Austenitic stainless, S31254, and Hastelloy, N10276, were clad on low carbon steel plates with explosive welding for testing in a geothermal environment. Results from visual inspection and microstructural & chemical composition analysis with a scanning electron microscopy and X-ray energy dispersive spectroscopy
Geothermal steam commonly contains CO2 and H2S dissolved gases which are corrosive substances. An explosive welding technique was used for preparing samples of clad carbon steel material with different corrosion resistant alloys (CRAs) for testing in geothermal environment. A test unit was connected to a high temperature geothermal well, KJ-34, at the Krafla geothermal system in Iceland for in-situ corrosion testing. The steam was around 190°C with 14 bar pressure, pH value 8.57 and contained dissolved gases, including H2S and CO2. For this preliminary experiment austenitic stainless steel, S31254, and Hastelloy, N10276, were clad on low carbon steel plates with explosive welding for testing in geothermal environment. This pre-test was performed in order to examine the performance of the materials and explore the possibility of protecting the un-clad sides of the samples from the steam by coating them with ceramic paint. This paper reports the results from the tests and inspection of the CRA clad material including visual inspection, microstructural and chemical composition analysis with SEM and XEDS.
Key words: Corrosion, clad steel, explosive welding, geothermal environment, austenitic stainless steel S31254, Hastelloy N10276