A stainless steel versions that are not certified often lack the necessary chromite content or have unknown elements added. As such, the material is more susceptible to environmental effects.
Non-ferrous metals in order to reduce the cost of manufacturing
Faster manufacturing, simpler processes and lowering prices by using cheaper metals have lead many manufacturers to create a stainless steel tube and fill it up with non-ferrous metals (aluminium, bronze, brass, etc.). Rust then moves to nearby parts, which then travels to the surface.
Inappropriate surface treatment
If the manufacturer is in a rush or does not pay special attention to this, the door handle will soon start to corrode.
Poor choice of stainless steel type
If standard stainless steel 304 is used instead of acid-resistant steel 316 in harsh environments (near the sea, traffic routes, areas with a lot of road salting), corrosion can occur quickly.
Low-quality coating protection
The worst coatings can even speed up the corrosion.
Improper cleaning and maintenance
Although stainless steel products are very resistant, they should not be cleaned with aggressive or abrasive agents. More information on proper cleaning can be found here.
SALT CHAMBER TEST: DETERMINATION OF RESISTANCE TO CORROSION
To determine the corrosion resistance, 99 front door hardware elements were sent for testing in a salt chamber.
Without such tests, it can still be predicted which factors will have the greatest impact on corrosion protection, however, it is difficult to foresee what would happen to door hardware over many years.
The products were exposed to a spray of salt spray for 720 hours, which accelerates corrosion conditions. This compares with exposure to humid and very salty environments for several decades.
Hardware elements were made of three type of stainless steel, satinised or polished with 25 different protective anti-corrosion coatings.
The same method is used by Mercedez Benz to test the G-Class chassis components.
Front door hardware samples
Salt spray chamber for corrosion resistance testing
For testing purposes, we obtained 25 protective coatings from several manufacturers to protect the surfaces of our samples.
We found out which coatings were the best and which ones made the condition of the samples worse.
Stainless steel type
Stainless steels exhibit different degrees of corrosion resistance, so the type of steel must be carefully chosen according to the environmental features it will be exposed to.
The hardware samples were made from 3 types of steel, with different surface treatments (satin or polished) and different protective coatings.
We found out which samples reacted to corrosion and which showed no change.
We sent two round-handled tubes for testing, one with an advanced Griffing satin finish and the other with a standard satin finish.
Half of the fittings were satin-finished and half were polished. Different protective coatings were applied to the samples. The results gave us an insight into the importance of surface treatment in different coatings.
Griffing stainless steel front door handles with a precise surface treatment and the best protective coating are corrosion-resistant and of high quality.