Rust is a type of corrosion that forms when iron or one of its alloys come into contact with oxygen, creating a reddish-brown coat of iron oxide. In addition to making metals look unpleasant, it weakens them to the point where they are unsuitable for their intended use.
Trying to remove rust from metal is very time-consuming and often unsuccessful, so it is usually better not to use rust-prone metals that contain iron at all, to avoid this form of corrosion altogether.
Therefore, opting for metal with anti-rust properties for your project will help reduce and even eliminate rust before it has a chance to form.
In the following sections, we will cover six metals that don’t rust and explain some of their other properties and common applications.
Armed with this knowledge, you will be able to save the time and money you would otherwise spend on trying to resolve this issue.
Regular steel is composed of iron and carbon, which means it commonly rusts due to oxidation.
However, stainless steel does not rust because of its high chromium levels (10 to 30%). Chromium oxidizes faster than iron and forms a chromium oxide layer on the surface, which prevents the formation of rust.
In addition to chromium, stainless steel also contains a significant amount of nickel (6 to 26%), which also prevents rust and corrosion in most atmospheric conditions.
Some other beneficial properties exhibited by stainless steel include:
Its strong rust-resistant nature, along with the other properties listed above, has made stainless steel a common manufacturing material. It is used to produce countless items we come into contact with every day.
For instance, it is used to produce metal components in the automotive and aerospace industries.
You will also find it in medical equipment (e.g., temporary crowns, surgical implants, and hemostats) and kitchen items (from cutlery and cookware, to sinks).
Finally, it finds a variety of applications in architecture (buildings, bridges, monuments, airport roofs).
As you can see, durability, longevity and anti-corrosion properties are essential for all the applications we’ve described.
Whether in a kitchen, a building, or a doctor’s office, it is almost a guarantee that an item made of stainless steel will be present.
Galvanized steel’s rust-resistant properties are a direct result of the galvanizing process.
Galvanizing is a process whereby steel is coated with a thin layer of zinc to form a barrier that prevents the formation of rust.
Zinc coatings stop corrosion from occurring on steel surfaces by preventing water and oxygen from reaching the iron and carbon elements within.
The protective zinc coating can last up to 35 to 50 years in highly corrosive environments and 75 years or more in less corrosive environments.
Other properties of galvanized steel include:
The most common applications that utilize galvanized steel include construction components (for instance, ladders, staircases, balconies, outdoor piping) and equipment (including nuts, bolts and nails), as well as automotive parts.
It is also used for many other common applications that require a high amount of corrosion resistance.
What is more, the cost of galvanized steel remains almost equal to that of plain structure steel, which has no rust protection. In other words, it costs four to five times less than stainless steel.
It also requires very little money to maintain as it remains durable and anti-corrosive for a very long time and in different atmospheric conditions.
Weathering steel is commonly known by its trademark name COR-TEN, which references its primary characteristics: COR (corrosion-resistance) and TEN (tensile strength).
It defends itself against corrosion with a unique rusting process that is quite effective, despite seeming counterintuitive.
Corten steel develops a natural protective layer known as patina when exposed to oxygen and water.
The patina is formed through a weathering process that can last anywhere from 10 to 15 minutes, to a week, a month, or even a year. The duration depends on how much water is present in the atmosphere.
Patina forms faster when exposed to various environmental cycles—heat, humidity, and wind.
Corten steel’s rusting process creates a stable, protective film that reduces porous gaps instead of creating them, thus preventing air and moisture from reaching the surface. That way, it stops further rusting from occurring.
What is more, the color of the patina that forms on corten steel is quite appealing, giving it a rustic look that is highly prized among architects and artists.
Some of the other benefits of corten steel include:
Corten remains pliable due to its low-carbon content, and it’s easy to work with. It can be cold-formed or hot-formed.
Additionally, it is 2 to 8 times more corrosive-resistant than carbon steel, and has very high tensile strength, while requiring less maintenance. This includes less repainting due to its lower base surface rust rate.
These properties make corten steel highly suitable for the construction industry.
It is used to create elements such as fences, gates, water fixtures, chimneys, outdoor lighting, and even bridges.
It is also a common material for making structures used in landscaping and gardening, as well as sculptures and wall paintings.
The material finds its purpose in the production of ships or railway cars as well.
In short, corten steel is an excellent choice of material for mid-sized to large outdoor projects that require strong anti-corrosive properties, high degrees of tensile strength, and an aesthetically appealing appearance.
Since aluminum contains no iron, it is not prone to rust. However, an oxide layer known as aluminum oxide is formed when oxygen reaches its surface.
Aluminum oxide is not like rust, as it protects the underlying surface from corrosion instead of promoting it.
It causes the atoms on the surface (shifting atoms) to become inert, thus preventing the underlying elements from reacting with moisture or oxygen as rapidly as they normally would.
Aluminum’s protective layer is difficult to remove, so it lasts a long time. It is also quite thin and transparent, which means that no discoloration appears on the surface.
