ASTM E3

Microstructures have a strong influence on the properties and successful application of metals and alloys. Determination and control of microstructure requires the use of metallographic examination.

Many specifications contain a requirement regarding microstructure; hence, a major use for metallographic examination is inspection to ensure that the requirement is met. Other major uses for metallographic examination are in failure analysis, and in research and development.

Proper choice of specimen location and orientation will minimize the number of specimens required and simplify their interpretation. It is easy to take too few specimens for study, but it is seldom that too many are studied.

1. Scope

1.1 The primary objective of metallographic examinations is to reveal the constituents and structure of metals and their alloys by means of a light optical or scanning electron microscope. In special cases, the objective of the examination may require the development of less detail than in other cases but, under nearly all conditions, the proper selection and preparation of the specimen is of major importance. Because of the diversity in available equipment and the wide variety of problems encountered, the following text presents for the guidance of the metallographer only those practices which experience has shown are generally satisfactory; it cannot and does not describe the variations in technique required to solve individual specimen preparation problems.

Note 1 - For a more extensive description of various metallographic techniques, refer to Samuels, L. E., Metallographic Polishing by Mechanical Methods, American Society for Metals (ASM) Metals Park, OH, 3rd Ed., 1982; Petzow, G., Metallographic Etching, ASM, 1978; and VanderVoort, G., Metallography: Principles and Practice, McGraw Hill, NY, 2nd Ed., 1999.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents

A90/A90M Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
E1077 Test Methods for Estimating the Depth of Decarburization of Steel Specimens
E1122 Practice for Obtaining JK Inclusion Ratings Using Automatic Image Analysis
E1245 Practice for Determining the Inclusion or Second-Phase Constituent Content of Metals by Automatic Image Analysis
E1268 Practice for Assessing the Degree of Banding or Orientation of Microstructures
E1558 Guide for Electrolytic Polishing of Metallographic Specimens
E1920 Guide for Metallographic Preparation of Thermal Sprayed Coatings
E340 Test Method for Macroetching Metals and Alloys
E407 Practice for Microetching Metals and Alloys
E45 Test Methods for Determining the Inclusion Content of Steel
E7 Terminology Relating to Metallography
E768 Guide for Preparing and Evaluating Specimens for Automatic Inclusion Assessment of Steel

Index Terms

alloys; grinding; metallography; metals; mounting; polishing; sectioning; specimen preparation (metallographic); ICS Number Code 77.040.99

Citing ASTM Standards

[Back to Top]