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General Guide to Machining Soft Magnetic Alloys


Soft Magnetic alloys can be machined by all of the common metal machining processes. No special equipment or procedures are required to produce parts with accurate dimensions with excellent finishes.

Soft Magnetic alloys that are primarily Nickel-Iron alloys (e.g. EFI Alloy 79, aka Magnifer 7904, HyMu 80, Hipernom, Moly- Permalloy and Permalloy 80, EFI Alloy 50, aka Magnifer 50, High Permeability 49 and Alloy 47-50 and Radiometal 4550) can be machined in accordance with the information found in our Machining Nickel-Iron Alloys guide.

This machining guide covers the machining of Hiperco 50, Hiperco 50A, and VIM VAR Core Iron.

Hiperco 50/50A


The choice between high-speed steel and carbide tools depends largely on production quantities. When using carbide tools, surface speed feet/minute (SFPM) can be increased between 2 and 3 times over the high-speed suggestions, Feeds can be increased between 50 and 100%.

The following charts include typical machining parameters used to machine Hiperco 50A. The data should be used as a guide for initial machine setup only.

Vim Var Core Iron

The following charts include typical machining used to machine Electrical Iron. The data listed should be used as a guide for initial machine setup only.

Figures used for all metal removal operations covered are average. On certain work, the nature of the part may require adjustment of speeds and feeds. Each job has to be developed for best production results with optimum tool life. Speeds or feeds should be increased or decreased in small steps.

Heat Treating for Optimal Magentic Properties

Items as supplied from the mill exhibit only a fraction of the soft magnetic properties which they are capable of attaining. To optimize their full magnetic properties, further heat treatment is a necessity.

Optimal heat treating procedures vary depending on the type of soft magnetic alloy – recommended heating temperatures, hold times, cooling rates, cycles, and types of atmospheres are all specific to each alloy. For the recommended heat treatment procedures for your material, please contact your Ed Fagan Inc. sales representative.

Guide to Machining Soft Magnetic Alloys Download PDF

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Controlled Expansion Alloys

Ed Fagan Inc. stocks a variety of similar alloys for low expansion, controlled expansion, glass-to-metal or ceramic sealing applications that may also satisfy your needs. EFI carries:
Super Invar
42 Alloy
46 Alloy
48 Alloy
52 Alloy

And we also have a large selection of other types of specialty metals and alloys for high technology applications, including:
Electrical/Electronic Nickel
Soft Magnetic Alloys
Refractory Metals and Alloys
Hard to Find Materials