PowderMet 2013: From raw material to new challenging applications – creating future PM growth

August 14, 2013

The Special Interest Program on Technologies for PM Growth at the MPIF Conference PowderMet 2013, held in Chicago, June 24-27, 2013, began with a series of presentations from the major powder suppliers, highlighting the material and process developments that they had introduced with a view to opening up new higher-performance application opportunities for the ferrous PM structural parts sector.


The opening presentation came from Ulf Engstrom, Hoganas AB, on behalf of his co-authors, Caroline Larsson, Sigurd Berg and Christophe Szabo. It is recognised that “green” issues are becoming an increasingly important factor in determining the relative merits of competing materials and technologies.

The benefits of PM, as compared with wrought steel processing routes in terms of reduced energy consumption and higher material utilisation in the component forming process itself, are well recognised. However, the comparisons provided at the opening of this presentation were considerably more rigorous than this in that they involved full life cycle analyses, beginning with mining/extraction of raw materials and ending with end-of-life recycling of components.

These analyses considered the environmental impact factors:

  • Global Warming Potential (CO2, CH4) – GWP
  • Photochemical Ozone Creation Potential – POCP
  • Acidification Potential (SO2, NOx) – AP
  • Eutrophication Potential (NOx, PO4) – EP
fig-1

 

table-1_1 

Fig. 1 The component selected for the life cycle analysis case study and the relevant material and processing data

 

As a case study, production routes for an injection yoke by wrought steel processing and by PM, using two different PM materials (Astaloy CrM + 0.3%C and Distaloy AE + 0.5%C), were assessed (Fig. 1).

Firstly, the presented results of these analyses showed the very significant advantage of PM over the wrought steel route in relation to the environmental impact factors (Fig. 2).

fig-2a

 

 fig-2b

 

Fig. 2 Life cycle analyses showing the superiority of PM over steel processing in terms of

environmental impact.

 

Secondly, the comparisons of the two PM material types showed the environmental credentials of using the chromium-containing Astaloy CrM material as compared with the 4% Ni Distaloy AE. Although the move away from PM materials highly alloyed with Ni is partially motivated by cost considerations, these “green” issues are also of increasing importance in material selection and Cr- and leaner Ni-alloyed grades offer the opportunity to fulfil these requirements.

The leaner Ni-alloyed material highlighted was Hoganas AB’s Distaloy AQ, containing diffusion-alloyed additions of 0.5%Ni and 0.5%Mo. This material can achieve density levels over 7.3 g/cm3 when warm compacted and can achieve very high levels of dynamic properties in the heat treated condition, particularly after case hardening.

Fig. 3 shows the levels of plane bend fatigue strength attainable in the case-hardened and through-hardened conditions at room temperature compaction and warm compaction density levels. The benefits of warm compaction in relation to fatigue strength are related to the reduction in both the size and frequency of occurrence of large pores in the sintered structure (Fig. 4)

fig-3

Fig.  3  Plane bend fatigue strengths of Distaloy AQ in the through-hardened (left) and case-hardened (right) conditions

 

fig-4

Fig. 4 Comparison of pore sizes and probability of occurrence in Distaloy AQ products produced by warm compaction and room temperature compaction

 

The highlighted Cr-alloyed materials were the fully pre-alloyed grades, Astaloy CrA (1.8% Cr) and Astaloy CrM (3% Cr, 0.5%Mo). In the assessments presented, Astaloy CrA was used as a base for the elemental addition of either 1% Cu or 2% Ni. Warm compaction of the material with the 2% Ni addition showed that a density level of around 7.25 g/cm3 could be attained compared with around 7.1 g/cm3 for room temperature compaction.

These materials are well suited to processing by sinter-hardening and Fig. 5 shows that, on sinter-hardening with a carbon gradient, the Astaloy CrA + 2% Ni material can achieve fatigue and tensile strength levels comparable to much more highly alloyed heat treated materials and unique combinations of fatigue strength and elongation, even at room temperature compaction density levels.

fig-5

Fig. 5 Fatigue and mechanical properties of sinter-hardened materials, based on Astaloy-CrA or Astaloy CrM

 

The presentation concluded with some predictions as to how these material and process developments can enhance PM’s capability for attacking growth opportunities in challenging product applications. Fig. 6 provides some views as to how the highlighted materials might fit into a number of important existing and potential product niches, including the industry’s “holy grail” of transmission gears.

fig-6

Fig. 6 Challenging growth areas for PM and potential materials

 

Finally, the promise was discussed of future developments of “low pressure processing”, involving vacuum sintering and gas quenching, that might provide further enhancements in the properties of the highlighted Cr-alloyed grades and how these processes might be combined with state-of-the-art hard finishing operations to provide an optimised PM gear production route.

Author

Dr David Whittaker is a consultant to the Powder Metallurgy and associated industries. Contact +44 1902 338498 email: [email protected]  

Dr David Whittaker is a consultant to the Powder Metallurgy and associated industries. Contact +44 1902 338498 email: [email protected]  – See more at: http://www.pm-review.com/articles/001587.html#sthash.dUVoZODj.dpuf
Dr David Whittaker is a consultant to the Powder Metallurgy and associated industries. Contact +44 1902 338498 email: [email protected]  – See more at: http://www.pm-review.com/articles/001587.html#sthash.dUVoZODj.dpuf

powdermet-logo

 

PowderMet2013 was organised by the Metal Powder Industries Federation. For more information please visit the MPIF website: www.mpif.org 

 

 

News | Articles | Market reviews | Search directory | Subscribe to e-newsletter

August 14, 2013

In the latest issue of PM Review…

Download PDF

Extensive Powder Metallurgy industry news coverage, and the following exclusive deep-dive articles and reports:

  • From powder modification to rejuvenation: Fluidised Bed Reactors in metal powder production and Additive Manufacturing
  • Retech: Enabling the atomisation of reactive and refractory alloys at substantially higher levels of productivity and lower cost
  • Sustainability in Powder Metallurgy: Highlights from the 41st Hagen Symposium
  • Innovations from Japan’s Powder Metallurgy industry: award winners highlight novel automotive and healthcare applications

The latest news from the world of metal powders, delivered to your inbox

Don't miss any new issue of PM Review, and get the latest industry news. Sign up to our weekly newsletter.

Sign up

Join our community

Discover our magazine archive…

The free-to-access PM Review magazine archive offers unparalleled insight into the world of Powder Metallurgy from a commercial and technological perspective through:

  • Reports on visits to leading PM part manufacturers, metal powder manufacturers and industry suppliers
  • Articles on technology and application trends
  • Information on materials developments
  • Reviews of key technical presentations from the international conference circuit
  • International industry news

All past issues are available to download as free PDFs or view in your browser.

 

Browse the archive

 

Looking for PM production equipment, metal powders, R&D support and more?

Discover suppliers of these and more in our
advertisers’ index and buyer’s guide, available in the back of PM Review magazine.

  • Powders & materials
  • Powder process, classification & analysis
  • PM products
  • Atomisers & powder production technology
  • Compaction presses, tooling & ancillaries
  • Sintering equipment & ancillaries
  • Post-processing
  • Consulting & toll sintering
View online
Share via
Copy link