Microstructure and Mechanical Properties of the Heat Treated Hy-TUF Steel

Abstract

A study of the high-strength HY-TUF steel applied for the manufacturing of heavy loaded parts was carried out. The mechanical properties of the austempered HY-TUF steel were compared to the characteristics obtained after the conventional oil quenching and tempering. The upper bainite with low impact strength was formed during the austempering at 400 °C and higher. Conventional oil quenching and tempering at temperature 400...500 °С also led to the embrittlement of the steel under consideration. The best combination of toughness and strength of the HY-TUF steel was achieved after the austempering at the temperature of lower bainite formation.