Structural steels

Structural steels Structural steel is a standard construction material made from specific steel grades and is available in industry standard cross sectional shapes. This steel exhibits desirable physical properties such as strength, uniformity of properties, light weight and ease of use etc. This makes it one of the most versatile structural materials in use. Major applications for these steels are in high rise and tall multi-storey buildings, industrial buildings, towers, tunnels, bridges, road barriers and industrial structures etc. The common shapes in which structural steels are available consist of sections (beams, channels, Tees section and angles), squares and rounds, hexagons, plates, pipes, hollow square sections, steel cable, Z sections and cold formed sections etc. (Fig 1). Fig 1  Some shapes of structural steels Structural grade steels have specific chemical compositions and mechanical properties required as per their application. These steels are produced as per the specifications included in different standards which are issued for structural steels. Structural steels for use at ambient or moderately elevated temperatures are of the following types. Carbon and carbon-manganese steels – In these steels the maximum content for alloying elements does not exceed the following: (i) manganese – 1.65 %, silicon – 0.40 % and (iii) copper – 0.6 %. The specified minimum of copper does not exceed 0.4 % and also there is no minimum content is specified for other elements to obtain a desired alloying effect. High strength low alloy (HSLA) steels – These steels have specified minimum yield strengths greater than 280 Newtons /Sq cm and achieve that strength in hot rolled condition rather than by heat treatment. Heat treated high tensile steels – Both Carbon and HSLA steels can be heat treated to provide yield strengths in the range of 350 to 520 Newtons/Sq cm....