Passivable metals and alloys. Rules of choice and usage types.

Wherever possible, alloy designations are expressed in the terms of French standards. Where this is impossible or unusual, we sometimes use trade marks that have passed into common parlance. Even if these trademarks still have an official owner, some of them no longer correspond to any specific product. So even for their owners, they no longer represent anything more than a radical identity covering a whole range of products derived from the common ancestor, and fortunately considerably improved on it. Their present use will therefore serve in the same way to designate all the current descendants of the ancestor of this name.

Unless otherwise stated, all percentages are expressed by weight.

The main methods of combating corrosion are described in the Corrosion of metals and alloys in aqueous media section of this treatise [M 150] .

This dossier is devoted to the use of metals and alloys whose range of passivity is sufficiently wide in a whole range of environments, and where they can therefore be used without any additional protection. Its aim is to provide a guideline for overcoming the three fundamental difficulties inherent in this use, namely :

• the discrepancy between general statements on corrosion, such as the chapter on Corrosion of metals and alloys in aqueous media [M 150] in this treatise, and the precise technical data on each family of alloys contained in the chapters of this treatise and the treatise on Metallic Materials:

  • stainless steels,

  • numerical data on stainless steels,

  • properties of wrought aluminum and aluminum alloys,

  • numerical data on aluminum and aluminum alloys for processing,

  • niobium,

  • titanium and titanium alloys ;

• the choice of alloy families. This choice is often more difficult than that of the alloy itself within a given alloy family. Yet it is rarely dealt with in books focusing on mechanisms, science or strictly technical...