OBRABOTKA METALLOV
METAL WORKING AND MATERIAL SCIENCEPrint ISSN: 1994-6309 Online ISSN: 2541-819X
Plasma nitriding is an effective method of the austenitic stainless chromium-nickel steels hardening. Usage of the low-energy electron beams (to 1 keV), that is typical for plasma generator, provides smaller loss of energy then usage of gas discharges. Low-energy electron beams allow change current density and ion energy independently of one another without using additional external heating devices. The lack of ion-plasma nitriding is deterioration of nitrided surface quality. Nanostructured deformation processing could be applied before nitriding with the aim of increasing growth rate of nitrided layer and reduction of nitrided surface roughness. In the paper, the influence of combined processing including nanostructuring frictional treatment by sliding indentor and following continuous and gas-cyclic plasma nitriding in electron-beam plasma at a temperature of 450 °С and 500 °С on hardening and surface quality of austenitic steel AISI 321 (0.04 wt.% С; 16.77 wt.% Cr; 8.44 wt.% Ni; 1.15 wt.% Mn; 0.67 wt.% Si; 0.32 wt.% Ti; 0.31 wt.% Cu; 0.26 wt.% Mo; 0.12 wt.% Co; 0.12 wt.% V; 0.04 wt.% P; 0.03 wt.% Nb; 0.005 wt.% S; and Fe for balance) is studied. It is established that friction treatment leads to occurrence of 95 vol. % α´ strain-induced martensite and increasing of microhardness to 780 HV0.025 on nitrided surface. On the nanostructured by frictional treatment surface of metastable austenitic steel AISI 321 (in contrast to nitrided coarse-grained steel) after continuous plasma nitriding in electron-beam plasma pore formation and intensive blistering is observed. Blistering is characterized by forming of steam blows and surface blowout. Obvious blistering appears due to advanced nitrogen diffusion into nanostructured surface with α´ stain-induced martensitic structure. Improvement in quality of the nitrided steel surface, hardened by frictional treatment (decreasing of blistering, pore formation and roughness), is achieved by means of: 1) gas-cyclic plasma nitriding is carried out at the conditions of periodic alternation nitriding semicycles in mixture of argon and nitrogen and denitriding (without nitrogen supply); 2) nitriding temperature decreasing from 500 °С to 450 °С. However after gas-cyclic plasma nitriding of nanostructured surface lower micro-hardness level (1 160…1 200 HV0.025) then after continuous nitriding (1 370…1 450 HV0.025) is observed
Makarov A. V.
1. Rolinski E. Plasma-assisted nitriding and nitrocarburizing of steel and other ferrous alloys. Thermochemical Surface Engineering of Steels: Improving Materials Performance, 2015, pp. 413–457. doi: 10.1533/9780857096524.3.413.
2. Gatey A.M., Hosmani S.S., Figueroa C.A., Arya S.B., Singh R.P. Role of surface mechanical attrition treatment and chemical etching on plasma nitriding behavior of AISI 304L steel. Surface and Coatings Technology, 2016, vol. 304, pp. 413–424. doi: 10.1016/j.surfcoat.2016.07.020.
3. Leonhardt D., Walton S.G., Fernsler R.F. Fundamentals and applications of a plasma-processing system based on electron-beam ionization. Physics of Plasmas, 2007, vol. 14, p. 057103. doi: 10.1063/1.2712424.
4. Gavrilov N.V., Menshakov A.I. Effect of the electron beam and ion flux parameters on the rate of plasma nitriding of an austenitic stainless steel. Technical Physics, 2012, vol. 57, iss. 3, pp. 399–404. doi: 10.1134/S1063784212030073.
5. Borgioli F., Fossati A., Galvanetto E., Bacci T. Glow-discharge nitriding of AISI 316L austenitic stainless steel: influence of treatment temperature. Surface and Coatings Technology, 2005, vol. 200, iss. 7, pp. 2474–2480. doi: 10.1016/j.surfcoat.2004.07.110.
6. Stinville J.C., Villechaise P., Templier C., Riviere J.P., Drouet M. Plasma nitriding of 316L austenitic stainless steel: experimental investigation of fatigue life and surface evolution. Surface and Coatings Technology, 2010, vol. 204, iss. 12–13, pp. 1947–1951. doi: 10.1016/j.surfcoat.2009.09.052.
7. Lin Y., Lu J., Wang L., Xu T., Xue Q. Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel. Acta Materialia, 2006, vol. 54, iss. 20, pp. 5599–5605. doi: 10.1016/j.actamat.2006.08.014.
8. Gleiter H. Nanocrystalline materials. Progress in Materials Science, 1989, vol. 33, iss. 4, pp. 223–315. doi: 10.1016/0079-6425(89)90001-7.
9. Lu K. Nanocrystalline metals crystallized from amorphous solids: nanocrystallization, structure, and properties. Materials Science and Engineering R-Reports, 1996, vol. 16, iss. 4, pp. 161–221. doi: 10.1016/0927-796X(95)00187-5.
10. Tong W.P., Tao N.R., Wang Z.B., Lu J., Lu K. Nitriding iron at lower temperatures. Science, 2003, vol. 299, iss. 5607, pp. 686–688. doi: 10.1126/science.1080216.
