The Paton Welding Journal, 2008, №02

2008 №02 (01)

2008 №02 (03)

---

The Paton Welding Journal, 2008, #2, 6-13 pages

Sensitivity to cracking and structural changes in ebw of single crystals of heat-resistant nickel alloys

K.A. Yushchenko¹, B.A. Zadery¹, A.V. Zvyagintseva¹, S.S. Kotenko¹, E.P. Polishchuk¹, V.S. Savchenko¹, I.S. Gakh¹, O.P. Karasevskaya²

¹E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine.
²G.V. Kurdyumov Institute for Metal Physics, NASU, Kiev, Ukraine

Abstract
Transverse cracks in the weld metal were found to be the main defects of the EB-welded joints in single crystals of heat-resistant nickel alloys. Sensitivity to formation of such cracks in EBW of single-crystal nickel superalloy JS-26 depends, primarily, upon the welding speed, preheating and structural state of the initial metal. A probable cause of cracking of the weld metal is its structural heterogeneity, which results from peculiarities of the thermal-deformation cycle of welding, as well as from the initial structural state of metal. The range of the welding speeds, where the cracks are not formed, was determined. Increase in the welding speed leads to growth of the quantity of the cracks, and preheating shifts the critical welding speed towards higher values.
Keywords: electron beam welding, nickel alloys, single crystals, weld, crack resistance, temperature-time conditions, welding speed, preheating, X-ray diffractometry, violation of single-crystal structure, dislocation structure, local zones of stresses

References

1. Yushchenko, K.A. (2004) Weldability and advanced processes for materials welding. The Paton Welding J., 9, 39–44.
2. Yushchenko, K.A., Derlomenko, V.V. (2005) Analysis of modern views on weldability. Ibid., 1, 5–9.
3. (1995) Superalloys II. Ed. by I.G. Sims et al. Moscow: Metallurgiya.
4. Ejdelshtein, V.E., Yakushin, B.F., Steblov, V.I. (1996) High-temperature deformation and formation of near-weld cracks in welding of alloy of Nimonic type. Avtomatich. Svarka, 11, 40–44.
5. Sorokin, L.I. (1997) About hot cracking in welding of highstrength alloys. Svarochn. Proizvodstvo, 7, 9–11.
6. David, S.A., Babu, S.S., Vitek, J.M. (2003) Solidification and microstructure. J. of Metals, 6, 14–20.
7. Barabash, O.M., Babu, S.S., David, S.A. et al. (2003) Deformation in the heat-affected zone during spot welding of a nickel-base single crystal. J. Appl. Phys., 94(1), 738–742.
8. Park, J.-W., Babu, S.S., Vitek, J.M. et al. (2003) Stray grain formation in single crystal Ni-base superalloy welds. Ibid., 94(6), 4203–4209.
9. Yushchenko, K.A., Karasevskaya, O.P., Kotenko, S.S. et al. (2005) Inheritance of structure-oriented state of metallic materials by welded joints. The Paton Welding J., 9, 2–9.
10. Pollock, T.M., Murphy, W.H. (1996) The breakdown of single-crystal solidification in high refractory nickel-base alloys. Metal. Mater. Transact. A, 27, 1081–1094.
11. Borland, J.C., Rogerson, J.H. (1962) Examination of the patch test for assessing hot cracking tendencies of weld metal. British Welding J., 9(8), 494–499.
12. Rundel, G.R., Nehrenberg, A.E. (1966) Weld metal cracking of Invar in circular patch test. Welding J., 45(4), 156–160.
13. Zessmenn, G.G. (1964) Welding evaluation of experimental columbium alloys. Ibid., 43(3), 103–115.
14. Fewster, P.F. (2000) Insight into polycrystalline materials with ultrahigh resolution and reciprocal space mapping. Commission on power diffraction. Microstructure of Materials, 24(12), 17.
15. Karasevskaya, O.P. (1999) Orientation X-ray experimental method of phase analysis. Metallofizika i Nov. Tekhnologii, 21(8), 34.
16. Ungar, T., Mughrabi, H., Ronnpagel, D. et al. (1984) Xray line-broadening study of the dislocation cell structure in deformed [001]-orientated copper single crystals. Acta Met., 32, 333.
17. Wilkens, M., Ungar, T., Mughrabi, H. (1987) X-ray rockin-curve broadening of tensile-deformed [001]-orientated copper single crystals. Phys. Status Solidi A, 104, 157–170.
18. Krivoglaz, M.A. (1996) X-ray and neutron diffraction in nonideal crystals. Berlin: Springer.
19. Mughrabi, H. (1983) Dislocation wall in deformed metal crystals. Acta Met., 31, 1367–1379.
20. Panin, V.E., Likhachev, V.A., Grinyaev, Yu.V. (1985) Structural levels of deformation of solids. Novosibirsk: Nauka.
21. Likhachev, V.A., Panin, V.E., Vladimirov, V.I. et al. (1989) Cooperative deformation processes and localization of deformation. Kiev: Naukova Dumka.
22. Malygin, G.A. (1995) Self-arrangement of dislocations and localization of sliding in plastically deformed crystals. Fizika Tv. Tela, Vol. 37, 3–42.
23. Sarafanov, G.F. (1998) On the theory of formation of heterogeneous dislocation structures. Fizika Metallov i Metallovedenie, 85, 46–53.
24. Koneva, N.A., Kozlov, E.V. (1990) Physical nature of plastic deformation staging. Izvestiya Vuzov. Fizika, 2, 89–106.
25. Maslenko, S.B. (1983) Heat-resistant steels and alloys. Moscow: Metallurgiya.
26. Yushchenko, K.A., Savchenko, V.S., Zvyagintseva, A.V. (2004) Effect of heat treatment and degree of alloying on structural changes in nickel alloys. The Paton Welding J., 7, 12–14.
27. Lippold, J.C., Kotecki, D.I. (2005) Welding metallurgy and weldability of stainless steels. Willey Interscience.
28. Savchenko, V.S., Markashova, L.I., Yushchenko, K.A. (1994) Effect of weld composition and fine structure on processes of thermoplastic deformation and under-bead crack formation in welding of austenitic steels. Avtomatich. Svarka, 4, 6–10.
29. Savchenko, V.S., Yushchenko, K.A. (1997) Mechanism of formation and methods of elimination of under-bead microcracks in multilayer welds with stable-austenitic structure. In: Proc. of Materials Solutions’97 Conf. on Joining and Repair of Gas Turbine Components (Indianopolis, Indiana, 15--17 Sept., 1997), 17–22.
30. Yushchenko, K.A., Savchenko, V.S., Chervyakov, N.O. et al. (2004) Character of formation of hot cracks in welding cast heat-resistant nickel alloys. The Paton Welding J., 8, 34–38.
31. Gessinger, G.Kh. (1988) Powder metallurgy of heat-resistant alloys. Chelyabinsk: Metallurgiya.

---

Suggested Citation

K.A. Yushchenko, B.A. Zadery, A.V. Zvyagintseva, S.S. Kotenko, E.P. Polishchuk, V.S. Savchenko, I.S. Gakh, O.P. Karasevskaya (2008) Sensitivity to cracking and structural changes in ebw of single crystals of heat-resistant nickel alloys. The Paton Welding J., 02, 6-13.

---