Distaloy 1), the low alloy steel powder, is today used all over the world in many applications demanding high strength and wear resistance. It's basic properties and composition were designed half a century ago by Athan Stosuy, who at that time was research metallurgist at Hoeganaes Corporation in Riverton NJ. U.S.A., then a subsidiary of Höganäs AB in Sweden. The basic advantage with the special alloying technique used in the manufacture of Ancoloy, as it was then called, rested in the fact that it was a partial prealloy - i.e. the alloying elements â copper, nickel and molybdenum - were only bonded in particulate form to the basic iron particles, thus avoiding any hardening of the powder, which would impair the compressibility. By balancing the contents of nickel and copper it was achieved that there was hardly any dimensional change upon sintering. By bonding the alloy particles to the iron powder particles, segregation was minimized. This also contributed to dimensional stability. Carbon was added in conventional way as fine graphite to the powder.
The use of Ancoloy didn't take off in America, however. This was partially due to lack of suitable applications, the relatively high cost of the alloying elements and - above all - the poor compressibility and high oxygen content of the iron powder, available as a base material at the time. Due to the relatively high and variable oxygen content of the powder, it was not possible to control the carbon content with the precision necessary for the achievement of the desired strength and hardness.
A few years into the nineteen sixties a demand for high strength precision parts came up in the European car industry. The first was Citroen, who pioneered increased use of PM parts in European cars. The component was (and still is) the synchronizing hub used in manual transmissions. As Höganäs in the middle of the sixties had developed a new sponge iron powder with much higher compressibility than before, this was taken as a raw material for an improved grade of Ancoloy, which was later to be called Distaloy SA. This new powder had a much improved compressibility and very low oxygen and carbon contents, which made it possible to make the high strength precision parts which the car industry required. Distaloy was immediately accepted and used, first in the French car industry, soon thereafter all over Europe and after a few years also in Japan.
Some years later, when high compressibility atomized powder became available, Höganäs applied the same basic technique to these and thus made the Distaloy A grades, which now are most popular.
Höganäs continues to improve and refine the production techniques and to come up with compositions for new applications.
The properties and the metallography of Distaloy-based materials have been thoroughly studied by metallurgists both at Höganäs and at PM laboratories all over the world and new results are still dropping in, both with respect to applications and fundamental properties. A parameter of great relevance is of course the cost of raw materials and much effort is going into finding more cost effective ways of achieving the same results.
1)Distaloy is a registered trade mark of Höganäs AB