A common task was initiated as a contribution to the problem of the determination of bi- and triaxial residual stress states in surface-near zones. The X-ray lattice-strain measurements were performed from the surface, therefore without any removal of layers, by 12 institutions from universities, research institutes and from industries. Samples of the case-hardened steel l6MnCr5 and of ceramic material Si{sub}3N{sub}4 were deformed on the surface by grinding procedures using different parameters. Differences of the absolute value of the peak position are the effects of the broad lines and of the choice of the peak-position determination. The result of the stress profile evaluation, performed by some participants using their measured lattice strain distributions did not lead to uniform profiles. Supposed residual stress profiles were transformed into the respective lattice distance distributions of two lattice planes. The latter were evaluated using different formulations into residual stress profiles. The agreement of these results is good. The conditions, the necessary measurement effort and the evaluation methods follow from these joint tests for a correct evaluation of steep residual stress gradients.
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