Steel and iron are two of the most often utilized metals in manufacturing. Generally speaking, iron is a naturally occurring metal element on earth. It is extremely versatile and one of the strongest and cheapest metals. Meanwhile, it is a crucial element in plant and animal life. However, steel is a man-made alloy created by mixing iron and carbon. It can be found in various human-made objects, from flatware to warships, skyscrapers, and space rockets.
While most people use the terms interchangeably, steel and iron are two distinct metals. This article will discuss their brief introduction, types, and differences between steel and iron. Read on for a detailed look at how iron and steel are different.
What is Steel?
Steel is an alloy of iron and carbon. By weight, steel contains about 2.14% carbon. The presence of carbon gives steel higher strength and fracture resistance than other types of iron. Steel can be added to other elements like silicon, manganese, phosphorus, sulfur, and oxygen, improving its properties. For example, corrosion- and oxidation-resistant stainless steels often require an extra 11% chromium. Here, the chromium with a lower oxidation potential is oxidized. This keeps the iron from getting oxidized. As a result, steel shines for much longer.
Steel can be used in construction, infrastructure, tools, ships, trains, vehicles, machines, electrical appliances, and weapons due to its high tensile strength and low cost. It is also important in the usage of steel guides for bespoke prototyping.
What are the Types of Steel?
Steel, as an alloy, may be strengthened by adding different chemical elements. This makes it possible to make more than 3,500 different steel grades, each with its properties. Nonetheless, these steel grades are commonly classified into four different types: carbon steel, alloy steel, tool steel, and stainless steel.
Carbon Steel
Carbon steel is the most prevalent type, accounting for 80% of all steel produced daily. Carbon steel is further grouped into low-carbon or mild steel, medium-carbon steel, high-carbon steel, and ultra-high-carbon steel based on carbon content.
Low-carbon Steel
Low-carbon steel, commonly known as mild steel, is the most popular type because it is inexpensive and has material properties suitable for various uses. Low-carbon steel has a carbon content of about 0.05-0.25%, making it malleable and ductile. Mild steel has low tensile strength but is cheap and easy to shape. The surface hardness of low-carbon steel can be enhanced by carburizing.
Medium-carbon Steel
The carbon content in medium-carbon steel is 0.3-0.6%. It has a strong wear resistance and a nice balance of ductility and strength. This steel grade usually makes machine components like shafts, axles, gears, crankshafts, couplings, and forgings. It could also be used to make rails and wheels for trains.
High-carbon Steel
Carbon makes up between 0.60 and 1.00% of high-carbon steel. Its hardness is higher than the other grades, but the ductility is lower. High-carbon steel could be made into springs, rope wires, hammers, screwdrivers, and wrenches.
Ultra-high-carbon Steel
The carbon percentage of ultra-high-carbon steel is roughly 1.25-2.0%. Steels that can be tempered to a high degree of hardness. This steel grade might be used for hard steel objects like truck springs, metal cutting tools, and other unique applications such as (non-industrial) blades, axles, or punches. Powder metallurgy serves to make the majority of steels with more than 2.5% carbon content.
Alloy Steel
Besides iron and carbon, alloy steels contain additional elements in sufficient quantities to affect the properties of the base steel, such as vanadium, molybdenum, or cobalt. Alloy steel has been alloyed with a range of elements in total proportions ranging from 1.0% to 50% by weight to improve its mechanical properties. Alloy steels are separated into two categories: low-alloy steels and high-alloy steels.
Tool Steel
Tool steel is an alloy steel that is very hard and is used to produce tools, dies, and parts for machines. They’re constructed of iron and carbon, with other elements like nickel, molybdenum, or tungsten added for enhanced hardness and wear resistance. Tool steels are also toughened by tempering, which involves heating steel to a high temperature, immediately cooling it, and then heating it again to a lower temperature.
Stainless Steel
Stainless steels are low-carbon steels that contain at least 10% chromium with or without other alloying elements. Because of its strength and corrosion resistance, it is frequently used in transportation and processing equipment, engine parts, and firearms. The presence of chromium enhances the hardness, strength, and corrosion resistance of stainless steel. Nickel provides comparable benefits but adds hardness without compromising ductility or toughness. It also lowers thermal expansion, resulting in greater dimensional stability.
What is Iron?
The symbol for iron is Fe, and its atomic number is 26. It is the most common element on earth by mass, merely ahead of oxygen. Iron makes up most of the outer and inner cores of the earth. It is the fourth most common element in the crust of the earth. In reality, iron is not the robust metal that is commonly employed to support buildings and bridges. Iron used in building and other purposes is not pure iron but rather an alloy blended with other elements to obtain the physical properties for which it is now famous.
Pristine and pure iron is a silvery-gray material that is very soft and brittle. Even though it has poor mechanical properties, pure iron possesses outstanding thermal and electrical conductivity and extraordinary magnetic properties. However, iron easily reacts with oxygen and water to make rust, which is hydrated iron oxides that are brown to black. High-purity irons (such as electrolytic iron) are more corrosion-resistant.
