RESEARCH ON THE POSSIBILITY OF IMPROVING THE VALUE OF LOW CARBON CHEAP STEELS BY CONTROLLED THERMAL PROCESSING

In this research paper, the authors present the possibility of efficiently improving the value of ordinary cheap steels by applying a controlled thermal processing technology. The studies showed that a controlled technological process applied in continuous flux on steel straps with known chemical composition can lead to a stressed structural state giving the material either an impressive increase of the tensile strength together with a high enough strain to avoid catastrophic failure; either a high strain together with a high tensile strength. The paper presents the structure and the mechanical characteristics (tensile strength and strain) obtained after the quenching-tempering thermal treatment on thin (<1mm) low manganese carbon steel straps, produced without any special prescription for purity. In order to perform the experiments an installation for continuous flux thermal treatment was built. The installation was equipped with automatic control of the quenching furnace temperature, the tempering furnace temperature and automatic control of the steel strap's speed. For the quenching treatment several quenching devices were designed, build and tested having the possibility to test different cooling speeds. For the experiments presented in this paper only the tempering temperature was varied while all the other technological parameters were kept constant.