Corrosion is the chemical or electrochemical reaction of metals with the environment, resulting in the impairment of material properties. Fundamentally, there are 3 different forms of corrosion:

Surface corrosion affects the entire surface evenly but an irregular progress can result in the formation of trough-shaped indentations. An early recognition is possible. Pitting develops in local indentations which are either crater-shaped or in a pin hole form, these eroding the surface. The most dangerous form of corrosion is the corrosion cracks which as with pitting are difficult to detect. The stress concentration of the crack opening under mechanical load results in excessive tension being applied and this together with the reduction in the cross-section resulting from the crack can in turn result in breakages occurring. This problem especially exists with regard to chains due to the fact that chains are subjected to heavy mechanical loads.

The standard non-alloy and low-alloy steels are practically unstable when used in a corrosive environment. A chromium content which exceeds the resistance threshold of min. 12% produces extremely thin (approx. 5 ì), tenacious, adhesive oxide films on the surface of the steel when subjected to oxidizing conditions: the steel is passivated, i.e. resistant against oxidizing media. Additional alloy elements such as nickel (increases the impact value), molybdenum (reduced susceptibility to pitting) or titanium (stabilisation against granular corrosion) increase the resistance against corrosion , result in a simplified processing, increase the solidity and improve the thermal behaviour. Fundamentally speaking, with stainless steels, differentiations are made between ferritic steels, martensitic steels, austenitic steels and austenitic-ferritic steels. Only the austenitic chain steels are used for the manufacture of chains due to their improved weld ability and cold formability. These include approx. 16 -26% chromium, 3,5-32% nickel and up to 7% molybdenum. The steels most widely used here are X 5 CrNiMo 17 12 2 (1.4401), X 2 CrNiMo 17 13 2 (1.4404), X 6 CrNiMoTi 17 12 2 (1.4571). The tensile strength of these steels amounts to approx. 500- 800 N/mm. The impact value is extremely high even when subjected to extreme cold. These steels also do not oxidize even when subjected to high temperatures. Stainless steel chains are fundamentally suitable for use in the food industry, chemicals industry, pharmaceutical industry, textile industry, use in cold forming technology, etc.

This situation is also valid for the oxygen corrosion, the most well-known form being the iron and steel corrosion. Hydrogen corrosion also exists. Hydrogen corrosion is only of interest in acidic solutions (Ph value < 7). This also includes acid attacks on metals (acidic corrosion). The alloy elements described above retain their properties even when subjected to hydrogen corrosion. For this reason, steels containing these alloy elements are not only resistant to oxygen corrosion (rust) but also to hydrogen corrosion, meaning that they are also resistant to acid.