Cold forming of hot strip or cold rolled sheet is a standard production step especially in the automotive industry. For tensile strength levels above 500 N/mm(2) microalloyed HSLA steels are quite. acceptable for many applications. However, dual-phase steels are also available for applications requiring superior formability. These steels, which have a dual/tri phase microstructure are produced by various processing routes or heat treatment, tuned with the chemical composition. Transformation induced plasticity can be incorporated. into certain kinds of dual phase steels, further improving user properties. In the optimization of all types of these steels it turned out, that microalloying with niobium improves the mechanical properties, especially by refining the microstructure. This not only includes higher tensile properties, also the ductility gets further improved, resulting in an exponential increase of the characteristic product tensile strength times elongation with higher niobium, levels. Consequently optimized multiphase steels rely also on the microalloy niobium.