Continuous casting crystallizer casting powder for P91 steam pipeline steel and preparation method of continuous casting crystallizer casting powder

Abstract

The invention belongs to the technical field of metallurgy materials, and particularly relates to continuous casting crystallizer casting powder for P91 steam pipeline steel and a preparation method of the continuous casting crystallizer casting powder. The casting powder is prepared from, by weight percent, 26.0%-35.0% of SiO2, 27.0%-37.0% of CaO, 0.4%-1.2% of Li2O, not larger than 6.0% of Al2O3, 7%-13% of Na2O, 4%-8% of F-, not larger than 4.0% of MgO, not larger than 1.0% of Fe2O3, 5%-9% of Csolid and 8%-12% of volatile components. The casting powder can achieve crystallizer lubricating during low-temperature casting, a slag film has sufficient crystallization to improve crystallizer heat transfer, P91 steel large round blank surface longitudinal cracks are reduced, and the casting blank quality is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgical materials, and in particular relates to a continuous casting crystallizer mold powder for P91 steam pipeline steel and a preparation method thereof. Background technique [0002] In the past, the pipes in the hot section of the steam pipeline were all made of P22 pipes, which belonged to pearlitic heat-resistant steel, and the maximum working temperature was 580-590 ℃. The biggest disadvantage is that the high-temperature durable strength is low, and the wall thickness of the steam pipe is too large, which not only increases the difficulty of manufacture, but also brings inconvenience to design, installation and operation. P91 steel is based on the original 9Cr-1Mo steel by adding V, Nb, N and other strengthening elements to improve the strength of the steel. Adding Cr, Si and other elements can make the oxide film formed by the metal at high temperature operation dense and firm, and improve...

AI Technical Summary

Problems solved by technology

However, the patent mold slag has a low binary alkalinity and cannot achieve the purpose of slow cooling of the slab during casting. Because the slab is cooled too quickly during casting and the shrinkage of the slab shell is too large, longitudinal cracks are easily generated, and the viscosity value is high. It also leads to poor fluidity of slag and uneven inflow

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