4
Views
3
CrossRef citations to date
0
Altmetric
Symposium on “Lubrication, Friction, and Wear (Tribology) in Powder Metallurgy” (24-26 November 1969)

VARIOUS FACTORS AFFECTING THE WEAR OF STEEL DIES USED FOR THE COMPACTING OF IRON POWDER

&
Pages 316-343 | Published online: 10 Nov 2014
 

Abstract

Small cylindrical iron powder compacts have been produced in series of ∼ 75 000 specimens, using an automatic compacting press running at a speed of 33 strokes/min. Die-wear rates were determined, as influenced by powder type, compacting pressure, compact density, type and hardness of die steel, and punch/die clearance. Simultaneously, the ejection forces were continuously recorded.

No substantial difference was found between the die-wear rates of common iron powder grades of an atomized or a sponge type, but an electrolytic grade of especially compact particle structure gave a lower rate. Die wear increases in roughly linear proportion both with the number of compacts and with the compacting pressure.

Steel type and hardness of the die had a pronounced influence upon die-wear behaviour, dies of higher hardness yielding lower wear rates. Unsuitable heat-treatment can cause high wear rates even though it might produce high die hardnesses.

A punch/die clearance of 10 μm resulted in the most favourable die-wear behaviour. At a clearance of only 5 μm the punches became stuck in the die very quickly; at clearances of 25 and 45 μm severe cladding of the die-bore surface with iron from the compacts occurred after 40 000-50 000 strokes.

The following, partly interacting, phenomena were found to be contributory factors in the die-wear mechanism: abrasion, cladding, surface cracking, and chipping. It proved impossible to establish a reliable correlation between ejection forces and die-wear rates.

Notes

* Manuscript received 25 June 1969. Contribution to a Symposium on “Lubrication, Friction, and Wear (Tribology) in Powder Metallurgy” to be held in Eastbourne on 24-26 November 1969.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.