Effects of Sintering Variables on the Physical and Mechanical Properties of Metal Injection Molding Molded 17-4 PH Stainless Steel

Abstract:

Metal injection molding (MIM) is a near net shape manufacturing technique for producing small, complex, precision parts in mass production. MIM process is manufacturing method that combines traditional shape-making capability of plastic injection molding and the materials flexibility of powder metallurgy. The process consists of the following four steps: mixing of metal powder and binder, injection molding to shape the component, debinding to remove the binder in the component, sintering to consolidate the debound parts. In this research, the physical and mechanical properties of metal injection molded 17-4 PH stainless steel were investigated with the variation of sintering temperatures (1300 °C - 1360 °C) and atmosphere conditions (argon and vacuum conditions). The relative density, microstructure, distortion, and hardness are measured and analyzed in this study. The results show that highest relative density of 87%, relative homogeneous shrinkage and high hardness are achieved by sintering at 1360 °C for 1.5 hours and argon atmosphere. At the same sintering temperature and time, sintering in vacuum shows lower relative density (81%) than that in argon condition due to pores growth. The pore growths were not observed in the argon atmosphere. It can be concluded that sintering stages more rapidly under vacuum condition. The hardness measurements result also showed that high hardness is obtained by high density parts. The optimum average hardness obtained in this study is 239 HV. However, the hardness properties results are still lower than 280 HV according to MPIF Standard 35 for MIM parts.

• Periodical: Materials Science Forum (Volume 1028)
• Pages: 403-408
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1028.403
• Online since: April 2021
• Authors: Apang Djafar Shieddieque*, Shinta Virdhian, Moch Iqbal Zaelana Muttahar, Muhammad Rafi Muttaqin
• Keywords: 17-4 PH Stainless Steel, Density, Hardness, Metal Injection Molding, Sintering

References

[1] H. Ye, X. Y. Liu, and H. Hong, Sintering of 17-4PH stainless steel feedstock for metal injection molding. Mater. Lett. 62(19) (2008) 3334–3336.

DOI: 10.1016/j.matlet.2008.03.027

[2] H. Ma, S. Li, Z. Jin, Y. Tian, F. Ren, Z. Zhou, W. Xu, Effect of 17-4PH stainless steel powders interaction on feedstocks. Powder Technology. 372 (2020) 204–211.

DOI: 10.1016/j.powtec.2020.05.106

[3] Ronal Machaka, Metal injection moulding of a 17-4 PH stainless steel: a comparativestudy of mechanical properties. IOP Conf. Ser.: Mater. Sci. Eng. 430 (2018) 012033.

DOI: 10.1088/1757-899x/430/1/012033

[4] Y. Wu, D. Blaine, B. Marx, C. Schlaefer, and R.M. German, Sintering Densification and Microstrutural Evolution of Injection Molding Grade 17-4PH Stainless Steel Powder. Metallurgical and Materials Transaction A. Vol 33A (2002) 2185-2194.

DOI: 10.1007/s11661-002-0050-4

[5] C. H. Ji, N. H. Loh, K. A. Khor, and S. B. Tor, Sintering study of 316L stainless steel metal injection molding parts using Taguchi method: Final density. Mater. Sci. Eng. A. 311 (2001) 74–82.

DOI: 10.1016/s0921-5093(01)00942-x

[6] A. Sathyanath and A. Meena, Microstructural evolution and strain hardening behavior of heat-treated 17-4 PH stainless steel. Mater. Today Commun. 25 (2020) 101416.

DOI: 10.1016/j.mtcomm.2020.101416

[7] H. Youhua, L. Yimin, H. Hao, L. Jia, and Tang Xiao, Preparation and Mechanical Properties of Inconel718 Alloy by Metal Injection Molding. Rare Metal Materials and Engineering. 39(5) (2010) 775-780.

DOI: 10.1016/s1875-5372(10)60100-2

[8] S. Virdhian, T. Osada, H. G. Kang, F. Tsumori, and H. Miura, Evaluation and analysis of distortion of complex shaped Ti-6Al-4V compacts by metal injection molding process. Key Eng. Mater. 520 (2012) 187–194.

DOI: 10.4028/www.scientific.net/kem.520.187

[9] H. Ye, X.Y. Liu, H. Hong, Sintering of 17-4PH stainless steel feedstock for metal injection molding. Materials Letters. 62 (2008) 3334-3336.

DOI: 10.1016/j.matlet.2008.03.027

[10] H.J. Sung, T.K. Ha, S. Ahn, Y.W. Chang, Powder injection molding of a 17-4 PH stainless steel and the effect ofsintering temperature on its microstructure and mechanical properties. Journal of Materials Processing Technology. 130–131 (2002) 321–327.

DOI: 10.1016/s0924-0136(02)00739-2

[11] M. Seerane, P. Ndlangamandla, R. Machaka, The influence of particle sizedistribution on the properties of metal injection moulded 17-4 PH stainless steel. The Journal of South African Institute of Mining and Metallurgy. 116 (2016) 935-940.

DOI: 10.17159/2411-9717/2016/v116n10a7

[12] B. Suharno, D. Ferdian, H. Restucondro, L. Pradinda, E. R. Baek, and S. Supriadi, Vacuum sintering process in metal injection molding for 17-4 ph stainless steel as material for orthodontic bracket. Solid State Phenom. 266 (2017) 231–237.

DOI: 10.4028/www.scientific.net/ssp.266.231

[13] J. Kazior, A. Szewczyk-Nykiel, T. Pieczonka, M. Hebda, and M. Nykiel, Properties of precipitation hardening 17-4 PH stainless steel manufactured by powder metallurgy technology. Adv. Mater. Res. 811 (2013) 87–92.

DOI: 10.4028/www.scientific.net/amr.811.87

[14] N. Kurgan, Effects of sintering atmosphere on microstructure and mechanical property of sintered powder metallurgy 316L stainless steel. Mater. Des. 52 (2013) 995–998.

DOI: 10.1016/j.matdes.2013.06.035