Stainless steel is a popular choice for metal fabrication projects due to its durability, aesthetic appeal, and resistance to staining and rusting. However, there is a common misconception that it doesn’t rust.
Stainless steel is an alloy of iron, chromium, and other metals. In reality, stainless steel does rust, but it is much more resistant to corrosion than other types of steel. Stainless steel’s rust resistance makes it one of the most used metals today.
Rust can be damaging both aesthetically and structurally speaking—so it’s important to take measures to prevent it from happening in the first place!
In this blog post, we’ll dispel some of the myths about rust and stainless steel, and explain why stainless steel is such a popular choice for metal fabrication projects. You’ll also learn what rust is and how it forms on metals like iron and steel.
If you want to protect your investment when it comes to steel fabrication, make sure to choose a high-quality product that contains a high percentage of chromium. Let’s take a closer look.
What is Stainless Steel?
Stainless steel is an alloy of iron, chromium, and nickel. It is a popular choice for many industries due to its durability and corrosion resistance.
Here are some of the benefits of stainless steel:
- It is durable and strong – Stainless steel is one of the most durable metals available. It does not rust or corrode easily. This makes it ideal for projects that require long-lasting materials.
- It is easy to clean – Stainless steel is easy to clean and maintain. This makes it ideal for applications where hygiene is important, such as in food preparation or medical facilities.
- It has a high resistance to heat – Stainless steel can withstand high temperatures without losing its strength or shape. This makes it ideal for projects that require heat-resistant materials, and stainless steel is suitable for welding.
- It is low maintenance – Once installed, stainless steel requires little maintenance. This makes it ideal for projects where maintenance costs are a concern.
Stainless steel is a versatile material that offers many benefits over other common types of steel. It is durable, easy to clean, and resistant to heat and corrosion. Its many benefits is why it’s one of the most commonly used metals across various industries.
Types of Stainless Steel
There are many different types of stainless steel, each with their own unique properties and benefits. The four most common types of stainless steel used in metal fabrication are austenitic, ferritic, martensitic, and duplex.
- Austenitic Stainless Steel: This type of stainless steel contains high levels of chromium and nickel. Austenitic stainless steel is non-magnetic, has good formability and weldability, and is resistant to stress corrosion cracking. Examples of austenitic stainless steel grades include 304, 316, and 317.
- Ferritic Stainless Steel: This type of stainless steel contains chromium but very little nickel. Ferritic stainless steel is magnetic, has good ductility but poor weldability, and is resistant to corrosion in high temperatures. Examples of ferritic stainless steel grades include 409 and430.
- Martensitic Stainless Steel: This type of stainless steel contains chromium and low levels of nickel. Martensitic stainless steel is magnetic, has good hardness and wear resistance, but is not as easily formed or welded as other types of stainless steel. Examples of martensitic stainless steels include 410 and 420.
- Duplex Stainless Steel: This type of stainless steel contains equal parts austenite and ferrite. Duplex stainless steels have good weldability, resistance to stress corrosion cracking, and improved strength over other types of stainless steel. Examples of duplex stainless steels include 2205 and 2507.
Picking the right type of stainless steel for your project is crucial to ensuring a long lifespan for your finished product. Be sure to consult with a metal fabrication expert to discuss which type of stainless steel will best suit your needs.
What is Rust?
Rust is a type of corrosion that occurs when iron or steel is exposed to oxygen and moisture. This contact causes a chemical reaction that creates hydroxide ions. These ions attach themselves to the metal surface and eventually cause the metal to break down.
This exposure causes the iron or steel to oxidise, which creates a red-brown substance on the surface of the metal. Rust can weaken the structural integrity of metal, making it more susceptible to breakage.
While iron is the most commonly corroded metal, steel is also susceptible to rusting. In fact, anywhere there is oxygen and moisture, rust can form. Even typically corrosion-resistant materials like aluminium and stainless steel can rust with time.
What is Corrosion?
Corrosion is a natural process that happens when metal is exposed to oxygen and moisture. Over time, this exposure causes the metal to break down and deteriorate. Rust is one type of corrosion that affects many metals.
While all metals are susceptible to corrosion, some are more resistant than others. Stainless steel is one of the more corrosion-resistant metals available on the market today.
Does Stainless Steel Rust?
The simple answer is yes, stainless steel does rust. It is much more resistant to corrosion than other types of steel, but not 100% rust proof. There are certain conditions—such as exposure to salt water or high temperatures—which can cause stainless steel to corrode.
However, with proper care and maintenance, stainless steel can last for many years without rusting. The reason stainless steel is so resistant to corrosion is because it contains chromium. Chromium forms a passive film on the surface of the stainless steel which protects it from oxidation.
However, there are a few conditions that need to be met for this to be true. Firstly, the stainless steel must have at least 12% chromium. Secondly, the steel underneath must be sheltered from exposure and protected from an oxygen-rich environment. If stainless steel has its integrity compromised, or is subject to long-term exposure, it can still suffer from rust.
