Martensite phase transformation enhanced type double-phase stainless steel and method for making seamless steel pipe from same

Abstract

The invention provides martensite phase transformation enhanced type double-phase stainless steel. The steel is composed of 0.05% or lower of C, 0.5% or lower of Si, 0.6% or lower of Mn, 0.02% or lower of P, 0.003% or lower of S, 16-18% of Cr, 3.0-5.5% of Ni, 1.5-4.0% of Mo, 1.0-2.0% of W, 1.5-3.5% of Cu, 0.1% or lower of V, 0.1% or lower of Nb, 0.01-0.05% of N, 0.02% or lower of Al, 0.005-0.02% of Ce and the balance Fe and impurities. Meanwhile, the invention provides a method for making a seamless steel pipe from the martensite phase transformation enhanced type double-phase stainless steel. The martensite phase transformation enhanced type double-phase stainless steel has the beneficial effects that the strength can reach 125 ksi after thermal treatment is conducted on the double-phase stainless steel, the production cost of the seamless steel pipe can be controlled at 50,000 yuan per ton or lower, and the CO2 stress corrosion resistance is not inferior to that of 2507 double-phase stainless steel.

Description

technical field [0001] The invention belongs to the field of manufacturing stress-corrosion-cracking-resistant duplex stainless steel, in particular to a high-strength, high-toughness martensitic transformation-strengthened duplex stainless steel used in oil and natural gas development and a method for manufacturing a seamless steel pipe. Background technique [0002] In recent years, due to the rapid economic development of emerging countries, the demand for energy such as oil and natural gas has increased significantly, so the exploration and production of natural gas and oil are facing a more stringent service environment, including formation temperature (100-250 ℃) Interaction with formation pressure, containing high chloride ion concentration, low pH and H 2 S and CO 2 Wet environment and complex corrosion environment can easily cause pitting corrosion and stress corrosion cracking of metal materials during use, which will cause failure of oil and gas production pipeli...

AI Technical Summary

Problems solved by technology

Among them, the chemical composition range of dual-phase steel is mainly 20-25% Cr, 4-8% Ni and 2-4% Mo, and the chemical composition of nickel-based alloy is mainly 19-30% Cr, 25-60% Ni and 2- 14% Mo, however, due to the high alloy element content of the above materials, the production cost of these alloys is high. In addition, in order to meet the strength requirements of oil well pipes, the subsequent cold working strengthening becomes an indispensable processing procedure, which further lengthens production cycle

In recent years, due to the sharp drop in international oil prices, the pressure on the cost of oil and gas extraction has increased significantly.

Images