Problems of application of standards in evaluation of microstructure of metals and alloys

Abstract

The purpose of this work is to consider the problems of applying some standards containing reference scales of structures: 1763-68, 1778-70, 5640-68, 9391-80, 10 243-75, 13938.13-93, 22 838-77, 3443-87 (materials: oxygenated copper, pipe and structural steels, cast iron). It is shown that the normative base of standards for metallographic analysis is morally outdated. The main problem is the discrepancy between the increase in standards and real modern structures. Basically, microstructure standards use a magnification of 100 times, in particular, for the analysis of oxygenated copper, banding of the rolled metal structure, Widmanstätt structure, phosphide eutectic. The analysis of modern materials requires an increase of about 500...800 times. The magnification of 360…400 times, used in some scales, is also insufficient, in particular, for the analysis of structurally free cementite. Also, the quality of images of structures makes them difficult to use. A common disadvantage of the considered standard scales of structures is the absence of metrics in photographs, which does not correspond to the modern level of metallurgy and causes certain inconveniences when comparing structures. It is necessary to revise the standards governing the structure of metals and alloys. Research should be carried out to develop a new generation of standards based on the real structures of modern industrial alloys. It is also necessary to develop new methods of structure analysis. This applies primarily to analysis in image processing programs.