Manufacturing technique of low compression ratio high grade pipe line steel

Abstract

The invention relates to a method for producing high-strength low-alloy steel. Wherein, it comprises smelting, refining, casting sheet blank, heating blank, removing phosphor, cooling and flattening; the smelting step uses pure steel, low phosphor, and low sulfur; in the casting step, the loose of blank and the aliquation are lower than B0.5level; in the heating step, vanadium+niobium+ titanium0.15%, nickel+chromium+copper<=0.50%, and the heating temperature is 1180-1220Deg. C; in the thermal rolling step, in the crystallize process, the deformation temperature is 1070-1000Deg. C, the deformation amount is 40-60%, and the rolling speed is 1.5-2.5m / s, and in the second step that rolling the non-crystallized area, the pressure is 200-400MPa, the rolling speed is 5-1.5m / s, and the deformation amount is 60-75%; and the interlayer cooling speed in the cooling step is 15Deg. C / s-25Deg. C / s.

Description

technical field [0001] The invention relates to a production process of high-strength low-alloy steel, in particular to a production process of high-grade pipeline steel with low compression ratio. Background technique [0002] Natural gas resources are mostly concentrated in oceans, hills, deserts, plateaus and alpine regions, far away from the consumer market. In order to reduce luck costs and enhance market competitiveness, pipeline design and construction must develop in the direction of large diameter, high steel grade, thick pipe wall, and high delivery pressure. With the construction of long-distance gas pipelines, the understanding of pipeline safety and high-quality materials is becoming more and more profound. Generally speaking, long-distance gas pipelines are often accompanied by large-diameter, high-pressure transmission, and thick-walled characteristics. Correspondingly, the requirements for high toughness and high strength are put forward for coils, especiall...

AI Technical Summary

Problems solved by technology

From the traditional concept, the production of pipeline steel must ensure a compression ratio greater than 10. In this case, the production line with thinner continuous casting slabs has no ability to produce thick specification pipeline steel. For example, if you want to get a qualified thickness of 20mm The above finished slabs must have a continuous casting production line with a thickness of more than 200mm, which is a big problem for some production lines that do not have the conditions

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