Two of the most important metals used to make products are aluminium and steel. Steel and aluminium are both examples of synthetic alloys, meaning they are not naturally occurring but are instead made from other, more fundamental elements. Aluminium goes through a series of transformations before it takes on the appearance of the familiar shiny silver metal.
Bauxite is a mineral that is mined mostly in tropical regions and is the base ingredient of aluminium. We make alumina by grinding bauxite into a thick paste, then we melt cryolite and shock it with electricity. The remaining liquid cools and turns into aluminium as the ions separate.
Both metals are synthesised from other, more fundamental elements; they do not occur in nature as such. The unique properties of aluminium and steel are a result of the contributions of these two basic elements, bauxite for iron and carbon for steel. So, how are the two materials different when it comes to fabrication? Find out how they differ and which one is ideal for your projects in this blog post.
Basics of Aluminum
Almost every living thing, from plants to animals to rocks, contains aluminium, a chemical and metallic element. The latter is true because aluminium is the main metallic component of the sedimentary rock mixture known as bauxite ore, which is present in the crust of the Earth. By itself, aluminium, a non-ferrous metal extracted from bauxite ore, is a malleable and soft metal.
In order to strengthen and improve the properties needed for product fabrication, it is alloyed with other elements, most commonly silicon, zinc, magnesium, copper, and manganese. Fabricators and designers are able to create one-of-a-kind shapes and intricate designs using aluminium because of the material’s extreme malleability.
Basics of Stainless Steel
The corrosion-resistant steel alloys known as stainless steels are made by mixing iron with a small amount of carbon and chromium, with a minimum concentration of 10.5%. Steel is an iron-and carbon-based alloy that gets its name from the chromium that gives it corrosion resistance and differentiates it from other steels that are solely carbon-based.
The addition of nickel, silicon, molybdenum, titanium, niobium, and manganese to stainless steel improves its mechanical properties and makes it more resistant to corrosion. The specific alloy composition of any stainless steel grade is determined by the properties needed for that specific application. The alloying elements work together to determine the alloy’s corrosion resistance, resistance to high or low temperatures, strength, weldability, and formability.
Aluminum vs. Steel:
For several reasons, aluminium and steel have surpassed all other fabrication metals in terms of global abundance. To start, they’re both extremely durable and inert, so they should be able to withstand most uses. Secondly, fabrication projects benefit from their strength and durability. Last but not least, they are versatile and easy to work with in a variety of ways, including rolling, stamping, milling, cutting, joining, and more.
What distinguishes them, though, from one another? Why is aluminium the material of choice for some projects and steel the material of choice for others? Side by side comparisons revealed the solutions. Despite how minor their distinctions are, they can significantly affect the final product of a fabrication project:
Fabrication Methods
Since it has only been readily accessible for the past hundred years or so, aluminium is a material that is relatively new when it comes to mass production. First, bauxite is mined. Then, it is ground into a fine powder known as “alumina.” After that, anodes are used to run an electric current through a bath of molten cryolite, which causes the alumina to dissolve. As the oxygen atoms are drawn out of the alumina by the current, the aluminium that is molten remains at the base of the container.
Before casting the aluminium into ingots, manufacturers transfer it to a holding furnace. It is always more efficient to recycle and reuse aluminium than to create new aluminium from scratch, even after procedures like aluminium extrusion fabrication shape it. Making steel is a lot less complicated than other metals because it just involves heating carbon and iron to more than 2,600°F. But there are two main methods that manufacturers use to complete their tasks.
“Pig iron” is the major raw material used in the steelmaking process. Smelted iron with an excess of carbon relative to what is needed to make steel is called pig iron. In order to achieve uniform oxidation throughout the molten metal, steelmakers employ a process that involves bubbling oxygen into the pig iron as it melts. When elements like silicon, manganese, or phosphorous undergo oxidation, any excess carbon is removed and any contaminants are removed as well.
