Cleaning and care of the appliance
28
FES/UES 07 25 13 Bl.28
Recommendations for caring for
large-scale kitchen appliances made of
“non-rust stainless steel”
What you should know about “non-rust stainless
steel”
Appliances for large-scale kitchens are usually made of non-rust stain-
less steel with the following material numbers:
-
1.4016 or 1.4511
= magnetisable chromium steel
-
1.4301, 1.4401 and 1.4571
= non-magnetisable chromium nickel steel
Chromium steel has advantageous heat properties. It is less likely to
become distorted when exposed to heat.
Chromium nickel steel, on the other hand, generally has more advan-
tageous non-rust properties.
The corrosion resistance of non-rust steel is due to a passive layer
which is formed on the surface when exposed to oxygen. The oxygen
in the air already sufficies to form the passive layer so that interferences
with or damage to the passive layer due to mechanical influences easily
remedy themselves. The passive layer is formed more rapidly or re-
formed when the steel comes into contact with running water contain-
ing oxygen. The effect is increased by acids which have an oxidising
effect (nitric acid, oxalic acid). These acids are used in the event that
the steel is exposed to strong chemicals, thus largely losing its passive
layer.
The passive layer can be chemically damaged or disturbed by sub-
stances which have a reducing effect (substances which consume ox-
ygen) when they are concentrated or come into contact with steel at
high temperatures. Examples of such aggressive substances are:
-
substances containing salt and sulphur
-
chloride (salts)
-
concentrated flavourings such as mustard, vinegar essence, flavour-
ing tablets, cooking salt solutions etc.
Further damage can occur due to:
-
extraneous rust
(e.g. from other components, tools or rust film)
-
ferrous particles (e.g. sanding dust)
-
contact with non-ferrous metals (element formation)
-
lack of oxygen
(e.g. no entrance of air, water with a low oxygen content).
Working principles for appliances made of “non-rust
stainless steel”
☞
Always keep the surface of non-rust stainless steel appliances
clean and accessible to air. Keep the door of the appliance open
when the appliance is not in operation so that air can enter.
☞
Regularly clean away any layers of calcium, grease, starch and
protein. Corrosion can be formed underneath this layer due to
lack of air. When cleaning the appliance no cleaning agents con-
taining bleaching agents or chlorine should be used.
If the manufacturer specifies separate recommendations for the
cleaning of the appliance we recommend that you only use the
listed cleaning agents and methods.
If no special cleaning recommendations are given, cleaning
agents low in chloride (e.g. Pril Supra) should always be used.
After each cleaning remove all traces of cleanser by rinsing well
with fresh water. Then dry the surface thoroughly.
☞
Do not allow parts made of non-rust stainless steel to come into
contact with concentrated acids, flavourings, salts etc. for long
periods of time. Acid fumes formed when the tiles are cleaned
also promote the corrosion of “non-rust stainless steel”. Clean the
contact surfaces with fresh water.
☞
It is not recommended, especially with boiling pans and combi-
nation cookers, to fill the cooking chamber with very salty foods.
A variety of foods is better, e.g. fat-containing foods or acid-con-
taining vegetables.
☞
Avoid damaging the surface of non-rust stainless steel, especially
by metals other than non-rust stainless steel. Remains of foreign
metals form chemical elements which can cause corrosion. Con-
tact with iron and steel should be avoided at all costs as these
metals cause extraneous rust. If non-rust steel comes into con-
tact with iron (steel wool, slivers from cables, water containing
iron), this can cause quite serious corrosion. Therefore you should
use only non-rust steel wool or brushes with natural, plastic, or
non-rust bristles for mechanical cleaning. Use of regular steel
wool or brushes with non-alloy steel will lead to rusting.
Fresh rust can be removed by using a mild abrasive cleaning
agent or fine emery paper. Heavier rust can be washed away us-
ing a warm solution with 2 - 3 % oxalic acid. If these cleaning
agents do not help, the rust must be treated with a solution con-
taining 10 % nitric acid:
[
Caution! This work should only be carried out by technically
trained staff observing the existing regulations!
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