11. Tong W.P., Liu C.Z., Wang W., Tao N.R., Wang Z.B., Zuo L., He J.C. Gaseous nitriding of iron with a nanostructured surface layer. Scripta Materialia, 2007, vol. 57, iss. 6, pp. 533–536. doi: 10.1016/j.scriptamat.2007.05.017.
12. Balusamy T., Narayanan T.S.N.S., Ravichandran K., Park I.S., Lee M.H. Plasma nitriding of AISI 304 stainless steel: role of surface mechanical attrition treatment. Materials Characterization, 2013, vol. 85, pp. 38–47. doi: 10.1016/j.matchar.2013.08.009.
13. Tong W.P, Sun J., Zuo L., He J.C., Lu J. Study on wear and friction resistance of nanocrystalline Fe nitrided at low temperature. Wear, 2011, vol. 271, iss. 5–6, pp. 653–657. doi: 10.1016/j.wear.2010.11.024.
14. Baraz V.R., Kartak B.R., Mineeva O.N. Special features of friction hardening of austenitic steel with unstable γ-phase. Metal science and Heat Treatment, 2011, vol. 52, iss. 9, pp. 473–475. doi: 10.1007/s11041-010-9302-x.
15. Makarov A.V., Osintseva A.L., Yurovskikh A.S., Savrai R.A. Povyshenie tribologicheskikh svoistv austenitnoi stali 12Kh18N10T nanostrukturiruyushchei friktsionnoi obrabotkoi [Improving the tribological properties of austenitic 12Kh18N10T steel by nanostructuring frictional treatment]. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2015, no. 4 (69), pp. 80–92. doi: 10.17212/1994-6309-2015-4-80-92.
16. Baraz V.R., Fedorenko O.N. Special features of friction treatment of steels of the spring class. Metal Science and Heat Treatment, 2016, vol. 57, iss. 11, pp. 652–655. doi: 10.1007/s11041-016-9937-3.
17. Makarov A.V., Gorkunov E.S., Skorynina P.A., Kogan L.Kh., Yurovskikh A.S., Osintseva A.L. Eddy-current control of the phase composition and hardness of metastable austenitic steel after different regimes of nanostructuring frictional treatment. Russian Journal of Nondestructive Testing, 2016, vol. 52, iss. 11, pp. 627–637. doi: 10.1134/S1061830916110048.
18. Makarov A.V., Skorynina P.A., Volkova E.G., Osintseva A.L. Nanostrukturiruyushchie kombinirovannye friktsionno-termicheskie obrabotki austenitnoi stali 12Kh18N10T [Nanostructuring combined frictional-thermal treatment of 12Kh18N10N austenic steel]. Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta = Vector of sciences. Togliatti State University, 2016, no. 4 (38), pp. 30–37. doi: 10.18323/2073-5073-2016-4-30-37.
19. Mamaev A.S., Chukin A.V. Gazotsiklicheskoe plazmennoe azotirovanie nerzhaveyushchei stali [Gas-cyclic plasma nitriding of stainless steel]. Izvestiya vysshikh uchebnykh zavedenii. Fizika = Russian Physics Journal, 2016, vol. 59, no. 9-2, pp. 244–249. (In Russian).
20. Gavrilov N.V., Mamaev A.S. Low-temperature nitriding of titanium in low-energy electron beam excited plasma. Technical Physics Letters, 2009, vol. 35, iss. 8, pp. 713–716. doi: 10.1134/S1063785009080082.
21. Kislitsin S.B., Vereshchak M.F., Manakova I.A., Ozernoi A.N., Satpaev D.A., Tuleushev Yu.Zh. Blistering i α↔γ-prevrashcheniya pri otzhige stali 12Kh18N10T, obluchennoi nizkoenergeticheskimi al'fa-chastitsami [Blistering and α'↔γ phase transitions at annealing of stainless steel C12Cr18Ni10Ti irradiated by low energy alpha-particles]. Voprosy atomnoi nauki i tekhniki = Problems of atomic science and technology, 2013, no. 2 (84), pp. 17–22.
22. Kondo Y., Tanei H., Ushioda K., Maeda M., Abe Y. Effect of nitrogen on blister growth process during high temperature oxidation of steel. ISIJ International, 2012, vol. 52, no. 9, pp. 1644–1648. doi: 10.2355/isijinternational.52.1644.
23. Lakhtin Yu.M., Kogan Ya.D., Shpis G.-I., Bemer Z. Teoriya i tekhnologiya azotirovaniya [Theory and technology of nitriding]. Moscow, Metallurgiya Publ., 1991. 320 p.
24. Belashova I.S., Shashkov A.O. Kinetics of growth of the diffusion layer in nitriding by the thermogasocyclic method. Metal Science and Heat Treatment, 2012, vol. 54, iss. 5, pp. 315–319. doi: 10.1007/s11041-012-9504-5.
The work was done on the topic "Structure" No. 01201463331 (project No. 15-9-12-45) with the support of the Russian Foundation for Basic Research (project No. 15-08-07947). Electronic scanning microscopy, profilometry and microdymetry were carried out in the Center of Plastometry, IMASH, UrB RAS.
