Combined pyrolytic boron nitride crucible lining

Abstract

The invention relates to a combined pyrolytic boron nitride crucible lining, belonging to the titanium and titanium alloy melting crucible lining, especially the pyrolytic boron nitride crucible lining. Said crucible lining is cup shape piled by pyrolytic boron nitride brick, which can accommodate titanium and titanium alloy fluid. The crucible lining in invention can be installed in the shell with insulation, heat conservation and support performances and can satisfy demands in industrial production such as big cubage, low cost, easy maintenance and long service life. It is provided with mature producing process, simple equipment, stable performance, easy maintenance. When titanium and titanium alloy are melted, the crucible lining can not be bonded, and big melting pool can be formed in the crucible lining in favor of diffusing alloy element. Components of the alloy melted and cast is even and stable performance.

Description

technical field [0001] The invention belongs to titanium and titanium alloy smelting crucible materials, in particular to pyrolysis boron nitride crucible lining. Background technique [0002] Due to the high melting point and very active chemical properties of titanium, liquid titanium can react with almost all crucible refractory materials such as zirconia, magnesia, silicon oxide and alumina during its smelting. Crucibles made of refractory materials are used for vacuum induction melting. At present, the melting of titanium and titanium alloys in industry often adopts vacuum consumable electrode arc shell furnace melting and forced water-cooled copper crucible cooling. When smelting in the vacuum arc shell furnace, a thin layer of "shell" is first solidified on the wall of the copper crucible to protect the titanium liquid from being polluted by the crucible material and to insulate heat, so as to form a molten pool in the crucible. Due to the rapid cooling of the water...

AI Technical Summary

Problems solved by technology

However, the technology disclosed in the above-mentioned patent cannot meet the requirements of industrial production due to the technical scheme of manufacturing the integral crucible by adding an appropriate amount of flux with boron nitride and sintering the blank after cold isostatic pressing, because the melting crucible required for industrial production The volume is large, and it is difficult to manufacture it with the technology of the patent ZL200410025119.0. The reasons are: (1), the crucible (generally in tons) used in industrial production is large in volume, and the cold isostatic pressing required for the overall manufacturing of the boron nitride crucible , sintering and other equipment requirements are high and expensive, and the equipment must be specially manufactured

(2) The boron nitride crucible manufactured as a whole is too expensive, and once damaged it cannot be repaired, it must be replaced as a whole, and the economic cost is not cost-effective

(3) Cracks are prone to occur during the manufacture and use of integrally manufactured boron nitride crucibles

[0004] Like the technology disclosed in Chinese patent ZL200410025119.0, Zhao Fengming et al. disclosed a pyrolytic nitrogen in the literature "Application of Pyrolytic Boron Nitride Crucible in Special Melting" and "Pyrolytic Boron Nitride Crucible Material Growth and Properties". The boron nitride crucible is a boron nitride crucible manufactured as a whole, which is only suitable for laboratory and small batch production. In the industrial scale production, there are three major shortcomings of the boron nitride crucible manufactured as a whole, so it is necessary to improve the existing Improve technology, propose new technical solutions, and improve the shortcomings of existing technologies

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