Cutting edges should be always sharp. But once they get dull, the consequence is that the cutting gets worse. That means the cutting quality is impaired and the power consumption increases. Other consequences won’t arise.
Garden shredder blades are different. The sharp knives pull the chopping crop autonomous into the machine. The automatic heeling won’t work with dull knives. The chaffi ng becomes a burden. A minimal wear at the cutting edge, even if it doesn’t affect the cutting process, will have a very negative impact on the automatic heeling of the crop.
Frielo® Dux is a procedure developed by FRIELINGHAUS
that is obtaining excellent results especially in that application. With usual techniques the knives are fully tempered (see fig. 1),
or partial heat treated on the cutting edge by induction
(see fig. 2).
The hardness is between 52 and max 56 HRC. A higher hardness wouldn’t be reasonable, because of the danger of complete breakage of the blade or disruptions at the cutting edge.
Frielo® Dux results in a core hardness of approximately 45 HRC. This is soft enough to prevent breakage and hard enough to provide suffi cient stability and rebound.
Only on the steel surface do we fi nd the very thin but extremely hard layers, merely 0,25 to 0,30 mm thick with a hardness of over 60 HRC (see fig. 3).
These thin, hard layers provide an excellent lifetime behavior. The hard layer on the upper side of the knife is caused by the process but without any importance. In the following illustration (see fi g. 4) you can easily recognize the hardness profi le, starting with the bottom side of the knife.
In the displayed micrograph (see fig. 5) you see the
Frielo® Dux microstructure.
Since the inner part of the cutting edge of the knife shows more wear, because of the lower hardness, the Frielo® Dux system provides an additional self-sharpening effect to some extent..
In the fi eld of garden shredder blades Frielo® Dux is proved and tested hundred thousandfold.