No other segment of heat treating has seen more changes in
technology than data-acquisition (DAQ) systems. While the investment in a new
data-acquisition system can seem quite high, the benefits and return on the
investment can happen quickly if the use is maximized.
Control-room instrumentation has come a long way from the days of drag pens on paper chart recorders and manually tuning temperature loops with trim pots. Most of these instruments were large and heavy steel-cased units that performed adequately for that time. Actually, some of these instruments may still be in use in some facilities if they have been well taken care of.
For many years, single-spot radiation thermometers (sometimes called pyrometers) have been widely used in the steel industry. They have many advantages compared to contact devices like thermocouples. They can be positioned at a distance to “look” at the process and measure the infrared radiation that is emitted by the target object. In this way, they can operate out of harm’s way. Because they don’t touch the surface, they can accurately measure fast-moving objects like steel strip, whereas a thermocouple would suffer from a frictional effect on the measurement.
Companies that manufacture parts for
the automotive industry have to produce products that have very high quality.
There can be no defective parts delivered to the factory, and, of course, the
automotive companies want the lowest price, fastest delivery and a record of
the quality tests.
Obtaining accurate temperature
readings in a high-temperature application is difficult. Thermocouples and
pyrometers have advantages and disadvantages. This article will address the use
of pyrometers in applications where the need for accurate and precise thermometry
We have a pretty good idea of what will happen to steel
parts if exposed to a defined atmosphere at a given temperature. In order to
determine the process parameters, we can use the well-known Lehrer Diagram for
a nitriding process, or we might use one of the various Fe-N-C phase diagrams
for a nitrocarburizing process.
vacuum furnaces are set up such that the power input to the furnace and thus
the temperature in the furnace is controlled by one thermocouple. Does that
mean the temperature in the entire furnace is what the thermocouple is reading?
Check out the May 2020 issue of Industrial Heating, which features "Automotive and COVID-19: Radiators to Respirators, "Developments of Plasma Processing in Surface-Treating Technology", and much more.