Doug, why you concern about fatigue strength? People normally care only about its magnetic performance and workability, so no such data is readily available.
MagBen
We're using it for its magnetic properties, but there is still vibration load, therefore cyclic stress and the potential for structural failure (though we expect that it is an extremely remote probability.) Our past experience is that we have so much margin that we don't care but a new application lives in such an outrageously high vibration environment that we must consider the possibility.
I donot believe even Carpenter has the fatigue data available for High Perm 49. You may have to do evaluation by yourself if it really matters. Please share with us if you get a result.
If the magnetics for your applicaitons is tolerable, you can anneal at lower temeprature or shorter time to yield a higher tensile strength but wuthout sacrifice much of magnetic proeprties. The final high tem anneal for 49 alloy is to optimize magnetics with very large grains. The other thing for a better fatigue might be to purchase vacuum melted material. Some Carpenter's competitors only offer air-melted High Perm 49.
