MuMETAL® is used primarily in low intensity fields where high attenuation, high initial permeability, and high shielding efficiency are desired. Available as stress annealed (partially annealed for ease of machinability), sheet stock is used for fabricated shields, such as enclosures, cylinders, cans, channels, or 3D boxes.
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Typically, atmospherically controlled annealing is required after stamping, machining, bending, rolling, or welding to provide maximum shielding performance. MuMETAL® Stress Annealed alloy is available in many forms, but most shields are fabricated from our sheet stock in gauges from .014" to .062" thickness [0,36mm to 1,57mm]. MuMETAL® Foil is fully annealed and available in stock gauges from .002" to .010" thickness [0,05mm to 0,25mm].
MuMETAL® is typically stocked in a stress annealed state to allow further fabrication, stamping, severe forming, or welding. During fabrication, a material’s grain structure is weakened. After final fabrication processes are completed, grain structure is then modified by controlled atmospheric annealing to relieve stress in the material, resulting in larger grain structure, softer temper, and ultimate shielding performance. Although MuMETAL® is available in many forms, most shields are fabricated from foil or sheet stock.
When your shield design requires severe forming, stamping, and/or welding, specifying MuMETAL® on your drawings ensures you will receive the highest level of initial permeability and shielding efficiency available. MuMETAL® is formulated and manufactured to exacting standards, which allows for consistent fabrication and final anneal. Not only does Magnetic Shield Corporation offer MuMETAL® alloy, we can provide a full range of manufacturing services. From your drawing or sketch, we can waterjet, laser, EDM, shear, slit, punch, blank, stamp, chemical etch, form, bend, roll, spot-weld, heliarc weld, and/or laser weld. Using MuMETAL® alloy, we can produce complete magnetic shields to your drawings or specifications.
MuMETAL® Chemical Composition % In Weight*
Nickel (Ni) 80-81%
Molybdenum (Mo) 4.5-6%
Silicon (Si) 0.05-0.4%
Manganese (Mn) 0-0.5%
Carbon (C) 0.01%
Iron (Fe) Balance
*Composition may vary by production lot.
TYPICAL ANNEALED PROPERTIES
0.2% Yield Strength 49ksi (338 MPa)
Density 0.316 lb/in³ (8.7 g/cm³)
Tensile Strength 99 ksi (682 MPa)
Electrical Resistivity 60 micro-ohm cm
Elongation 32% in 2" (51 mm)
Grain Size ASTM 7 or finer
Hardness 15T 85
TYPICAL MAGNETIC PROPERTIES*
DC µ @ 40 gauss 80,000
DC µ @ 100 gauss 105,000
DC µ maximum 350,000
DC Hc 0.0005 Oe
DC Br (gauss) 4,000
AC 60Hz @ 40 gauss 65,000
*Data are typical of .014" [0.36mm] annealed sample and should be not be construed as maximum or minimum values for specification or final design. Data for each material thickness and/or lot may vary.