Gas stir devices with refractory material erosion depth indicator and method of making the same

US5421561A · kind A · utility

Assignee

• Martin & Pagenstecher, Inc. · DE

Inventors

• Eckehard Eisermann · Grefrath, DE
• Robert J. Mascara · Canfield, US

Key dates

• Filing date: Nov 15, 1993
• Grant date: Jun 6, 1995
• Expiry date: Nov 15, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21C2005/448
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A device, e.g., a stirring plug or a mono-block stirring plug and pocket block set, for introducing gas into a mass of molten metal. The devices each have a body formed of a first refractory material. The stirring plug has plural V-shaped, gas carrying slots extending therethrough, while the mono-block set includes plural helical passageways extending therethrough. A wear indicator comprising a thin walled, thermally insulative tube having a central core of a second refractory material of a different coefficient of light emission but similar coefficient of thermal expansion to the first material is disposed within a central recess in the body adjacent either the top or the bottom end of the device. The wear indicator extends towards an intermediate point representing the remnant height of the device. In one embodiment the wear indicator is in the top of the device so that the refractory material making up the central core is visually distinguishable from the material making up the body so that when the upper end of the central core is exposed by the erosion of the device it provides a visual indication that the device should be replaced.