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TECHNOLOGY. — Temperature measurements in Bessemer and open 

 hearth practice. George K. Burgess. Bureau of Standards 

 Technologic Paper No. 91. Pp. 29. 1917. 



The problem of temperature measurement and pyrometric control 

 of furnace casting and ingot teeming temperatures is shown, by a se- 

 ries of observations taken in several steel plants, to present no serious 

 difficulties or uncertainties. 



For this purpose the most satisfactory type of instrument is one of 

 the optical pyrometers using monochromatic light and permitting ob- 

 servation of streams of metal from a distance. 



It is shown that the necessary corrections to the observed optical 

 pyrometer readings for emissivity of metal and oxides to give true 

 temperatures, are sufficiently well known, but there may be uncer- 

 tainty in the case of liquid slags. 



For streams of liquid iron or steel the most probable value of emis- 

 sivity to take, with a pyrometer using red light of wave length X = 

 0.65 n, is e = 0.40, corresponding to a correction of 139° for an ob- 

 served temperature of 1500°C. The value of e for liquid slags is usu- 

 ally about 0.65 but varies with the composition of the slag. A table 

 of emissivity corrections is included in the text. 



It is believed that a continuous, systematic following of the tem- 

 perature by the methods outlined in the paper would show the possi- 

 bility of improvements, and give a greater certainty of the production 

 of the desired quality of product. G. K. B. 



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