Steel for high-frequency resistance straight weld oil well pipe and production method thereof

Abstract

The present invention relates to a steel for a high-strength oil well pipe and a production method thereof, in particular to a steel for a high-frequency resistance straight weld oil well pipe and a production method thereof, solving the technical problems that the steel for an ERW (Electrical Resistance Weld) oil well pipe in the prior art cannot meet the steel for N80 grade non-quenched ERW welding non-quenched oil well pipes due to extremely-low strength and toughness, higher yield, no favorable matching of the strength and the plasticity. The present invention designs the steel for the high-frequency resistance straight weld oil well pipe. The steel is characterized by comprising the following chemical components in percentage by weight: 0.05-0.13 percent of C, 0.10-0.40 percent of Si, 1.0-1.8 percent of Mn, 0.1-0.5 percent of Cr, 0.1-0.5 percent of Mo, 0.02-0.06 percent of Nb, 0.02-0.06 percent of Ti, not more than 0.025 percent of P, not more than 0.020 percent of S and the balance of Fe and inevitable doped elements. The invention can be used for producing oil casings and oil pipes.

Description

Technical field: [0001] The present invention relates to high-strength oil well pipe steel and its manufacturing method, in particular to high-frequency resistance straight seam welding oil well pipe steel and its manufacturing method, referring to N80 grade ERW welded non-quenched and tempered oil well pipe steel, which can be used to make oil casing and tubing. Background technique: [0002] The traditional high-strength oil casing is mainly made of seamless steel pipes, which require quenching and tempering treatment, the production process is complicated, and the cost is high. The seamless steel pipe also has a series of problems such as poor mechanical properties, eccentricity of the steel pipe, large roundness error, uneven wall thickness, and poor quality of the inner wall of the pipe. [0003] High-frequency resistance straight seam welded oil well pipe (referred to as ERW welded oil well pipe) is a new type of oil pipe developed in the late 1970s abroad and gradual...

AI Technical Summary

Problems solved by technology

Solve the technical problems of the existing ERW oil well pipe steel with low strength and toughness, relatively high yield strength, and poor matching of strength and plasticity, which cannot meet the requirements of N80 level non-quenched and tempered ERW welded non-quenched and tempered oil well pipe steel

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