Effect of cold rolling and annealing on mechanical properties of HSLA steel

Purpose: was to examine effect of the parameters of cold deformation and recrystallization annealing on mechanical properties of a Nb-microalloyed HSLA steel. Design/methodology/approach: Research of strip steel QStE 420 was based on a combination of laboratory cold rolling, recrystallization annealing in vacuum furnace, mechanical (particularly tensile) tests and metallographic analyses. Findings: It was validated that by a sophisticated combination of size of previous cold reduction size and parameters of the following annealing it is possible to impact markedly a set of final properties of particular strips. Formability of the studied HSLA steel rises and vice versa strength properties fall with an increasing temperature of annealing. Research limitations/implications: The experiment should be supplemented by additional TEM analyses explaining the behaviour and role of precipitates. Practical implications: The experimentally obtained particular trends of mechanical properties may be utilized for optimization of conditions of heat treatment of the investigated HLSA steel in a cold strip rolling mill, reflecting the specific requirements for a relation between strength and plastic properties. Originality/value: Experimental potentialities of the Institute of Modelling and Control of Forming Processes in the sphere of cold rolling and heat treatment were introduced in their integrity for the first time.