Hot rolling flat steel for high toughness X80 elbow and production method thereof

Abstract

The invention relates to hot rolling flat steel for a high toughness X80 elbow and a production method thereof and belongs to the technical field of low carbon microalloyed steel. The hot rolling flat steel for the high toughness X80 elbow comprises the following components in percentage by weight: 0.060-0.085% of C, 0.10-0.35% of Si, 1.40-1.80% of Mn, less than or equal to 0.015% of P, less than or equal to 0.003% of S, 0.04-0.07% of Nb, less than or equal to 0.06% of V, 0.010-0.020% of Ti, 0.15-0.50% of Ni, less than or equal to 0.20% of Cr, less than or equal to 0.50% of Mo, 0.010-0.040% of Al, less than or equal to 0.50% of Ceq, less than or equal to 0.23% of Pcm and the balance of Fe and inevitable impurities. A production process comprises the following steps: preparing molten iron in a blast furnace, pre-desulphurizing the molten iron, smelting in a converter, refining under LF and RH conditions, continuously casting slab, heating slab, rolling by adopting a 4300 rolling mill, rapidly cooling by virtue of ACC (activated calcium carbonate), cooling in heap, sampling and testing as well as warehousing and despatching. The hot rolling flat steel for the high toughness X80 elbow has the advantages that mechanical performance indexes of a steel plate are stable, plasticity and toughness are high, and excellent toughness is still maintained after high temperature baking, moulding and heat treatment are carried out.

Description

technical field [0001] The invention belongs to the technical field of low-carbon micro-alloy steel, and in particular relates to a hot-rolled flat steel for high-toughness X80 bent pipe and a production method thereof, which are suitable for hot-simmered bent pipe oil and gas transmission pipelines. Background technique [0002] With the development of pipeline construction in the direction of long transportation, large diameter and high strength, in order to meet the design requirements of the line direction, the pipeline usually needs to turn to change the direction. Elastic laying, elbows or cold-bent pipes used in pipeline steering are limited by certain objective conditions in use and manufacturing technology, and the number of applications is gradually decreasing. With strong applicability and other characteristics, it can better adapt to the development of various oil and gas pipelines and has a good market prospect. [0003] The hot-simmered elbow is an important p...

AI Technical Summary

Problems solved by technology

According to relevant data, the X80 hot-simmered pipe steel that can be produced at present is not only high in production cost and insufficient in toughness, but also generally thin in size. Large-wall thick and large-diameter steel pipes are only in the trial production stage and cannot be commercialized.

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