necessary to obtain a given accuracy is significantly smaller for method 3 than for method 2. For Untersdh
1 mm? the experimental error of method 2 corresponds to that of method 1. Probeno
Flavio 5
Conclusions en
For regularly structured surfaces, 3D roughness parameters obtained from profilometry can "Max!
conveniently be used to assess local plastic deformation with a resolution corresponding to that of
the usual measuring grid technique (1x1 mm?). Automatic measurement is possible but the accuracy
is limited to about +/-0.05 true strain which may prove insufficient for practical purposes. Kurzfas
Surface patterns like lubricant pockets or microstructural features visible in etched surfaces can Die Kırate
advantageously be used instead of grids. The grain structures of the ferritic steel investigated here [ie
offers excellent opportunities for assessment of strain with a high resolution. The experimental error u.
is related to the resolution by the usual rules of statistics. If a comparison of same location before IS de
and after deformation is possible, a high lateral resolution and a high precision, independent of each oh
other, are obtained. The limit of resolution depends only on the size of the smallest features which Die ing
can be relocated in the magnified images after deformation and the experimental error is Lisi
appreciably smaller than for all other methods tested in this work. in wi
Auflösung
Acknowledgements PE
The authors are grateful to Prof. H. E. Exner for helpful discussions on the subject matter and Zur Char
suggestions for improving the manuscript. The project was supported within the fri
“Sonderforschungsbereich 298, Teilprojekt A10” of the “Deutsche Forschungsgemeinschaft”. Die beste
zu durchs
References wr
(1) R.C. Brewer, J. M. Alexander: “A New Technique for Engraving and Measuring Grids in (onenstre!
Experimental Plasticity”, J. Mech. Phys. Solids 8 (1960) 76-80
(2) Topograf, version 1/2000, http://www.ptu.tu-darmstadt.de
(3) M. Pfestorf, J. Staeves, S. Wagner: “Definition von 3-D-Oberflichenkenngrofien”, Stahl und I. Eine
Eisen 117 (1997) 7, 89-94 Warn .
4) K. J. Stout: "The Development of Methods for the Characterisation of Roughness in Three Pa 3
Dimenstions”, Report-Nr. EUR 15178 EN, Commission of the European Communities, oo
Bruxelles (1993) he
(5) J. Staeves: "Beurteilung der Topografie von Blechen im Hinblick auf die Reibung bei der oo
Umformung”, Shaker Verlag, Aachen (1998) Te
(6) H.E. Exner: “Quantitative Description of Microstructural Geometry — A Practical Guide to es
Manual Processes, Part III”, Prakt. Metallogr. 30 (1993) 287-293 = =
(7) O. Kienzle, K. Mietzner: “Atlas umgeformter metallischer Oberflichen”, Springer Verlag, 52%
Berlin (1967) I
(8) O. Kienzle, K. Mietzner: “Grundlagen einer Typologie umgeformter metallischer he
Oberflächen mittels Verfahrensanalyse”, Springer Verlag, Berlin (1967) N
Mikrotop
für vers
Gefügeir
Um ein
EN bo
68
