The HIPERC study was a European research project involving several steel companies and research organisations which examined the effects of alloying elements and processing conditions in low carbon (<0.09 wt %),niobium containing (0.05%-0.12 wt.%) steels.Laboratory-scale heats and pilot rolling trials simulating air and water-cooled plate production as well as hot-rolled strip production were made and the effects of C,Mn,Ni,Cu,Cr,Mo,Nb,Ti and B on transformation characteristics and temperatures of recrystallisation determined.Regression equations for the characterisation of microstructure,tensile and impact properties and for the weldability of these steels were derived.Steels were manufactured and processed into plate and coil-plate by three steel companies and pipe produced from both products.Properties from these,plus thicker plate for structural use,were determined and these compared well with the values predicted from the regression equations.The project has shown that excellent combinations of strength,toughness and weldability can be obtained for a wide variety of applications.Economic benefits were seen and recommendations on altering the limits for niobium in Euronorms have been proposed. The HIPERC study was a European research project involving several steel companies and research organizations dealing with the effects of alloying elements and processing conditions in low carbon (<0.09 wt%), niobium containing (0.05% -0.12 wt.%) Steels. Laboratory- scale heats and pilot rolling trials simulating air and water-cooled plate production as well as hot-rolled strip production were made and the effects of C, Mn, Ni, Cu, Cr, Mo, Nb, Ti and B on transformation characteristics and temperatures of recrystallization determined. Regression equations for the characterization of microstructure, tensile and impact properties and for the weldability of these steels were derived. Steels were manufactured and processed into plate and coil-plate by three steel companies and pipe produced from both products. Properties from these, plus thicker plate for structural use, were determined and these compared well with the values ​​predicted from the regression equations. The project has shown that excellent c ombinations of strength, toughness and weldability can be obtained for a wide variety of applications. Economic benefits were seen and recommendations on altering the limits for niobium in Euronorms have been proposed.