When it comes to comparing metals such as steel and aluminum, both have a very wide range of applications. They are crucial in so many industries, providing parts for cars, planes, rails, pipelines, and bridges, along with thousands of different less prominent uses. They are equally vital for construction as they are for manufacturing and production of other parts. But, if we were to compare the two, we would need to look at different aspects of the two substances.
The good news is that we decided to address some of the most frequently asked questions relating to conductive stainless steel and nonconductive aluminum and tried to provide objective answers. This will help you determine which materials to buy for your upcoming project and gain some useful general knowledge.
Which One Is Better Aluminum or Stainless Steel?
This may seem like a simple question, but the answer seems to be elusive. Is it going to be a challenge for you to decide between aluminum vs stainless steel? The best way to answer both of these questions is to examine the intended use before purchasing the material.
After reading this article and reviewing your individual circumstances and needs, you will know which one is going to work better for you. In the following questions, we are going to touch on the pros and cons of aluminum, as well as the types of stainless steel and their traits. First, let’s take a look at aluminum and stainless steel individually, taking note of their most prominent characteristics.
Conductive (Ferrous) Stainless Steel
When it comes to steel properties, you’ve heard of stainless steel innumerable times. One steel alloy does have properties that render it less likely to stain, but it’s not entirely immune to corrosion. There is regular steel, as well as a mild version, but in this article, we are focusing on stainless steel.
The reason behind this is that stainless steel is the ‘improved’ version of steel, and it is usually compared to aluminum across many scales. For example, various metals are often compared in electrical conductivity, thermal conductivity, density, and similar factors. Stainless steel is, for example, denser than aluminum, and the scale also proves that stainless steel is a much better conductor of heat than aluminum.
The term ferrous next to stainless steel means that it contains (or consists of) iron. Due to the high amounts of carbon used when creating them, most ferrous metals and alloys are vulnerable to rust when exposed to the elements. Thus, carbon steels are typically galvanized to give them higher resistance to corrosion. Corrosion-resistant galvanized steel has an outer layer of zinc that becomes a part of the steel’s chemical composition.
The Different Types of Stainless Steel
Stainless steels can be separated into three main categories. These are as follows:
Austenitic Stainless Steels: Austenitic steels are non-magnetic types of stainless steels that contain high levels of chromium (16-26%) and nickel (6-12%). They also contain low levels of carbon. These compositions give austenitic steels high formability and corrosion-resistant properties. As such, these types of stainless steel are the most frequently used. Two common types of these austenitic steels are 304 and 316 stainless steel.
304 Stainless Steel: Determining which materials are made of 304 or 316 stainless steel is impossible with the naked eye. However, their chemical composition, properties, and uses differ. For instance, 304 steel is an austenitic alloy made up of 18% chromium and 8% nickel. Therefore, 304 steel is oxidation and corrosion resistant, and it has enhanced durability. Common uses for 304 steel include auto molding and trim, electrical enclosures, wheel covers, stainless steel cookware, storage tanks, and piping, among others. Put simply, 304 steel is the lowest-cost corrosion-resistant option.
316 Stainless Steel: Its chemical composition contains 16% chromium, 10% nickel, and 2% molybdenum. The added molybdenum further increases the steel’s corrosion-resistant properties. It fares much better to chemical corrodents such as seawater and brine solutions, as well as sulfuric acid solutions, iodides, and fatty acids at high temperatures. Molybdenum-containing steels are often used in certain pharmaceutical equipment (to prevent metallic contamination), as well as in various offshore, marine, and washdown applications.
Ferritic Stainless Steels: Ferritic stainless steels have a high chromium concentration (typically 12.5% or 17%, but sometimes as much as 27%) and low carbon content. They are also nickel-free. As such, ferritic steel is magnetic and non-heat-treatable. And although it is subject to impact transition (brittleness), it does possess adequate formability, corrosion resistance, stress corrosion cracking, and ductility.
