QUANTUM LEAP FOR METALLURGY

ALCHEMY: A small Danish metal company, FJ Sintermetal, has developed and patented a new material which matches high-speed steel in terms of density, hardness and wear resistance. But at a significantly lower price, and with properties that can be tailored exactly to the components’ use. 

As the name suggests, FJ Sintermetal manufactures geometrically complex metal components via sintering. This is a process where metal powder is compressed under high pressure into a completed item. The item is then sintered at a temperature just below the melting point. Before sintering the item is brittle and porous, but heating starts a process where the molecules in the powder alloy fuse together and form carbides which make the item hard and wear resistant. “Sinter technology is a relatively young technology, which is seeing rapid growth,” says director Søren Weis Sørensen of FJ Sintermetal. “Up to now the technology has been used for manufacturing items that would otherwise require a lot of processing. Sinter technology can produce very large batches and is thus significantly cheaper. Sintered items are for example extensively used in the automotive industry, such as for the production of gearbox cogs.”

Eliminates costly process
Sinter technology has many advantages. There is no material waste and the more complex the item is, the more money is saved. But the technology has – or rather had – a disadvantage.

“Conventional sintering does not make the density as high as in solid steel,” says Weis Sørensen. “When the metal powder is compressed, small air pores are created in the metal. Up to 15% of the item can be air pores. In most cases this has no importance, but in some cases there is a need for a material with high density as well as high wear resistance. We have solved that problem with our new patented powder alloy, Weardens®, which without subsequent processing reduces the porosity to under 2%.”

Weardens® is the result of a focused research effort at FJ Sintermetal, which has experimented with many compositions of additives and high-speed steel with added hard carbides. The result is a milestone in the development of sinter technology, since the alloy’s unique composition of chromium, tungsten, molybdenum and vanadium carbides eliminates the need for the alternative, costly vacuum process that conventionally sintered items need to go through to achieve high density.

Alchemy at high level
“An interesting aspect of our technology is the opportunity to tailor materials with properties that precisely fit the task and the environment in which the item will be used,” says Weis Sørensen. “We can do that because we mix the powder which is used for the production. That is alchemy at a high level.

The technology, which FJ Sintermetal is the only company to offer worldwide, is a gift for industries requiring cutting tools exposed to hard wear, such as the asphalt, forestry or drilling industries. There are great savings to gain from the
new technology, even with relatively small batches.

http://www.fji.dk