In this research, we aimed to investigate the level of damage occurred in the steel tube
material grade CK45 (AISI 1045) after a short period of service in an output desalination
unit of an oil refinery industry. Visual examinations revealed that the material of the failed
tube had significant thickness reduction and also localized corrosion damage. Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction spectrum show that the corrosion
products mostly consist of oxygen as the main element and slightly sulfur. Metallographic
observations on the failed sample show that the observed pinholes were initiated on the
inner surface of the tube sample where the surface was exposed to a possible mixed corrosive gas of H2S, CO2, and naphthenic acid. It is assumed that a severe thickness reduction
has been initially taken place from the inner surface of the tube, and consequently the condensation of byproducts led to development of a localized corrosion and formation of pinholes due to flow stream of corrosive exhausted gases in output oil–gas separator vessel of
the desalination unite. Presence of metallic elements in the EDS analysis such as calcium,
magnesium, potassium, aluminum, manganese, silica, and zinc confirmed the possibility of
condensation of corrosive compounds on the inner surface of the carbon steel tube grade
CK45 in output oil–gas separator vessel of desalination unit. Microhardness measurements
confirm that the steel tube has no hardness change in its core and outer surface. However,
slight reduction in hardness is noticed near the inner surface of the tube sample which can
be attributed to the presence of the pinholes. Electrochemical corrosion studies were carried out in the corrosive media filled up with a NACE ID 182 solution. Electrochemical
investigations revealed that the corrosion products formed are typically porous which cannot provide a protective layer on the surface of the steel tube sample. Finally, recommendations mainly include appli