Employment of Fuzzy Logic Modelling in Quenching of Steel Rods for Reinforced Concrete After Hot Rolling

Abstract

The traditional production of steel rods for reinforced concrete, a long time considered of short technological interest, has been recently modified with the development of new procedures, which enhance mechanical characteristics without adding micro-alloys. In particular, the process outlined in this paper, said tempcore process, enables to graduate mechanical and technological properties of the steel rods, so that these characteristics can vary in assigned limits. The underlying principle of this innovative process lies in surface quenching of the rods on leaving the last stand in the hot rolling mill, followed by self-tempering. Process adjustment still relies on the experience of the production manager, taking as a parameter for assessing process efficiency the temperature reached by the rod on the cooling plate. In this paper, the influence is examined of the process variables (final rod diameter, chemical composition, water flow rate and velocity), on the ultimate rod structure, upon which all mechanical properties, in general, depend. Based on the finding of a previous study, the possibility is examined of applying fuzzy logic techniques to the heat treatment process under examination with a view to rendering it more rational and independent of operator unreliability. The study will have a dual future aim. To evaluate the possibility of predicting the properties of the reinforced concrete rods when chemical composition of steel and final diameter are known, and secondly, to graduate the intensity of the treatment to obtain rods with predetermined properties from steel with known chemical composition.