Causes of Fracture of Welded Joints of Flexible Tubing String

Abstract

Results of a study of failure of a continuous flexible tubing string transporting working environments under the conditions of alternate bending and corrosive action of the environments containing acid solutions and hydrogen sulfide at an operating pressure exceeding 30 MPa are presented. Fracture surfaces are studied and metallographic analyses of tubes after failure are performed. Specimens of the matrix metal are subjected to mechanical tests. The causes of failure of welded joints are considered and methods for prolonging the service life of flexible tubing strings are recommended.