Device for determining phase transitions using a sample of molten metal

Abstract

A device to determine phase transitions by means of thermal analysis using a sample taken from molten metal comprises an expendable measuring probe with a solidification chamber into which the molten metal flows, whereby the solidification chamber contains a thermocouple with which the course of cooling is recorded over a specific time period. According to the invention, the side walls of the solidification chamber 3 comprise a metal casing 4 that completely surrounds the chamber and extends lengthwise of the measuring probe 1. Both open ends of the casing 4 are covered by plugs 5,6 made of a material whose heat conductivity is substantially less than that of the casing material. The casing is completely surrounded by a covering 2,8 which is made of a material whose heat conductivity is substantially less than that of the metal casing. The supply orifice for the molten metal comprises a quartz pipe 9 surrounded by a metal pipe 10. According to the invention, the mass of the casing 4, which results from its height (h) and the thickness of its walls (b), is proportioned so that the heat which is given off by the molten metal flowing into the solidification chamber and absorbed by the metal casing produces, in the area of the thermocouple, an equilibrium temperature which approximates the solidification temperature as closely as possible.