What are the Types of Iron?
Pure iron is too soft and reactive to be very useful, so most of the “iron” we use daily is iron alloys, made by mixing iron with other elements (especially carbon) to make stronger, more resilient metal forms like steel. Some common iron types include pig iron, cast iron, and wrought iron.
Pig Iron
Pig iron is the name given to basic raw iron because it is manufactured as chunky molded blocks known as pigs. A blast furnace is used to heat an iron ore high in iron oxide to make pig iron. It’s a huge industrial fireplace in the shape of a cylinder. Huge hot air is blown into it in regular “blasts”.
The iron ore reacts chemically with coke (a carbon-rich type of coal) and limestone within the furnace. In a chemical process called “reduction”, the coke “pulls” the oxygen from the iron oxide, producing a relatively pure liquid iron. The limestone helps eliminate the other parts of the rocky ore, like clay, sand, and small stones, which make up a waste slurry called “slag”.
The iron created in a blast furnace is an alloy comprising 90-95% iron, 3-4% carbon, and traces of additional elements such as silicon, manganese, and phosphorus. Pig iron is way harder than 100% pure iron, yet it is still too weak for most ordinary applications.
Cast Iron
Cast iron is just liquid iron that has been cast. The iron is melted, poured into a mold, and cooled and hardened to produce a final structural shape, such as a pipe, gear, or large iron bridge girder. Cast iron’s high carbon content (about the same as pig iron—approximately 2-4%) makes it exceedingly hard and brittle: big carbon crystals in cast iron prevent iron crystals from migrating around. Cast iron has two major disadvantages: first, because it is hard and brittle, it is nearly impossible to shape even when heated; second, it rusts quite readily.
Wrought Iron
Wrought iron is a unique substance formed by mixing liquid iron with slag (leftover waste). It is an iron alloy that has a fairly low carbon content. Wrought iron is softer and less tough than cast iron, allowing you to shape it more readily and less prone to rusting.
Steel vs. Iron: What are Their Differences?
While both metals begin with the same base compound but convert into distinct metals after manufacture. As a result, they frequently display variances. Let’s look more closely at the difference between steel and iron.
Elemental Composition
Iron is a natural element found in rocks beneath the earth’s surface, and steel is made by mixing iron with other elements. Before mixing iron with other elements, it must be refined and added carbon. You add elements such as manganese and silicon to create various types of steel. Alloy steels may be obtained by adding chromium, nickel, molybdenum, and other elements. For example, people can add chromium and nickel, resulting in stainless steel. Stainless steel is extremely valuable since it is far more durable than standard steel and rusts slowly. Since certain stainless steels are corrosion resistant, they are utilized to produce cutlery.
Corrosion Resistance
Corrosion is a natural process that changes the metal composition through chemical oxidation. Oxidation causes metal to rust and become orange. Steel is believed to be significantly more corrosion-resistant than iron.
Iron is prone to oxidation and so rust. While water can compromise steel’s integrity, some steps can be taken to lessen this risk and boost resistance. For example, steel can have protective paints and sprays on its surface. In addition, it can also be covered with fire-resistant materials against corrosion. Steel is also a non-porous alloy, which is naturally corrosion-resistant.
Strength and Weight
Steel has a higher density and is stronger than iron. Because of its high strength and versatility, steel is widely used in buildings, residences, and railway lines. Steel is also lighter than iron and can handle tensile stress better. The strength and weight of steel make it unlikely to warp, distort, or bend.
Cast iron is well-known for its strength but not for its ductility. However, cast iron may be more brittle and less helpful in the building. Since this is the case, iron is more often used to make tools.
Durability and Weather Resistance
Steel is the greatest material to use when constructing a structure that will withstand the test of time and the elements. Extreme force and heat may be tolerated by structural steel. This implies it can endure fire and resist other elements like wind and rain. Steel is less likely than iron to be impacted by mold or mildew.
Steel is recognized as one of the most enduring construction materials due to its versatility. Steel does not deform, twist, fracture, or rot. Iron can’t share these characteristics. Steel’s durability is one of the primary reasons it is preferred over iron in building projects. Steel is also well adapted to producing sections like I Beams and simple cross sections.
Versatility
Steel gives us flexibility and inventiveness in the building. Steel may be bent and shaped to meet the requirements of any project. Because of this, steel is used to make parts with complicated shapes, like hollow cross-section parts. Architects favor steel due to its flexibility in design and expression without sacrificing functionality.
Iron is frequently too soft to utilize in its pure form. Iron’s versatility rises when combined with an alloy or carbon. In the past, architects liked iron because it could be shaped into complicated shapes. This resulted in numerous classic ornamental elements that may still be seen today. While iron allows for beautiful ornamental elements in architecture, it is not as versatile as steel.
