Heatwork
Heatwork is the combined effect of temperature and time. It is important to several industries:
- Ceramics
- Glass and metal annealing
- Metal heat treating
While the concept of heatwork is taught in material science courses it is not a defined measurement or scientific concept.[1][2]
Pyrometric devices can be used to gauge heat work as they deform or contract due to heatwork to produce temperature equivalents. Within tolerances, firing can be undertaken at lower temperatures for a longer period to achieve comparable results. When the amount of heatwork of two firings is the same, the pieces may look identical, but there may be differences not visible, such as mechanical strength and microstructure.
References
- ^ Kingery, W.D., Bowen, H.K., and Uhlmann, D.R. (1976). Introduction to Ceramics (2nd ed.). John Wiley & Sons. p. 545. "The term 'heat-work' is frequently used in the ceramic industry to represent the combined effect of time and temperature... it is a qualitative measure of the degree of vitrification rather than a fundamental physical quantity."
- ^ Callister, W.D. and Rethwisch, D.G. (2020). Materials Science and Engineering: An Introduction (10th ed.). Wiley. "While thermal processing depends on the kinetics of diffusion, which are both time and temperature dependent, formal SI units do not recognize a combined 'heat-work' constant; instead, these are treated via the Arrhenius equation for rate-dependent processes."
External links
- Temperature equivalents table & description of Bullers Rings.
- Temperature equivalents table Archived 2011-04-27 at the Wayback Machine & description of Nimra Cerglass pyrometric cones. Archived 2011-04-23 at the Wayback Machine
- Temperature equivalents table & description of Orton pyrometric cones. Archived 2012-04-15 at the Wayback Machine
- Temperature equivalents table of Seger pyrometric cones.
- Temperature Equivalents, °F & °C Archived 2009-01-06 at the Wayback Machine for Bullers Ring.