Investigation of Microstructure weld zone of Hastelloy X Pulsed Nd-YAG laser welds

Subject Areas : Chemistry

Farrokh  Najafzadegan ¹ (Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Isfahan, Iran)
Hojatallah  Mansori ² (Department of Materials Engineering, Malek-E-Ashtar University, Isfahan, Iran)
Morteza  shamanian ³ (Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran)

Received: 2013-08-27 Accepted : 2013-12-01 Published : 2013-10-01

Keywords: Microstructure, Nd-YAG laser, Hastelloy X,

Abstract :

In the present study, the microstructure of welded zone of Hastelloy X sheets with thickness of 1 mm via pulsed Nd-YAG laser welding were studied. This welding process was done by autogenus and conductive method. Microstructure were observed by metallurgical OM and SEM. Results shown Solidification of the weld metal is dendritic. The dendrites in the central zone of the welding are fine and equiaxed while they are larger and columnar in the fusion boundary. Epitaxial growth was observed in the interface of base metal and weld metal. Alloy elements Segregation did not occur during the solidification process and the fine cracks were not observed in the welding zone of the alloy. Micro hardness results indicated that the hardness of welded metal were more than base metal and cause to decrease grain size at welded metal more than base metal. This phenomenon was occurred due to more differences between heating and cooling rate in this welding process.

References:

1. E. F. Bradley, “Welding of Superalloys, A Technical Guide”, 1989, pp.197-90.


2. J. K. Tien, “Super Alloy, Super Composite and Super Ceramics”, 1989, pp.1-14 &
   142-144.


3. J. Wily, Inc. Sons, “The Super Alloys”, 1976, pp.509-532.


4. D. F. Paulonis, W.A. Owczaski, “Joining of Powder Metal Superalloys”, 1980, pp. 77-102.


5. M. Arkoosh, N. F.Fiore, “Elevated Temperature Ductility Minimum in Hastelloy X”, Metallurgical Transactions, Vol. 3, Aug. 1972, 935.


6. M. Aghaie, N. Golarzi, “Dynamic and Metadynamic Recrystallization of Hastelloy X Superalloy”, J Mater Sci, 43, 2008, pp. 3717–3724.


7. R.V. Miner, M.G. Castelli, “Hardening Mechanisms in a Dynamic Strain Aging Alloy, HastelloyX, during Isothermal and Thermomechanical Cyclic Deformation”, Metallurgical Transactions A, Vol. 23A, Feb., 1992, 551.


8. H. M. Tawancy, “Long-Term Ageing Characteristics of Hastelloy X”, J Mater Sci 18, 1983, pp. 2976-2986.


9. Li. Zhang, S. L. Gobbi, K. H. Richter, “Autogenous Welding of Hastelloy X to Mar-M 247 by Laser”, J MaterPro Tech ,70, 1997, pp. 285-292.


10. S. Muraoka, H. Itami, S. Nomura, “Carburization of Hastelloy X”, J Nuclear Mater, 1975, 58 , pp. 18-24.  


11. J. Matthew, S. Donachie, J. Donachie, “Superalloys, A Technical Guide”, 2nd ed., ASM International, USA, New York, 2002, pp. 192-265.


12. J. C. Lippold, J. W. Sowards, G. M. Murray, B. T. Alexandrov, A. J. Ramirez, “Weld Solidification Cracking in Solid-Solution Strengthened Ni-Base Filler Metals”, 2008, pp. 147-170.


13. M. Pang, G. Yu, H. H. Wang, C. Y. Zheng, “Microstructure Study of Laser Welding Cast Nickel-Based Super Alloy K418”, J Mater Pro Tech, 207, 2008, pp. 271–275.


14. G. D. Janaki Ram, A. Venugopal Reddy, K. Prasad Rao, G. M. Reddy, J. K. Sarin Sundar, “Microstructure and Tensile Properties of Inconel 718 Pulsed Nd-YAG Laser Welds”, J Mater Pro Tech, 167, 2005, pp. 73–82.


15. M. Shamanian, A. Ashrafi, “Welding of Metallurgy”,IsfahanUniversityof Technology, 1388.


16. N. S. Stoloff, “Speciality Steels and Heat-Resistant Alloy”, Metals Handbook, 1st ed., Vol. 1, ASM Handbook, 2005, pp. 1478-1549.