Heat resistant steel tube and manufacturing process thereof

Abstract

The invention discloses a heat resistant steel tube and a manufacturing process thereof. The heat resistant steel tube is prepared from the following components in percentage by mass: 0.25-0.32 percent of C, 0.20-0.37 percent of Si, 0.9-1.1 percent of Mn, no larger than 0.017 percent of P, no larger than 0.008 percent of S, 0.02-0.1 percent of Ni, 0.9-1.2 percent of Cr, no larger than 0.04 percent of Nb, no larger than 0.25 percent of Cu, 0.02-0.06 percent of Al, 0.02-0.07 percent of Ti, 0.1-0.2 percent of Mo, no larger than 0.04 percent of V and the balance of Fe and inevitable impurities and is prepared by the following steps: melting by an electric furnace, refining outsides the furnace, vacuum degassing, continuous casting, steel billet heating, steel tube rolling, quenching and tempering treatment, straightening and the like. According to the manufacturing process disclosed by the invention, with adoption of the melting mode, steel purity is ensured; the manufactured steel tube is excellent in room temperature performance, is good in matching of strength and toughness and has the characteristics of high high-temperature strength and good heat stability, thus ensuring safety of oil extraction in an oil well; the heat resistant steel tube is suitable for the field of thermal recovery of high-density oil and has wide application prospect.

Description

technical field [0001] The invention relates to the production field of seamless steel pipes, in particular to a heat-resistant steel pipe and a production process thereof. Background technique [0002] The world's high-density oil resources are quite rich, but there are fewer and fewer thin oil resources available for exploitation. High-density oil will be an important energy source in the future. my country's Shengli, Liaohe, Xinjiang and Zhongyuan oil fields are rich in high-density oil resources. Due to High-density oil has a high viscosity, so oil recovery is very difficult, and thermal extraction is generally used. [0003] In my country, the steam stimulation method is mainly used. The heat of injected steam is used to raise the temperature of high-density oil, which is easy to flow and easy to mine. During the production process, the casing is fixed in the wellbore in a restrained state and cannot freely expand and contract. During the injection stage of high-tem...

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Problems solved by technology

During the production process, the casing is fixed in the wellbore in a restrained state and cannot freely expand and contract. During the injection stage of high-temperature and high-pressure steam, the casing is subject to a large compressive stress due to thermal expansion and restraint. Shrink and relax and bear a lot of tensile stress, and the casing is easily damaged due to repeated high tensile-compressive stress

[0004] In the past, ordinary API P110 casing was mainly used, and its pipe material was C-Mn steel, which had poor thermal stability. When the temperature ranged from room temperature to 350°C, the yield strength and tensile strength of P110 casing material generally decreased by 25%.

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