scope:

Introduction

The test methods presented herein are based on the so-called "wheel test"1-3 which is versatile in that it has often been adjusted to test a variety of inhibitors, and has been performed on various test specimens. Its versatility has also enabled modifications to specific test variables, such as temperature, film life, surface conditions, concentration of corrosive agents, and oil-to-water ratios. With respect to its versatility, the test is similar to other tests with the same general intent. The low level of reproducibility of test results is considered by some to offset the advantages of its versatility. Reproducibility problems seem to be encountered when the test is performed by more than one technician. A single technician appears to be more likely to reproduce his/her own results on a regular basis.

This report describes the wheel test and discusses the various conditions in which it has been used. The wheel test is a dynamic test performed by placing fluids (oil, water, and inhibitor) in a 200 mL (6.80 oz) beverage bottle with a metal test specimen, purging with a corrosive gas, and capping the bottle. The bottle generally has then been agitated for a period of time by securing it to the circumference of a "wheel" and rotating the wheel. After agitation, the test specimens have been transferred to another bottle containing no inhibitor (only corrosive fluids) and agitated for a longer period of time. At the end of this time, the metal test specimen has been removed and cleaned and the mass loss has been measured.

Techniques used in both test procedures are described.