Iron vs steel: Differences and which is better?

 

Iron and steel are two of the most important industrial commodities used for a variety of purposes like construction, manufacturing utensils and cookware, building machinery, etc. These commodities have shaped construction, engineering and manufacturing industry and has become indispensable components. Learning iron vs steel differences can help businesses identify which component is ideal for the requirement.

What is iron?

Iron is one of the commonly used metals that is cheap and available in plenty. According to Britannica, iron is second in abundance to aluminum among the metals of the earth. Nearly every construction of man sports a little iron.

Also read: Iron scrap rate per kg in India

How is iron made?

The chief source of iron is obtained from iron ore which is found in iron ore deposits. Iron is extracted from iron ore and partially refined to remove most of the impurities. Here is a step by step look at how iron is made:

1. Iron ore is extracted through open pit mining where a large surface of the earth is removed to expose the iron ore beneath it
2. Machines are deployed to mine the iron ore
3. The mined iron is crushed and sorted
4. The iron this obtained is refined using various methods including washing with water to float sand and clay away, magnetic separation, pelletising, and sintering
5. The iron is then put through a blast furnace and mixed with coke (processed coal), and limestone are poured into a vessel lined with heat-resistant bricks
6. The blast furnace produces liquid iron which is then used to form a workable metal.

Also read: Iron rod – Meaning, prices in India, types

Types of iron

There are three types of iron:

• Pig iron

Obtained directly from the blast furnace this is impure iron containing about 5% carbon and other impurities such as phosphorus, silicon, sulphur and manganese. Pig iron is used in steel making, foundries, alloy making, automotive castings and other iron-based castings.

• Cast iron

Manufactured from pig iron, cast iron is obtained by melting some scrap iron and pig iron and then cooled in moulds to give the desired shapes. It cannot be welded or forged. It is used to make objects that do not require high tensile strength such as stoves, lamp posts, railings, radiators and cookers.

• Wrought iron

This is considered the purest form of iron and contains only about 0.1% carbon. It is obtained by heating cast iron with iron ore and haematite in a furnace. It is used for making nails, rods, chains, horseshoes, agricultural implements, and the core of electromagnets.

Properties of iron

Like every metal iron has distinct properties:

• Malleability
• Ductility
• Ferromagnetism
• High tensile strength
• Dissolvable in dilute acids

Applications of iron

Given below are some of the objects manufactured with iron:

• Industrial machinery
• Ferrous metals/alloys and steels
• Toys
• Sports equipment
• Tools and instruments

What is steel?

Iron combined with small amounts of carbon creates steel. Although all steel is made of iron and carbon, there are different types of steel with different compositions of each element. It can also include other elements like nickel, molybdenum, manganese, titanium, boron, cobalt, or vanadium.

How is steel made?

The main raw material used to manufacture steel is iron. The main component of a steel alloy is iron and includes 0.002–2.1 % carbon by weight.

Steel is produced when pig iron undergoes the Electric Arc Furnace or EAF method or Basic Oxygen Steelmaking or BOS method.

• EAF method: This method is used to produce refined steel from scrap steel. It involves putting recycled scrap steel through a high-power electric arc with temperatures as high as 1650°C. The electric arcs melt large quantities of steel scraps into liquid. Oxygen, lime and fluorspar are then blasted into the furnace to purify the liquid and convert it to high quality steel.
• BOS method: Under this method, recycled scrap steel is added to molten iron in a furnace. This mixture is combined with oxygen at a really high temperature, to reduce the overall carbon content and create equal oxidisation throughout the molten metal.

Types of steel

There are four main types of steel used in various applications:

• Carbon steel

Featuring a mix of iron and carbon, it is the most produced steel in the world. Carbon steel is classified into three subcategories – low carbon steel (0.03-0.15% carbon), medium carbon steel (0.25%-0.50% carbon), and high carbon steel (0.55%-1.10% carbon). The higher the percentage of carbon, the harder it is to bend and weld.

• Alloy steel

Alloy steel is made by mixing metal and non-metal elements with carbon steel. These alloys have different environmental, chemical and physical properties based on the elements mixed to make the alloy.

• Tool steel

Tool steel possesses a mix of carbon, tungsten, chromium, vanadium, and molybdenum. It is known for its hardness and resistance to wear and tear making it an ideal metal for machining and tool making.

• Stainless steel

An alloy of iron with chromium, nickel, and molybdenum, stainless steel is one of the most popular metals used in every industry. This alloy is commonly used in food handling, food processing, medical instruments, hardware, and appliances as it has high corrosion resistance.

Also read: Steel vs stainless steel: Key differences in compositions, properties, and other factors

Properties of steel

Properties of steel are also based on the additives combined with it during steel manufacturing. When elements are mixed during steel manufacturing, it can increase the strength, hardness, etc., of the steel according to the element being mixed.

• Hardness
• Toughness
• High tensile strength
• Ductility
• High yield strength

Also read: Is steel more elastic than rubber?

Applications of steel

There are numerous applications of steel the scope of which is increased by the additives mixed with the alloy:

• Construction of ships and pipelines
• Automotive parts
• Chemical processing machines
• Kitchen appliances
• Industrial machinery

Iron vs steel: Differences

Iron vs steel use cases are different due to steel being an alloy that contains other substances mixed with it during the manufacturing process. Here are the differences between iron and steel:

Iron	Steel
Pure element	Alloy of iron mixed with other elements like carbon
Strong	Comparatively stronger than iron. Iron vs steel hardness is also in favor of steel
Brittle	Comparatively more brittle than iron
Easier to cast than steel due to its lower melting point.	Expensive to cast due to high melting point
Usage of iron is limited	Steel has replaced iron in most use cases as it is more durable
Rusts easily	Can withstand rust to a certain extend

Iron vs steel: Which is better?

Steel is stronger than iron when it comes to yield and tensile strength. Iron has been replaced by steel as it is the superior metal that doesn’t crack, warp, twist, rot, or split. Steel is tough and provides more stability and magnetisation than iron.

Steel when mixed with other elements forms better quality metals with additional properties. This process is followed widely in the industries for making steel with desired properties to perfectly match the industrial needs. These additional properties make steel more valuable than iron.