Low-cost X80 straight seam welded pipe and manufacturing method thereof

Abstract

The invention discloses a low-cost X80 straight seam welded pipe and a manufacturing method thereof. Chemical components of the low-cost X80 straight seam welded pipe include, by weight percent, 0.039%-0.079% of C, 0.16%-0.26% of Si, 1.33%-1.83% of Mn, smaller than or equal to 0.017% of P, smaller than or equal to 0.0046% of S, 0.14%-0.24% of Cr, 0.019%-0.059% of Nb, 0.019%-0.039% of V, 0.0051-0.028% of Ti, 0.011%-0.057% of Al, 0.13%-0.28% of Ni and the balance Fe and a trace of inevitable impurities. According to technological characteristics, the soaking temperature ranges from 1120 DEG C to 1220 DEG C, two-stage control rolling is adopted, and the rolling temperature in a recrystallization area ranges from 950 DEG C to 1200 DEG C; second-stage rolling is conducted in a non-recrystallization area, and the air cooling ending temperature ranges from 650 DEG C to 750 DEG C; and the laminar cooling speed ranges from 5 DEG C / s to 25 DEG C / s, JCO or UO is adopted for pipe manufacturing, the expanding rage e is larger than or equal to t / D, and the maximum value of the expanding rate is 2.5%. The low-cost X80 straight seam welded pipe and the manufacturing method thereof have the beneficial effects that a low-grade steel plate is used for manufacturing the high-grade X80 straight seam submerged arc welding pipe, strength and plasticity indexes are good, and the production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of pipeline steel, in particular to a low-cost X80 straight seam welded pipe and a preparation method thereof. Background technique [0002] With the rapid development of the economy, the global demand for oil and natural gas is increasing day by day. As one of the safest ways to transport oil and gas over long distances, pipeline transportation has attracted much attention. In recent years, X70 and X80 line pipes have become the mainstream pipes in pipeline construction. Through a large number of production practices, people have found that when the matrix structure of LSAW pipes is acicular ferrite or ferrite + pearlite, especially steel pipes of X80 and below grades, after the entire pipe is expanded, the steel pipe The strength is not always higher than that of the corresponding steel plate. Therefore, for the sake of safety, the same grade of steel plate has to be used to prepare the same grade of we...

AI Technical Summary

Problems solved by technology

For the sake of safety, when selecting materials for pipe making, the performance of the same steel plate is usually used and cannot be utilized to the greatest extent, resulting in unnecessary waste

[0006] Based on the above background technology, X80 longitudinal welded pipes have some problems, such as high cost, complicated preparation process, and insufficient product potential exploration, both in terms of composition design and preparation methods.

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