The Study of Cramer’s V for Variables Association on Stainless Steels Corrosion Problem

Stainless steel (SS) is a type of material used in the Oil and Gas Industry because of its corrosive resistance. A σ phase will be formed if SS is exposed to high temperatures for a long time. The appearance of σ occurs slowly, which is manifested by a change in the color of the SS surface. The presence of σ marked in dark blue indicates that the area has been corroded. This study is a follow-up study from the previous one aiming at testing the association between the variables involved in the SS corrosion problem. The material was processed with a series of treatments in the laboratory to produce images. Then, three locations were selected from the images to carry out a circular grid process and calculate the frequency of their color. The frequency listed in the contingency table was the data used to calculate the association between the location and color-based corrosion indicator variable using Chi-square and Cramer’s V. The result showed that although locations A, B, and C were from the different grain, location variables and corrosion indicator variables based on color were dependent.