EP2309012B1 - High Yield Ratio and High-Strength Cold Rolled Thin Steel Sheet Superior in Weldability and Ductility, High-Yield Ratio High-Strength Hot-Dip Galvanized Cold Rolled Thin Steel Sheet, High-Yield Ratio High-Strength Hot-Dip Galvannealed Cold Rolled Thin Steel Sheet, and Methods of Production of Same | Patent Bear