Some of the major properties of aluminum are as follows:
Since aluminum is lightweight, flexible, and does not rust, it is a very versatile manufacturing material, which is why it is used in so many applications today.
These range from airplane and car parts, through telescope mirrors and electrical transmission lines, to packaging (cans, foil, decorative paper), and even toys and kitchen utensils.
Aluminum is often mixed with other elements because of its low tensile strength. Usually, it is combined with copper, magnesium, silicon, and manganese to increase its strength without decreasing its formability.
Copper, bronze and brass are called red metals because they can be distinguished by their reddish color.
These three metals will never rust for one primary reason—they don’t contain any iron.
However, as with aluminum, all three metals will form a patina on the surface that does not flake as rust does, through a process known as copper oxidation.
The green patina that forms through that process prevents further oxidation from occurring on red metals.
While all of the three red metals are different in composition, they do have one unifying element—copper.
Copper ensures that their rust and corrosion resistance remains intact even when combined with other alloying elements.
Finally, copper, bronze, and brass are completely recyclable and do not lose their special qualities when reused.
This sustainability, combined with their anti-corrosion and rust-prevention capabilities, makes them essential for a variety of important applications we depend upon today.
Let’s take a closer look at each of the red metals.
This element can be found in nature in its pure metallic form, meaning it needs no alteration to its composition to develop its rust-resistant and corrosion-resistant properties.
It also has the following useful characteristics:
Because of its very high electrical conductivity, copper is primarily used for electrical wiring, such as electrodes, power transition lines and electrical cables. It is also present in spark plugs and busbars.
Other applications include heat exchangers and other architectural applications, as well as cooking utensils.
Two added benefits of copper are that it is inexpensive and plentiful, so a shortage is not expected to happen anytime soon.
Brass is composed of copper and zinc, making it more ductile than pure copper.
In fact, zinc is so ductile that it can be rolled into sheets in hot temperatures (100 °C, or 212 °F).
It also tends to be stronger than pure copper, which—along with its other properties—also makes it a good fit for many marine applications.
Some other primary properties of brass include:
Brass is often used for creating decorative parts and pieces, especially in items like clocks and watches, musical instruments, and even rifles. It is also a common sight in different bearings and gears, even construction tools.
Finally due to its ease of manufacturing and corrosion resistance, brass has played an important role throughout human history in the construction of time-telling instruments and navigation tools.
This alloy is a combination of copper and tin, which makes it softer and more pliable than pure copper.
Tin does not rust or oxidize and will not corrode in sea and freshwater environments.
However, even though bronze is a highly corrosion-resistant alloy, it can lose its properties on rare occasions due to a chemical process known as bronze disease.
Nevertheless, bronze’s beneficial properties include:
Due to its low friction with other metals, it was a very important material for the construction of big guns (e.g., canons) in the past.
It is currently used in the production of decorative elements like sculptures or medals, musical instruments, building components and bearings, as well as a variety of nautical applications.
Since bronze can be ground and buffed to a greater extent than copper and brass, it is the material of choice for applications that require precise geometrical shapes and edges.
As with the other metals mentioned in this guide, titanium also has a high degree of rust and corrosion resistance.
Titanium is just as strong as steel and almost 50% lighter. Still, despite being so lightweight, it has a very high tensile strength.
When titanium interacts with very hot temperatures, and other corrosive compounds like acid, chlorine and saltwater, it forms a hard layer known as titanium oxide. This layer protects its surface from rusting.
Although titanium oxide will form in most corrosive environments, it will not do so if there is a limited amount of oxygen in the surrounding atmosphere. Oxygen is necessary for the protective layer to occur.
Therefore, using titanium might not be effective in preventing corrosion in low-oxygen environments.
In spite of this, titanium has many beneficial properties:
In short, titanium is very durable in extreme temperatures and highly corrosive environments.
Since it is strong, lightweight, and anti-corrosive, it is extensively used in airplane, chemical, engineering, sports, and military applications.
It can also be polished extensively to create a luster finish.
The most common applications associated with titanium include the aerospace industry (aircraft bodies, jet engine parts), as well as furnishing industrial sites (seawater distillation plants, LNG plants, and petroleum refineries).
Titanium is also used in producing sports equipment like golf clubs, tennis rackets and even rifles, air guns and mufflers. It is even found in motorbike parts and bicycles.
Titanium is considered one of the strongest and most durable metals on earth, with a tensile strength of 63,000 psi.
Therefore, it is a great choice for applications that need to retain structural integrity and functionality in extremely hot temperatures.
Rust is always a cause for concern for metals and alloys that contain iron.
The metals we’ve described in this guide do not contain any iron, thus exhibiting anti-corrosion properties. As such, they help prevent rust before it has a chance to inflict damage.
The protection against rust and other beneficial qualities make these materials invaluable in the construction, marine, chemical, and decorative industries.
Contact BUNTY Today
If you require a rust-free metal for your projects and applications, make sure to consult a metal manufacturing expert like Bunty to help you choose the right materials for your specific requirements.
Contact us through our website form or request a quote here. We welcome your inquiries.