Damage to Special-Purpose Ring Wavy Springs under the Influence of Hydrogen Sulfide-Containing Media

Abstract

Annular wavy springs are widely used in the oil and gas industry and most often serve either as compensators for temperature deformations or for mechanical seals of various joints in equipment transporting oil and gas media. These springs provide high load capacity with a relatively low draft, which ensures a compact design. Most often, such springs are made by stamping from sheet steel. When operating technological equipment that transport hydrogen sulfide-containing oil and gas media, hydrogen sulfide stress corrosion cracking occurs quite often, which can lead to failure of industrial equipment. In particular, damage to annular wavy springs can cause depressurization of elements of industrial equipment and cause significant harm not only to the environment, but also to maintenance personnel. The object of research was annular wavy springs made of steel type X15N7M2YU. The purpose of the study is to determine the resistance of the spring material to stress corrosion cracking. This article discusses the test results of special purpose annular wavy springs in an aggressive hydrogen sulfide-containing medium artificially prepared according to the recommendations of ANSI/NACE TM 0177. The results of hardness studies, strength calculations and metallographic studies of damage to a wavy spring are presented. The chemical composition of the metal of the spring fully corresponds to the steel type X15N7M2YU declared by the enterprise. According to the studies conducted in environments containing hydrogen sulfide, the wavy spring is not recommended for use in oil and gas equipment, since it is not resistant to hydrogen sulfide cracking under stress.