1.1 本试验方法的目的是检测选定的贫双相不锈钢中是否存在有害的含铬相，从而显著影响韧性或耐腐蚀性。这些阶段可以在精益双重产品的制造和制造过程中形成。本试验方法不一定检测可归因于其他原因的韧性或耐腐蚀性损失，也不会确定导致任何韧性或耐腐蚀性损失的有害相的确切类型。测试结果是一个简单的通过/失败语句。 1.2 贫双相（奥氏体-铁素体）不锈钢通常是由30 % 至70 % Cr>17的典型合金成分的铁素体含量 % 和Mo<1 % 并添加镍、锰、氮和控制低碳含量以及其他合金元素。本标准试验方法仅适用于下列合金: 表1 . 试验方法中描述了一些高合金双相不锈钢的类似试验方法 A923 ，但本标准中描述的所有三种方法的程序与测试方法中描述的程序有显著差异 A923 . 1.3 贫双相不锈钢容易形成有害的含铬化合物，如氮化物、碳化物和其他不需要的相。通常，在大约300℃的温度范围内暴露时会发生这种情况 °C至955 °C（570 °F至1750 ºF），最大敏感度在650左右的温度范围内 °C至750 °C（1200 °F至1385 华氏度）。这些沉淀反应的速度是成分和每个单件的热或热机械历史的函数。大量这些相的存在可能对韧性和耐腐蚀性有害。 1.4 由于钼含量低，贫双相不锈钢对sigma或其他类型的含钼金属间相的敏感性较小。热处理可能导致形成少量含钼金属间化合物，在观察到sigma和类似相的任何迹象之前，会导致大量有害氮化物或碳化物沉淀。 1.5 对贫双相不锈钢进行正确的热处理可以消除或减少这些有害相的数量，改变其特性，并将铬降至最低- 紧靠这些相附近的基质相中的损耗。在适当的退火温度下充分快速冷却产品，可最大限度地防止后续热暴露形成有害相。有关所述合金和产品的适当退火温度建议的详细信息，请用户参阅相关适用的ASTM产品规范。 1.6 符合适用产品规范的化学和机械要求并不一定表明产品中不存在有害相。 1.7 这些试验方法包括: 1.7.1 试验方法A- 检测贫双相不锈钢中潜在有害相存在的蚀刻方法 1.7.2 试验方法B- 夏比V型缺口冲击试验，用于确定贫双相不锈钢中有害相的存在。 1.7.3 试验方法C- 测定贫双相不锈钢中有害相存在的抑制氯化铁腐蚀试验。 1.7.4 热暴露、有害相的出现以及韧性和耐腐蚀性退化的相关性示例如所示 附录X2 , 附录X3 ，以及参考文献。 1.8 小组委员会A01.14考虑在本标准试验方法中列出贫双相不锈钢所需数据的指南见 附件A1 . 1.9 以国际单位制表示的数值应视为标准值。括号中给出的值是到其他单位的数学转换，这些单位仅供参考，不被视为标准。 1.10 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、健康和环境实践，并确定监管限制的适用性。 1.11 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 试验方法A仅用于补充试验方法B和C的结果。它不得用作拒收标准，也不得用作验收标准。试验方法B和C旨在为本标准提供验收标准。 4.2 试验方法A可以揭示金相结构中的潜在有害相。由于沉淀的有害相可能非常小，因此该试验要求金相学家熟练掌握，尤其是较薄的材料。 4.3 如果选择了适当位置和方向的样品，则通过试验方法B和C很容易检测到有害相的存在。 4.4 这些测试并不能确定有害相的精确性质，而是确定是否存在有害相，从而显著影响材料的正常预期韧性和耐腐蚀性。 4.5 本标准涵盖了从钢卷、钢卷和板材轧机、板材、管材、管道、棒材和变形棒材中提取的样品的测试，尽管其中一些产品可能不适合根据方法B进行测试（更多详细信息，请参阅测试方法B）。到目前为止，其他产品形式尚未进行充分测试并记录为本标准的组成部分，尽管本标准并不禁止根据三种测试方法对这些产品形式进行测试。对于这些其他产品形式，本标准仅就结果和相关验收标准的解释提供了有限且非详尽的指导。 4.6 买方和供应商应就本标准当前范围外的产品形式测试达成一致。

1.1 The purpose of this test method is to allow detection of the presence of detrimental chromium-containing phases in selected lean duplex stainless steels to the extent that toughness or corrosion resistance is affected significantly. Such phases can form during manufacture and fabrication of lean duplex products. This test method does not necessarily detect losses of toughness nor corrosion resistance attributable to other causes, nor will it identify the exact type of detrimental phases that caused any loss of toughness or corrosion resistance. The test result is a simple pass/fail statement. 1.2 Lean duplex (austenitic-ferritic) stainless steels are typically duplex stainless steels composed of 30 % to 70 % ferrite content with a typical alloy composition having Cr > 17 % and Mo < 1 % and with additions of Nickel, Manganese, Nitrogen and controlled low carbon content as well as other alloying elements. This standard test method applies only to those alloys listed in Table 1 . Similar test methods for some higher alloyed duplex stainless steels are described in Test Methods A923 , but the procedures described in this standard differ significantly for all three methods from the ones described in Test Methods A923 . 1.3 Lean duplex stainless steels are susceptible to the formation of detrimental chromium-containing compounds such as nitrides and carbides and other undesirable phases. Typically this occurs during exposures in the temperature range from approximately 300 °C to 955 °C (570 °F to 1750 ºF) with a maximum susceptibility in the temperature range around 650 °C to 750 °C (1200 °F to 1385 ºF). The speed of these precipitation reactions is a function of composition and the thermal or thermo-mechanical history of each individual piece. The presence of an amount of these phases can be detrimental to toughness and corrosion resistance. 