Cost and Economy
Structural steel is usually more economical to utilize in the building than iron. Steel has been an economically beneficial material due to mass production since the Industrial Revolution.
Structurally, steel has much more lightweight than iron. This has a significant influence on overall construction costs. Steel production is also thought to be less expensive than iron production. The price of steel is affected by its grade. Similarly, the higher grade will also affect iron prices. Stronger irons, such as cast iron, need greater manufacturing levels, resulting in higher prices.
Sustainability and Eco-friendly
Both iron and steel are considered environmentally friendly and sustainable. Structural steel is 100% recyclable and one of the most sustainable materials in the building sector. Steel may be recycled indefinitely without sacrificing durability. Steel is considered better for the environment than iron because it is long-lasting.
While iron is recyclable, its production process is energy-intensive manner. Besides, iron is less sustainable because the steel industry’s carbon footprint is lowered.
Colors and Applications
Steel is typically silver in color; however, this varies depending on alloys and coatings. Iron is a silver-grey element that occurs naturally.
Steel is used everywhere: pipes, nuts and bolts, fasteners, valves, TMT, structures, defense, railway parts, aerospace, etc. Buildings and infrastructure, mechanical equipment, and automobiles are three important applications in that steel is used. Iron has three important uses: as a central ingredient of metals and alloys, magnets, and manufactured metal goods.
Steel vs. Iron: What are Their Advantages And Disadvantages?
Because of their strength, durability, and versatility, steel and iron are two prominent metals in manufacturing. Knowing the advantages and disadvantages of steel and iron can help you decide which one to choose. Let us examine them more closely.
Advantages And Disadvantages of Steel
Advantages of Steel
- Steel is a versatile material with several applications.
- Steel is extremely strong, long-lasting, and resistant to corrosion and fire. As a result, it is perfect for building projects where safety is a priority.
- Because of its malleability, steel can be readily shaped into complex designs or structures.
- Steel may give the strength and durability you want for any home improvement project.
Disadvantages of Steel
- Steel tends to be more expensive than other materials like aluminum.
- Because steel is so heavy and dense, it requires specialized tools and equipment, which can add further costs.
Advantages And Disadvantages of Iron
Advantages of Iron
- Iron could fill intricate molds.
- Cast irons have good machinability.
- Iron is durable, can withstand extreme weather conditions, and can last long without maintenance.
- Iron is also fire-resistant, making it an ideal choice for construction.
- Iron is easily available in large quantities as compared to steel.
Disadvantages of Iron
- Iron is susceptible to rusting, which weakens its structure over time.
- Iron is dense and heavy so transportation can be costly.
- Iron will often be too soft for use in its pure form.
Steel vs. Iron: Which One to Choose?
The primary distinction between iron and steel is that the former is a naturally occurring element, while the latter is an alloy of iron and carbon, which does not exist naturally.
Steel is stronger than iron in yield and tensile strength domains but is also substantially tougher. Steel is superior for various purposes because it does not fracture, bend, twist, rot, or split.
Aside from stainless and galvanized steel, all steels are generally corrosive, but since they are non-porous alloys, they do not get corrosion as easily as iron. Putting on a protective coating helps a lot with this.
Steel is lighter, stronger, and more durable than iron, and employing steel is cheaper and more effective in most circumstances and conditions. On the other hand, iron is more ductile than steel, which means it can be readily shaped and molded. The choice of these two metals depends on your project’s required properties and application.
In Summary
Iron is a ferromagnetic metal and a necessary mineral. This metal is malleable but also an essential element in a nutritious diet. It facilitates the formation of hemoglobin, which is required for healthy red blood cells. Steel is a ferrous alloy constructed of mainly iron and carbon. Adding other elements to steel can create various types of steel. Steel is also stronger than iron, lasts longer, and does not rust quickly, making it excellent for a wide range of products and building demands.
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References
Steel – From Wikipedia
Iron – From Wikipedia
Steel vs. Iron – Comparison – Pros and Cons – From Material Properties
Iron and steel – From Explainthatstuff
Iron vs. Steel: What’s The Difference? – From Reid Supply
What Is the Difference Between Iron and Steel? – From Steel Fabrication Services
FAQ
The main difference between iron and steel is that the former is metal, and the latter is an alloy. Iron is a naturally occurring metal element on earth. On the other hand, steel is a man-made alloy created by mixing iron and carbon.
Steel has somewhat more carbon than pure iron since it is an alloy. When the carbon content of steel increases, it becomes more durable. As a result, steel is stronger than iron because it comprises more carbon, allowing it to withstand higher pressures than iron. Steel is a metal with a lengthy history of usage.
Steel will rust because it is a mixture of iron and carbon. The element chromium distinguishes steel from stainless steel; chromium creates a rust-resistant shield, making stainless steel more corrosion-resistant.
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