Steel for petroleum casing connecting piece and manufacturing method thereof

Abstract

The invention discloses steel for a petroleum casing connecting piece and a manufacturing method thereof, and belongs to the technical field of metallurgy. The steel for the petroleum casing connecting piece comprises the following chemical ingredients in percentage by mass: 0.28 to 0.33 percent of C, 0.20 to 0.35 percent of Si, 0.45 to 0.60 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.025 percent of S, 0.90 to 1.10 percent of Cr, 0.18 to 0.25 percent of Mo, 0.020 to 0.050 percent of alt, less than or equal to 0.25 percent of Cu, less than or equal to 2.0*10<4> percent of H, 40*10<4> to 70*10<4> percent of N, less than or equal to 15*10<4> percent of T.O and the balance of Fe and inevitable impurities. The manufacturing method comprises the following production processes: an initial refining process of an electric furnace, a refining process of a ladle furnace (LF), a vacuum degassing (VD) process, a continuous casting process, a casting blank slow cooling process and an inspection and finishing process. The cleanliness, tissue compactness and uniformity of continuous casting round billets for the petroleum casing connecting piece are improved greatly, and the requirement of the steel for the petroleum casing connecting piece is met.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a steel for oil casing connectors and a manufacturing method thereof. Background technique [0002] As the "industrial blood", petroleum work plays an irreplaceable important role in ensuring economic development. With the rapid development of petroleum work, oil well development is developing in the direction of deep wells, ultra-deep wells, and extended displacement. Oil casing is a key equipment widely used in the field of oil exploitation, and its main function is to fix the oil well wall. Due to the particularity of the oil extraction process, the quality of the oil casing directly affects the production safety of the oil well. The outside of the casing has to bear all kinds of substratum pressure and groundwater pressure, and the inside of the casing has to bear mud, internal pressure and water. Vapor pressure, sometimes also bears the erosion of corrosive liquid and gas,...

AI Technical Summary

Problems solved by technology

At present, users mainly use steel ingots as raw materials for forgings. However, due to problems such as low yield, compact structure, and poor composition uniformity of steel ingots, the quality stability of forgings is low, the scrap rate is high, and the cost of raw materials increases.

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