Fasteners made from the most common stainless steel types A 2 and A 4 come into contact with all kinds of substances. Using them will be problematic if their chemical stability vis-à-vis some substance or other is restricted.
To make it easier to use fasteners made from these special steel types, we are showing you an extract from the stability list. Please note that the stability information can change in practice, since the substances seldom appear in their purest form. For safety reasons we would always recommend to test the stainless steel fasteners under operational conditions.
The chemical composition of the stainless steels that are suitable for fasteners according to DIN EN ISO 3506 is indicated in the following table.
If nothing to the contrary was agreed between the customer and the manufacturer, the manufacturer is at liberty to choose the chemical composition within the agreed steel type.
In cases of application where there is a danger of intercrystalline corrosion, testing in accordance with DIN EN ISO 3651-1 (corrosion trial in nitric acid) or -2 (in sulphuric acid) is recommended. In these cases, the use of stabilized stainless steels A 3 and A 5 (or A 2 and A 4 steels with a carbon content of less than 0,03%) is recommended.
Of course Lederer will place its articles and the exact chemical composition of the basic substances in the International Material Data System IMDS if it´s necessary (and on demand of the customers in the automobile industry).