Mechanical properties and galling resistance of API grade steels: A comparative study

Abstract

Galling is a type of wear that affects the oil and gas industry causing loss of profits due to unexpected stops in the exploration and extraction process. In the present work, the galling resistance of four API grade steels (L80 type 1, T95 type 2, P110, and Q125) used in the industry was evaluated by means of cross-cylinder tests. The surfaces were analyzed, and a Galling Tendency number was computed in order to rank the materials. Additionally, tensile and hardness tests were conducted to analyze the influence of the mechanical properties on galling. It was found that P110 exhibited the worst response and T95 the best one. For materials with the same ductility, an increase in strength is associated with higher galling resistance. A new index, based on the ductility and yield strength of the material, is proposed to predict the galling performance, demonstrating a strong correlation with the galling tendency.