How to Test Riveting Nut Mechanical Properties?(Ⅲ)

Hardness test

Hardness is one of the important mechanical properties of nuts. Not only because of the convenience of hardness testing, more importantly, it is the only acceptable standard currently known to measure those nuts of the test load that beyond the common tensile strength testing and the similar strength tests. Unlike externally threaded fasteners, for steel rivet nuts or the nuts made of other metal materials, their hardness has no relation with the strength. The reason is that the geometry of nut will impact on the nuts strength.

In general, the nut of the specified test load lower than the 120,000 psi can carry out experimental load tests. For those nut has a higher strength, they must be tested in a reference to the basis of the minimum hardness value. In addition, the nut strength rating requires for nuts of all sizes and grades having hardness tests to ensure that their hardness does not exceed the specified minimum value. These are particularly important for the heat-treated nuts, since it can confirm the nut has been processed to eliminate any possible embrittlement. Read more...