Though not as corrosion resistant as austenitic-grade steels and, generally, less expensive, ferritic steels have their applications in the automotive and industrial industries, as well as certain stainless steel cookware. Some ferritic steels also contain molybdenum, aluminum, or titanium.
Martensitic Stainless Steels: As the least common category of stainless steel alloy, martensitic stainless steels are low in carbon, containing anywhere from 0.2%-1%, and their chromium content is between 10.5% and 18%. Generally, there is no nickel present, but small amounts will sometimes be added to increase corrosion resistance and toughness. Selenium or sulfur may also be added to some grades to increase machinability.
The low chromium, low alloying content of martensitic stainless steel makes them less costly than other types of stainless steel. However, they are known for their hardness, strength, and moderate corrosion resistance. As such, martensitic stainless steels are generally used for their metal-to-metal wear and abrasion resistance properties in the form of industrial blades, vehicle springs, staple guns, cutlery, cookware, springs, scissors, and some surgical and dental instruments.
Nonconductive (nonferrous) Aluminum
Galvanization is to steel as anodization is to aluminum. The creation of this outer, passive layer of thick oxide coating improves aluminum resistance to corrosion and abrasions. Aluminum and stainless steel do have some similarities, but we will focus more on how they differ. Differences between aluminum and steel start with the conductivity and ferrousness.
Non-ferrous materials like aluminum don’t have magnetic properties, which makes them perfect for small electronics, for example. Aluminum is typically the first thing that comes to mind in regards to malleability. It’s easily bent, molded, and pressed into shape without using too much strength. The strength of steel can be an advantage over this, but aluminum can also be hard-anodized to provide equal strength when needed or when there is no alternative.
Which is Better, Hard-anodized Aluminum or Stainless Steel?
Perhaps the easiest way of looking at this would be to compare which pots are better, aluminum or stainless steel. Hard-anodized aluminum pots are usually non-stick and don’t tend to rust easily. Stainless steel pots and pans may last a little longer and are generally easy to maintain. Anodized aluminum has an advantage over steel and regular aluminum in the sense that it is an excellent heat conductor. Aluminum vs stainless steel cookware is often a big concern for chefs and home-makers, so if you plan on spending a lot of time in the kitchen, you should look into these differences.
Which is Heavier, Aluminum or Stainless Steel?
We’ve briefly mentioned the density of steel. In fact, one of the biggest differences between stainless steel and aluminum is in density. Stainless steel is extremely dense in comparison to aluminum, making it much more difficult to scratch stainless steel. Aluminum is, on the other hand, two and one-half times lighter than Stainless Steel.
Which is Stronger, Aluminum or Stainless Steel?
When it comes to strength, stainless vs aluminum is hardly a competition. Steel is a lot tougher, not easy to bend or mold, and very impact resistant. However, aluminum can be hard-anodized to render it much stronger than it would otherwise be. This process ensures the aluminum’s durability. If you need to achieve strength but have to limit the weight of the components, then anodized aluminum is the right choice.
Which is Safer, Aluminum or Stainless Steel?
The answer to this question depends on the context. Both are safe to use in construction, but degrees of safety can vary depending on the use. Similarly, when it comes to cooking and cookware, both of these components are used in making food, and neither is a bad choice. While steel might be considered the ‘safest’ material, aluminum and anodized aluminum are right behind it.
Which is More Expensive, Aluminum or Stainless Steel?
Steel is more common and easy to come by, and it can easily be recycled and sold again, which makes its price much more affordable compared to aluminum. Steel can be cheaper, even when processed, galvanized, chem-treated, and painted, than its lighter counterpart. Aluminum is more difficult to create or find in scrap, which is why its price can be slightly steeper.
Now that you know the basics of these two metals, you can start preparing your project, buying better appliances, and choosing the right tools. We may have listed the most important factors when it comes to steel vs aluminum, but your quest shouldn’t end here. You can look up more on anodized aluminum on our site, or offer your opinion below and let us know about your take on the whole stainless steel vs aluminum showdown.
If you are interested in having your parts fabricated or processed, please contact us at www.aerospacemetalsllc.com