Method for manufacturing oil casing with k55 steel grade steel plate hfw

Abstract

The invention discloses a method for manufacturing an HFW (High Frequency Welding) oil casing by a K55-grade steel plate. A coiled sheet for producing a steel tube comprises the following chemical components by weight: 0.22 to 0.30 percent of C, 0.10 to 0.40 percent of Si, less than or equal to 1.5 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, less than or equal to 0.60 percent of K55 carbon equivalent and the balance of iron. The method comprises the following machining processes of: uncoiling and flattening, shearing and butt welding, base metal fault detection, plate edge processing, forming, high-frequency welding, heat treatment, air cooling and water cooling, sizing and straightening, online stenciling, fixed-length pipe cutting, physical and chemical test, head flattening, hydrostatic test, ultrasonic weld joint fault detection, pipe end fault detection and finished product checking. The method has the beneficial effect that various indexes of the K55-grade steel HFW oil casing manufactured by the method disclosed by the invention meet the requirements of the API5CT standard.

Description

technical field [0001] The invention relates to a method for manufacturing oil casing pipes by using K55 steel plate HFW, which is suitable for the technical field of steel pipe manufacturing. Background technique [0002] Oil casing is an important material that consumes a lot in the process of oil and gas extraction. It is mainly used to protect the well wall during the drilling process and after the completion of the well, so as to ensure the smooth progress of the drilling process and oil production after the completion of the well. The oil casing is the lifeline to maintain the operation of the oil well. Due to the different geological conditions, the downhole stress state is complex, and the tensile, compressive, bending, and torsional stresses act on the pipe body, which puts forward higher requirements on the quality of the oil casing itself. . Once the casing itself is damaged for some reason, it may lead to a reduction in production of the entire well, or even scr...

AI Technical Summary

Problems solved by technology

At the same time, as the carbon content increases, the banded structure tends to be serious, which is not conducive to forming welding

[0005] Shear butt welding: K55 steel grade carbon equivalent ≤ 0.60%, welding is difficult, if the quality of steel strip butt welding is not good, the butt weld seam is easy to crack during the forming process, and may even cause damage to the forming welding equipment, and cannot be continuous normal production

[0006] Forming welding process: After the coil enters the rolling mill, it is easy to form a work hardening effect, and the forming process will easily lead to an increase in the longitudinal yield strength of the pipe body and a decrease in the tensile strength

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