Microalloying steel for ultra-high-strength sucker rod

Abstract

The invention relates to a Nb microalloyed steel for an ultrahigh strength sucker rod. The sucker rod made of steel is suitable for a heavy oil well, a deep well, a large pump strong exploitation well, etc, and is a special type oil rod urgently needed for oil fields in China. The steel comprises the following chemical compositions in percentage by weight: 0.12 to 0.20 percent of C, 0.50 to 1.60 percent of Si, 0.90 to 1.60 percent of Mn, 0.90 to 2.00 percent of Cr, less than or equal to 0.20 percent of Mo, less than or equal to 0.20 percent of Ni, 0.035 to 0.055 percent of Nb, 0.010 to 0.030 percent of Ti, less than or equal to 0.050 percent of V, 0.0010 to 0.0020 percent of B, less than or equal to 0.025 percent of P, less than or equal to 0.020 percent of S and the balance being Fe. The tensile strength of rolled steel is high than 965 MPa; the minification of a plastic surface is higher than 50 percent; and the specific elongation delta200 of the plastic surface is more than 10 percent. The Nb microalloyed steel is suitable for manufacturing the sucker rod for an overweight loaded oil pumping field and has good fatigue resistance, corrosion resistance and economy.

Description

technical field [0001] The invention relates to a multi-element alloyed round steel for ultra-high-strength sucker rods, which is processed into a sucker rod by using the steel of the invention, and has a tensile strength higher than 965Mpa, good toughness and plasticity, good corrosion resistance and fatigue resistance, and is economical. Good sex. Background technique [0002] In order to adapt to the increase of crude oil geological reserves in my country and meet the needs of deep oil exploration and development in the desert, ocean and cooperation with foreign countries in the Tarim Basin of Xinjiang, there will be extensive demand for sucker rods for various deep wells and ultra-deep wells in domestic and foreign markets. The exploitation of oilfields in eastern my country has entered the late stage. Deep wells, ultra-deep wells, and waxy wells have higher requirements for the strength and toughness of sucker rods. The original 20CrMoA and other D-grade high-strength s...

AI Technical Summary

Problems solved by technology

[0007] Low-cost (the price is not higher than 500 yuan compared with 20CrMo D-grade sucker rod steel) high-performance and stable ultra-high-strength hot-rolled round steel for sucker rods, currently there is a blank in the market supply