Quenched-and-tempered (QT-) steels are used for applications needing a good combination of strength and toughness. Low-alloy QT-steels are supplied in heat-treated execution. Generally speaking, QT-steels can be subjected to higher static or variable loading than other simpler steels for structures and machines. QT-steels are thus an interesting option for weight reduction of parts that do not require welding.
The hardness of QT-steels is rather high and machining can be troublesome. Through so-called M-treatment, machinability is improved considerably with few negative repercussions for other properties. For this reason, QT-steels in Tibnor’s stock programme are for the most part M-treated.