Low-roll-force gas-transmission pipeline steel and production method thereof

Abstract

The invention relates to low-roll-force gas-transmission pipeline steel which unit roll-force is lower than 18Kn / mm and a production method thereof. The pipeline steel comprises the following main components in percentage by weight: 96.3-98.6 wt% of Fe, 0.030-0.010 wt% of C, 1.20-1.90 wt% of Mn, 0.10-0.35 wt% of Si, 0.015-0.120 wt% of Nb, 0.005-0.025 wt% of Ti, 0.001-0.005 wt% of N and 0.020-0.040 wt% of Alt, wherein the Ti / N ratio is equal to 3-6, and the Ca / Alt ratio is greater than or equal to 0.10. The pipeline steel also comprises the following residual components in percentage by weight: at most 0.004 wt% of O, at most 0.010 wt% of P, at most 0.003 wt% of S, at most 0.03 wt% of As, at most 0.02 wt% of Sn and at most 0.02 wt% of Sb. A thick / medium plate rolling machine, of which the unit roll force is lower than 18 kN / mm, can be utilized to effectively roll various thin / medium / thick casting blanks to produce the gas-transmission pipeline steel with favorable anti-cracking performance in a ferrous metallurgy enterprise on a common equipment level by slightly adjusting the technique.

Description

technical field [0001] The invention relates to a metallurgical steel product, more specifically, the invention relates to a gas transmission pipeline steel product and a production process thereof. Background technique [0002] Natural gas or petroleum gas is a gaseous fuel with high combustion value and relatively clean and environment-friendly, which has become one of the important energy pillars of the national economy. With the determination of my country's west-east gas transmission economic strategy, high-pressure gas transmission pipeline projects have entered the implementation stage, and the construction of these projects has an increasingly urgent demand for high-grade pipeline steel; The development has entered a new stage, which has accelerated the pace of development and application of domestic pipeline steel. [0003] As we all know, once the high-pressure transmission pipeline breaks, it often causes unimaginable major accidents: in addition to causing huge e...

AI Technical Summary

Problems solved by technology

[0009] The patent document with the publication number CN101476026 and the name "A Method for Improving the Dropping Weight Performance of Steel Pipeline Steel" discloses that the deformation rate of the rough rolling pass is 15%. ~30%, to compress the defects of the continuous casting slab and ensure the uniformity of the austenite grains. This technology requires high capacity of the rolling mill, which is difficult to achieve in thick plate production

[0010] In summary, it can be seen that the traditional technology is to achieve a high degree of uniformity of the micro-level grains of the pipeline steel, so as to achieve excellent crack arrest performance, or to control the steel billet too high and too strictly The purity of certain elements, or the combination of low temperature and high rolling reduction rate, puts forward high requirements that are difficult to achieve in the steelmaking process, and requires the minimum rolling force per unit width of the rolling mill in the rolling process. Rolling can only be carried out when it is above 18kN / mm. Thirdly, the plate types that can be rolled by these traditional technologies are also limited, and it is not possible to flexibly use three types of thin, medium and thick billets to produce high-pressure pipeline steel.

[0011]However, most domestic medium and heavy plate production line enterprises only equip rolling mills with rolling force per unit width lower than 18kN / mm. Performance pipeline steel, not to mention that the produced pipeline steel has excellent crack arrest performance

This not only restricts the development and progress of the majority of iron and steel production enterprises, but also is not conducive to the research and development of steel for gas pipelines.

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