Effect of temperature dropping during solution treatment during rejuvenation heat treatment on final microstructures in cast nickel base superalloy, grade Inconel-738
Keywords:Nickel base superalloy, Rejuvenation heat treatment, Inconel-738, Temperature dropping, Solution treatment
AbstractGenerally, the rejuvenation heat treatment of degraded turbine blades, which were made of cast nickel based superalloy, Grade Inconel 738, usually consist of solution treatment condition with temperature range of 1125ºC- 1205ºC for 3 hours and then following with double aging processes, which include primary aging at 1055ºC for 1 hour and secondary aging at 845ºC for 24 hours. However, in practical working conditions of reheat treatment processed, the possible change of temperature during solution treatment can be obtained by error or malfunction of heating furnace, which usually provides the temperature dropping down. To simulate this effect, the dropping temperature during solution treatment was chosen to decrease till the level of 845ºC, which usually happens in practices then immediately heating up again to solution temperature level. The various selected temperature dropping programs were performed during solution treatment. The maximum number of temperature droppings during the single solution treatment is up to 3 times. From the received results, it was found that the effect of temperature dropping during solution treatment has extremely influenced on the final rejuvenated microstructures.
El-Bagoury, N., Waly, M. and Nofal, A. (2008). Effect of various heat treatment conditions on microstructure of cast polycrystalline IN738LC alloy. Mater. Sci. Eng. 487(1) : 152-161.
Hoseini, S. H., Nategh, S., and Ekrami, A. (2012). Microstructural evolution in damaged IN838LC alloy during various steps of rejuvenation heat treatment. J. Alloys Compounds. 512 : 340-350.
Krongtong, V., Tuengsook, P., Homkrajai, W., Nisaratanaporn, E., Wangyao, P. (2005). The effect of re-heat treatments on microstructural restoration in cast nickel superalloy turbine blade, GTD 111. Acta Metallyrgica Slovaca. 11(2) : 171-182.
Matthew, J. D. and Stephen, J. D. (2002). Superalloys a technical guide. second edition, ASM International, USA.
Sajjadi, S.A., Zebarjad, S.M., Guthrie, R.I.L. and Isac, M. (2006). Microstructure evolution of high-performance Ni-base superalloy GTD-111 with heat treatment parameters. J. Mater. Process. Tech. 175(1) : 376-381.
Wangyao, P., Korath, T., Harnvirojkul, T. Krongtong, V. and Homkrajai, W. (2005). The SEM study of microstructural restoration by re-heat treatment in cast superalloy turbine blade. Acta Metallurgica Slovaca. 11(1) : 25-35.
Wangyao, P., Krongtong, V., Tuengsook, P. Hormkrajai, W. and Panich, N. (2006). The relationship between reheattreatment and hardness behaviour of cast nickel superalloy, GTD-111. J. Met. Mater. Miner. 16(1) : 55-62.
Wangyao, P., Homkrajai, W. Krongtong, V., Panich, N. and Lothongkum, G. (2007). OM Study of Effect of HIP and Heat Treatments on Microstructural Restroration in Cast Nikel Based Superalloy, IN-738. J. Met. Mater. Miner. 17(2) : 51-56.
Wongnawapreechachai, P., Homkrajai, W., Lothongkum, G. and Wangyao, P. (2012). Effect of temperature dropping during reheat treatments on GTD-111 microstructure. High Temp. Mater. Process. 31(2) : 113-123.
How to Cite
Copyright (c) 2015 Journal of Metals, Materials and Minerals
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Authors who publish in this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.