WAYS OF DETERIORATING THE BALLS WITH STRUCTURAL GRADIENT FROM THE VALVES USED IN THE OIL EXTRACTION INDUSTRY

Abstract

Valves (formed from ball and seat) equip pumps with pistons and ensure the movement of the petroleum from the deposit to the surface. The balls must withstand the complex erosive-abrasive wear determined by the corrosive environments, while having a resistance to micro cutting and micro fatigue as good as possible. In the case of extraction through underground combustion the effect of high temperatures will also occur. Several experimental batches of balls with structural gradient were made using different extremely hard alloys. An analysis, using finite elements, of the tension states which occur during the process was performed and the life span of the balls was estimated. We present the analysis of the ways of deterioration caused not only by usage in the process but also by the manufacturing defects of balls with structural gradient. The complex analyses that were performed to determine the causes and the mechanisms of deterioration are presented and technological ways to improve the life span are proposed.