Effect of Processing Parameters on Intermetallic Phase Content and Impact Toughness for Super Duplex Alloy PM HIP Sandvik SAF 2507™
Martin Östlund, Linn Larsson, Tomas Berglund
download PDFAbstract. PM HIP is a widely applied manufacturing technology to produce thick walled and complex shaped duplex and super duplex stainless steel (DSS and SDSS) components for the petrochemical as well as the oil and gas industry. The PM HIP process offers the advantage of a fine-grained microstructure which generates an increased resistance to HISC (Hydrogen Induced Stress Cracking) as well as higher yield strength. A limiting factor when producing thick walled components of DSS and SDSS alloys is the precipitation of brittle intermetallic phases which results in decreased corrosion resistance and impact toughness if high enough fractions are precipitated. The precipitation of intermetallic phases is a diffusion controlled process that may take place during quenching following solution annealing if the cooling rate is too slow. The cooling rate during quenching is mainly depending on the section thickness of the component, where large sections are subjected to slower cooling and thus increased intermetallic phase precipitation. In this article, it is shown that a coarser PM HIP microstructure results in lower contents of intermetallic phases after water quenching. However, despite of the lower intermetallic phase content the impact toughness is not improved and this is explained by the fracture mechanisms as shown by instrumented impact testing and fracture surface analysis.
Keywords
Powder Metallurgy, HIP, Super Duplex Stainless Steel, Intermetallic phases, Sigma Phase, Impact Toughness
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: Martin Östlund, Linn Larsson, Tomas Berglund, Effect of Processing Parameters on Intermetallic Phase Content and Impact Toughness for Super Duplex Alloy PM HIP Sandvik SAF 2507™, Materials Research Proceedings, Vol. 10, pp 128-134, 2019
DOI: https://dx.doi.org/10.21741/9781644900031-18
The article was published as article 18 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.
References
[1] L. Larsson, M. Bjurström, Properties of PM HIPed SAF 2507 super duplex stainless steel, Proceedings of Euro PM2012 Conference (2012).
[2] J. O. Nilsson, Overview Super duplex stainless steels, Mat. Sc. Tech. 8 (1992) 685-699. https://doi.org/10.1179/mst.1992.8.8.685
[3] L. Larsson, Internal Sandvik R&D technical report, 120894TEA (2012).
[4] L. Larsson, Internal Sandvik R&D technical report, 121625TEA (2012).
[5] M. Östlund, Internal Sandvik R&D technical report, 170270TEA (2017).
