Materials Used For Calorimetric Monitoring Heads; Stainless Steel 1.4571/Aisi 316 Ti; Nickel-Based Alloy Hastelloy C4/2.4610; Titanium G7, 3.7235 - Flow vision FC01-Ex User Handbook Manual

Flow Meter | FC01- Ex

2 .3 Materials used for calorimetric monitoring heads

The following information contains general recommendations which must be rechecked by the user
for the individual application.
2 .3 . 1 Stainless steel 1 .4571/AISI 316 Ti
The standard monitoring head material is stainless steel 1.4571, an austenitic, acid resisting stainless
steel that is commonly used throughout industry. Manufacturers claim it also withstands oxidizing
organic and anorganic acids, and partly even reductive media.
The resistance of this stainless steel should however be verified by the user, particularly when it is
used in medium mixtures that may from time to time be exchanged with cleansing agents. Its chemical
resistance also depends on temperature, flow rate and concentration of the medium.
Stainless steel owe their resistance to rust mainly to their alloy combination with chromium, the
formation of chromic oxide on the steel surface resulting in a passive state. Contamination, deposits
on the surface, or foreign rust may however neutralize the passivity. Therefore care should be taken
to keep the surfaces clean.
Stainless steel heads must not get in contact with steel parts other than stainless steel or with che-
mically dissimilar metals, as this would cause electrolytic corrosion.
2 .3 .2 Nickel-based alloy Hastelloy C4/2 .4610
Hastelloy 2.4610 is a material with a chemical resistance generally exceeding that of stainless steel.
It is particularly suitable for alkaline media (pH > 7). It should however be examined for suitability for
each specific application using resistance tables and pragmatical values.
2 .3 .3 Titanium G7, 3 .7235
Titanium is characterised by non-magnetizability and excellent corrosion resistance, particularly against
oxidising media. The resistance is due to the fact that the surface of titanium immediately builds up an
oxidation layer in presence of oxidation means protecting the material beneath against corrosion.
The technological characteristics of low-alloy titanium G7 are equal to those of plain titanium of the
same strength category. Adding approximately 0.2 % palladium does not influence the mechanical
properties, but also adds considerably to the corrosion resistance of plain titanium. So titanium G7
has proved to be extremely suitable for use in hydrochlorid or sulphuric acid solutions with little
concentration as well as – with due care – in oxalic acid.
A wide range of applications is possible in aggressive media an zones endangered by sea water.
Please note that physical contact between titanium and magnesium, aluminium, copper or their alloys
might lead to increased electrolytic corrosion of these materials.
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EX ATMOSPHERE
Definitions and mounting instructions