welding HYMU 80 & heat treatment 1

[jcole]

Can anyone provide me with or point me to some specific information regarding the exact heat treatment required after welding HYMU 80 (a mu metal).

Thanks,
jcole

 

[Rich2001]

http://www.hightempmetals.com/hitempHymu80data.htm

Welding

HyMu 80 alloy is readily welded by following the usual pracitices for ferrous alloys. If a filler metal is required, use the same analysis. Finish annealed parts can be soft or hard soldered. Do not braze or solder prior to final heat treatment.


Heat Treatment
In-process anneal

To relieve all strains and restore the alloy to a soft condition suitable for drawing, spinning, forming, bending or similar operations, anneal at 1450/1850°F (788/1010°C) for not more than 1 hour. Since the high nickel, high permeability alloys readily absorb carbon, sulfur, oxygen and other contaminants from combustion furnace gasses, in-process annealing should be conducted in dissociated ammonia, hydrogen, vacuum or inert gas atmospheres.

Hydrogen anneal

For maximum softness and optimum magnetic and electrical properties, HyMu 80 alloy should be annealed in an oxygen-free, dry dydrogen atmosphere with a dew point below -40°F at 2050/2150°F for 2 to 4 hours. Furnace cool to 1100°F. From 1100 to 700°F, cool at rate between 350 to 600°F per hour.

Oil, grease, lacquer and all other contaminants must be removed before annealing. The individual parts should be seperated by an inert insulating powder such as magnesium and aluminum oxide during hydrogen annealing.

Vacuum heat treating can be employed. Generally, there is some small sacrifice in magnetic properties compared to heat treating in a dry hydrogen atmosphere.