Types of Steels Alloy steels contain elements such as chromium copper manganese nickel or silicon in addition to iron and carbon These elements give alloy steels additional properties as compared to carbon steels They are often stronger and harder than carbon steels Tool steels are made with added elements such as nickel and tungsten to make them especially strong These steels are used to make tools and machine parts Tool steels are usually tempered to make them tough In tempering steel is heated to a high temperature and then cooled very quickly Then it is heated again at a lower temperature Many household items are made with stainless steels This type of steel contains high amounts of chromium and nickel Stainless steels resist corrosion They are easy to clean polish and sterilize In the kitchen our refrigerator is made of steel and so many other appliances have steel components On our way to the office a job site or to school we rely on the safety of steel to reinforce our roads define our bridges and form the body of our cars and trucks As we glance out our windows we may notice that signs guardrails railroad tracks construction cranes pipes commercial buildings and telephone utility poles are all made of steel And even though we may not notice the computers we use 24-7 have steel in them 3 BUILDING A SUSTAINABLE FUTURE Steel also has an important role in the world’s sustainable future One of the biggest challenges facing countries worldwide is the growing need for sustainable energy As energy demands increase and fossil fuel reserves are depleted steel will be an integral part of delivering renewable energy 10
The structural strength of steel enables the building of tall wind turbine towers that can catch high winds hundreds of feet above the ground Modern steel can build taller stronger and lighter-weight towers for wind turbines Roofing systems using solar power combine photovoltaic cells with steel panels coated in zinc In the fields of wind solar wave and tidal power steel is an essential element for renewable energy Steel is also an important part of a variety of sustainable products High-strength steels are strong and light allowing less steel to deliver the same amount of strength Using these steels manufacturers can create lighter vehicles which require less fuel and release less emissions Such steels are also used to build energy-efficient appliances They frame energy efficient buildings too 11
Steel Automobiles According to the International Organization of Motor Vehicle Manufacturers 90 1 million vehicles were produced worldwide in 2015 a 1 1 percent increase compared to 2014 Approximately 12 million of them were built in the United States 7 On average approximately 2,000 pounds 900 kg of steel is used in each vehicle 8 Nearly every new vehicle uses high-strength steels which makes them lighter safer and more fuel efficient The steel strengthens the body structure panels and doors and it provides energy absorption to protect passengers during a crash Inside the vehicle the drivetrain uses steel to create wear-resistant gears More steel is found in the wheels tires and fuel tank as well as in the steering and braking systems Once made steel can be used again and again In fact steel is the world’s most recycled material More steel is recycled each year than aluminum copper paper glass and plastic combined According to the World Steel Association more than 65 million short tons 59 million metric tons of steel are recycled each year 4 This number is expected to grow as more communities develop local recycling programs Steel is also continuously recyclable which means it can be recycled many times without affecting its performance In addition more than 97 percent of by-products from steel manufacturing can be reused 5 For example the slag formed in steel production can be used to make concrete Steel plays a key role in the new circular business model in which all products must be designed and manufactured to be repaired remanufactured reused and recycled says Edwin Basson the Director General of the World Steel Association Steel thanks to its strength adaptability flexibility and durability is the essential material in the circular economy 6 12
Steel Recycling In the modern steel industry steel is constantly cycling through a recycling process Recycled steel along with iron ore and other raw materials is processed and used to create new steel products When those products wear out or are disposed of they become scrap steel and eventually are processed into yet more products Recycled Steel Raw Materials Steel Products Steel Production 13