While all several conditions need to be met for rusting to occur, the compromised chromium layer is by far the most important factor. This is because chromium creates a thin layer of oxide on the surface of the stainless steel that prevents further corrosion from happening.
This means that the rust-proof properties of stainless steel can be compromised when engraving stainless steel if precautions aren’t taken.
As you can see, while stainless steel doesn’t easily rust, there are certain circumstances where it can become corroded. If you want to avoid this from happening, it is important to choose a high-quality stainless steel that contains a high percentage of chromium.
Does Stainless Steel Corrode?
There are many different types of corrosion that can affect all types of metals, including stainless steel. The four most common types of corrosion are general corrosion, pitting corrosion, crevice corrosion, and Stress Corrosion Cracking (SCC).
General corrosion is the most common type of corrosion that affects all metals, including steel. General corrosion occurs when metal is exposed to oxygen and moisture, causing it to break down over time. The best way to prevent general corrosion is to regularly inspect your equipment for signs of rust or other forms or deterioration and perform routine maintenance as needed.
Pitting corrosion occurs when small holes or pits form in the surface of the metal due to exposure to oxygen and moisture. This type of corrosion can be difficult to detect because it often happens below the surface where it cannot be seen with the naked eye. Pitting corrosion can be prevented by regularly inspecting your equipment for signs of pits or other irregularities in the surface of the metal
Crevice corrosion occurs when there is a build-up of stagnant water or other liquids in small cracks or spaces on the surface of the metal exposed to oxygen and moisture. In order for crevice corrosion to occur, there must be two conditions present: an anodic area and a cathodic area. The anodic area is where the oxidation reaction occurs, while the cathodic reacts as a base from which electrons are transferred.
Crevice corrosion affects stoves, pipes, cars, bridges, boats, water treatment plants, food processing equipment, and any other metal structures or surfaces that may have tiny cracks or spaces where water or other liquids can pool. Crevice corrosion can be combined with pit formations to cause even more extensive damage. It is important to regularly inspect your equipment for signs of anomalies or deformations that may indicate possible crevices in which corrosive liquids can accumulate.
Prevention of crevice corrosion can be achieved by design modifications, regular cleaning and maintenance of equipment surfaces, and proper storage of corrosive materials.
Stress Corrosion Cracking
Stress corrosion cracking (SCC) is a corrosion process that occurs when there is a failure to relieve internal stresses in a metal. SCC can be prevented by maintaining low levels of tensile stress in the metal during service exposure to corrosive conditions. It is important to consult with a metal fabrication professional before attempting to prevent SCC in service materials because some methods for relieving internal stresses may in fact increase the risk for SCC.
In order for stainless steel to maintain its resistance to corrosion, it must be cleaned and maintained on a regular basis. In addition, it is important to pick the right type of stainless steel for the specific application in order to prevent widespread damage from occurring.
Why Choose Stainless Steel for Metal Fabrication?
Despite its susceptibility to corrosion in some cases, stainless steel remains one of the most popular materials used in metal fabrication due to its durability, aesthetic appeal, and resistance to staining and rusting. When properly cared for, stainless steel can last for many years without losing its lustre.
While it’s true that stainless steel does rust under certain conditions, with proper care and maintenance, it can last for many years without corroding. So if you’re looking for a material that will stand the test of time, stainless steel may be the right choice for your next project.
If you are considering using stainless steel for your next project, be sure to contact a reputable metal fabrication company in Australia to get started.
What are Rust Inhibitors?
Rust inhibitors are chemicals that are applied to metal surfaces to prevent or slow down the corrosion process. There are two types of rust inhibitors: passive and active. Both can be used to stop metal from rusting outdoors.
What are Active vs Passive Rust Inhibitors?
Passive rust inhibitors form a barrier between the metal surface and the environment, while active rust inhibitors chemically react with the metal surface to create a protective layer. Both types of rust inhibitors are effective at preventing or slowing down the corrosion process.
Active rust inhibitors typically provide better protection than passive inhibitors because they create a stronger bond with the metal surface.
This article is published in good faith and for general informational purposes only. Kanyana Engineering does not make any warranties about the ongoing completeness and reliability of this information. Always seek specific advice on your metal fabrication project to ensure all variables are taken into consideration.
Graham Dawe is the Managing Director and Works Manager of Kanyana Engineering. With decades of experience in the metal fabrication industry, he is dedicated to keeping Kanyana at the forefront of the sector’s technological growth. Looking beyond the process itself to holistic, integrated CAD, CAM and MRP solutions, Graham believes Australian manufacturing has an enduring place on the global stage. In Kanyana Engineering’s state-of-the-art workshop in Mandurah, WA, Graham delivers an exceptional standard of work for commercial, industrial and government clients alike.