Science of Corrosion

This paper describes corrosion rate prediction models for the main corrosion mechanisms of carbon steel in Exploration and Production service. The models succeed earlier work by De Waard, Milliams, and Lotz.

The research was focused to assess the key factors concerning relaxation cracking and how to control it. It included the effect of chemical composition of the base materials (both Fe and Ni base alloys), heat to heat variation, grain size, cold deformation, welding, operating temperature and heat treatments.

A laboratory investigation of corrosion under insulation (CUI) using methods given in ASTM G189 for cyclic temperature, wet/dry conditions. Two long term exposure tests of three material conditions and two insulative materials (mineral wool and calcium silicate insulations).

Corrosion of carbon steel materials in brine solutions.  Model results will be compared with literature data and lab experiments. Conditions will be limited to near neutral pH (5-9), temperature  from 22oC to 55oC, and O2 atmospheres up to 101.325 kPa.

This Phase II work in NH₃-dominated sour waters studied the impact of several process variables including NH₄HS concentration, NH₃ partial pressure, H₂S partial pressure, temperature, cyanide concentration, and velocity (wall shear stress).

A laboratory study was performed by exposing seven candidate heat exchanger alloys to simulated 2 (sCO2) Brayton power cycles. The alloys, consisting of fineirtriaitilcly s 3te.6e%ls ,O austenitic stainless steels, and nickel-base alloys, were exposed to impure CO2 containing 2 and 5.3% H2O at a constant pressure of 200 bar.

In Finland, nuclear waste will be disposed in a geological repository in copper canisters.  Here, biotic and abiotic mesocosms, containing copper coupons and an artificial groundwater at 10 °C under argon atmosphere. Sulfate reducing bacteria and methanogens were added to the biotic experiments.

This paper describes the formation of a mackinawite scale on carbon steel in a borate buffer pH = 8.4. Then, it was exposed to different buffers with lower pH. The integrity of the scale and the corrosion occurring underneath was monitored with electrochemical impedance spectroscopy (EIS).

Experiments were done with two levels of electrode diameters. Average localized corrosion rates and maximum pit-depths were monitored over time. Coupons of 17-4PH and GTD450 stainless steels were placed in the same environment to compare the results with that of CMEAS probes.

Evaluation of sheet and foil samples of two Cr2O3- and two Al2O3-forming alloys - tested for 360 days in air + 10 vol. % H2O at 760oC and 871oC. Alloys were ranked on weight change behavior and metal recession measurements, average internal penetration, and maximum internal penetration.

 This study was to monitor the growth of the marine bio-film, of micro/macro-organisms, on the surface of different metallic alloys in seawater by electrochemical impedance spectroscopy (EIS).

The susceptibility of a high strength low alloy nanostructured steel to sulfide stress corrosion cracking (SSCC) resistance is assessed.