Press mold for isostatic pressing of melting crucibles

Abstract

As is well known [1][2][3][4], the isostatic method of pressing is one of the prospective methods in the production of refractories. The authors*of the present article developed a mold for making crucibles 150 mm high and 220 mm in diameter by the isostatic method using a "free matrix" scheme. The mold is shown in Fig. 1. It consists of a rigid matrix-ring 1, fitted on a thread in a flange 2 placed on the columns 3, and spring loaded on the axle of the press mold with springs 4. The external rigid-plunger 5 is connected with the upper plate 6. The internal elastically deformable plunger (press buffer) 7 made of polyurethane is fitted to the rigid cylindrical table-pusher 8 connected by means of a shaft 9 and an ejector 10 with the press ejector 11. The annular ejector 12 is installed concentrically on the table-pusher 8 on a cross piece 13, connected with a locking device 14. Two electromechanical vibrators 15 of the type PV-66 are fitted to the flange 2, and the intermediate plate 16 --to the bottom plate 17. The regulating supports 18 are placed on the upper plate 6.

Production technology for mullite corundum crucibles

“…The variation in the density over the height of the crucible is 2.3-5.7, which is somewhat lower than for magnesite crucibles made by the same methods (5-7% [3]). …”

“…The authors of [3] provide some information on obtaining crucibles by the isostatic pressing method using an elastic plunger for forming the internal surface.This article gives the results of an investigation to obtain crucibles by both of these methods.For the vibration casting of the crucibles we used starting materials in the form of electrocorundum, fused-mullite and GK alumina [4]; for the pressing method we used Latnensk clay in addition to the other materials. The mass proportion of AI203 in the electrocorundum was 99%, in the alumina 98.2%; in the fused mullite 74.3% AI203 and 25.2% SiO2, and in the clay, respectively, 36.87 and 58.85%.…”

Quasi-isostatic pressing?a promising technology in the production of refractory components

“…The service life of these crucibles was 150 heats. The QISP technology has provided a route towards a highly efficient production of melting crucibles readily amenable to automation [5].…”