Laboratory tests are not strictly comparable with actual service conditions, where the corroding medium often contains impurities. These may in some cases increase corrosion, in others decrease it. In unfavorable cases, the increase can be very great.
Before making the final selection of material, therefore, it is in many cases necessary to make tests. The best results of laboratory tests are obtained if the solution used is identical with that which occurs in practice. This includes any effect impurities may have on corrosion. It is even better to expose test pieces to the actual process or environment concerned. Weighing and microscopical examination of the test specimens after a certain period of exposure will give a good idea of the corrosion risks to be expected.
Advice on material selection
When there is some doubt about the material selection, it is always advisable to contact us. It is very important to furnish full information about the corrosion conditions concerned. The following information is necessary:
- Corrosion environment (including chemical formulae if possible)
- Concentrations (if possible also pH)
- Content of impurities, e.g. Cl- , oxidizing agents etc.
- Temperature
Information concerning the type of structure, preferably with sketches, drawings or process descriptions, previously used materials, flow velocities, temperature variations, service life requirements etc., is also very valuable.