Q. Explain about Corrosion Rates?

Corrosion rates of < 5 mpy (< 0.13 mmpy) will produce minimal dimensional changes over the service life of the metal. Rates of 5-20 mpy (0.13-0.50 mmpy) will produce dimensional changes that may require inclusion of a corrosion allowance in the design of the equipment. Corrosion rates may not be the only deciding factor in choosing a material for a design application. Other factors may take priority (e.g. contamination of the product by corrosion may render a specific material unacceptable).

Corrosion data presented in these standards are in graphical form. The corrosion curves for the majority of the metals are presented in the form of temperature vs. concentration. Some curves, however, are plotted as corrosion rate vs. temperature. This was done to aid in interpretation of the data.