Research Of Regular Pattern On Corrosion Resistance Of 00Cr9NiMo Steel

Petrochemical pipelines play an extremely important role in our oil and gas extraction industry.The losses caused by corrosion in the exploitation of oil and gas fields are extremely large and need to be resolved as soon as possible.Chromium-containing stainless steels maintain a high resistance to CO₂ corrosion by adding 9% to 14%（by mass fraction）Cr,and in severely corrosive environments.This paper mainly studie on 00Cr9NiMo multi-component chromium-molybdenum-resistant carbon dioxide-corrosion oil well pipes and reduces the cost of oil and gas field exploitation.It is used in oil and gas fields with a temperature of 60-90℃ and a carbon dioxide partial pressure of less than 3 MPa.The annual corrosion rate is less than 0.076 mm/a.With a relatively low cost,no pitting reaction occurs during service.The mechanical properties of 00Cr9NiMo steel were tested,as well as various corrosion resistance assessments,supplementary corrosion resistance data,influencing factors of corrosion performance,corrosion resistance of experimental steel,and optimization of heat treatment process.The corrosion resistance of the experimental steel in the laboratory simulation of oil well mining environment conditions was analyzed by means of corrosion weight loss test,scanning electron microscopy（SEM）,metallographic observation,in situ statistical analysis,and electron probe（EMPA）.The effect of temperature,C element content,CO₂ gas partial pressure and quenching and tempering treatment process on corrosion resistance of experimental steel.The yield strength,tensile strength,hardness,elongation,and i MPact energy of the experimental steel were tested.The quenching and tempering process at 920℃ and 640℃ were determined by the corrosion weight loss test.In the low-temperature environment,the corrosion resistance of 9Cr-0.085C steel and 13Cr steel is equivalent.Under the condition of no higher than 90℃,the corrosion rate of the test steel after quenching and tempering can reach the engineering requirements（<0.076 mm/a）,and all kinds of test steels exhibit excellent corrosion resistance at 60℃..It can be concluded that the lower the temperature is,the corrosive effect of CO₂ on Cr-containing steels will be greatly reduced.The anti-hydrogen induced cracking（HIC）performance of 00Cr9NiMo steel is very good,and the results of anti-sulfide stress corrosion（SSCC）are poor.The results of SEM and EMPA show that the segregation of the experimental steel is severe and the presence of Cr carbide precipitates.