Effects of Deep Cryogenic Treatment on the Microstructural Properties of Medium Carbon Spring Steels

Abstract

The cryogenic treatment is a complementary procedure that has been applied to a variety of materials to improve their mechanical and physical properties. It was first commercially recognized as an effective method in achieving complete martensitic transformation in the alloyed steels. In this study, microstructural investigations were carried out in order to relate the microstructural properties to the mechanical properties following the cryogenic treatment. For this purpose, the conventional heat treatment (CHT) and the deep cryogenic treatment (DCT: -196°C) procedures were applied to various medium carbon spring steels. Microstructural examinations were carried out by using scanning electron microscopy. The martensite lattice parameters and the amount of retained austenite were measured by using a high-resolution X-ray diffractometer. Rietveld analysis was used to deconvolute the overlapping peaks of martensites.

Keywords

• Steels
• Cryogenic Treatment
• Microstructure
• Alloying

References

1. Lobodyuk, V. A., Meshkov, Y. Y., & Pereloma, E. V. (2019). On Tetragonality of the Martensite Crystal Lattice in Steels. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 50(1), 97–103. https://doi.org/10.1007/s11661-018-4999-z
2. Lu, Y., Yu, H., & Sisson, R. D. (2017). The effect of carbon content on the c/a ratio of as-quenched martensite in Fe-C alloys. Materials Science and Engineering A, 700(April), 592–597. https://doi.org/10.1016/j.msea.2017.05.094
3. Maruyama, N., Tabata, S., & Kawata, H. (2020). Excess Solute Carbon and Tetragonality in As-Quenched Fe-1Mn-C (C:0.07 to 0.8 Mass Pct) Martensite. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 51(3), 1085–1097. https://doi.org/10.1007/s11661-019-05617-y
4. Nishiyama, Z. (1978). Martensitic Transformation. (M. E. Fine, M. Meshii, & C. M. Wayman, Eds.). Kawasaki: Academic Press Inc.
5. Özden, R., & Anik, M. (2020). Enhancement of the mechanical properties of EN52CrMoV4 spring steel by deep cryogenic treatment Verbesserung der mechanischen Eigenschaften von EN52CrMoV4 Federstahl durch Tieftemperaturbehandlung. Materialwissenschaft Und Werkstofftechnik, 51, 422–431. https://doi.org/10.1002/mawe.201900122
6. Su, Y. Y., Chiu, L. H., Chen, F. S., Lin, S. C., & Pan, Y. T. (2014). Residual stresses and dimensional changes related to the lattice parameter changes of heat-treated JIS SKD 11 tool steels. Materials Transactions, 55(5), 831–837. https://doi.org/10.2320/matertrans.M2014031
7. Villa, M., Hansen, M. F., & Somers, M. A. J. (2017). Martensite formation in Fe-C alloys at cryogenic temperatures. Scripta Materialia, 141, 129–132. https://doi.org/10.1016/j.scriptamat.2017.08.005