Fracturing pump head body failure analysis and improvement measures

Abstract

The head body of fracturing pump is one of the most easily damaged parts in fracturing equipment. Due to its own structure and working environment, it is easy to cause stress concentration, fatigue cracking and other problems. The working time of a batch of fracturing pump head body used in an oilfield is more than 300 h, and the pump head body is designed by the manufacturer for the oilfield.In this paper, the five-cylinder fracturing pump head body of this batch of cracking occurred as the research object. Firstly, the macro fracture analysis, physical and chemical properties analysis and micro fracture analysis were carried out at the cracking place. Secondly, the finite element analysis and fatigue life analysis were carried out by using ANSYS Workbench software and nCode software to explore the cause of pump head cracking failure. The results show that the crack originates from the sharp corner of the outer corner and spreads to the inner cavity. The chemical composition and mechanical properties of the pump head meet the requirements of the technical agreement. The grain size of the material does not meet the requirements of the technical agreement. The primary fracture morphology observed is indicative of fatigue streaking, while stress concentration can be identified at the location of this crack. There are two reasons for the cracking. First, the structure design is unreasonable and there is a large stress concentration at the cracking location. Second, the grain size of the material is large, resulting in a significant reduction in fatigue life, which is mainly related to the chemical composition of the material, forging process and heat treatment process, and ultimately lead to the pump head body cracking at the outside right Angle shoulder, expanding to the inner cavity, and cracking. According to the analysis results, the improvement measures of pump head body can improve the stress distribution and relieve fatigue. The results can provide a reference for the structural design and optimization of the pump head body.