130KSI-grade and 135KSI-grade corrosion-resistant drill tool steel for oil and gas fields and manufacturing method thereof

Abstract

The invention relates to high-toughness and hydrogen sulfide corrosion resistant round steel and a manufacturing method thereof. The round steel comprises, by mass, 0.25-0.40% of C, 0.20-0.45% of Si, 0.95-1.50% of Mn, 1.35-1.90% of Cr, less than or equal to 0.002% of S, less than or equal to 0.008% of P, 0.75-1.30% of Mo, 0.10-0.30% of Ni, 0.05-0.25% of V, 0.010-0.050% of Nb, 0.10-0.30% of Cu, less than or equal to 0.050% of Al, 0.0005-0.005% of Ca, and the balance Fe and unavoidable impurity elements. The hot-rolled round steel is produced through a process route of continuous casting-continuous rolling-annealing, the round steel is subjected to heat treatment directly, or a machined semi-finished drill tool is subjected to heat treatment. On the premise that related 130KSI and 135KSI synthesized mechanical properties are met correspondingly, according to an America NACE TM0177 standard hydrogen-sulfide-resistant stress corrosion test, a product is not broken for 720 hours under the condition that 70% of nominal yield stress is pre-loaded in a saturated H2S solution. The material is suitable for 130KSI-strength-grade and 135KSI-strength-grade drill tools under the mining environment of acidic oil and gas fields.

Description

technical field [0001] The invention belongs to the field of round steel preparation, and in particular relates to a 130KSI and 135KSI steel grade H 2 S corroded drill steel and method of manufacture. Background technique [0002] With the development of the world economy, energy consumption is increasing rapidly, and conventional oil, natural gas and other easy-to-exploit resources are becoming less and less, making it difficult to meet the growing energy demand. The exploitation of oil and gas fields has to be developed in deep sea, desert, north and south pole regions, and the environment of strong corrosive media such as hydrogen sulfide and carbon dioxide. H resistance of conventional 110KSI steel grade 2 S corrosion and 120KSI steel grade ordinary drilling tool materials often fail in today's harsh mining environment, causing the drilling system and even the entire well to be scrapped, bringing huge economic losses to oil and gas fields. Therefore, ordinary drilling...

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Problems solved by technology

However, in order to meet the requirements of the harsh working environment, new materials must meet high technical indicators. The design, production and manufacture of the elemental composition of steel is a difficult point. At present, there is no high-strength, toughness, H-resistant steel grade higher than 120KSI steel grade in China. 2 S corroded drilling tool steel for oil and gas field development

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