Refining and alloying the steel takes place “in the ladle,” during the secondary steelmaking process. The goal of this procedure, known as “de-slagging,” is to obtain desired alloys by adding elements to the molten metal. In order to finish the required chemical processes, steel manufacturers either heat or cool the ladle.
Strength
Compared to aluminium, stainless steel is thicker, heavier, and stronger. Aluminium has a superior strength-to-weight ratio than stainless steel, despite being around a third as heavy as steel. Thanks to its low density and high strength-to-weight ratio, it finds widespread application in the aerospace and automotive sectors, where it enhances fuel economy and increases payload capacity. Fabricators, on the other hand, prefer stainless steel for structural components and architectural details due to the material’s strength.
Particularly in high-stress contexts, a material’s strength is typically among its primary attributes considered during the selection process. When comparing the two, steel typically has more strength than aluminium. However, when considering the material’s strength-to-weight ratio, aluminium emerges as the clear winner due to its lighter weight.
The adaptability of your design is the determining factor in determining the optimal metal strength for your application. Consider the case where a bigger aluminium component provides greater strength at a reduced weight compared to its steel counterpart.
Electrical and Thermal Conductivity
Stainless steel isn’t as good a conductor of heat and electricity as aluminium. Aluminium is the metal of choice when electrical conductivity is a critical factor in making a material selection.
Aluminium is perfect for power lines because of its high electrical conductivity, lightweight nature, and resistance to corrosion. Heat sinks made of aluminium, a thermal conductor, are standard in radiators, LED lights, electronics, and air conditioners, among other things, because of the rapid cooling they provide.
Corrosion Resistance
Corrosion resistance is low for plain carbon steel. It corrodes rapidly and rusts readily when left out in the weather. However, an oxide layer forms on aluminum’s surface, which prevents additional oxidation and serves as an inert barrier. As long as it stays out of environments that degrade it, aluminium will keep providing great corrosion resistance.
It’s important to know that steel can be transformed into “stainless steel” with a minimum of 11% chromium in the alloying substances, making it extremely corrosion resistant. Stainless steel, on the other hand, can change other physical characteristics of steel and is more expensive than regular carbon steel.
Thermal Properties
Because of its remarkable thermal properties, stainless steel is ideal for uses involving high temperatures. While stainless steel can withstand temperatures of up to 400°C, aluminium starts to soften at temperatures higher than 200°C.
Weldability
Stainless steel is much easier to weld than aluminium, which is great if your application calls for welding. The low melting point and high thermal conductivity of aluminium make it difficult to work with, and that is a major contributing factor. When aluminium starts to cool, a phenomenon known as hot cracking can happen. Welds made of stainless steel can match or exceed the strength of the joined components, and the material itself has a high tensile strength that is two to three times that of aluminium.
Malleability
One drawback of steel is its high strength, which makes it difficult to shape, particularly in complex shapes, compared to aluminium. Extreme heat treatment of the steel can alleviate this problem to a certain extent, but at the expense of other desirable qualities and at a high cost. Aluminium, in contrast, is well-suited to industrial processes like extrusion and rolling because it is easy to shape while hot or cold.
Cost
The availability of iron and bauxite ore, fuel costs, and supply and demand all play a role in the ever-changing price of aluminium and steel. Aluminium is typically twenty to thirty percent more expensive than stainless steel due to its higher raw material costs. Remember that aluminium has a greater ratio of strength to weight than stainless steel, so less material might be needed to complete a project-and that means less money spent-if that’s what you prefer.
Specific Industries
Due in large part to foil, aluminium has a poor reputation when it comes to its use in food applications. Actually, it’s more prone to leaching or dissolving into foods when used at higher concentrations, under high heat, or with acidic or spicy liquids or foods. Food products can become discoloured or lose some of their flavour as a result of these reactions. Fortunately, there are food-grade aluminium products on the market that are perfectly fine to use while cooking.
Aluminium, on the other hand, is more porous and easily dented and scratched, which makes cleaning it a more tedious task. Because of its strength and longevity, stainless steel is the material of choice for professional chefs and food service companies. Cutlery, cookware, and kitchen equipment are just a few examples of the many uses for its non-porous surface. The material is impermeable to germs and bacteria.
