A kind of manufacturing method of x70m pipeline steel plate used under low-cost and ultra-low temperature conditions

Abstract

The invention relates to a manufacturing method of X70M pipeline steel plate used under low-cost and ultra-low temperature conditions, KR molten iron pretreatment-BOF smelting-RH vacuum degassing-LF refining-RH vacuum degassing-150mm thickness continuous casting slab continuous casting-continuous Billet inspection and cleaning—350~680°C hot charging and hot delivery—casting billet heating—high pressure water descaling—rolling—ACC cooling—straightening—steel plate shearing—inspection of warehousing process steps, low-cost manufacturing and use under ultra-low temperature conditions X70M pipeline steel plate. The pipeline steel plate produced by hot charging and hot delivery process, ultra-low C, micro-alloy composite addition and controlled rolling and controlled cooling process can meet the Charpy impact energy of ‑80 °C ≥ 120J and the drop hammer shear area of ​​‑20 °C ≥ 85%. Requirements for use under ultra-low temperature conditions.

Description

technical field [0001] The invention relates to a manufacturing method of X70M pipeline steel plate. Background technique [0002] For X70M pipeline steel plate, M means deformation heat treatment, which means that the delivery state of the material is heat treatment state. Oil and natural gas are important energy sources for the development of industrialization, the blood of economic development, and provide a driving force for social progress. Oil and natural gas are still the core of the entire energy. For this core energy, the most economical transportation method is pipeline transportation. From the initial development of industrial pipelines to the present, the construction of oil and gas pipelines has experienced more than two centuries of development. The early transmission pipelines were relatively close to the central city, and the geographical environment and social support conditions were superior. Most of the newly discovered oil fields are in remote areas, e...

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Problems solved by technology

At present, there are few reports on X70M pipeline steel products that can be used under low temperature conditions and are produced by hot charging and hot delivery. On the one hand, they are limited by the design of steelmaking and rolling workshops; High, especially the requirements for internal segregation and H content of the billet are high, so the use of hot charging and hot delivery technology for production will bring greater production difficulties to enterprises, and there are relatively few related researches

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