Structural steels are "standard" steels for the steel and engineering industries. The varieties which are most used belong to the category of the base steels. They are usually low alloyed and not heat treated. The results are moderate properties (which are sufficient for many applications) at a low price.
The classical distinction between construction and quality steels is no longer appropriate due to technological progress today , because it discriminates between the classification according to composition and technical parameters on the one hand and by purpose other. Alloy steels are used as structural steels for example.
Generally all low-carbon steels belong to structural steels. In the carbon- yielding strains the boundaries are fluid and not to determine via this rule of thumb. Structural steels usually have a minimum tensile strength of less than 500 N / mm². According to the new DIN EN standards, all structural steels are steels, which are used not just as a tool steel.
The noble structural steel we use are boron-alloyed and then processed to produce screws and bolts. Most of them later get hardened and tempered .
Hardened and tempered screws and bolts with boron content are superior to comparable screws without boron in the dynamic strength .