FLD₀ and microstructural features and mechanical properties. As a microstructural feature grain size and as a mechanical property anisotropy coefficient gave the most reliable correlations.