Hardenability Characterization and Microstructural Evolution in Heavy Gauge Plate Steels

High strength heavy gauge plate steels for structural applications are used in the construction of buildings, bridges, sport stadia, power plants, etc. In order to reach the desired mechanical properties, these steels are subjected to a quenching process followed by a tempering treatment. However, different cooling rates are obtained throughout the thickness of the material during quenching and several grades do not fully harden to martensite. In the present study, six alloys containing 0.17 wt pct carbon and different amounts of molybdenum, vanadium, chromium, and silicon were used. The objective was to characterize hardenability by evaluating the influence of alloying on hardness and microstructure. The Jominy End-Quench test was used to assess hardenability and scanning electron microscopy was conducted for microstructural characterization. The effects of grain size and alloying content to the obtained hardenability response for each alloy is discussed.