Preparation method of seamless mother pipe of mechanical composite pipe used in acid environment

Abstract

The invention relates to a preparation method of a seamless mother pipe of a mechanical composite pipe used in an acid environment. The preparation method comprises the following steps of a smelting procedure, a rolling procedure, a heat treatment procedure, a water pressing procedure and a pipe end machining procedure. The rolling procedure comprises the procedures of cold centering, annular furnace heating, pipe blank dephosphorization, hot centering, perforation-continuous rolling, pipe removal, high-pressure water dephosphorization, hot sizing, cold straightening and flaw detection, and the wall thickness unevenness of the obtained pipe is smaller than or equal to 20%, and the ovality is smaller than or equal to 1%; the heat treatment procedure comprises high-temperature walking beam heating, high-pressure water descaling, high-temperature quenching, high-temperature tempering, high-pressure water descaling, a high-temperature hot straightening process and cooling bed whole pipe air cooling; the pipeline pipe mother pipe can achieve high dimensional precision, high performance stability, high toughness (the ductile-brittle transition temperature is smaller than or equal to-60 DEG C), high ductility (the ductility is larger than or equal to 30% (plate)) and high SSC corrosion resistance (90% AYS four-point bending for 720 hours does not break).

Description

technical field [0001] The invention belongs to the technical field of pipe preparation, in particular to a method for preparing a seamless parent pipe of a mechanical composite pipe used in an acidic environment. Background technique [0002] As the conditions of oil and gas extraction and transportation continue to deteriorate, the oil and gas extracted and transported become more complex, and the demand for composite pipes is increasing. Composite pipe, that is, the base material is carbon steel pipe, and the composite layer is 316L stainless steel or duplex stainless steel or nickel-based alloy. The parent pipe ensures the basic strength, and the composite layer ensures sufficient corrosion allowance, so as to meet the use requirements of the transportation environment in harsh environments. Compared with ordinary line pipe, the seamless parent pipe of composite pipe has special characteristics. For the parent pipe, the composition is stable, the performance fluctuation ...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems existing in the above-mentioned technologies, the purpose of the present invention is to provide a method for manufacturing a mechanical composite pipe master pipe for acidic environments, so as to meet the needs of the development of mechanical composite pipe master pipes in harsh environments such as deep seas, and to solve the problem of line pipes in mechanical In the case of compounding, the performance is unstable, the size is inconsistent and cannot meet the design requirements, etc.

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