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IS ASTM F 138 STAINLESS MAGNETIC?

2004

HI,

I HAVE A METAL PROSTHESES IMPLANT IN MY EAR WHICH IS MADE OF ASTM F138 STAINLESS WIRE LOOP. I NEED AN MRI AND NEED TO KNOW IF THIS MATERIAL IS FERROMAGNETIC OR NON FERROMAGNETIC I HOPE SOMEONE ON THIS SITE CAN HELP ME WITH THIS.

THANK YOU,.

KATHY FITZSIMMONS
researcher - TRACY, CA, U.S.A.

Kathy, the problem is that this 18 Chromium, 14 Nickel, 2.5 Molybdenum alloy is available in several conditions- hot worked, annealed, cold worked, and extra hard. The hot worked and annealed have low enough strength that I am certain they are non-ferromagnetic. The cold worked and extra hard have minimum tensile strengths of 125 and 196 ksi, so they likely have been worked enough to become magnetic.

See, as the material is drawn into thin wires the atomic arrangement changes, and the more heavily worked, higher strength arrangement is ferromagnetic.

You'll have to check with the manufacturer to know for certain.

Lee Gearhart
metallurgist - E. Aurora, New York
2004