Heat treatment method for seamless mother pipe of mechanical composite pipe used in acid environment

Abstract

The invention relates to a heat treatment method of a seamless mother pipe of a mechanical composite pipe for an acid environment. The heat treatment method comprises the following steps of 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 mother pipe comprises the following components in percentage by weight: 0.06% < = C < = 0.12%; 0.10% < = Si < = 0.30%; 1.00% < = Mn < = 1.60%; 0.02% < = Nb < = 0.10%; 0.04% < = V < = 0.10%; 0.20% or less of Ni + Mo; less than or equal to 0.20% of Cr + Cu; other elements and the balance Fe; 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 heat treatment for pipe material preparation, in particular to a heat treatment method for 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 sta...

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Problems solved by technology

[0005] In order to solve the problems existing in the above-mentioned technologies, the object of the present invention is to provide a heat treatment method for composite pipe master pipes used in acidic environments, so as to meet the needs of mechanical composite pipe master pipes for the development of harsh environments such as deep seas, and to solve the problem of mechanically composited pipe master pipes for line pipes. Under the circumstances, the performance is unstable, the size is not suitable and cannot meet the design requirements, etc.

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