Temperature is one of the most critical process parameters affecting the resulting quality, strength and working properties of a metal casting. Molten metal which is too hot will damage the sand molds. A temperature which is too low will result in low fluidity. Especially complex and thin-walled cast metal parts demand precisely controlled casting temperatures. Strict compliance with process parameters is therefore of high importance – and this requires precise temperature monitoring and control.
The temperature of molten metal is most commonly measured using immersion thermocouples. This device is dipped into the molten metal before the ladle is filled, that is before pouring even begins. Data accuracy is subject to the precision with which the foundry operator performs the measurement. Depending on the immersion depth and the position of the probe, temperature readings can deviate.
Liquid metal presents a unique characteristic because its surface is particularly susceptible to slag and oxides, these are cleaned and the pyrometer is submerged into the molten metal, this way a precise measurement can be obtained.