Steel vs. Iron

Steel and iron are important materials in our modern society. Some people may actually interchange the two, but steel and iron are very different. Iron is an element, while steel is an alloy made up of both iron and carbon. An alloy is just a mixture of two or more elements, generally two or more metallic, or one metallic and one nonmetallic. Other elements can be added to steel to create products with different characteristics. Stainless steel is comprised of steel and chromium; this product doesn’t rust and is very durable. Other elements that can be added to steel are silicon and manganese. By adding these other elements, one can control the strength, ductility, and hardness of steel.

Steel is the main product used in construction, as it is much stronger than iron and has better compression and tension characteristics. Iron that contains more than 2% carbon is called pig iron. But iron that contains less than 2% carbon is steel. Pure iron is very soft and susceptible to rust when in contact with moist air, making it unsuitable to be used in construction or in making utensils, cookware, or many other products. Steel, in comparison, can be up to 1000 times harder than pure iron, hence its widespread use in manufacturing many products we use today.

Although steel is much stronger than iron, it is still very malleable and thus able to be manipulated to create certain shapes. Because of it’s properties, it is the most common alloy used today. It is used for manufacturing weapons, vehicles, tools, buildings, and more. One famous building, the Eiffel Tower, was constructed from puddle iron, which is an iron alloy with very low carbon levels. If it was built today though, it would likely be made of steel.

An important form of iron is that found in our bodies. It is used to carry oxygen to the body in the form of hemoglobin. Many foods we eat are rich in iron such as red meat, tofu, beans, and fish. People who are iron deficient can take iron pills, to ensure that they don’t suffer from fatigue and weakness which is common in those with low iron levels. Vegetarians are among those most at risk for iron deficiency.

As you can see, there are many differences between iron and steel. Steel is comprised of iron and carbon, it is malleable, and has a greater strength than pure iron. Iron was very common before steel production became cheap. Today steel is used in manufacturing many products and for constructing bridges, railroads, buildings, and more. So next time someone confuses steel and iron, you can explain just how different they are.

Key Facts About the World Steel Industry

 

Steel: A key driver of the world’s economy

• The industry directly employs more than two million people worldwide, with a further two million contractors and four million people in supporting industries.
• Considering steel’s position as the key product supplier to industries such as automotive, construction, transport, power and machine goods, and using a multiplier of 25:1, the steel industry is at the source of employment for more than 50 million people.
• World crude steel production has increased from 851 megatonnes (Mt) in 2001 to 1,606 Mt for the year 2013. (It was 28.3 Mt in 1900).
• World average steel use per capita has steadily increased from 150kg in 2001 to 225 kg in 2013.
• India, Brazil, South Korea and Turkey have all entered the top ten steel producers list in the past 40 years.

Sustainable steel: At the core of the green economy

Steel is at the core of the green economy, in which economic growth and environmental responsibility work hand in hand.

• Steel is the main material used in delivering renewable energy – solar, tidal and wind.
• All steel created as long ago as 150 years can be recycled and used in new products and applications.
• By sector, global steel recovery rates for recycling are estimated at 85% for construction, 85% for automotive, 90% for machinery and 50% for electrical and domestic appliances. This leads to a global weighted average of more than 83%.
• The amount of energy required to produce a tonne of steel has been reduced by 50% in the past 30 years.
• 97% of steel by-products can be reused.
• Figures for water uptake and discharge are close to each other, with any small loss due to evaporation. Water recycled back into rivers and other sources is often cleaner than when extracted.

Steel: Everywhere in our lives

Steel touches every aspect of our lives. No other material has the same unique combination of strength, formability and versatility.

• Almost 200 billion cans of food are produced each year. Steel cans mean saving energy as refrigeration is not needed. Cans mean tamper-free and safe food, nutritional value and beneficial environmental impact from recycling.
• Steel used for double-hulled capesize vessels delivering raw materials, finished goods and energy must have the highest impact toughness (to withstand constant wave motion), corrosion resistance (from sea water) and weldability (for manufacturing reasons).
• Skyscrapers are made possible by steel. The housing and construction sector is the largest consumer of steel today, using around 50% of world steel production.
• Approximately 25% of an average computer is made of steel. More than 305 million PCs were sold in 2012.
• Steel looks after our health. Steel surfaces are hygienic and easy to clean. Surgical and safety equipment and commercial kitchens are all made with steel.

Safe, innovative and progressive steel

Steel is an innovative and progressive industry committed to the safety and health of its people.

• The industry is committed to the goal of an injury-free workplace.
• The lost-time injury frequency rate has decreased from 5.1 in 2004 to 1.41 in 2012.
• The number of worldsteel member organisations participating in the annual safety metrics survey has increased from 46 in 2005 to 89 in 2012.
• The steel industry globally spends more than €12 billion annually on improving the manufacturing process, new product development and future breakthrough technology.
• New lightweight steel is dramatically changing the market. In 1937, 83,000 tonnes of steel were needed to build the Golden Gate Bridge in San Francisco. Today, only half of that amount would be required.
• Vehicles structures using Advanced High Strength Steel (AHSS) weigh up to 35% less than those made with former conventional steel, substantially reducing greenhouse-gas emissions.

Life cycle thinking: New solutions for new times

• Life cycle assessment (LCA) is vital for the future. Environmental regulations that only regulate one phase (the use phase) of a product’s life cycle can create unintended consequences, such as increased CO₂ emissions.
• One example of this is vehicle exhaust or tail pipe regulations, which encourage the use of low density materials that are more CO₂ intensive to produce.
• LCA considers production, manufacture, the use phase and end-of-life recycling and disposal. Life-cycle thinking leads to immediate environmental benefit.
• In addition to CO₂, LCA assesses other impacts such as resource consumption, energy demand and acidification.
• LCA is easy to implement, cost effective and produces affordable and beneficial solutions for material decision-making and product design.
• worldsteel developed one of the first global sector databases for life cycle inventory data, and invests on a regular basis to keep it up to date.

Source: World Steel Association