Saturday, September 8, 2012

Do You Need Help Heat Treating or Testing HyMu 80 Alloy?

HyMu 80 is a nickel base alloy that has as principal alloying elements 80% nickel, 4.2 % molybdenum and remainder iron. The alloy is used primarily for transformer cores, tape wound torroids, laminations, and for shielding to protect electrical components from stray magnetic fields. Its value is that it provides low initial and maximum permeability, with low hysteresis losses. The alloy is available in bar, sheet or wire.
When sold to the user, the material is accompanied by a certification that states  the material satisfies the required properties. The problem is that once the material is altered, such as by machining, stamping or other mechanical operation, the certified properties no longer apply. The user then must provide a heat treatment that restores the magnetic properties to the properties originally certified. Heat treating may be a problem because there are different furnaces, atmospheres and proceedures that may not provide the heat treatment required to restore the original properties of the material. In addition, testing becomes the second problem. Equipment for testing is expensive, and unless you are a large company it is difficult to justify its purchase. In addition, the tests available also are fraught with error, and repeatability between laboratories is not good. The problem is that hysteresigraphs and other similar test equipment are composed of an ammeter to measure the current to define the applied field. The measurements required to calculate the applied field are at the extreme lower end of the ammeter and therefore are prone to maximum error. In addition, the flux meter also requires the most sensitive scale for measurement of the magnetic induction. It too is at a scale where the error is maximum. Throw in zeroing capability of a hysteresigraph and you have a third major error. Therefore, couple sensitive heat treatment with high risk of measurement in testing and you may have a problem. MagnaTech has worked with many customers to resolve the headaches that result after the material has been received and altered. MagnaTech can help you to resolve your heat treating inconsistities, and also can provide accurate test results that are within 3% error. If you are having a problem either heat treating or testing this magnetic alloy, please consult MagnaTech to resolve your problem.