Magnetization of steel via sawing
Magnetization of steel via sawing
(OP)
We are a tool steel distributor of pieces for molds, dies, etc. After cutting large blocks with band saws some steels (especially prehardened alloys) develop residual magnetism to the extent that we get customer complaints of sticking chips during their machining processes. The field varies widely and can reverse polarity many times along a single edge or face of a cut block. I have measured mag before and after cutting with a gaussmeter and it definately increases after sawing. I cannot find any literature to explain why sawing would induce mag into steel alloys. Any info?
RE: Magnetization of steel via sawing
Buy yourself a simple AC demag coil and keep everyone happy.
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Plymouth Tube
RE: Magnetization of steel via sawing
RE: Magnetization of steel via sawing
Also in the hardening process steels tend to develop a preferred magnetic orientation.
Your large plates are loaded with small internal areas that are magnetized, and it is a material that retains field well. When you cut them apart the fields are now unbalanced and can be measured.
I remember the drill, cut the block and demag, finish grind and demag, trial fit the die blocks, take it apart and demag.
Often before finish grind we would re-temper parts in an effort to minimize the fields. Sometimes it helped.
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Plymouth Tube
RE: Magnetization of steel via sawing
RE: Magnetization of steel via sawing
I got couple of papers published on that. check with these if interested:
"Giant strain-induced ferromagnetism in Fe59Mn17Al24", Philosophical Magazine, 2011, 1–12.
"Magnetic properties and thermal ordering of mechanically alloyed Fe–40 at% Al", Intermetallics 14 (2006) 396–405.
RE: Magnetization of steel via sawing