This work deals with the characterisation and conditioning of heat resistant materials and their use in aggressive fluids. Industry is always looking for new approaches for extending the lifespan of tools while processing aggressive fluids. By acid or alkaline attacks on tools, usually metals or ceramics, tools only show a very short lifespan, which can range from seconds to a few days. In order to enable large-scale implementation of such processes with aggressive fluids, a special protection for tools is needed. Of course, the protection of tools must also correspond to a certain cost-value ratio. Based on these considerations, methods for protection were researched, and it was tried to condition some Iron based materials with simple methods to resist aggressive fluids. In the beginning, heat treatment methods were used on selected materials on small scale only. After chemical testings and characterisation of the surface, a variety of materials for practical testing in aggressive fluids was made. By this selection, the number of materials was restricted. The chosen materials were tested on their durability and the data was projected for long term usage.