To the Issue of Accuracy of Determining the Temperature of Fire Exposure by Fire Traces


After the fire is extinguished, it is required to study a set of the parameters, the most important of which is the temperature of fire exposure. The material of building metal structures, including hazardous production facilities that are in the zone of high temperatures, is undergoing changes. According to them, the magnitude of the temperature effect is determined, that is, metal structures act as natural thermal witnesses. Currently, the temperature effect is assessed visually by the colors of thin oxide films (tint colors) on the metal structures surface. It is experimentally proven that such an assessment is subjective. Recommendations based on this method cannot be considered sufficiently reliable.
The purpose of the conducted study is to determine the effect of temperature loading on the hardness and magnetic properties of the carbon building steels. During heating and subsequent cooling, two synergetically affecting each other processes occur simultaneously in steel: a change in the structure and properties of the base metal, as well as the appearance of oxide films on the surface. It is established that the characteristics of the metal — hardness and coercive force do not correlate with each other in all the temperature ranges of heating. However, each exposure temperature corresponds to only one pair of hardness and coercive force values.
Based on the results of the conducted experiments, the method was developed for determining the temperature effect by a complex change in the hardness and coercive force of the steel structures. The proposed method will allow to improve the reliability of expert opinions on the possibility of further operation of the buildings and structures after a fire.

1. Determination of fire exposure temperatures by fire traces. Available at: (accessed: March 25, 2022). (In Russ.).
2. Panchenko V.S., Merzhinskaya E.V., Kardailskaya E.V., Zgera D.N. Investigation of etchability of steel scale in the hydrochloric acid. Stal = Steel. 2013. № 10. pp. 42–44. (In Russ.).
3. Garber E.A., Gatiyatullin D.Z. Factors that cause residual scale surface defects on hot-rolled wide strips and methods of their elimination. Mekhanicheskoe oborudovanie metallurgicheskikh zavodov = Mechanical Equipment of Metallurgical Plants. 2017. № 2 (9). pp. 18–21. (In Russ.).
4. Pokachalov V.V. Phase composition of the scale and defects that occur during wire drawing. Metizy = Metalwares. 2006. № 3 (13). pp. 30–33. (In Russ.).
5. Sychkov A.B., Koptseva N.V., Efimova Yu.Yu., Zhloba A.V., Kamalova G.Ya. Identification of the surface defects of sheet «Rolled scale». Modelirovanie i razvitie protsessov obrabotki metallov davleniem: mezhdunar. sb. nauch. tr. (Modeling and Development of the Metalworking Processes by Pressure: International collection of the scientific papers). 2018. № 24. pp. 12–18. (In Russ.).
6. Merkulov A.A., Efimov S.A., Korolev A.V. Mathematical modeling of the process of rotary cleaning of the rolled metal from scale. Matematicheskie metody v tekhnike i tekhnologiyakh — MMTT = Mathematical Methods in Technique and Technologies — MMTT. 2014. № 5 (64). pp. 133–137. (In Russ.).
7. Druz O.N., Nikitin Yu.N. Improvement of technology for processing scale into powder material. Resursosberegayushchie tekhnologii proizvodstva i obrabotki davleniem materialov v mashinostroenii = Resource Saving Technologies for Production and Pressure Shaping of Materials in Machine-Building. 2020. № 4 (33). pp. 28–39. (In Russ.).
8. Degay A.S., Zuev M.V., Zasukhin A.L., Karmanov O.B., Mikurova M.I., Orekhov O.E., Gusev R.V. The method for preparing oiled scale for processing. Patent RU 2279491 C2. Applied: July 8, 2004. Published: July 10, 2006. Bulletin № 19. (In Russ.).
9. Korts T., Vulfert Kh. Cost-effective process of processing and use of the oil-containing rolling scale. Chernye metally = Ferrous Materials. 2012. № 2. pp. 25–30. (In Russ.).
10. Lipatkina T.N. Receiving and iron-rich product from scale. Lityo i metallurgiya = Foundry Production and Metallurgy. 2016. № 1 (82). pp. 72–75. (In Russ.).
11. Kornilova A.V., Idarmachev I.M., Paing T., Zayar C. A method of determination of the service life of a die tool with application of magnetic methods of nondestructive control and diagnostics. Journal of Machinery Manufacture and Reliability. 2014. Vol. 43. Iss. 5. pp. 439–444. DOI: 10.3103/S1052618814050082
12. Zaya K., Paing T., Kornilova A. The effects of operational thermal cycling on mechanical and magnetic properties of structural steels. IOP Conference Series: Materials Science and Engineering. 2019. Vol. 675. pp. 012041. DOI:10.1088/1757-899X/675/1/012041
13. Kornilova A.V., Batarin R.V., Galov N.A., Vygovskiy A.M., Paing T. Magnetic method application of nondestructive inspection as express-evaluation way of strength properties and residual life of metal. Proizvodstvo Prokata = Rolled Products Manufacturing. 2018. № 5. pp. 31–37. (In Russ.).
14. Rajput S.K., Chaudhari G.P., Nath S.K. Characterization of hot deformation behavior of a low carbon steel using processing maps, constitutive equations and Zener-Hollomon parameter. Journal of Materials Processing Technology. 2016. Vol. 237. pp. 113–125. DOI: 10.1016/J.JMATPROTEC.2016.06.008
15. Wang Y., Li J., Xin Y., Li C., Cheng Y., Chen X., Rashad M., Liu B., Liu Y. Effect of Zener-Hollomon parameter on hot deformation behavior of CoCrFeMnNiC0.5 high entropy alloy. Materials Science and Engineering: A. 2019. Vol. 768. pp. 138483. DOI: 10.1016/j.msea.2019.138483
16. Аryshenskii E., Kawalla R., Pral U., Hirsch J., Bazhin V. Impact of Zener-Hollomon parameter on substructure and texture evolution during thermomechanical treatment of iron-containing wrought aluminium alloys. Transactions of Nonferrous Metals Society of China. 2019. Vol. 29. № 5. pp. 893–906. DOI: 10.1016/S1003-6326(19)64999-X
DOI: 10.24000/0409-2961-2022-5-42-47
Year: 2022
Issue num: May
Keywords : твердость fire металлоконструкции temperature fire exposure thermal witnesses wustite magnetite hematite coercive force
  • Kornilova A.V.
    Kornilova A.V.
    Dr. Sci. (Eng.), Prof., Moscow State University of Civil Engineering, Moscow, Russia