A production process of high-strength x80 steel plate for bent pipe

Abstract

The invention relates to a production process of high-strength bent pipe steel, which is a production process of high-strength X80 steel plate used for bent pipes. Composition: C: 0.015-0.080%, Mn: 1.50-1.80%, Si: ≤0.30% , S: ≤0.0030%, P: ≤0.015%, Nb: 0.04~0.15%, Ti: 0.005~0.030%, V: ≤0.120%, Alt: ≤0.060%, N: ≤0.010%, Mo: 0.10~0.60 %, Cu: 0.10~0.50%, Ni: 0.10~0.50%, Cr: 0.10~0.30%, Ca: ≤0.01%, the rest is iron; in the slab reheating process, the slab heating temperature: 1100~1200℃; In the controlled rolling process, the termination temperature of controlled rolling in the recrystallization zone: 1000-1080°C, the start temperature of controlled rolling in the non-recrystallization zone: 900-980°C, the termination rolling temperature: 760-880°C; In the cooling process, the termination cooling temperature: 300-550°C, and the cooling rate: 3-40°C / s. The product of the invention has good comprehensive properties, especially excellent performance in low-temperature impact toughness, and can still maintain a Charpy impact energy of about 300J at about -30°C.

Description

technical field [0001] The invention relates to a production process of steel for high-strength bent pipes, in particular to a production process of high-strength X80 steel plates for bent pipes. Background technique [0002] In recent years, with the increasing demand for energy and the rapid development of the long-distance natural gas transmission industry, high-grade pipeline steel has attracted more and more attention because of its significant cost advantage. Among them, elbows are used in pipeline construction. play a very important role. With the continuous improvement of equipment, the new generation of steckle rolling mill has gradually occupied a position that cannot be ignored in the field of pipeline steel production. From IPSCO in North America and Oregon in the United States to the successive commissioning of the steel coil production lines of major steel companies in China, the technology for producing pipeline steel with steel coil mills has also become mor...

AI Technical Summary

Problems solved by technology

However, due to the high difficulty in the production of steel plates for X80 bent pipes, there have been no relevant reports on the production of steel plates for X80 bent pipes on the production line of steckel mills in the literature at home and abroad.

[0003]Application number: 201010199050.9, application date: 2010-06-04, patent name: a preparation method of steel for X80 elbows and pipe fittings, publication number: CN101880818A The Chinese patent proposes the preparation method of steel for X80 elbows and pipe fittings, which requires extremely high N content, which is difficult to achieve in the current industrial steelmaking production line. In addition, the C content is also high, and the crystallizer liquid in the continuous casting production process Surface fluctuations