Molten Aluminum temperature measurement at the time of transfer from casting crucible to the die
European Aluminum Casting Producer produces castings of aluminum alloys for the automotive industry. In their foundry the alloy is melted in one furnace and transferred to a holding furnace before a controlled amount is fed into a casting crucible along a launder.
Measurement of temperature of the metal during the transfer from the casting crucible to the die is crucial at this stage for maintaining the homogeneous quality of the casting.
Image showing the casting line of the European customer.
Our experience suggests that an immersion thermocouple cannot be used for this application. Temperature measurement using a conventional single color infra-red pyrometer can be a complicated task due to the low and varying emissivity factors and they assume a constant emissivity. AST A5-IN pyrometer has been developed for this specific application.
A5-IN should be installed approximately 1200 mm above the launder and aligned using the in-built laser. This gives a spot size of approximately 38mm at the point of measurement. The pyrometer is then connected to a laptop / PC running theSD3000 software used to set the specific pyrometer parameters, display the results graphically and log the results in an Excel format. This software is supplied with the pyrometer and can be used to fine tune the settings to improve the accuracy in any specific location. The unit is used in its plug and play mode for liquid aluminum.
The practical adverse site condition for such application is lot of heat will be generated by the liquid metal or by the heating/use of the gravity die. Withstanding such harsh atmosphere is a challenge for such application. By installing the Pyrometer A5-IN at certain angle and by using some bright reflective screen can protect from the radiated heat also Air cooling jacket can be used.
Below is the sketch which explains the query.
A5-IN pyrometer measures over the full range 450-900°C without problems in a linear manner. User can cut lower readout by setting required threshold “T brightness min”. The lower temperature recorded can be set by adjusting the “T brightness min” Also with the use of Analog output 4-20mA/0-10V you can set any scale between 300 to 1000C. General question from the users are whether this system can be used as a portable unit. Generally, it is not a mobile device, (weighs 3.5kg) and needs constant power supply of 24V DC. A suitable mounting system could be designed to enable two different measurement positions provided the cable connections to the unit are long enough. It is also possible to have a paired Bluetooth device for Pyrometer –PC wireless communication (standard device provide up to 100m communication distance – incase when no obstacles) but the pyrometer will still need the 24V supply. A5-IN with SD3000 software provides the facility to record the two readings temperature and emissivity under one sequence number in EXCEL file.
