We started to develop this improved SN grade as many customers started complaining about the quality of the castings for several applications, mainly automotive.

It happens more and more often to machine workpiece in “not aged” materials, so that the usual toughness of SN grades is no more enough even lowering Vc.

As it seemed impossible to keep the same cutting speed as with DT850, we worked on toughness, to increase the feed range. At the end, lowering Vc of 10% and increasing at the same time feed of 20% our inserts work more than before keeping a longer tool life.

DT850BK is already now the most used grade on several kind of bad castings.

When problems become opportunities.