engleski

Effect of heat treatment on Charpy impact energy of microalloyed steel

In this paper the microalloyed high-strength low- alloy (HSLA) Niomol 490K steel with an addition of niobium (0, 032 wt. %) has been investigated. Heat treatment of the steel consisted of austenitisation at 1250 °C for 3 minutes and reheating up to 750 °C for 5 s. After austenitization the quenching was carried out in water with temperature of 70 °C and then in a lead bath up to 400 °C following cooling on the air. It was found that Charpy impact energy is higher and the transition temperature is lower for the transformation of austenite to bainite than to martensite microstructure. Experimental results showed that different fracture surface was observed. It is shown that preferred cleavage fracture occurred in the lattice plane (001) independently of steel microstructure.

charpy impact energy, Fracture surface, HSLA steel, Microstructure, Transition temperature

nije evidentirano