The effect of cooling rate-induced microstructural changes on CO2 corrosion of low alloy steel. (December 2022)

• Record Type: Journal Article
• Authors: Gupta, Kapil K.; Haratian, Saber; Gupta, Shivangi; Mishin, Oleg V.; Ambat, Rajan
• Is Part Of: Corrosion science. Volume 209(2022)
• Publication Date: 2022-12
• Subjects: Low alloy steel -- Microstructure -- CO2 corrosion -- Electrochemical impedance spectroscopy -- Electron microscopy; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110769
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: The effect of cooling rate-induced microstructural changes on corrosion resistance in a CO2 -saturated 3.5 wt% NaCl solution have been explored for the API L80–1Cr steel. The corroded layer majorly contains siderite, akagenite, and undissolved cementite. The amount of FeCO3 in this layer is larger for the water-cooled sample with a martensitic structure, whereas the furnace-cooled sample with a ferritic-pearlitic structure contains a larger amount of akagenite. The retained cementite and the microrough surface of the furnace-cooled sample provide greater anchoring to the scale. Comparing samples cooled at different rates, the furnace-cooled condition appears to provide better CO2 corrosion resistance. Highlights: CO2 corrosion resistance decreases with increasing cooling rate after austenization. Slow Fe dissolution allows formation of akagenite as corrosion product on pearlite. Small crystallite size and high dislocation density accelerate Fe dissolution. Scale adherence is improved by residual lamellar cementite and microrough surface.