When planning a fabrication project, it can be difficult to decide between stainless steel and aluminium. Consult your fabricator about the best material for the job; it’s in your best interest to do so. In the end, the properties your product needs to succeed will determine whether aluminium or stainless steel is the better metal to use for fabrication.
Weight
The vast majority of people would correctly identify aluminium as the lighter metal if you were to ask them. The significantly higher density of steel is a trade-off for its exceptional strength. Actually, steel can weigh up to three times as much as aluminium for two pieces with the same volume.
Should You Choose Steel or Aluminum for Your Project?
Project specifics, forming method, and available funds will determine whether steel or aluminium is the better material choice. For designs where strength and longevity are paramount and where the shape is not overly intricate, a steel alloy could be the superior choice. However, aluminium is likely the superior material to use if you require a high strength-to-weight ratio, resistance to corrosion, and the capacity to shape it into an unusual shape.
Conclusion
Aluminium and steel are two crucial metals used in fabrication. Aluminium is a chemical and metallic element found in bauxite ore, a sedimentary rock mixture. It is malleable and soft, making it ideal for creating unique shapes and intricate designs.
Stainless steel, on the other hand, is a corrosion-resistant steel alloy made by mixing iron with a small amount of carbon and chromium. The addition of nickel, silicon, molybdenum, titanium, niobium, and manganese to stainless steel improves its mechanical properties and resistance to corrosion.
Aluminum and steel have surpassed all other fabrication metals in terms of global abundance due to their durability, inertness, versatility, and ease of work in various ways. Fabrication methods for aluminium involve grinding bauxite into a fine powder called alumina, which is then heated to over 2,600°F.
Steelmaking involves heating carbon and iron to over 2,600°F, with pig iron being the major raw material used in the steelmaking process. The process involves bubbling oxygen into the pig iron, removing excess carbon and contaminants, and refining and alloying the steel during the secondary steelmaking process.
Steel and aluminium are two materials with different strengths, electrical conductivity, thermal properties, weldability, and cost. Steel is thicker, heavier, and stronger than aluminium, making it suitable for aerospace and automotive sectors. However, aluminium is preferred for structural components and architectural details due to its strength.
Stainless steel has better electrical and thermal conductivity, making it ideal for power lines and heat sinks in radiators, LED lights, electronics, and air conditioners. It also offers excellent corrosion resistance, but can be transformed into “stainless steel” with a minimum of 11% chromium in the alloying substances.
Stainless steel is ideal for high temperatures, as it can withstand temperatures up to 400°C. It is easier to weld than aluminium due to its low melting point and high thermal conductivity. However, aluminium’s high strength makes it difficult to shape, especially in complex shapes.
Cost is another factor to consider when choosing between steel and aluminium. Aluminium is typically twenty to thirty percent more expensive due to higher raw material costs, but it has a greater strength-to-weight ratio, making it less material-intensive.
In food applications, aluminium is more prone to leaching or dissolving, while stainless steel is impermeable to germs and bacteria. When planning a fabrication project, consult your fabricator about the best material for the job and consider the properties your product needs to succeed.In conclusion, aluminium and steel are both essential metals for various fabrication projects due to their unique properties and versatility.
Content Summary
- Two of the most important metals used to make products are aluminium and steel.
- Steel and aluminium are both examples of synthetic alloys, meaning they are not naturally occurring but are instead made from other, more fundamental elements.
- Both metals are synthesised from other, more fundamental elements; they do not occur in nature as such.
- The unique properties of aluminium and steel are a result of the contributions of these two basic elements, bauxite for iron and carbon for steel.
- Find out how they differ and which one is ideal for your projects in this blog post.
- The corrosion-resistant steel alloys known as stainless steels are made by mixing iron with a small amount of carbon and chromium, with a minimum concentration of 10.5%.
- The addition of nickel, silicon, molybdenum, titanium, niobium, and manganese to stainless steel improves its mechanical properties and makes it more resistant to corrosion.
