In designing structures or equipment, first consideration is usually, and should be, given to ful-filling the mechanical or physical requirements. It is of fundamental importance that the article being designed will have sufficient strength to withstand the service conditions during its initial period of use. However, it is also usually desired that the article remain in serviceable condition for some minimum period of time. Thus, factors which are functions of time must generally be taken into consideration. Factors of this type are fatigue, creep, certain metallurgical transformations, and corrosion. Of all of these factors, corrosion is probably the one most difficult to take into account. This is because the specific conditions of the service often greatly affect corrosion rates; and these specific conditions are frequently not known, or their importance is not appreciated, in advance.
Because corrosion is a complicated problem, frequently no specific steps are taken by the design...
