| High Permeability "49" alloy is a 48% nickel-iron alloy which has a saturation flux density of approximately 15,000 Gauss after hydrogen annealing. Hysteresis loss is very low in either DC or AC circuits in which the frequency is less than 400 cycles per second. Following a low temperature hydrogen anneal at 1300/1400°F (704/760°C), alloy 49 exhibits constant permeability characteristics. Its initial permeability is approximately 500 Gauss. High Permeability "49" alloy resists weather and moisture corrosion to a moderate extent. High permeability "49" alloy has been used in laminated cores for instrument transformers, magnetic shields and cores for certain electronic and communications devices in which extremely high permeability at low magnetizing forces greatly increases the efficiency and effectiveness of the equipment. Because of its high permeability, it has also been used in solenoid cores in light, sensitive relays that must operate and respond to weak currents that induce low magnetizing forces. If components are to machined in volume from bar stock, High Permeability "49"-FM, a free-machining grade, is recommended. The standard grade , High Permeability "49" alloy, machines somewhat like the austenitic stainless alloys. It develops gummy chips but does not work harden as rapidly as the stainless alloys. Sulfur-bearing cutting compounds are highly detrimental to the final magnetic properties. Animal lard oil should be used in drilling and machining operations which must be performed at low speeds. Work hardened bars offer the best machining characteristics. Parts should be degreased and cleaned as soon as possible. Information provided by High Temp Metals. |
