Large-swelling-amount welded tube and manufacturing method thereof

Abstract

The invention relates to a large-swelling-amount welded tube and a manufacturing method thereof, belonging to the technical field of welded tube steel. The welded tube contains the following chemical components in percentage by mass: 0.02-0.10wt% of C, 2.0-6.0wt% of Mn, 0.2-1.0wt% of Si, less than 0.01wt% of S, less than 0.02wt% of P and the balance of Fe and inevitable impurities, and can also contain the following one or more chemical components: 0.1-0.6wt% of Ni, 0.1-0.6wt% of Cr, 0.1-0.5wt% of Cu, 0.01-0.1wt% of Nb, 0.01-0.1wt% of V and 0.01-0.02wt% of Ti. The manufacturing method comprises the following steps: performing converter steel making, controlled rolling and controlled cooling; then performing crimping plate processing on steel strips; forming a swollen blank tube through high frequency welding (HFW); and finally performing heat treatment to obtain residual austenite of which the volume fraction is larger than 5% in the structure. The invention ensures that the material has high strength level and simultaneously has high plasticity, the uniform elongation rate is up to 20% or above, and all the mechanical performance indices meet the requirements of API and other relevant standards.

Description

technical field [0001] The invention belongs to the technical field of welded pipe steel, in particular to a large expansion welded pipe and a manufacturing method thereof. Background technique [0002] Expandable pipe technology is an emerging technology to reduce the cost of oil drilling and completion. It is known as one of the "core technologies of the oil drilling industry in the 21st century" and is increasingly attracting widespread attention in the industry. The expandable tube is a new type of casing that undergoes mechanical expansion, deformation and expansion after going into the well. It can be widely used in drilling, well completion, oil production, well workover and other operations. The emergence of this technology has fundamentally changed the deep well and complex geological conditions in the future. oil drilling technology. The core advantage of the expandable tubular technology is that it can save the wellbore size. Practical engineering applications h...

AI Technical Summary

Problems solved by technology

[0005] Secondly, the manufacturing process is complicated and the process cost is high

For example, in the preparation method of N80 steel grade expansion pipes disclosed in Chinese patent CN 102534369 A, the ideal matching of strength and toughness can be obtained only after two times of quenching and tempering in the two-phase zone, and complicated heat treatment The process is not conducive to large-scale industrial production, which increases the cost of the process and reduces the production efficiency

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