Research on Heat Treatment Applied to High Strength Construction Steels

Résumé

The paper presents the research carried out on a laboratory scale in order to establish the heat treatment parameters for the thick sheets used for naval constructions (welded joints). Investigations were carried out on steel sheets with two different chemical compositions.
In the same cooling conditions, returns were made at different times and temperatures. For the different sheet thicknesses of 15, 20, 22 and 24 mm, various heat treatment options were performed, by changing the cooling conditions of the sheets, respectively the cooling speeds, conditions that can be achieved in the industry.
The laboratory results showed that the required values for the mechanical characteristics are obtained only by cooling in water under pressure followed by a return at temperatures equal to or greater than 650 °C, a time greater than 70 min.