disclosed are a method of and apparatus for radiation pyrometric temperature measurement of a continuous cast metal bar . cast bar advancing from a continuous casting machine is continuously monitored for temperature without contacting the cast bar with any apparatus by applying a layer of soot onto the surface of the bar , detecting infrared radiation emitted from the sooted area , converting the detected radiation into a temperature signal , displaying the temperature , and completely removing the soot from the cast bar before it enters a rolling mill .