Steel in use for fire resistant, heat insulated oil line, and preparation method

Abstract

This invention discloses a method for manufacturing steel for high-temperature-resistant and heat-insulating oil pipes. The steel comprises: C 0.05-0.25 wt.%, Si 0.10-0.6 wt.%, Mn 0.10-1.0 wt.%, Cr 0.5-2.0 wt.%, Mo 0.10-1.0 wt.%, W 0.1-1.0 wt.%, Fe and inevitable impurities. The method comprises: (1) smelting, casting and hot-rolling seamless steel pipes; (2) performing austenite treatment in 920-1000 deg.C temperature zone; (3) quenching and tempering at 620-720 deg.C. The yield strength of the pipes at room temperature is greater than 650 MPa. After thermal treatment, the pipes can be combined with suitable solder and welded under CO2 protection to obtain heat-insulating oil pipes with increased high temperature strength (30%), and can be used for gasoline-driving thick oil extraction.

Description

technical field [0001] The invention relates to a high-temperature-resistant heat-insulating oil pipe steel and a manufacturing method thereof, in particular to a steam drive heat-insulating oil pipe steel suitable for long-term use at a temperature of 300-400°C and an air pressure of about 20Mpa 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, the annual output of heavy oil in my country is more than 15 million tons, among which Liaohe Oilfield and Karamay Oilfield in Xinjiang account for 1 / 2 and 1 / 3 of the total crude oil output respectively. There are usually two production methods for heavy oil production: steam stimulation and steam flooding. Steam huff and puff refers to the heavy oil recovery method that completes the t...

AI Technical Summary

Problems solved by technology

[0006] In view of the fact that the existing 25Mn2, 25CrMo4 and other conventional heat-insulating tubing steels have poor high-temperature performance when used for a long time at 350°C and 20Mpa air pressure, and are not suitable for the use of heat-insulating tubing in steam drive wells, the purpose of the present invention is to propose a High-temperature-resistant heat-insulated oil pipe steel and its manufacturing method are finally used to solve the problem of poor high-temperature performance and easy deformation of heat-insulated oil pipes used in steam drive wells in oil and gas fields