Udo Vogler
Stainless steel can rust
Rust on stainless steel
Most people think that stainless steel is rust-free. But doesn’t every metal rust? And if so, what are the conditions that cause rust on the component?
Stainless steel is “corrosion resistant” due to a number of alloys added and without an additional coating. But this doesn’t necessarily mean that stainless steel is corrosion-free. Air humidity, temperature, and other environmental influences such as sea salt or pollution from particles in industrial areas can affect the durability of stainless steel.
To prevent rust patches, a few important points must be observed when processing stainless steel:
- Select the right stainless steel
- Good component design
- Proper and professional processing of the material
- After-treatment and product care
Selecting the right stainless steel for your requirements
Corrosion Resistance Class (CRC)
There are many different types of stainless steel with different properties, e.g., in terms of their corrosion resistance or strength based on the added alloys and the structure. In order to classify stainless steels and get a better overview of their corrosion resistance, they are allocated into so-called corrosion resistance classes. This classification goes from
- class I (low corrosion resistance) up to
- V (high corrosion resistance).
Various factors, such as exposure to chlorides and sulfur dioxide, are considered when classifying stainless steel.
Arnold can use any type of stainless steel with a wide range of surface qualities and grinding patterns. Let us know if we can help you select the right type for your requirements.
Stainless steel design to prevent corrosion
Proper stainless steel construction
A well thought-out design can increase the service life of stainless steel components. This entails taking into account the areas where liquids or particles from the ambient air stagnate and are difficult or impossible to remove. The risk here is crevice corrosion.
A good stainless steel construction avoids
- tight undercuts and small bending radii as well as
- material overlaps.
In addition, hard-to-reach welding seams in edges are often very difficult to grind and polish. Small pores and crevices offer additional opportunities for corrosion to attack.
The smoother the surface of the stainless steel, the lower the risk of dirt adhering to the component. This is where electropolishing comes in handy, because it reduces the roughness of the surface, making it even harder for dirt and particles to adhere.
It’s about proper processing
Correct processing of stainless steel
In principle, stainless steel and steel should always be kept separate when processing. Even the most minute particles suspended in the air or mechanically introduced into the surface of the stainless steel can cause surface corrosion.
Arnold takes numerous measures to protect our customers’ stainless steel components.
- We keep the bending tools for steel and stainless steel separate and ensure careful cleaning if they are used multiple times.
- The metal sheets that we process are protected by foil. This allows us to protect the surface during processing, such as when bending, and prevents damage such as scratching during in-house transport or handling.
- We weld and grind steel and stainless steel in different rooms.
The after-treatment of the stainless steel components, such as pickling or electropolishing, is carried out by long-standing Arnold partners.
Good care for stainless steel
Proper care for stainless steel
To make sure stainless steel looks like new for a long time, all adhesive residues are carefully removed, e.g., on film-covered metal sheets and other surface residues. Fingerprints and oily stains are best removed with a dry microfiber cloth or fleece and cleaning agents such as spirits, acetone, or isopropanol alcohol. Nylon brushes and sponges also do a great job at gently cleaning the stainless steel surface.
When cleaning ground and brushed stainless steel, it is important to always wipe in the direction of the grinding pattern.
Stainless steel loves regular cleaning. The tougher the ambient conditions, the more frequently the stainless steel surfaces must be cleaned of dirt particles.
Would you like to discuss which stainless steel is right for your product?
Please send us an e-mail.
What are the different processing methods for different types of stainless steel?
Different stainless steel types may require different bending radii in order to prevent the formation of cracks.
Moreover, different welding materials and possibly also shielding gases are required for welding.
What are the price differences for stainless steel?
With the current shortage of stainless steel on the market, it is difficult to predict prices.
In 2019, the prices ranged from about EUR 1.60 to EUR 7.00 per kilogram.
Why is stainless steel varnished?
It is true that varnish or powder coatings do not adhere as well to stainless steel compared with steel. But there can still be good reasons to varnish stainless steel.
At pay stations with a coin slot, for example, continued use may scratch off the varnish. But it should still be rust-proof. In these types of situations, it is better to provide the stainless steel with friction areas from the start.
Please contact us.