Determination of Emissivity Characteristics for Controlled Cooling of Nickel-Alloy Forgings

Abstract:

The paper presents the methodology and the results of determination of emissivity coefficient for nickel alloy Inconel 718 in the temperature range predicted for thermomechanical processing of these alloys and its application for correction of temperature during cooling and modeling. The idea presented in the paper is an iterative use of automatic system of temperature measurement and control, facilitated with thermocouples and pyrometer gauge to provide temperature dependent characteristics of the alloy. In addition to estimation of temperature dependence of the emissivity coefficient, the results of cooling tests for simple and complex geometry of nickel alloy forgings are contained, obtained with modeling based on assumption of the determined characteristics. To verify obtained characteristic, they were used in modeling of cooling and compared to those obtained in measurements based on assumption of constant value of emissivity coefficient. Measurement errors obtained were used to indicate show the significance of application of functional dependence in comparison with constant value, as well as, magnitude of error made during temperature measurement or modeling, when neglecting the temperature dependence.

• Periodical: Solid State Phenomena (Volume 208)
• Pages: 1-7
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.208.1
• Online since: September 2013
• Authors: Piotr Skubisz, Piotr Micek
• Keywords: Controlled Cooling, Emissivity Coefficient, Inconel 718, Nickel Alloy, Pyrometer, Remote Temperature Measurement, THERMOMECHANICAL PROCESSING

References

[1] ASM Handbook vol. 4, Heat Treating. ASM International Handbook Committee, Ohio 2002.

[2] Y. Wang, W.Z. Shao, L. Zhen, B.Y. Zhang: Hot deformation behavior of delta-processed superalloy 718, Materials Science and Engineering, A 528 (2011) 3218–3227.

DOI: 10.1016/j.msea.2011.01.013

[3] Y. Wang, L. Zhen, W.Z. Shao, L. Yang, X.M. Zhang: Hot working characteristics and dynamic recrystallization of delta-processed superalloy 718, Journal of Alloys and Compounds, 474 (2009) 341–346.

DOI: 10.1016/j.jallcom.2008.06.079

[4] M.K. Miller, S.S. Babu, M.G. Burke: Comparison of the phase compositions in Alloy 718 measured by atom probe tomography and predicted by thermodynamic calculations, Materials Science and Engineering A327 (2002) 84–88.

DOI: 10.1016/s0921-5093(01)01881-0

[5] K. Chrzanowski: Problems of determination of effective emissivity of some materials in MIR range, Infrared Phys. Technol., Vol. 36, No. 3, 1995, 679-684.

DOI: 10.1016/1350-4495(94)00107-v

[6] R. Brandt, C. Bird, G. Neuer: Emissivity reference paints for high temperature applications, Measurement, 41, 2008, 731–736.

DOI: 10.1016/j.measurement.2007.10.007

[7] A. Mazikowski, K. Chrzanowski: Non-contact multiband method for emissivity measurement, Infrared Physics & Technology, 44, 2003, 91–99.

DOI: 10.1016/s1350-4495(02)00182-2

[8] P. Skubisz, P. Micek, J. Sińczak, M. Tumidajewicz : Automated determination and on-line correction of emissivity coefficient in controlled cooling of drop forgings, Solid State Phenomena, Vol. 177, 2011,  76-83.

DOI: 10.4028/www.scientific.net/ssp.177.76

[9] P. Skubisz, J. Sińczak: Precision forging of thin-walled parts of AZ31 magnesium alloy, Archives of Metallurgy and Materials, 2007, vol. 52 iss. 2,  329–336.

[10] N. Biba, S. Stebounov, A. Lishiny: Cost-effective implementation of forging simulation, Journal of Materials Processing Technology, 113 (2001) 34-39.

DOI: 10.1016/s0924-0136(01)00616-1