Author(s):
1. Mirko Gojić, Croatia
2. Gorazd Kosec, Acroni d.o.o., Slovenia
3. Franc Vodopivec, Slovenia
4. Stjepan Kožuh, 1University of Zagreb, Faculty of Metallurgy Sisak, Croatia
5. Jelena Vojvodič Tuma, Slovenia
6. Aleš Nagode, University of Ljubljana, Faculty of Natural Science and Engineering, Slovenia
7. Borut Kosec, University of Ljubljana, Faculty of Natural Science and Engineering, Slovenia

Abstract:
In this paper the effect of heat treatment on mechanical properties and microstructure for microalloyed high-strength low-alloy (HSLA) steel is investigated. Austenitization of the steel samples was performed at 920 oC for 15 minutes. After austenitization the quenching procedure was carried out in both, hot water (at 70 °C) and lead bath at 400 oC, following by cooling on air. Tensile strength, hardness and Charpy impact energy are tested. Microstructural analysis was carried out using optical and scanning electron microscopy. Values of tensile strength were in the range from 1160 to 1824 MPa, while values of hardness were in the range from 205 to 282 HV. The microstructure of base material consisted of acicular ferrite and degenerated pearlite. The quenching in water from 920 oC produced a coarse microstructure with platelets of ferrite and lath primary martensite. The cooling in lead bath from 920 oC to 400 oC produced microstructure consisted from ferrite and bainite.

Key words:
microalloed steel, heat treatment, mechanical properties, microstructure

Thematic field:
Chemical Engineering

Date of abstract submission:
15.07.2016.

Conference:
XI Savjetovanje hemičara, tehnologa i ekologa Republike Srpske

Abstract Final paper