9 Applications For Passivated Stainless Steel in Automotive Components

Stainless steel is an ideal material choice for cars as a strong and durable metal that resists corrosion. Both of these qualities help to significantly extend the life of the vehicle, much to the joy of owners everywhere. Stainless steel can also help reduce the weight of a car, which improves things like fuel economy, reduces carbon emissions, and helps in terms of performance.

Of course, that's not to say that stainless steel is inherently perfect. Many stainless steel automotive components must go through a process called passivation to help improve their natural resistance to rust and corrosion, extending benefits like those outlined above even further.

What is Passivated Stainless Steel? 

The passivation of stainless steel is a process that uses either nitric acid or citric acid to eliminate all free iron from the surface of the material. First, the stainless steel component will be thoroughly cleaned, at which point the acid bath will take place. It is then rinsed and, after a period of between 24 and 48 hours, a protective oxide layer forms.

This leads to a component that is far more resistant to oxidation than before, fending off issues like corrosion and rust over time.

Does Stainless Steel Need to Be Passivated?

Especially when you're talking about sensitive and safety-related applications like with automotive components, stainless steel should absolutely be passivated before use. It is this process that allows the stainless steel to remain "stainless" in the way people expect.

Metals like stainless steel can be contaminated in a number of ways, especially in a manufacturing environment and through the fabrication process. By creating a uniform chromium protective layer on the surface, there is less of a concern of issues like rust (and ultimately component failure). Passivation also helps the stainless steel maintain that sleek visual look, which is particularly critical when used in an automotive setting.

Where Passivated Stainless Steel Matters

Because of the sheer volume of stainless steel in your average automobile, it should come as no surprise that passivation has a number of essential applications. These include but are certainly not limited to ones like:

1. Catalytic Converters. Stainless steel is the perfect material choice for catalytic converters because it can resist not only chemicals, but dust, and grime as well. Passivated stainless steel is also able to handle extremely high temperatures during a car's normal operation without causing performance-related issues. 
2. Exhaust Systems. A major function of any vehicle's exhaust system is to control noise and to improve the performance of the engine. Passivated stainless steel helps tremendously to that end and helps an exhaust system continue to function even though it is exposed to essentially constant levels of fumes. 
3. Fittings. Because stainless steel is resistant to heat as well as being anti-corrosive, it is a common material choice for fittings on most makes and models. It is also visually pleasing, which is a big factor for most people.
4. Fuel Tanks. In addition to the aforementioned benefits of stainless steel, it also doesn't absorb chemicals like other materials do. This makes it perfect for use in fuel tanks as it improves not only their overall reliability (and thus the fuel economy of the car), but their sustainability as well.
5. Head Gaskets. Because head gaskets are a major reason why a car engine's combustion chamber is able to function, the durability and consistent surface of passivated stainless steel is the only viable option for their creation.
6. Heat Shields. Passivated stainless steel's incredible resistance to very high temperatures comes in handy when used for the heat shield on a vehicle. Heat shields need to isolate the engine so that the excessive heat doesn't prematurely damage other parts of the car. 
7. Hose Clamps. These are a small part of a car, but a crucial one as if a hose clamp fails, it could lead to a catastrophic system failure as inherently corrosive liquids are unable to effectively make it from one part of the engine to another. 
8. Pump Bodies. Stainless steel is often chosen for pump bodies because of its manufacturability, but passivation is required to prevent contamination from cutting and welding equipment. 
9. Seatbelt Springs. One of the reasons stainless steel is preferred in automotive settings is its natural structural integrity, making it incredibly crashworthy. Obviously, if a car is involved in a crash, you don't want the seatbelt to fail — making stainless steel the perfect material so long as it has been properly passivated.

These are all essential components that ensure not only the peak performance of a vehicle, but the safety of those riding inside it as well. If something like a seatbelt spring or a heat shield were to fail, it could be catastrophic. Passivated stainless steel goes a long way toward preventing that from happening. 

If you'd like to find out more information about the myriad of different applications for passivated stainless steel in automotive components, or if you'd just like to discuss related topics with an expert in a bit more detail, please don't hesitate to contact us today.