The cooling system of a railroad Diesel locomotive presents a complex corrosion problem, due to the number of different metals used and the wide range of conditions encountered. These factors are discussed in relation to the development of test methods for the laboratory evaluation of corrosion inhibitors.
Two types of tests were developed: a flask type test for screening and development work, and a recirculating test, including a heat transfer surface, designed to more nearly duplicate the actual use conditions, and to give a final evaluation to a product.
Test results are given for several commercial and experimental inhibitors of the "boron-nitrite," "soluble oil" and other types. Results are also presented for variation of factors such as coupling or insulation of the various metals, inhibitor dosage level, water composition, presence of anti-freeze, etc., as well as effect of the treatment on various non-metallic parts of the system.
The importance of inhibition behavior under these various conditions is discussed in relation to actual use conditions. It is shown that the results of the laboratory tests have correlated well with field use. 2.3.4
