1.1 这些程序描述了宏观蚀刻金属和合金以揭示其宏观结构的方法。 1.2 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 有关特定警告声明，请参阅 6.2 , 7.1 , 8.1.3 , 8.2.1 , 8.8.3 , 8.10.1.1 和 8.13.2 . ====意义和用途====== 3.1 宏观蚀刻的应用: 3.1.1 宏观蚀刻用于揭示金属和合金的异质性。 金相试样和化学分析将提供有关特定位置的必要详细信息，但它们无法提供从一个地方到另一个地方的变化数据，除非采集过多的试样。 3.1.2 另一方面，宏观蚀刻将提供有关( 1. )结构，如晶粒尺寸、流线、柱状结构、枝晶等；( 2. )化学成分的变化，表现为偏析、碳化物和铁素体带状、取芯、夹杂物和渗碳或脱碳深度。提供的有关化学成分变化的信息是严格定性的，但将显示偏析中极端的位置。必须进行化学分析或其他确定化学成分的方法，以确定变化程度。 宏观蚀刻还将显示不连续性和空洞的存在，例如接缝、重叠、孔隙、薄片、爆裂、挤压破裂、裂纹等。 3.1.3 宏观蚀刻在金属制造中的其他应用包括研究焊缝结构、定义焊缝熔透、母材稀释填充金属、焊剂截留、气孔以及焊缝和热影响区中的裂纹等。它还用于热处理车间，以确定硬点或软点的位置、钳痕、淬火裂纹、浅淬硬钢的表面深度、模具渗碳的表面深度、渗碳中止动涂层的有效性等。在机器车间，它可用于确定工具和模具中的磨削裂纹。 3.1.4 宏观蚀刻广泛用于钢铁行业的质量控制，以确定 语气 关于夹杂物、偏析和结构的坯料热量。此外，锻造车间在建立最佳锻造实践、模具设计和金属流时，使用宏观蚀刻来显示流线。有关在钢锻造行业中使用宏观蚀刻的示例，请参阅方法 E381 . 锻造车间和铸造厂也使用宏观蚀刻来确定是否存在内部故障和表面缺陷。铜业使用宏观蚀刻来控制线材的表面孔隙度。在铝工业中，宏观蚀刻用于评估挤压件以及其他产品，如锻件、板材等。确定了取芯、裂纹和分流模焊缝等缺陷。

1.1 These procedures describe the methods of macroetching metals and alloys to reveal their macrostructure. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 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. For specific warning statements, see 6.2 , 7.1 , 8.1.3 , 8.2.1 , 8.8.3 , 8.10.1.1 , and 8.13.2 . ====== Significance And Use ====== 3.1 Applications of Macroetching: 3.1.1 Macroetching is used to reveal the heterogeneity of metals and alloys. Metallographic specimens and chemical analyses will provide the necessary detailed information about specific localities but they cannot give data about variation from one place to another unless an inordinate number of specimens are taken. 3.1.2 Macroetching, on the other hand, will provide information on variations in ( 1 ) structure, such as grain size, flow lines, columnar structure, dendrites, and so forth; ( 2 ) variations in chemical composition as evidenced by segregation, carbide and ferrite banding, coring, inclusions, and depth of carburization or decarburization. The information provided about variations in chemical composition is strictly qualitative but the location of extremes in segregation will be shown. Chemical analyses or other means of determining the chemical composition would have to be performed to determine the extent of variation. Macroetching will also show the presence of discontinuities and voids, such as seams, laps, porosity, flakes, bursts, extrusion rupture, cracks, and so forth. 3.1.3 Other applications of macroetching in the fabrication of metals are the study of weld structure, definition of weld penetration, dilution of filler metal by base metals, entrapment of flux, porosity, and cracks in weld and heat affected zones, and so forth. It is also used in the heat-treating shop to determine location of hard or soft spots, tong marks, quenching cracks, case depth in shallow-hardening steels, case depth in carburization of dies, effectiveness of stop-off coatings in carburization, and so forth. In the machine shop, it can be used for the determination of grinding cracks in tools and dies. 3.1.4 Macroetching is used extensively for quality control in the steel industry, to determine the tone of a heat in billets with respect to inclusions, segregation, and structure. Forge shops, in addition, use macroetching to reveal flow lines in setting up the best forging practice, die design, and metal flow. For an example of the use of macroetching in the steel forging industry see Method E381 . Forging shops and foundries also use macroetching to determine the presence of internal faults and surface defects. The copper industry uses macroetching for control of surface porosity in wire bar. In the aluminum industry, macroetching is used to evaluate extrusions as well as the other products such as forgings, sheets, and so forth. Defects such as coring, cracks, and porthole die welds are identified.