Oil as the blood of industry, occupying the important status in the energy strategy. Expandable tubular technology is an important oil and gas engineering technology which developed at the end of last century, and the beginning of this century. It is in the mine by using the method of mechanical or hydraulic pressure, through the expansion cone from top to bottom or from down to up movement, permanent plastic deformation in the steel casing, to achieve the expansion of casing with the purpose of close to the wall. The expandable tube technology can greatly improve the efficiency of drilling engineering in the development of oil and gas production, save manpower, material, time and cost, and promote the development of other related technologies, it is one of the key technology of oil and gas industry in the 21st century, and the expansion pipe material is one of the most critical problems of bulged tube.
Duplex steel is mainly composed of ferrite and martensite, also called martensite duplex steel. It has characteristics of no yield Extension, low yield strength and high tensile strength, high strength plasticity It is expected to become the preferred material of oil industry expansion pipe manufacturing. Excellent properties of duplex steel depend mainly on martensite morphology and quantity, and the quenching temperature on the amount of martensite in dual phase steel has the decisive effect.
For the research of quenching temperature on the microstructure and mechanical properties of dual phase steel. The results show that the quenching temperature, the martensite volume fraction increased, leading to higher yield strength and tensile strength. Quenching temperature is 820 ℃, the expansion work duplex steel can obtain the best comprehensive performance.