A long-life steel suitable for fracturing pump valve body in unconventional oil and gas operations and its forging method

Abstract

The invention discloses a long-life steel for fracturing pump valve body suitable for unconventional oil and gas operations, which belongs to the field of alloy steel. The steel for fracturing pump valve body contains: C 0.30%-0.45%, Si 0.15 %~0.35%, Mn 1.5%~2.5%, Cr 0.8%~1.0%, Mo 0.6%~0.8%, Ni 2.00%~2.50%, V 0.05%~0.25%, Al 0.015%~0.040%, Sb 0.01% ~0.03%, P≤0.015%, S≤0.015%, N≤0.0080%, O≤0.004%, the rest is Fe and other unavoidable impurities; the above element composition ratio should meet: 1) 0.20%≤%C‑ (0.077×%Cr+0.24×%V)≤0.32%; 2) 4×%Ni+1.2×%Cr‑1.5×%Si+17×%Sb+10×%V‑9×%Ni×%Sb‑ 5 x %Mn ≥ 1.0. The tensile strength at 1 / 4 thickness of the fracturing pump valve body prepared by using the above steel is ≥1050MPa, the yield strength is ≥900MPa, ‑27℃KV 2 ≥100J; 140MPa stress, fracturing fluid environment, stress corrosion fatigue life ≥3.5 million times, meeting the 350h service requirement of fracturing pumps.

Description

technical field [0001] The invention belongs to the field of alloy steel, and in particular relates to a steel alloy suitable for tensile strength ≥ 1050MPa, yield strength ≥ 900MPa, -27°C KV 2 ≥100J, unconventional oil and gas operation fracturing pump valve body steel and forging molding process with good stress corrosion fatigue life. Background technique [0002] As the oil and gas drilling environment deteriorates, 90% of oil and gas wells need to be fractured to increase recovery. The fracturing pump is an important equipment for fracturing and acidizing operations in oilfields, to break open formations, and to increase oil and gas production and recoverable reserves. With the gradual decrease of my country's oil and gas reserves, the difficulty of oil and gas well exploitation continues to increase. In order to improve extraction efficiency and increase oil and gas production, fracturing parameters (pressure, speed, etc.) are also increasing year by year. [0003] T...

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Problems solved by technology

[0004] The prior art with Chinese patent publication number CN112501507A discloses a high-strength alloy structural steel for fracturing pump cylinders and its preparation method, in order to solve the cracking failure and fatigue damage of the above-mentioned materials in fracturing operation equipment The problem is to provide high-strength alloy structural steel for fracturing pump cylinders. The technical proposal is as follows: the chemical element composition of the steel and the weight percentage of each component are: C 0.300.36, Mn0.230.28, P≤0.015, S ≤0.010, Si0.050.10, Ni 3.203.30; Cr 1.401.50; Mo 0.550.60, V 0.110.15, H≤1.5ppm, O≤112ppm, N≤70120ppm, others are Fe

[0006] At present, the commonly used materials for pressure pump valve bodies in the world are 4130 and 4330. In my country, there are 30CrNi2MoA, 35CrNi2MoA, 40CrNi2MoA, etc., but they all face the problem of short service life.

Some enterprises use stainless steel 15-5 and 17-4 to manufacture fracturing pump valve bodies. Although they can improve the service life, they face the problems of high cost and difficult forming

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