Petroleum steel tube capable of anti hydrogen sulfide stress corrosion and its manufacturing method

Abstract

The invention offers oil steel pipes which can resist stress corrosion by hydrogen sulfide. Weight proportion of their compound is: C 0.25-0.32%,Si 0.10-0.40%,Mn 0.60-1.20%, P<=0.020%,S<=0.010%,Ni<=0.25%,Cr 0.55-1.20%,Mo 0.10- 0.50%,Cu<=0.30%,Al 0.010-0.040% and the allowances are Fe. Scrap steel and spongy iron or melted iron is taken as melting materials. After arc melting, external refinement and vacuum deaeration, they are cast continuously to get round billiets. Then, they are hot rolled to seamless steel pipes and finally to bushing and oil pipes by heat processing of quench and temper. The steel pipes have good physicochemical property and their indexes all reach or exceed API standard. Threshold value of resisting stress corrosion by hydrogen sulfide reaches 90%SMYS, which precedes the standard request and can be extensively applied in oil-gas field with hydrogen sulfide.

Description

technical field [0001] The invention relates to a hydrogen sulfide stress corrosion resistant petroleum steel pipe with a yield strength lower than 758MPa (110ksi) and a manufacturing method thereof. Background technique [0002] About 1 / 3 of the world's oil and gas fields contain hydrogen sulfide gas. When ordinary steel pipes are used for the exploitation of oil and gas resources containing hydrogen sulfide, under the action of stress and hydrogen sulfide gas, the steel pipes tend to be brittle suddenly when the stress is much lower than its own yield strength (this phenomenon is called sulfide Hydrogen stress corrosion), the mild case will cause the steel pipe column or the whole well to be scrapped, and the severe case will cause a blowout, causing the hydrogen sulfide to overflow together with the oil and gas, causing huge damage to the entire drilling rig and the surrounding ecological environment. Therefore, hydrogen sulfide-resistant steel pipes must be used in the ...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a hydrogen sulfide stress-corrosion-resistant petroleum steel pipe and its manufacturing method, to solve the problem of extremely adverse effects of harmful elements such as P and S and strip-shaped MnS on the steel pipe's resistance to hydrogen sulfide stress corrosion; Quenching bending deformation of long steel pipes and quality problems that are prone to cracks; it is also necessary to solve the technical problem of low hydrogen sulfide stress corrosion resistance threshold of high-strength hydrogen sulfide-resistant steel pipes in hydrogen sulfide stress corrosion sensitive areas

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