High-grade steel designed for hardened tools with durable cutting edges, such as knife blades, surgical cutting instruments, circular knives for the meat industry, skate blades, etc.

690 steel is produced in Austria by Böhler using hot rolling. It can be machined and ground extremely well, even after hardening. If the steel is heat-treated correctly – ideally at precise temperatures in a vacuum hardening furnace – and tempered, it achieves very good mechanical properties at the cutting edge. A hardness of around 60–61 HRC following correct hardening will meet most of the anticipated requirements for normal to moderate blade stress. However, if the steel is drawn at a shallow angle practically into the cutting edge, it becomes highly susceptible to chipping. If you use such a blade for chopping, you will certainly ruin it.

The steel is highly resistant to corrosion, due to its high chromium content. It is therefore very commonly used for kitchen and hunting knives. In the case of hunting knives in particular, the blade is only treated after a considerable period of use, which is why hunters appreciate this property.

N690 polishes very easily and well, and a mirror-like finish can be achieved. This steel is easily recognised by the clusters of carbides visible after polishing, which form characteristic lattices visible to the naked eye.