Structural steel is used in the steel skeletons of buildings and for bridges, crane masts, wind turbines, etc. Characteristics of structural steel are good weldability, good machinability and a relatively low price. High-tensile steels belong to a more or less special group within structural steel and have an improved strength to weight ratio.
An example of an application using high tensile steel is the construction of the masts of mobile cranes.
Here are more examples of the designation of some widely-used steel grades:
S355J2+N (EN 10025-2).
S stands for Structural
355 is the designation of the minimum yield strength (in N/mm² (MPa)) in the smallest thickness range.
J2 is the designation that refers to the notch impact value at a certain temperature: 27 Joules at - 20°C
+N indicates that the material is normalised.
S690 QL (1), S960 QL (EN 10025-6).
These are designations of refined, fine-grained steels with (very) high tensile strength. They are used in constructions where the combination of high strength and low weight is important, such as movable bridges and the masts of mobile cranes.
S stands for Structural, (structural steel). 690 and 960 indicate the values of the yield strength in N/mm² (MPa) in the smallest thickness range.
Q stands for Quenched.
L indicates that the impact value (27 Joules) was measured at a temperature of - 40°C,
L1 indicates that this impact value has been measured at a temperature of - 60°C.