I've been playing with ways to make my world interesting, and also further justify the limited use of ferrous metals. One idea I had was that my world might undergo regular and intense geomagnetic storms, probably caused by solar flares, on a scale equaling and exceeding the most powerful recorded on Earth.
Ideally this would cause brilliant auroras, and be powerful enough to make using or storing weapons made of ferrous metals very impractical. (The image in my head is of iron weapons being torn right out of your hands. On Earth geomagnetic storms can disrupt compass activity, but I'm not sure how far this could be scaled up.) This might also encourage the formation of early states near the equator, which is good, since that's where I've put most of my earliest civilizations anyway.
Are geomagnetic storms that intense possible on a generally Earth-like world? If so, what might they look like, and would they have any other important effects?