Structural steel
Structural steels are steels for steel and engineering industries.
General
The varieties most commonly used belong to the category of the base steels. They are usually low-alloyed and partially heat-treated (if heat treated then normalized, also called normalizing ). This results in moderate yield properties ( but which are sufficient for many applications ) at a reasonable price.
The distinction between construction and quality steels is no longer appropriate due to technological progress today, when a distinction is made between the classification by composition and technical parameters on one hand and on the intended use on the other. Also alloyed stainless steels can be used for example as structural steel use.
In general, include virtually all low-carbon steels to structural steels. In the carbon- yielding strains the limits are to be determined fluent and not using this rule of thumb. According to the new EN standards structural steels are all steels, which are not used directly as a tool steel. Structural steels are weldable and can be stress relieved.
Reinforcing steel, which is used as a reinforcement in reinforced concrete and prestressing steel in prestressed concrete, count under the new systematics not to the structural steels.
In the structure of the steels according to EN 10027 and you get the prefix symbol S for " Structural Steel " ( Structural steels ). The following number indicates the yield strength ( Re) in N / mm ².
Usual designations are
- S235JR AR ( new edition of EN 10025-2:2004-10, formerly S235JRG2, even earlier 37-2, material number 1.0036 to 1.0038, previous name by EU 25-72 also Fe 360 B)
- S355J2 N ( new edition of EN 10025-2:2004-10, formerly S355J2G3, even earlier St 52-3 N, material number 1.0577 or 1.0570, previous name by EU 25-72 also Fe 510 D1)
The structural steel grades are standardized in EN 10025.
The designations according to DIN 17100 with the prefix letters "ST " ( values in brackets above St 37 ... ) are invalid and should no longer be used, but are, in the still widely used. The supplement of the yield strength are additional symbols.