Oxygen Content in PM HIP 625 and its Effect on Toughness
Tomas Berglund, Fredrik Meurlingdownload PDF
Abstract. Oxygen control during powder manufacturing and handling is crucial when manufacturing HIPed parts. The influence of elevated oxygen content on mechanical properties is something that has been debated and investigated for many years. The general consensus in the industry is that oxygen has a very detrimental effect on the toughness of the material if present in excessive amounts. The detrimental effect of oxygen content on the impact toughness of the material has resulted in HIPed specifications, both existing and under development, with limits on the oxygen content in the material. Many specify a relatively low limit on oxygen content at e.g. 120 ppm which can have adverse effects on yield in powder manufacturing which might increase costs without accomplishing the desired effect of ensuring sufficient toughness. As this study show, oxygen content and chemistry alone is not enough to describe the effect of oxygen content on the HIPed material. Setting a limit at e.g. 120 ppm will not guarantee that one gets better properties or even reaches the desired properties of the material. The study show it is important where the oxygen is located in the powder and to separate bulk oxygen content and the surface oxygen content, where the latter has a more pronounced effect on toughness. In the study four batches of alloy 625 have been investigated, all with only relatively small variations in oxygen content but with drastically different toughness and differences in how oxygen is distributed in the material.
HIP, Wear, Tribology, Metal Matrix Composites, MMC, Wear Resistant
Published online 2/11/2019, 7 pages
Copyright © 2019 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Tomas Berglund, Fredrik Meurling, Oxygen Content in PM HIP 625 and its Effect on Toughness, Materials Research Proceedings, Vol. 10, pp 135-141, 2019
The article was published as article 19 of the book Hot Isostatic Pressing
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
 A. Angré, A. Strondl, The effect of drastically lowered oxygen levels on impact strength for HIP’ed 316L-material, Preceedings HIP-14, 2014. p. 205-211.
 C. Cédat: Development of HIP technology on Stainless Steels, Paris, April 18th, 2013
 A. Lind, J. Sundström, A. Peacock, The effect of reduced oxygen content powder on the impact toughness of 316L powder joined to 316 steel by low temperature HIP, Fusion Engineering and Design, Vol 75-79, Nov 12-16 2000, Kyoto Japan.
 J. Sundström, Influence of oxygen content on impact strength of hot isostatically pressed PM superduplex stainless steel and 316L stainless steel, Swedish Institute for Metals Research, Report IM-2005-509 (2005), ISSN 1403-848X.
 J. Sundström, S. Wikman, S. Caddéo, Further assessment of the low oxygen pretreatment method for improved mechanical properties of hot isostatically pressed PM-alloys, Swedish Institute for Metals Research, Report IM-2005-554 (2005), ISSN 1403-848X.
 J. Sundström, The effect of oxygen on impact energy for HIPed PM-steels. Part 1, Swedish Institute for Metals Research, Report IM-2003-811 (2003)
 T. Berglund, L. Larsson, M Östlund, Impact toughness of HIPed vs. conventional 316L, ASMP PVP 2015, 45534
 T. Berglund, M. Östlund, Impact toughness for PM HIP 316L at cryogenic temperatures, ASMP PVP 2016, 64008. https://doi.org/10.1115/PVP2016-64002