STEEL- A CONSTRUCTION MATERIAL GROUP MEMBERS -Aayush nair -Anushka Juneja -Bhavya Soni -Dhruvi Galiara -Harshil Shah -Nishikesh Tathe 14SA105 14SA110 14SA117 14SA123 14SA126 14SA156
ORIGIN Steel has been known in antiquity but the actual origin of steel is not to be known. The development of steel can be traced back to 4000 years to the beginning of the Iron Age. The earliest known production of steel is a piece of ironware excavated from an archaeological site in Anatolia and thus, the Iron Age began. Proving to be harder and stronger than bronze, which had previously been the most widely used metal, iron and steel began to displace bronze in weaponry and tools.
COMPOSITION Steel is an alloy of iron and carbon that is widely used in construction and other applications because of its high tensile strength and low cost. It also comprises other elements such as carbon, manganese, sulphur, nickel, chromium and more. Variations in steel compositions are responsible for a great variety of steel grades and steel properties. Carbon, other elements, and inclusions within iron act as hardening agents that prevent the movement of dislocations that naturally exist in the iron atom crystal lattices. Steel's strength compared to pure iron is only possible at the expense of ductility.
TYPES OF STEEL Carbon steel Alloy steel Stainless steel Tool steel
CHEMICAL PROPERTIES Mild steel Most common form of steel. Contains up to 0.25% carbon. Inexpensive and strong. Is not corrosion resistant and will readily oxidise when exposed to air. Stainless steel: Contains combination of: vanadium, molybdenum, chromium, nickel, titanium and silicon. Tends to resist corrosion and other forms of chemical attacks.
PHYSICAL PROPERTIES Ability to cool down rapidly from an extremely hot temp after being subjected to water or oil. Includes high strength, low weight, durability, ductility and resistance to corrosion. Good conductor of electricity. Fire resistant. Higher the carbon contents the harder and stronger is the steel content. On the contrary high quality steel containing less carbon is more ductile. Galvanized steel coated with zinc, stainless steel with chromium to protect it from corrosion.
MAKING OF STEEL Steelmaking is the process for producing steel from iron and ferrous scrap. Impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon are removed from the raw iron, and alloying elements such as manganese, nickel, chromium and vanadium are added to produce different grades of steel. There are two major processes for making steel, such as: - Basic oxygen steelmaking which has liquid pig-iron from the blast furnace and scrap steel as the main feed materials. - Electric arc furnace (EAF) steelmaking which uses scrap steel or direct reduced iron (DRI) as the main feed materials.
Oxygen steelmaking is fuelled predominantly by the exothermic nature of the reactions inside the vessel where as in EAF steelmaking, electrical energy is used to melt the solid scrap and other materials. In recent times, EAF steelmaking technology has evolved closer to oxygen steelmaking as more chemical energy is introduced into the process.
RECYLING PROCESS Sorting Bailing Shearing Media separation Melting
TYPES OF PROCESSES BESSEMER PROCESS First inexpensive industrial process. Key principle: removal of impurities from iron by oxidation SIEMENS-MARTIN PROCESS A kind of open-hearth process GILCHRIST THOMAS PROCESS A type of Basic Bessemer Process
BESSEMER PROCESS SIEMENS-MARTIN PROCESS
STEEL AND BUILDING INDUSTRY A steel building is a metal structure fabricated with steel for the internal support and for exterior cladding, as opposed to steel framed buildings which generally use other materials for floors, walls, and external envelope. They are classified into specific types depending on how they are used. Steel buildings first gained popularity in the early 20th century and have been widely accepted due to the cost efficiency. The range of application has expanded with improved materials, products and design capabilities with the availability of computer aided design software.
ADVANTAGES IN CONSTUCTION Steel is a "green" product; it is structurally sound and manufactured to strict specifications and tolerances. Energy efficient and also can be erected easily. Recyclable and thus a repetitive use is allowed. Doesn t warp, buckle, twist or bend, and is therefore easy to modify and offers design flexibility. Is also easy to install. It is cost effective and rarely fluctuates in price. Allows for improved quality of construction and less maintenance, while offering improved safety and resistance. Has good fatigue strength. Also the steel buildings and steel bridges can be extended and widened.
DISADVANTAGES IN CONSTRUCTION Heat conductivity: Steel conducts heat 10 times more in comparison to wood which reduces the strength of steel. Corrosion: Faulty design leads to the corrosion of iron and steel in buildings. Fireproofing: As steel has high conductivity, steel frames must have adequate fireproofing which increases the cost. Maintenance: Due to corrosion, steel structures are to be painted regularly.
USES OF STEEL
USES IN BUILDING INDUSTRY Strength, beauty, design freedom -offers more design freedom in colour, texture and shape. -combination of strength, durability, beauty, precision and malleability gives architects broader parameters to explore. Fast, efficient, resourceful -can be assembled quickly and efficiently in all seasons. -steel s lighter weight enables a smaller, simpler foundation. Adaptable and accessible -steel-built structures can cater for any types of changes. -steel framing and floor systems allow easy access and alterations to existing electrical wiring, computer networking cables and communication systems.
Less columns, more open space -steel sections provide an elegant, cost-effective method of spanning long distances. Endlessly recyclable -When a steel-framed building is demolished, its components can be reused or circulated into the steel industry. Added fire resistance Earthquake resistance -It flexes under extreme loads rather than crushing or crumbling. Aesthetics, meet function More usable space, less material Lighter and less impacting on the environment
USES OF STEEL IN DIFFERRENT FIELDS
EIFFEL TOWER
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