硫化水素を含む高温塩化物溶液中における高Ni合金の耐食性

概要

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Effects of environmental and material factors, such as temperature, partial pressures of hydrogen sulfide and carbon dioxide and alloy composition on corrosion resistance of Ni-Cr-Fe alloys in H_2S-CO_2-Cl~ environments simulating sour oil and gas wells are discussed. Main factor controlling the resistance to stress corrosion cracking (SCC) of high Ni alloys in Ni content as far as the results in the present work are concerned. Higher Ni content gives higher resistance to SCC. For a certain content of Ni in an alloy, there are optimum content of Cr and Mo to improve SCC resistance. When Δ is determined by the following formula : Δ=Ni-(Cr+1.5Mo-20)^2/12 SCC was not observed in alloys that had composition range of Δ>19 in 20% NaCl solution saturated with 1 atm. H_2S at 230℃. Higher Ni content gave higher critical temperature for the occurrence of SCC in H_2S-CO_2-Cl~ environment. While the presence of hydrogen sulfide in itself does not affect corrosion resistance of Ni-Cr-Fe alloys, hydrogen sulfide coexisting with chloride ions increases the detrimental effect of chloride ions for passivating metals. Cold working in Ni-Cr-Fe alloys increases the susceptibility to SCC in sour environment.
社団法人日本鉄鋼協会の論文
1988-06-01