Steel continuous casting process for ultra supercritical high-pressure boiler tube

Abstract

The invention relates to a steel continuous casting process for an ultra supercritical high-pressure boiler tube. The steel continuous casting process is characterized in that a process control method is adopted for a continuous casting working procedure, totally protective casting is adopted for continuous casting; elongated nozzle argon seal protective casting is adopted in a process from a ladle to a tundish; integral built-in submerged nozzle protective casting is adopted in a process from the tundish to a crystallizer; a covering agent is adopted for molten steel in the tundish; the tundish is subjected to continuous temperature measurement; in the continuous casting process, full-automatic liquid level detection is carried out on the liquid level of the crystallizer; the pulling rate of continuous casting is automatically controlled according to the superheat degree of the tundish; automatic water distribution is adopted for the crystallizer and secondary cooling; and protecting slag used in the crystallizer during the casting process comprises the following components: 1.0+ / -0.15% of R, 36+ / -3% of SiO2, 36.0+ / -4% of CaO, less than or equal to 7.5% of Al2O3, less than or equal to 3.0% of Fe2O3, less than or equal to 3.0% of MgO, less than or equal to 3.9+ / -2.5% of F, 5.2+ / -2.0% of K2O+Na2O and 3.9+ / -2.0% of solid C. The steel continuous casting process provided by the invention can be used for effectively preventing surface cracks caused by transverse and longitudinal recessions of peritectic reaction corner parts during the casting process, effectively reducing the element segregation, improving the low-power quality of a casting blank and improving the quality of steel casting blank for the ultra supercritical high-pressure boiler tube.

Description

technical field [0001] The invention relates to a continuous casting process of steel in the field of metallurgy, in particular to a continuous casting process of steel for ultra-supercritical high-pressure boiler tubes. Background technique [0002] The electric power industry is one of the key steel users in China, and the steel products used are of various varieties and specifications. Among them, steel technology for power stations and power systems is a national strategic technology, and its products have extremely high added value, which has a direct and decisive support for the development of the national economy and national defense construction. Therefore, the governments and enterprises of the United States, Europe, Japan and other countries have long-term funded the research and development of thermal power steel technology. [0003] According to China's natural resources and national conditions, for a long period of time in the future, thermal power generation w...

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Problems solved by technology

[0006] Most of the ultra-supercritical boiler tube steel required by domestic boiler manufacturers is mainly supplied from abroad, but the supply period is long and the price is expensive, which seriously restricts the development of my country's electric power industry, thereby affecting the speed of my country's economic development

China started the trial production of steel pipes for ultra-supercritical boiler pipes relatively late, and at the present stage it is mainly based on die casting. This type is in the category of low-carbon peritectic steel with large alloy content and unstable internal and external quality. It is mainly manifested in the existence of element segregation, excessive central cracks in the center of low-magnification shrinkage cavities, surface depressions and cracks, and can not be welded during rolling. Low qualified rate results in very low finished product rate