INFLUENCE OF NITROGEN ALLOYING AT STRENGTHENING AND STABILITY OF AUSTENITE STEEL TYPE Cr18Ni10

The hardening and austenite stability as a result of nitrogen alloying steel type Cr18Ni10 in the temperature range, which is usual for the application of such steels as corrosion-resistant structural heat-resistant and/or cryogenic ones was studied. It is shown that the nitrogen alloying is perspective for strengthening and increasing of stability of austenitic stainless steels. Additional strengthening due to the preliminary cold or warm deformation hardening increases a tendency to the martensite formation under load, which limits the operating temperature of these steels. High-strength non-magnetic nitrogen-alloyed steels on the base of Cr18Ni10 steels containing up to 0.22 % of nitro gen are suitable for cryogenic application of non-deformed articles only. Otherwise, a strain-induced martensite will always be formed in them at temperatures below –70 °С. High strength, ductility and toughness of these steels can be achieved simultaneously only as a result of the trip-effect or fine-grained structure formation. Nitrogen effectively strengthens solid solution in a high-temperature condition. The combination of hot and warm deformation can be used for additional hardening of steels during at thermomechanical treatment, including strain-aging process, which is effective for applications of such steels as heat resistant ones. 

1. Solntsev Yu.P. Khladostoikie stali i splavy [Cold-resistant steels and alloys]. St. Petersburg: Khimizdat, 2005. 480 p. (In Russ.).

2. Solntsev Yu.P., Ermakov B.S., Sleptsov O.I. Materialy dlya nizkikh i kriogennykh temperatur: Entsiklopedicheskii spravochnik [Materials for low and cryogenic temperatures: An Encyclopedic Reference]. St. Petersburg: Khimizdat, 2008. 768 p. (In Russ.).

3. Khimushin F.F. Nerzhaveyushchie stali [Stainless steels]. Moscow: Metallurgiya, 1967. 800 p.

4. Svyazhin A.G., Kaputkina L.M., Prokoshkina V.G. Effect of nitrogen on structure and properties of thermomechanically strengthened steels. Proceed. of 10th Int. Conf. on High Nitrogen Steels. Moscow: MISiS. 2009. pp. 77–82.

5. Svyazhin A.G., Siwka J., Kaputkina L.M. High-nitrogen steels – The current state and development trends. Proceed. of Int. Conf. Advanced Steels. China, Beijing. Metallurgical Industry Press. 2010. Pp. 352–356.

6. Speidel M.O., Speidel H.J. Commercial low-nickel and high nitrogen steels. Proceed. of 10th Int. Conf. on High Nitrogen Steels. Mos-cow: MISiS. 2009. Pp. 121–128.

7. Mushnikova S.Yu., Legostaev Yu.L., Khar’kov A.A. etc. Voprosy materialovedeniya. 2004. No. 2 (38). Pp. 126–135. (In Russ.).

8. Birman S.R. Ekonomnolegirovannye martensitnostareyushchie stali [Economically alloyed мaraging steel]. Moscow: Metallurgiya, 1974. 208 p. (In Russ.).

9. Lozhnikov Yu.I., Kaputkina L.M. Izvestiya VUZov. Chernaya met-allurgiya = Izvestiya – Ferrous Metallurgy. 2004. No. 5. Pp. 50–54. (In Russ.).

10. Pikering F.B. Fizicheskoe metallovedenie i razrabotka stalei [Physical metallurgy and development of steels]. Moscow: Metallurgiya, 1982. 184 p. (In Russ.).

11. Hirayama T., Ogirima M. J. Japan. Inst. Metals. 1970. Vol. 34. Pp. 507–516.

12. Matsuoka Y., Iwasaki T., Nakada N. etc. ISIJ International. 2013. Vol. 53. No 7. Pp. 1224–1230.

13. Kaputkina L.M., Prokoshkina V.G., Khadeev G.E., Elantsev S.N., Karpukhina I.V. Diagrams and other hot and warm deformation and strain aging of nitrogen-containing austenitic steels. MiTOM = Metal Science and Heat Treatment. 2013. No. 6. Pp. 38–43. (In Russ.).

14. Bernshtein M.L., Dobatkin S.V., Kaputkina L.M. etc. Diagrammy goryachei deformatsii, struktura i svoistva stalei [Diagrams of hot deformation, the structure and properties of steels]. Moscow: Metallurgiya, 1989. 544 p. (In Russ.).

15.