Increasing density and reducing lubricant content with AncorMax 225 from Hoeganaes Corporation

February 26, 2014

February 26, 2014

As the applications for Powder Metallurgy (PM) structural parts become increasingly more demanding there is a need for parts with higher strength, hardness, and ductility. The most effective way to satisfy customer needs and achieve improvements in all of these areas simultaneously is to raise the density of the compacted parts, claims Hoeganaes Corporation.  

“Because of the desire for higher and higher densities, it is the responsibility of both the parts maker and powder producer to develop ways to improve density across the board for an array of material compositions,” stated Tim Hale, Global Marketing Manager, Hoeganaes. “This has been achieved at Hoeganaes Corporation using an advanced lubricant and binder system called AncorMax 225.”

“The AncorMax 225 system is becoming popular among customers who desire high density parts. The material is currently used at more than 20 of our customers for applications worldwide,” added Hale.

In order to achieve high density parts, it is vital to reduce the total amount of lubricant in the powder premix, as lubricants have a significantly detrimental effect on the maximum green density that can be attained during compaction. The value of the maximum green density achieved if all porosity was removed is known as the pore free density (PFD). While lubricants are necessary for protecting parts and tooling during forming and ejection, for each 0.1% lubricant added to a premix, there is a 0.05 g/cm3 loss in PFD.



Fig. 1 98% PFD vs. graphite addition for three lubricant levels

Fig. 1 shows the effect of both graphite and lubricant content in a premix on achieving 98% of the PFD, which is generally the highest that can be attained during compaction. Thus, to achieve higher green and sintered densities via single press single sinter processing, lower lubricant levels are necessary. The AncorMax 225 system utilises warm die compaction technology and allows for lubricant levels as low as 0.25%, which enables for green densities in compacted parts up to approximately 7.5 g/cm3.



Fig. 2 Green density vs. compaction pressure for three lubricant systems

By raising green and sintered densities, overall strength, hardness and ductility in PM parts can be improved dramatically. Physical properties such as transverse rupture strength, apparent hardness, ultimate tensile strength, and Charpy impact toughness are directly related to part density. Fig. 2 shows the elevated green density values that can be achieved in an FLN2-4405 mix with the AncorMax 225 system compared to another high density system, AncorMax 200, and a standard premix with 0.75% Acrawax.



Fig. 3 Green strength vs. green density for three lubricant systems

In addition to increasing part density and strength, the AncorMax 225 system gives several other advantages including better material flow, improved part-to-part consistency, higher green strength, reduced part ejection forces, and lower burn-off emissions during sintering.

By nearly doubling the green strength of a compacted part, this advanced lubricant system allows for easier part handling with less cracking and chipping in the green condition. Meanwhile, the reduction in the ejection forces is extremely beneficial for reducing scoring on the part, die, and punches, while increasing overall tool life. As an added benefit, the lower burn-off emissions can lead to lower maintenance costs.    


February 26, 2014

In the latest issue of PM Review…

Download PDF

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

  • Phoenix Sintered Metals: A story of transformation, growth and community from America’s PM heartland
  • World PM2024 Yokohama: The stage is set for the PM industry to find a path to sustainable growth
  • The state of Europe’s hard magnets industry and the challenge of optimising the mass production of Nd2Fe14B permanent magnets

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