Steel for heat-resisting casing pipe and manufacturing method thereof

Abstract

The invention discloses a steel for heat-resisting casing pipes, which comprises the components in percentage by weight: 0.2-0.30% of C, 0.10-0.3% of Si, 0.4-1.0% of Mn, 0.5-1.5% of Cr, 0.1-0.5% of W and the balance Fe and inevitable impurities. The manufacturing method comprises the following steps: according to the above component proportion, smelting, casting and hot rolling to form a seamless steel pipe; after counterbalancing temperature in a temperature zone of 820-920 DEG C, keeping warm for 30-60 minutes, and carrying out austenitizing full treatment; carrying out quenching treatment; counterbalancing temperature of a quenching pipe in a temperature zone of 580-720 DEG C, keeping warm for 30-90 minutes, and carrying out drawing temper. The heat-resisting casing pipe produced with the above manufacturing method by the above components can obviously improve high-temperature behaviour, corrosion resistance and creep resistance therefore, especially can improve the permanence property thereof under high-temperature working environment for a long time and can greatly lower production cost.

Description

technical field [0001] The present invention relates to a steel for heat-resistant casing and a manufacturing method thereof, in particular to a steel for heat-resistant casing suitable for heavy oil heating at a temperature of 300-400°C and an air pressure of about 20Mpa and for long-term use and a manufacturing method thereof . Background technique [0002] With the continuous development of the oil exploitation industry and the continuous increase of oil consumption, the exploitation of heavy oil has become the main source of output for many oil companies at home and abroad. At present, my country's annual output of heavy oil has reached more than 300 million tons, of which Liaohe Oilfield and Xinjiang Karamay Oilfield have accounted for 1 / 2 and 1 / 3 of their total crude oil output respectively. In addition, foreign countries such as Canada, the United States and Venezuela have relatively high heavy oil production. Heavy oil production at home and abroad adopts single we...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a heat-resistant casing steel and its manufacturing method through reasonable composition design and process design, so as to solve the problem of conventional heat-insulating casing steel such as 25Mn2 and 25CrMo4 under 350°C and 25Mpa air pressure. Poor high-temperature performance, easy to deform, and unsuitable for use in oil and gas field steam drive wells during long-term use, and can effectively reduce manufacturing costs

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