A kind of m65 resistance welding sleeve and its manufacturing method

Abstract

The invention discloses an M65-grade electric resistance welding casing pipe and a manufacturing method thereof. The M65-grade electric resistance welding casing pipe comprises, by weight percentage, 0.14-0.18% of C, 0.15-0.30% of Si, 1.10-1.40% of Mn, less than or equal to 0.020% of P, less than or equal to 0.008% of S, 0.06-0.12% of Ti, 0.02-0.05% of Als, less than or equal to 0.008% of N, less than or equal to 0.40% of carbon equivalents and the balance Fe and unavoidable elements. A continuous casting sheet billet is heated to 1150-1200 DEG C through a heating furnace and subjected to hot continuous rolling. The finishing rolling temperature is 780-840 DEG C. After being rolled, a steel belt is cooled at the speed of 8-12 DEG C / s. The steel belt is coiled at the temperature of 560-620 DEG C. The steel belt is subjected to high frequency / medium frequency electric resistance welding and made into a steel pipe through an ERW unit. The whole pipe is subjected to the normalizing heat treatment process, wherein the whole pipe is heated to 880-910 DEG C, the temperature is preserved for 30-50 minutes, and air cooling is conducted. The steel belt is good in weldability and impact toughness; normalizing treatment is adopted, so that banded structures and residual stress are eliminated; the heat treatment process is simplified; and performance consistency of a pipe body and weld joints is guaranteed.

Description

Technical field [0001] The invention belongs to the technical field of steel for petroleum casing, relates to a resistance welded casing and a manufacturing method thereof, and particularly relates to an M65 petroleum casing in API SPEC 5CT steel grade and a manufacturing method thereof. Background technique [0002] Petroleum casing is one of the most commonly used special oil pipes in oil fields. It is used in large quantities and costs a lot. It is an indispensable construction material in oil and gas field drilling operations. Compared with seamless pipes, ERW casing has significant advantages such as uniform wall thickness, high dimensional accuracy, good perforation performance, strong collapse resistance, and low cost. ERW casing is welcomed by manufacturers and oilfield users. The development of high value-added, different grades of longitudinally welded oil layer casings to improve market competitiveness has far-reaching significance for saving oil production costs and i...

AI Technical Summary

Problems solved by technology

[0009] The present invention aims at the technical problems existing in the current production of straight seam electric resistance welded petroleum casing M65, such as: high carbon content, poor weldability and impact toughness of the steel strip, complex quenching and tempering heat treatment process, etc., and proposes the technical solution of the present invention , the purpose of which is to provide an M65 steel grade electric resistance welded oil casing pipe and its manufacturing method, especially designed with low-carbon titanium-containing components, the yield strength of the hot-rolled steel strip is greater than 530MPa, the tensile strength is greater than 620MPa, and the whole pipe is normal Straight seam electric resistance welded petroleum casing with performance of M65 grade after fire heat treatment and manufacturing method thereof

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