Petroleum sleeve steel and manufacturing method thereof

Abstract

The invention provides petroleum sleeve steel which comprises the following components in mass percent: 0.31-0.35 of C, 0.1-0.45 of Si, 0.8-1.5 of Mn, not more than 0.02 of P, not more than 0.01 of S, not more than 0.024 of Al, not more than 0.1 of V, not more than 0.35 part of Mo, and the balance Fe and inevitable impurities. The invention further provides a manufacturing method of the petroleum sleeve steel. The manufacturing method comprises the following steps: smelting molten steel by a converter or an electric furnace, and then casting the smelted molten steel into board blank; heating the board blank to the temperature of 1190-1260 DEG C, and then primarily rolling into board bands; conveying the primarily rolled board bands and then finally rolling through a final roller, wherein, the temperature for final rolling is 820-920 DEG C; and cooling the finally rolled board bands, and then rolling up the bands into steel coils at the temperature of not less than 610 DEG C. In the invention, the steel coils produced by the manufacturing method can meet the requirements of the steel with all specifications (i.e. the ratio of radius to thickness is not more than 0.049) for a non-integral pipe thermal-treatment straight welding petroleum sleeve API K55 on the hot-rolled steel coils.

Description

technical field [0001] The invention relates to the technical field of metal material manufacturing, in particular to a non-integral heat-treated straight seam welded oil casing steel with low yield ratio API K55 and a manufacturing method thereof. Background technique [0002] Compared with seamless pipes, straight seam welded casings have been widely used in the oil exploration industry due to their advantages of high dimensional accuracy, good crush resistance and low cost. Among them, the amount of J55 casing is the largest, while the amount of K55 casing is relatively small due to the difficulty of production. [0003] The technical difficulty of K55 casing lies in the production difficulty of the hot-rolled steel coil used for pipe making. Since the API standard of K55 casing stipulates that the yield strength of the pipe body is between 379 and 552MPa, and the tensile strength is ≥655MPa, the hot-rolled steel coil used must meet this performance requirement after pip...

AI Technical Summary

Problems solved by technology

However, in view of the high cost of heat treatment of the whole pipe after the pipe is made, and most of the pipe factories do not have a heat treatment furnace for the heat treatment of the whole pipe, some people have also studied the manufacturing process of the K55 casing steel for the non-whole pipe heat treatment (see the application number for details). 200610027021.8 Chinese patent application "A Steel for Longitudinal Seam Welding Petroleum Casing Pipe with Low Yield Strength Ratio and Its Manufacturing Method", however, after applying the technical solution disclosed in this patent application document for production, it was found that the product also had a yield strength exceeding API The case of the standard upper limit

Therefore, the technical solution disclosed in the patent application document can produce K55 casing steel, but cannot stably produce K55 casing steel of all sizes at the same time

Images