Cleaning and care of stainless steel surfaces
The stainless steel used in professional equipment is of high quality, and if properly maintained it can allow long use without incurring in any problem. It would however be wrong to think that stainless steel is indestructible and can resist any kind of damage or corrosion.
Stainless steel (or inoxidizable steel), which is characterized by the presence of chromium within the metal alloy, and possibly other alloying elements (such as molybdenum, nickel, etc.), is so called because of its high resistance to corrosion. This resistance is due to a very thin layer of chromium oxides/hydroxides that forms on the surface of the steel thanks to the oxygen absorbed by exposure to the air of the metal itself. This thin protective layer ensures the metal resistance against corrosion, i.e. it allows it not to rust like normal carbon steel.
However, should this protective layer be damaged by mechanical or chemical action (such as scratches, dents, cuts, use of bleach and corrosive agents, etc.), and if its reformation is prevented by isolating it from the oxygen present in the air, then even the best stainless steel can undergo corrosion phenomena and therefore rust.
Specific warnings
Here below we list specific warnings to be respected to ensure that the stainless steel appliances remain in excellent conditions of use over time:
- Keep the surfaces clean and dry, ensuring contact with the air;
- Use only neutral detergents without abrasive powders or bleach, making sure to rinse the surface thoroughly with clean water, and to dry it with a clean cloth;
- Never clean the appliances with high pressure water jets;
- Never leave the stainless steel surfaces in contact for a long time with acid substances (including mustard, vinegar, tomato, etc.), salt or bleach;
- Avoid prolonged contact of stainless steel surfaces with surfaces or objects made of normal (not stainless) carbon steel. Prolonged contact between stainless steels and carbon steels could cause the ignition of galvanic cells in the presence of an electrolyte, causing corrosion of the less noble metal;
- Avoid that carbon steel (not stainless) particles can deposit on the stainless steel surfaces, such as welding spatter, iron filings or the like. These deposits may produce localized corrosion even just with contact with the air, inhibiting the formation of the protective oxide layer of stainless steel;
- Do not scratch, gouge or cut the stainless steel surfaces. Avoid using sharp objects on stainless steel surfaces;
- Any small signs of corrosion or rust must be immediately removed using specific products, mild abrasives or very fine sandpaper (only in exceptional cases). In case of extended signs of rust and corrosion, 5% diluted oxalic acid may be used. Always make sure to rinse the surface with clean water after treatment, and dry it well with a clean cloth.
Effects of some substances on stainless steel
- Hydrocloric acid
- Hydrofluoric acid
- Muriatic acid
- Bleach
- Damp chlorine gas
- Copper sulphate 10%
- Turpentine
- Alcohol
- Sodium bicarbonate
- Soap
- Solvents (triethylene, benzol, etc.)
- Paints