Bohler N690 Stainless Steel

Description

Heat Treating N690 from Bohler Uddeholm (recommended)

Annealing N690:

It is recommended to anneal after any laser cutting or hammering of steel to relieve any possible stress in the steel.

Heat the blade in the furnace to 750°C and hold for 30 minutes. Allow the blade to cool slowly inside the furnace to room temp.

Hardening N690:

Heat the furnace to the desired temperature between 1040 – 1080°C as per the recommendations below. Once the furnace has reached the temperature you can place the blade/s in the furnace. Once the temperature has reached the desired temp, soak according to the following:

Hardening Temperatures:

• 1040°C if not doing cryo-treatment after the quench.
• 1060°C if cooling in a domestic deep freezer.
• 1080°C if doing cryo-treatment using dry ice or liquid nitrogen.

Soak Times:

• 2,5mm thick hold for 5 minutes;
• 3,25mm thick hold for 7 minutes;
• 4mm thick hold for 10 minutes;
• 5mm thick hold for 12 minutes.

Quench rapidly in oil (i.e. PQ20 quench oil) or between plates with air cooling. After quenching follow up with deep freezing / Cryo-treatment if desired for at least 2 hours prior to tempering.

Tempering:

Temper between 150 – 200°C twice for 1 hour