Last year I fell and broke my wrist. I wound up with a plate in it which is a very common occurance.
I’m surprised when I pass my metal detector over my wrist, it has a difficult time registering it. This is a metal detector that I’ve used to find BB’s an inch or two underground.
Are there any reasons why it would be so insensitive to a metal plate in my wrist? I don’t know if the plate is titanium, or stainless steel, but either way, I’d expect more signal.
What kind of metal detector are you using? Titanium and stainless steel implants are generally non-ferrous (not magnetic) and may not set off home metal detectors. You still may set off more sensitive airport style detectors.
Ferrous doesn’t mean magnetic, it means made of or containing iron. It is not entirely clear how stainless steel could be non-ferrous.
:smack: you’re right. Regardless the point remains, titanium and stainless are generally non-magnetic
It’s probably a titanium plate. My husband has one in his arm as well and it’s not picked up by metal detectors.
It can still be non-ferritic, though.
I have pins and a plate in my ankle. My husband’s metal detector will give a signal if it’s in close proximity. Boston Logan is the only airport that ever noticed it.
He is probably confused because of the similar terms ferritic and ferromagnetic. Ferritic and martensitic stainless steels are ferromagnetic (i.e. magnetic) - austenitic (non-ferritic) stainless steels are not. These terms refer to different types of crystalline structure of the grains in the material.
In any case - there are many different kinds, but in general, metal detectors work by emitting a oscillating magnetic field. This induces an oscillating electrical current in metal objects, and the resulting electrical oscillations in the object themselves produce a magnetic field. The induced secondary magnetic field can be sensed by the detector.
Different metals have different degrees of magnetic permeability and electrical conductivity, which influence the degree to which they perturb the field of the metal detector. Fancy metal detectors can differentiate different types of metal by the timing and amplitude of the perturbation in the field, and adjust their sensitivity based on the type of metal being detected. Simple metal detectors generally just have a fixed sensitivity level, and will respond differently to different amounts of metals with varying permeability / conductivity.
The shape of an object and orientation relative to the detector can affect detection as well.
Airport metal detectors typically have their sensitivity set relatively low to avoid slowing down the lines by picking up zippers and other metal components in people’s clothing. Often these components are made of metal which responds relatively strongly to a metal detector, so it is not surprising that the detectors tuned to ignore such things fail to pick up larger, implanted objects made of material which responds less strongly.