Quenched and tempered high strength steel: A review

Abstract

Quenched and tempered steel are broadly classified as low alloy conventional grades with C content of 0.15-0.40% and tool steels with C content as high as 2% alloyed with strong carbide forming elements such as Cr, V, Mo etc. in the range of 1-12%. In both the cases, steels are used in hardened/quenched and tempered or auto tempered condition for improved toughness, strength and wear resistance. The C content and tempering temperature are optimized based on desired application. However, achieving high strength/hardness along with adequate toughness is a challenge. The chemistry design is one of the important parts of developing these grades. The judicious amount of hardenability elements like Mn, Cr, Mo, B etc. are added for achieving required as quenched hardness while excess addition of these elements will not be cost effective. Optimized austenite grain size before quenching is also key to achieve hardenability as well as toughness. All these points have been reviewed systematically in this paper for the first time as there is no such review available covering all aspect of quenched and tempered grade. Unlike text books or any past review articles, this is a systematic review of quenched and tempered steel which will help in designing suitable chemistry and process parameters for producing different grades of quenched and tempered steel in industrial scale.