Preparation method for twinning induced plasticity (TWIP) steel for low-cost large-expansibility expansion pipe and steel pipe

Abstract

The invention relates to a preparation method for TWIP steel for a low-cost large-expansibility expansion pipe and a steel pipe. The TWIP steel comprises the chemical components, by weight percentage, 0.30-0.65% of C, 15-30% of Mn, 0.10-1.0% of Cr, 0.01-0.20% of Al, 0.10-1.0% of Si, 0.030-0.30% of Re, S<=0.002%, P<=0.005% and the balance ferrum. Component design is instructed through alloy stacking fault energy, vacuum smelting is conducted, rare earth ferroaluminum is deoxidized, a right amount of Cr and Si elements are added, a small amount of rare earth elements are added, and steel with low content of sulphur and phosphorus and certain grain scale for the large-expansibility expansion pipe is obtained, wherein a base body of the steel is austenite, and the steel has a twinning inducedplasticity effect. The steel is manufactured into large-expansibility large-size expandable casing pipes through hot extrusion.

Description

technical field [0001] The invention belongs to the fields of metal materials and petroleum and natural gas industries, and relates to TWIP steel containing C, Mn and alloying elements Cr, Si and Re. The steel is suitable for making expandable pipes with a large expansion rate. Background technique [0002] Expandable pipe technology (Ma Hongtao. Development and application of foreign expandable pipe technology [J]. Foreign Oilfield Engineering, 2006, 2(22): 20-24) is a mechanical or hydraulic method used in the downhole, through the expansion cone from above Move down or from bottom to top to cause permanent plastic deformation of the casing steel, so that the expanded casing can stick to the well wall. It is an advanced process technology developed in recent years for drilling, completion and workover in the oil and gas industry. Some people also call it the moon landing technology in the field of geosciences in the 21st century. One of the key technologies in the oil and...

AI Technical Summary

Problems solved by technology

[0003] However, the currently used expandable steel pipes include the K55, J55, and L80 casings used in the existing API casing steel pipes and the LSX-80 expandable casing developed by Shell, and even the stainless duplex casing developed in my country in recent years. Steel and TRIP steel expandable pipe sleeves (Xu Ruiping. Research and Development of Expandable Pipe Materials [D]. Master's Degree Thesis of Tianjin University, 2006, 2), while ensuring strength, often have high yield strength and insufficient expansion rate 25%; the problem of material selection for large-scale expansion sleeves above this expansion rate has not been well resolved

Although the yield strength of this kind of steel with TWIP / TRIP effect is only less than 200MPa, the tensile strength can reach more than 1000MPa, and the elongation can reach 50%, but due to the TRIP effect, the expansion force in the later stage of deformation increases, so it is also inappropriate.

[0011] Because the steel used for large-size and large-expansion-rate expansion pipes for single-caliber wells requires uniform wall thickness and small ellipticity during the expansion process, the current hot-rolled seamless steel pipe preparation technology cannot meet the requirements of the current API standards. The expansion tube technology is difficult to meet the requirements, so the present invention adopts advanced metal processing technology and hot extrusion technology to prepare expansion casing with large size and large expansion rate for single diameter wells

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