Steel is one of the most common metals used for structural applications. It is strong, tough, ductile, formable, weldable, and, equally as important, affordable. As there are many different types of steels available, each with unique chemical and mechanical properties, it is important to know some of the key attributes of S275 steel.

Chemical Composition

S275 is a low carbon steel. Low carbon steels are classified by having less than 0.3% carbon by weight. With a maximum carbon of 0.25%, S275 steel is easily machined, welded, and formed, making it extremely useful as a general-purpose steel. The low carbon also prevents heat treatment from having much of an effect on S275 steel. S275 steel usually has small amounts of other alloying elements as well, including manganese, sulfur, phosphorus, and silicon. These alloying elements are added to give the steel its desired chemical and mechanical properties. Since S275 does not contain large amounts of nickel or chromium, it lacks corrosion resistance.

Designation

Unlike most steel grades, S275 is not designated by its chemical composition. Instead, S275 is designated by its mechanical properties. This means that, while most grades must have added alloys that fit between certain percentages, S275 must meet specific mechanical standards. For example, steel bars and plates must have a minimum yield strength of 36,000 ksi or 275N/mm² – hence the name S275. The tensile strength must be the range of 370 – 530 MPa.

How S275 is Made

S275 is made in a fashion similar to most carbon steels. First, iron ore and coal are combined in a furnace. Impurities are burned away and alloying elements are added to the molten steel. Once the chemical composition of the S275 steel is achieved, it is solidified in into a rectangular ingot. S275 steel is normally hot rolled. This means that it is formed to its final dimensions in using rollers while the ingot is at an elevated temperature.

Common Uses

S275 steel is used in many different industries for a variety of applications because of its relatively low cost. As mentioned, the mechanical properties make it particularly suited for structural applications. Many bridges are constructed with S275 steel. Likewise, buildings are frequently created with S275 steel because of its high strength and toughness. S275 steel is also used for components in the automotive, construction, heavy equipment, and oil and gas industries.