The high strength and corrosion resistance of nickel-chromium alloys such as Alloy 718 and nickel-iron-chromium alloys such as Alloys 945 and 945X make them particularly good candidates for use in demanding environments in the upstream oil and gas industry. These materials generally perform well where resistance to sulphide stress cracking and chloride stress corrosion cracking is required. However whilst these alloys are considered ‘NACE compliant' environmentally-assisted failures can still occur.It is generally accepted that for hydrogen cracks to initiate there must be a critical combination of stress susceptible microstructure and hydrogen concentration. In this project the effect of microstructure is explored by heat treating Alloy 718 945 and 945X to standard and non-standard conditions. Tensile specimens were slow-strain-rate-tested in air and under CP to explore sensitivity to hydrogen embrittlement. Finally the effect of a severe stress concentration in the form of a sharp notch was used to determine whether there is an enhanced susceptibility to hydrogen embrittlement due to the presence of local stress raisers. The results are compared with tests undertaken by other authors under various hydrogen-charging conditions.

Precipitation hardenable nickel alloys are commonly used in oil and gas offshore structures where requires outstanding mechanical strength and corrosion resistance. In seawater galvanic coupling to steel or cathodic protection promotes the formation of atomic hydrogen on the surface of Inconel 718. Hydrogen atoms further dissolve into the metal matrix and cause hydrogen embrittlement. The unconventional Additive Manufacturing (AM) process generates fine microstructure and alters surface finish that affect hydrogen intake process and the subsequent hydrogen embrittlement. The effects of hydrogen embrittlement are investigated on different build orientations and surface finish of AM Inconel 718 by slow strain rate (SSR) testing in seawater environment under cathodic protection. The susceptibility of AM 718 to hydrogen embrittlement is discussed based on the SSR results and metallography analysis with respect to its wrought counterpart.

Corrosion, either internal or external, along with other types of defects on pipelines eventually lead to leaks without proper treatment. This gives rise to several issues, including environmental and safety hazards, and in case of pipe leaks in a plant, a loss of the efficiency of the process or, ultimately, failure of the process. Replacing the corroded pipelines (piping) can be difficult, costly and time consuming especially for plant. A required shutdown causes major economic loss. Thus, instead of a replacement of the defected pipelines, the installation of online repair is a better option.
Repairs of pipelines include metallic and non-metallic repairs. Metallic repairs generally require welding or hot works which is not suitable for online repair of pipes containing hydrocarbons. In such cases the use of non-metallic composite repairs is the optimum solution. A non-metallic composite repair system is a system used to reinforce structures using a fiber equipped with a thermoset epoxy system. The epoxy system consists of a hardener and a resin which, after mixing, become solid through a polymerization reaction after a short duration of time, a process that is called curing. Depending on the temperature, the duration of time changes in an inverse relation. The higher the temperature, the smaller the duration of time needed for curing. This system can be used to reinforce pipelines with both external and internal corrosion and it can be used on Straight Pipes, Tees, Elbows, Flanges and weld joints. The repair system can also be installed online without the need for a shutdown in a short amount of time and a small requirement of labor intensity, making it cost effective. It is also environmentally friendly. In this paper we are going to present cases that were resolved by our company that demonstrate how successful these non-metallic composite repairs are and how diverse their applications can be