1.4 Because of the low molybdenum content, lean duplex stainless steels only exhibit a minor susceptibility to sigma or other types of molybdenum containing intermetallic phases. Heat treatment, that could lead to formation of small amounts of molybdenum containing intermetallics, would result in a large amount of precipitation of detrimental nitrides or carbides, long before any signs of sigma and similar phases would be observed. 1.5 Correct heat treatment of lean duplex stainless steels can eliminate or reduce the amount and alter the characteristics of these detrimental phases as well as minimizing Cr-depletion in the matrix phase in the immediate vicinity of these phases. Adequately rapid cooling of the product from a suitable annealing temperature provides the maximum resistance to formation of detrimental phases by subsequent thermal exposures. For details of the proper annealing temperature recommendations for the alloy and product in question, the user is referred to the relevant applicable ASTM product specification. 1.6 Compliance with the chemical and mechanical requirements for the applicable product specification does not necessarily indicate the absence of detrimental phases in the product. 1.7 These test methods include the following: 1.7.1 Test Method A— Etch Method for detecting the presence of potentially detrimental phases in Lean Duplex Stainless Steels 1.7.2 Test Method B— Charpy V-notch Impact Test for determining the presence of detrimental phases in Lean Duplex Stainless Steels. 1.7.3 Test Method C— Inhibited Ferric Chloride Corrosion Test for determining the presence of detrimental phases in Lean Duplex Stainless Steels. 1.7.4 Examples of the correlation of thermal exposures, the occurrence of detrimental phases, and the degradation of toughness and corrosion resistance are given in Appendix X2 , Appendix X3 , and the References. 1.8 Guidelines for the required data needed for subcommittee A01.14 to consider listing a lean duplex stainless steel in this standard test method are given in Annex A1 . 1.9 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to other units that are provided for information only and are not considered standard. 1.10 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.11 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 Test Method A shall only be used to supplement the results of Test Methods B and C. It shall not be used as a rejection criterion, nor shall it be used as an acceptance criterion. Test Methods B and C are intended to be the procedures giving the acceptance criteria for this standard. 4.2 Test Method A can reveal potentially detrimental phases in the metallographic structure. As the precipitated detrimental phases can be very small, this test demands high proficiency from the metallographer, especially for thinner material. 4.3 The presence of detrimental phases is readily detected by Test Methods B and C provided that a sample of appropriate location and orientation is selected. 4.4 The tests do not determine the precise nature of the detrimental phase but rather the presence or absence to the extent that the normally expected toughness and corrosion resistance of the material are significantly affected. 4.5 This standard covers testing of samples taken from coil, coil- and plate mill plate, sheet, tubing, piping, bar and deformed bar, though some of these products might not be suitable for testing according to Method B (see Test Method B for further details). Other product forms have thus far not been sufficiently tested and documented to be an integral part of this standard, though the standard does not prohibit testing of these product forms according to the three test methods. For these other product forms, this standard gives only limited and non-exhaustive guidance as to interpretation of result and associated acceptance criteria. 4.6 Testing on product forms outside the present scope of this standard shall be agreed between purchaser and supplier.