The various types of non-alloyed steels, i.e. without the addition of alloy elements, differ from one another in particular due to the greater or lesser presence of carbon - the higher the carbon content, the greater the hardness of the steel in question after the quenching and tempering treatment. Non-alloyed quenched and tempered steels in any case have a limited temperability and do not allow, even when tempered in water, well-transformed structures to be obtained on pieces with elevated thickness.
