Steel and its types

Steel and its types Steel is basically an alloy of iron and carbon to which sometimes other elements are added to achieve certain properties for specific performance of the steel. It is the most common material which the people come into contact with every moment, all the day and every day. There is hardly any object that people use today which does not contain steel or which is not created with equipment made of steel. In fact, today it is hard to imagine a life without the use of steel in some shape or form.  One has to just think of what would be missing in everyday life if there is no steel. Mass production of steel started late in the nineteenth century. From that time onwards steel has become the material of choice in most of the applications which make the daily lives of the people possible. This position of steel is due to its versatility, strength, and recyclability. The versatility of steel is well known. It can be used in diverse applications which includes transportation, infrastructure, building structures etc. on one side and sewing needles, screws for laptops, mother board sheets for mobile phones, springs for wrist watches and many others such smaller applications. Ballpoint pens rely on a steel sphere less than 1 mm in diameter to dispense ink. Steel can also be used in a wide variety of atmospheres which include extremes of cold and hot climates as well as in both arid and wet climates. World today depends on the strength of steel. Steel makes it possible to build skyscrapers and long span bridges since it has strength, rigidity and durability. Tankers and bulk carriers which help in moving resources across the world are made of steel. Wind mills...

Carbon and low alloy steels...

Carbon and low alloy steels  The definition of the carbon steels by American Iron and Steel Institute (AISI) is as follows: “Steel is considered to be carbon steel when no minimum content is specified or required for chromium, cobalt, columbium [niobium], molybdenum, nickel, titanium, tungsten, vanadium or zirconium, or any other element to be added to obtain a desired alloying effect; when the specified minimum for copper does not exceed 0.40 %; or when the maximum content specified for any of the following elements does not exceed the percentages noted: manganese 1.65 %, silicon 0.60 %, copper 0.60 %.” Steels can be classified based on different systems depending upon: The composition: Carbon, micro alloy, low alloy, high alloy or stainless steel. The manufacturing processes: Open hearth furnace, basic oxygen process, energy optimizing furnace or electric arc furnace. The finishing methods: Hot rolling, cold rolling or forging etc. The type of product: Flat such as plate, sheet, strip, long such as wire rods, reinforcement bars, rounds and shapes, pipes and tubes or forged products. The de oxidation method: Killed, semi-killed, rimmed or capped steel The microstructure: Ferritic, austenitic, pearlitic, bainitic or martensitic The strength levels: HSS, HSLA or normal strength to meet standard requirement The heat treatment process: Annealing, normalizing, thermo mechanical treatment, quenching and tempering etc. Quality defining designations: Forging quality, commercial quality, drawing quality or welding quality etc. Carbon steels As a group carbon steels are the most frequently produced and used steels. More than 85 % of the steels produced presently are carbon steels. Variations in the carbon content of the steels have the greatest impact on the mechanical properties of steels. Increase in the carbon content also results into increase in the hardness of the steels as well as their strengths. Hence carbon steels are generally...