- The alloying elements work together to determine the alloy’s corrosion resistance, resistance to high or low temperatures, strength, weldability, and formability.
- For several reasons, aluminium and steel have surpassed all other fabrication metals in terms of global abundance.
- Secondly, fabrication projects benefit from their strength and durability.
- Last but not least, they are versatile and easy to work with in a variety of ways, including rolling, stamping, milling, cutting, joining, and more.
- What distinguishes them, though, from one another?
- Why is aluminium the material of choice for some projects and steel the material of choice for others?
- Side by side comparisons revealed the solutions.
- Despite how minor their distinctions are, they can significantly affect the final product of a fabrication project: Fabrication Methods Since it has only been readily accessible for the past hundred years or so, aluminium is a material that is relatively new when it comes to mass production.
- Pig iron” is the major raw material used in the steelmaking process.
- The goal of this procedure, known as “de-slagging,” is to obtain desired alloys by adding elements to the molten metal.
- Strength Compared to aluminium, stainless steel is thicker, heavier, and stronger.
- Aluminium has a superior strength-to-weight ratio than stainless steel, despite being around a third as heavy as steel.
- Fabricators, on the other hand, prefer stainless steel for structural components and architectural details due to the material’s strength.
- Particularly in high-stress contexts, a material’s strength is typically among its primary attributes considered during the selection process.
- When comparing the two, steel typically has more strength than aluminium.
- However, when considering the material’s strength-to-weight ratio, aluminium emerges as the clear winner due to its lighter weight.
- The adaptability of your design is the determining factor in determining the optimal metal strength for your application.
- Consider the case where a bigger aluminium component provides greater strength at a reduced weight compared to its steel counterpart.
- Stainless steel isn’t as good a conductor of heat and electricity as aluminium.
- Aluminium is the metal of choice when electrical conductivity is a critical factor in making a material selection.
- Aluminium is perfect for power lines because of its high electrical conductivity, lightweight nature, and resistance to corrosion.
- Corrosion resistance is low for plain carbon steel.
- It’s important to know that steel can be transformed into “stainless steel” with a minimum of 11% chromium in the alloying substances, making it extremely corrosion resistant.
- Because of its remarkable thermal properties, stainless steel is ideal for uses involving high temperatures.
- Stainless steel is much easier to weld than aluminium, which is great if your application calls for welding.
- Extreme heat treatment of the steel can alleviate this problem to a certain extent, but at the expense of other desirable qualities and at a high cost.
- The availability of iron and bauxite ore, fuel costs, and supply and demand all play a role in the ever-changing price of aluminium and steel.
- Aluminium is typically twenty to thirty percent more expensive than stainless steel due to its higher raw material costs.
- Due in large part to foil, aluminium has a poor reputation when it comes to its use in food applications.
- Food products can become discoloured or lose some of their flavour as a result of these reactions.
Frequently Asked Questions
Which Is Better Aluminium Or Steel?
Despite being at risk for corrosion, steel is still harder than aluminum. While aluminum does increase in strength in colder environments, it is generally more prone to dents and scratches than steel. Steel is less likely to warp or bend from weight, force, or heat.
How Does The Weight Of Aluminum Compare To Steel In Fabrication?
Aluminum is about one-third the weight of steel, making it preferable for applications where weight reduction is crucial, such as in automotive or aerospace industries.
Is Aluminum More Expensive Than Steel For Fabrication?
Generally, aluminum is more expensive than steel. However, the total cost depends on the project’s specifics, including design complexity, fabrication processes, and material grades.
Which Is More Sustainable, Aluminum Or Steel?
Both materials have aspects of sustainability. Steel is highly recyclable, and many steel products contain recycled content. Aluminum is also recyclable and requires less energy to recycle than to produce new aluminum.
How Do The Fabrication Techniques Differ For Aluminum And Steel?
Fabrication techniques can vary significantly. Aluminum often requires different cutting tools and welding methods due to its softness and lower melting point. Steel fabrication might involve heavier machinery and different welding techniques.
