Invar 42 is a 41% nickel-iron controlled expansion alloy which has been used in a wide variety of glass-to-metal sealing applications.While the expansion properties of this alloy most closely match 1075 glass, it has also been used in seals for the 0120 and 0010 glasses. It may also be used with hard glasses if a thin edged tubular seal is used. For seals that are not hydrogen annealed prior to sealing, a variation of this alloy containing small additions fo titanium, Glass Sealing 42 Gas-Free, has been used to promote gas-free sealing characteristics.
Invar 36 Nickel alloy similar material are:UNS K94100
Invar 42 nickel-iron usually used in the following industries :
Invar 42 has been used for semiconductor lead frames in integrated circuits, bi-metal thermostats strip, thermostat rods, for ceramic-to-metal seals with alumina ceramics, and various glass-to-metal seals such as the core of copper-clad-wire for sealing into glass envelopes of electric bulbs, radio valves, television tubes and fluorescent lights.
Invar 42 nickel-iron steel chemical composition:
Invar 42 nickel-iron steel Mechanical Property:
Heat to 1450°F (788°C) and hold at heat for at least one-half hour per inch of thickness, air cool.
The forging temperature should be 2150/2200°F (1177/1204°C). Avoid prolonged soaking to prevent sulfur absorption from the furnace atmosphere.
Glass Sealing 42 may be swaged or cold upset.
Blanking or forming
For clean blanking of Glass Sealing 42, a Rockwell hardness of about B90 is suggested. Where any sharp bends are involved in forming finished parts from strip or rods, a hardness of not over Rockwell B93 is suitable.
A silicon carbide wheel is desirable, preferably a soft wheel which will wear without loading. For finish grinding, a satisfactory grade to start with is No. 80 grit.
Any of the conventional welding methods can be used. When filler rod is required, Glass Sealing 42 is suggested.
Invar 42 nickel-iron Product form and Specifications:
|MIL-I-23011 CL 5/ASTM F30||UNS K94100/Werkstoff Nr.1.3917/DIN 17745/AFNOR NF A54-301/S.E.W.385|