A high uniform deformation performance, high steel grade sew expansion tube and its manufacturing method

Abstract

The invention discloses a high-homogeneous-deformation-performance and high-grade steel SEW expansion pipe and a manufacture method thereof. Chemical components of the expansion pipe include, by mass, 0.08%-0.25% of C, 0.1%-0.6% of Si, 0.6%-2.5% of Mn, not larger than 0.015% of P, not larger than 0.003% of S, 0.1%-0.6% of Ni, 0.3%-1.0% of Cr, 0.1%-0.6% of Mo, 0.1%-0.6% of Cu, 0.01%-0.06% of Nb, 0.001%-0.003% of B and the balance Fe and inevitable impurities. A mother pipe is manufactured through HFW welding, then, full-pipe-body medium frequency induction heating and hot tension reducing are conducted, a high-temperature heat tension reducing pipe blank is immediately air-cooled to a certain specific temperature, is then rotated and is directly water-cooled to the room temperature through an online cooling controlling device, finally, medium and low temperature destressing tempering is conducted, and M-A components with the volume fraction being 20% or above are obtained in the structure and are distributed in a fine-particle-shaped dispersion manner. The defects in the prior art are overcome, and multiple factors adverse to the full-pipe-body homogeneous deformation in the expansion operation process, for example, the poor size precision of seamless expansion pipes, the large difference between weld joints of traditional HFW welding expansion pipes and the base material structure performance, the high manufacture cost of high-alloy automobile steel expansion pipes, the poor reliability that the weld joint quality is 100% free of defects and the like, are avoided.

Description

technical field [0001] The invention belongs to the technical field of welded steel pipes, and in particular relates to a SEW expansion pipe with high uniform deformation performance and high steel grade and a manufacturing method thereof. Background technique [0002] Physical expansion pipes were originally mainly used in repairing casing damage wells, oilfield water plugging and formation sealing, deepening / sidetracking in secondary development of old oilfields, and emergency casings in complex situations such as drilling collapse and lost layers. , with complex formation wells, highly deviated wells, mature wells, depleted wells, deep wells, and high-temperature and high-pressure wells becoming more and more common, their application methods have changed from the previous emergency means to conventional and planned solutions. Because the expansion tube technology has many incomparable advantages such as optimizing the wellbore structure, reducing drilling and production ...

AI Technical Summary

Problems solved by technology

The second is to use the traditional HFW welded steel pipe as the expansion pipe. Although the pipe body has high dimensional accuracy, the structure and properties of the base metal and the weld still exist because the whole pipe deformation heat treatment process (that is, HFW welded pipe thermal tension reduction) has not been introduced. Large differences; for example, the Chinese patent application number 201210009842.4 directly performs off-line heat treatment on the welded tube blank. From the attached drawings, it can be seen that there are still obvious differences in the microstructure of the base metal and the weld zone

The third is that most of the raw materials directly use the high-alloy composition design of the third-generation automotive steel with high plastic deformation properties (such as TRIP steel, TWIP steel or Q&T steel, etc.), in order to ensure that the retained austenite can be obtained at room temperature through a simple heat treatment process structure, so that it is affected by plastic deformation to induce phase transformation and transform into martensite, and then the local hardness of the steel increases and it is difficult to continue to deform, resulting in delayed necking and improved plasticity due to phase transformation. Therefore, this type of material generally contains very unfavorable The total content of welding Si, Al, P and other elements is relatively high (≥1%) and often contains medium and high content of Mn, so the weldability of raw materials is poor, and the reliability of 100% defect-free welds is poor, and it is very easy to produce in the welding process. There are a large number of welding defects such as pores, inclusions, segregation, and delamination. Therefore, TRIP steel or Q&T steel is mainly used for laser welding in the automotive industry and the wall thickness of the plate is relatively thin (generally ≤ 3.0mm), while the wall of the expansion tube used in the oil field The thickness is generally 6.35-15.70 mm, which is difficult to manufacture by this welding method; for example, Chinese patent CN 102345077A discloses a steel for high-strength plastic product and large expansion rate expansion pipe and its preparation method. The raw material component has added up to 10-26% Mn and 0.05-0.3% strategic rare-earth element Re; another example, Chinese patent CN 102517511B discloses a method for manufacturing a low-carbon silicomanganese-type phase transformation-induced plastic steel expansion tube, which adopts straight seam resistance welding The raw materials of the tube-making examples 1, 8 and 11 contain as high as 2.0% Si or 4.0% Mn, which is difficult to achieve at the current level of high-frequency welding at home and abroad

Finally, the heat treatment process used to achieve the goal of tissue regulation is generally more complicated, which directly leads to increased costs and is not conducive to large-scale promotion; for example, Chinese patent CN102534166 A discloses the preparation of a J55 steel grade ERW expansion tube with high diameter expansion performance The method includes three off-line heat treatments. First, the ERW tube blank is heated to 1000-1150°C, held for 30-60 minutes and then air-cooled, and then the whole tube body is heated to the austenitization phase transition temperature A of the tube. c3 Above 50-100°C, keep warm for 30-60 minutes, then air-cool, and finally heat the whole tube to the two-phase area of ​​700-750°C, keep warm for 30-60 minutes, and then air-cool