Low Cr (3 to 5%) bearing steels have been developed and used in CO2 environment as materials to meet "Fitness for Purpose". However, the SSC and SCC resistance of low Cr bearing steel have not been clarified. This paper presents the effect of carbon content, microstructure, and tempering temperature on the SSC and SCC resistance as well as CO2 corrosion resistance of low Cr steel (3%Cr steel).
Product Number:
51300-02041-SG
ISBN:
02041 2002 CP
Author:
Hideki Takabe and Masakatsu Ueda
Publication Date:
2002
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Low Cr (3 to 5%) bearing steels have been developed and used in CO2 environment as materials to meet "Fitness for Purpose". As well as CO2 corrosion resistance, sulfide stress corrosion cracking (SSC) resistance and stress corrosion cracking (SCC) resistance of steel have also been important in the oil and gas industries. However, the SSC and SCC resistance of low Cr bearing steel have not been clarified. This paper presents the effect of carbon content, microstructure, and tempering temperature on the SSC and SCC resistance as well as CO2 corrosion resistance of low Cr steel (3%Cr steel). The effect of carbon content, microstructure, and tempering temperature on CO2 corrosion resistance in 96 hour-corrosion test and SCC resistance of 3%Cr steel are not significant. U bend test results show that 0.16%C-3%Cr steel does not suffer SCC in a boiling-40%CaCl2 solution. A high tempering temperature has a beneficial effect on SSC resistance, because yield strength and hardness decrease as tempering temperature increases. NACE tensile test results show that 0.16%C-3%Cr steel with martensitic microstructure and yield strength of L80 grade survives in a 0.1MPa H2S environment (pH =2.7) and has superior SSC resistance to API L80 13Cr steel.
Key words" sweet corrosion, CO2 corrosion, sulfide stress corrosion cracking (SSC), stress corrosion cracking (SCC), Cr bearing steel, oil country tubular goods (OCTG), martensitic steel
Key words" sweet corrosion, CO2 corrosion, sulfide stress corrosion cracking (SSC), stress corrosion cracking (SCC), Cr bearing steel, oil country tubular goods (OCTG), martensitic steel