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适用范围：<p>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.</p> <p>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.</p> <p>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.</p><p id="s00002">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. <p class="desc" id="N00001"> <span class="smallcap">Note</span> 18212;For a more extensive description of various metallographic techniques, refer to Samuels, L. E., <span class="italic"> Metallographic Polishing by Mechanical Methods</span>, American Society for Metals (ASM) Metals Park, OH, 3rd Ed., 1982; Petzow, G., <span class="italic"> Metallographic Etching, ASM, 1978; and VanderVoort, G., </span><span class="italic"> Metallography: Principles and Practice</span>, McGraw Hill, NY, 2nd Ed., 1999.</p> </p> <p id="s00003">1.2 <span class="italic">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.</span>