Estimation of the Heat Stability of Hardened Cr-V Cast Irons

Abstract:

The paper describes the structure, properties and heat stability of white cast irons containing 2.5 – 3.0 %C, 14 and 20 %Cr, 3 %V after the secondary hardness treatment (quenching from 1150 °C and double tempering at 560 °C). It is shown that after the secondary hardness treatment M₂₃C₆ carbides appear along with the M₇C₃ phase. Heat stability of the alloys is estimated according to GOST 19265-73 standard. The effect of the temperature and duration of holding at 520–620 °C on structural changes and softening of secondary hardness treated cast irons is considered in comparison with high-speed steel and cast irons of the same composition quenched for the maximum hardness (from 1050 °C). The processes occurring at higher temperatures and long holdings that are responsible for softening of secondary hardness treated cast irons are studied. It is shown that the alloys under consideration after the secondary hardness treatment achieve the hardness of HRC 60 and more, and are able of pertaining it when heated up to 540 °C for 20 hours. This allows using these alloys as wear-resistant materials in the said temperature range.

• Periodical: Materials Science Forum (Volume 870)
• Pages: 558-563
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.870.558
• Online since: September 2016
• Authors: Yu.D. Koryagin*, V.L. Il'ichev
• Keywords: Chromium-Vanadium Cast Irons, Hardening, Secondary Hardness, Softening, Structure

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