Temperature Measurement of Pouring Streams
When liquid steel is tapped from a basic oxygen (BOF) or electric arc (EAF) furnace, it is advantageous to minimize the quantity of slag carried over into the ladle. Measuring the average temperature of the pouring stream during the pour can be a challenge with the presence of slag and oxidation. Previously, temperature measurement was completed by visual observation of the tapping stream or using electromagnetic induction coils mounted onto the furnace. However, neither of these methods have proven to be entirely reliable.
In most foundries, the temperature of the metal melt is usually measured by thermocouple immersion probes. These immersion measurements can only be made in the crucibles or the transfer ladles where the melt is stationary, but not in the pouring stream where insertion of a probe would disturb the flow into the cast. However, the direct temperature of the pouring stream is critical to the quality of the final casting. By continuous monitoring of the pouring stream temperature and pour quality for each cast, the foundry is able to better control of the casting process.
An undisturbed temperature measurement of the pouring stream can only be obtained by non-contact infrared pyrometers. Where castings are made of different alloys, conventional pyrometers and ratio pyrometers often cannot be used for the measurement of the pouring stream due to considerable differences in the measuring conditions and the characteristics of the metal.
Advanced Energy offers specialized solutions to address these issues and to provide robust temperature measurement by using both a portable as well as a fixed measurement system.
Our infrared thermometer IMPAC ISR 12-LO/GS incorporates a fixed system solution for measuring the exact casting temperature of each pouring process, covering a wide temperature range from 600 up to 2500 °C depending on selected model.
This rugged and very reliable industrial pyrometer system was designed to overcome many of the issues that complicate the temperature measurement of the pouring steam such as changes in stream location and width, start and stop time variation, and slag interference.
An accurate temperature of each pour is displayed online and corrective action can be taken immediately if defined limits are exceeded. In this way, the narrow process window for quality castings can be maintained. Especially for accurate measurement of pouring streams the IMPAC ISR 12-LO/GS provides special features and functionalities, based on these applications:
Impac ISR 12 GS – with fiber optic heads for pouring stream measurements
- By using armored fiber optics cables with high temperature precision optics lens head, this fixed Pyrometer can be used for non-contact measurement in difficult installation areas.
- Its line spot shape optical beam minimizes effects of pour stream location variation. An integrated laser targeting function serves for ease of alignment.
- Via a short wavelength ratio detector, the signal is maximized from low emissivity metals and systematic errors due to emissivity changes are minimized, as well as interference from dust and vapor. Moreover, the Pyrometer provides an integrated lens contamination warning system.
- The exact pouring stream temperature is determined via an advanced algorithm. This robust tuning procedure includes start and stop pour signals, pouring time calculation and is immune to random slag events, and pre/post pour drips.
Using Advanced Energy’s infrared instrumentation for accurate measurement of all relevant process temperatures ensures steel manufacturers production engineers to establish a stable production process in steel manufacturing and allow operators to better control and influence parameters for best product quality and top level of process efficiency.
Contact:
Advanced Energy – LumaSense Technologies GmbH
[email protected]
www.advancedenergy.com
