2007-11-23 03:34:26 · 4 answers · asked by isihan 1 in Science & Mathematics ➔ Engineering
Something to do with heat treatment, the carbon percentage and the grain size and shape.
2007-11-23 08:42:07 · answer #1 · answered by Anonymous · 0⤊ 0⤋
In steel if you keep the cyclical stress under the fatigue limit it should never experience fatigue failure - called "infinite life". Most nonferrous metals WILL fail - even at low levels of cyclical loading - eventually. However metal fatigue is still not very well understood and at our current levels of testing you won't get consistent results even with identical samples so numbers are based on expected number of cycles before failure usually 10^7 (10 million) cycles. Rule of thumb for nonferrous is about .4 of the ultimate tensile strength will get you through that number of cycles before failure. Thus the limit on hours for the aircraft mentioned before. Grain size, heat treatment, surface finish, temperature etc can all affect the endurance limit (almost always negatively.)
2007-11-23 15:35:52 · answer #2 · answered by Hate the liars and the Lies 7 · 0⤊ 0⤋
Non- ferrous metals don't list an endrance limit because they do not have one.
Non-ferrous metals cannot be used for designs in which they are subjected to stress reversals, because they fail after only a few cycles.
2007-11-23 17:51:00 · answer #3 · answered by gatorbait 7 · 0⤊ 0⤋
Non ferrous do! Aluminum is more susceptible to fatigue than steel. That is why a pressurized plane is only allowed to make 20,000 flights then the airframe must be scrapped.
2007-11-23 12:43:00 · answer #4 · answered by Tim C 7 · 0⤊ 0⤋