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MG5- Ferritic Soft Magnetic Steel

Steel data sheets

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Valbruna Grade


Steel type

Ferritic Soft Magnetic Steel

Description of material

MAGIVAL® MG5 is ferritic low Chromium free machining stainless steel grade with high magnetic properties and very good machining. Its resistance corrosion is lower than the grades of 18% Cr such as MG1, MG2, MG3 and MG4. It is extensively used in the automotive industries and soft magnetic components. A carefully controlled chemical analysis as well as special metallurgical processes provide a ferritic structure that is very sensitive to magnetic fields. MG5 can be supplied (1) as annealing+ cold finished or (2) annealed+ cold finished + magnetic annealed + cold finished. See Soft Magnetic Steels brochure for more information about magnetic, mechanical and physical properties.


MG5 is widely used in automotive fuel injection systems and antilock brake systems.

Melting practices

Argon Oxygen Decarburization

Corrosion resistance

It should be well considered that, as with all free machining grades, Sulphur is added to improve machinability and the formation of MnS inclusions could prime points of pitting if exposed to some corrosive environments. In addition, it is useful point out that MG 5 has a Chromium content lower than the MG series. MG5 has a good corrosion resistance useful for the fuel injection environments of engines. It should be noted that this grade, as for every kind of stainless steel, surfaces should be free of contaminant and scale, heat tint, and passivated for optimum resistance to corrosion.


Although it has the same Sulphur content and hardness values as the Ferritic free machining grades of the MG series, MG5 has a better machinability. Productivity gain depends on types of machines, the kind of tools used and their geometry, cutting fluids and kind of machine operations on the pieces produced. This grade cannot be cold deformed or upset worked.


MG5, as with other free machining grades with high Sulphur content, is not recommended for welding because the fused zone tends to form porosity and cracks. In any case, low heat inputs and a type 430 filler metal should be used. Austenitic fillers in order to increase ductility of weld, don’t solve the problems in HAZ unless a PWHT is applied. It should be pointed out that the low magnetic permeability of the Austenitic structure of the fused zone dramatically modifies the magnetic flux causing a flux leakage generated by the high difference of magnetic permeability between the two structures. Autogenous high energy welding could create some Martensitic structure in the fused zone and HAZ due to the formation of Austenite at those high temperatures and the very rapid cooling of this kind of welding. In this case, a PWHT must be applied.


W.N. 1.4005
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