Effect of aluminium content on penetration shape of stainless steel in TIG arc welding. Effect of chemical composition on weldability in fabrication of high‐alloyed steel (3rd report)

Summary

Accurate measurement of temperature is of considerable importance in materials processing, such as welding, thermal cutting, and heat treatment of metals. Radiation thermometry has a distinct advantage over other temperature detection methods, since it requires no physical contact with the work. The reliability of thermometry, however, is limited if the emissivity of the work to be measured is not accurately known.

Planck's law of radiation shows that the effect of temperature on the spectral radiance is greater at shorter wavelengths. The present paper experimentally describes the characteristics of UV (ultraviolet) thermometry. A temperature measurement test by the UV spot sensor (spectral range: 0.25 μm) shows that the melting point of Ni can be measured with an accuracy of ± 1 % regardless of any emissivity fluctuation. The CCD camera with UV filter used in this investigation makes it possible to detect the temperature image on the work in welding virtually independently of the emissivity of the object.