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4.1 This test method can be used to determine the appearance of propagating fractures in plain carbon or low-alloy pipe steels (yield strengths less than 825 MPa) over the temperature range where the fracture mode changes from brittle (cleavage or flat) to ductile (shear or oblique).4.2 This test method can serve the following purposes:4.2.1 For research and development, to study the effect of metallurgical variables such as composition or heat treatment, or of fabricating operations such as welding or forming on the mode of fracture propagation.4.2.2 For evaluation of materials for service to indicate the suitability of a material for specific applications by indicating fracture propagation behavior at the service temperature(s).4.2.3 For information or specification purposes, to provide a manufacturing quality control only when suitable correlations have been established with service behavior.1.1 This test method covers drop-weight tear tests (DWTT) on ferritic steels with thicknesses between 3.18 mm and 19.1 mm.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 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.

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4.1 This classification establishes categories of insulating coatings based on their chemical nature, relative insulating ability, and typical applications. These categories describe general physical and chemical characteristics of the coatings that are useful in making broad estimates of their insulating ability and suitability for various applications.1.1 This document classifies insulating coatings for electrical steels according to their composition, relative insulating ability, and functionality. The purpose of this classification is to assist users of insulating coatings by providing general information about the chemical nature and use of the coatings, as well as to provide important data concerning limits to their use, that is, relative insulating ability, punchability, temperature stability, weldability, and fabricability. Specific surface insulation resistivity values for each coating are not included in this classification. The user is referred to the flat-rolled electrical steel specifications noted in 1.2 should more detailed information concerning surface insulation resistivity values be required.1.2 This classification is to be used in conjunction with the various specifications for flat-rolled electrical steels under the jurisdiction of Committee A06, including Specifications A345, A677, A683, A726, A840, A876, and A1086. However, in those instances in which the coating descriptions and characteristics differ between this classification and any of the specifications, this classification shall supersede the specification.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to customary (cgs-emu and inch-pound) units which are provided for information only and are not considered standard.1.4 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.1.5 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.

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ASTM A681-24 Standard Specification for Tool Steels Alloy Active 发布日期 :  1970-01-01 实施日期 : 

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5.1 In the past, ASTM specifications for low-alloy weathering steels, such as Specifications A242/A242M, A588/A588M, A606/A606M Type 4, A709/A709M Grade 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M stated that the atmospheric corrosion resistance of these steels is “approximately two times that of carbon structural steel with copper.” A footnote in the specifications stated that “two times carbon structural steel with copper is equivalent to four times carbon structural steel without copper (Cu 0.02 maximum).” Because such statements relating the corrosion resistance of weathering steels to that of other steels are imprecise and, more importantly, lack significance to the user (1 and 2),4 the present guide was prepared to describe more meaningful methods of estimating the atmospheric corrosion resistance of weathering steels.5.2 The first method of this guide is intended for use in estimating the expected long-term atmospheric corrosion losses of specific grades of low-alloy steels in various environments, utilizing existing short-term atmospheric corrosion data for these grades of steel.5.3 The second method of this guide is intended for use in estimating the relative atmospheric corrosion resistance of a specific heat of low-alloy steel, based on its chemical composition.5.4 It is important to recognize that the methods presented here are based on calculations made from test data for flat, boldly exposed steel specimens. Atmospheric corrosion rates can be much higher when the weathering steel remains wet for prolonged periods of time, or is heavily contaminated with salt or other corrosive chemicals. Therefore, caution must be exercised in the application of these methods for prediction of long-term performance of actual structures.1.1 This guide presents two methods for estimating the atmospheric corrosion resistance of low-alloy weathering steels, such as those described in Specifications A242/A242M, A588/A588M, A606/A606M Type 4, A709/A709M grades 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M. One method gives an estimate of the long-term thickness loss of a steel at a specific site based on results of short-term tests. The other gives an estimate of relative corrosion resistance based on chemical composition.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 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.

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This specification covers the passivation by electropolishing of stainless steel alloys in the 200, 300, and 400 series, as well as precipitation-hardened alloys. Basis materials shall be free of clearly visible defects, and if necessary, shall undergo preparatory cleaning procedures prior to electropolishing. Post-coating procedures such as post dip and final rinsing shall be performed as well. The performance of the specimens during passivation shall be evaluated by one or more of the following procedures: water immersion test; humidity test; salt spray test; copper sulfate test; and modified ferroxyl test for free iron.1.1 This specification covers the passivation of stainless steel alloys in the 200 (UNS2XXXX), 300 (UNS3XXXX), and 400 (UNS4XXXX) series, and the precipitation-hardened alloys, using electropolishing procedures.NOTE 1: Surface passivation occurs simultaneously with electropolishing under proper operating conditions. The quality of passivation will depend on the type of stainless steel, the formulation of the electropolishing solution, and the conditions of operation. Free iron on the surface of the stainless steel is removed resulting in improved corrosion resistance. Surface smoothing obtained by electropolishing will also improve corrosion resistance. Electropolishing will also remove heat tint and oxide scale.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This specification may involve hazardous materials, operations, and equipment. This specification 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.1.4 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.

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5.1 This test method describes an EPR test method for quantitatively determining the relative degree of sensitization in AISI Type 304 and 304L stainless steels. The EPR test has found wide use as a means to provide a numerical level of sensitization in studies of the effects of sensitization on intergranular corrosion and intergranular stress corrosion cracking behavior. The results of this test method correlate with other test methods (for example, Practices A262 and Test Methods G28) that are commonly used to assess sensitization in stainless steels.5.2 The EPR test can also be used for product acceptance, service evaluation, regulatory statutes, and manufacturing controls providing that both the supplier and user have agreed upon appropriate acceptance criteria and a sensitizing treatment. The test is not intended for design purposes since the test conditions accelerate corrosion in a manner that does not simulate any actual service environment.5.3 The EPR test involves the measurement of the amount of charge resulting from the corrosion of the chromium-depleted regions surrounding the precipitated chromium carbide particles. Most of these particles in a sensitized microstructure are located at the grain boundaries. However, discrete particles located within grains (referred to as intragranular precipitates) will also contribute to the total measured charge. (See Fig. 2.) Therefore, it is important to examine the alloy microstructure following an EPR test to determine the relative proportion of corrosion sites associated with intergranular versus intragranular precipitates. Sites of intergranular attack will appear similar to grain boundary ditching as defined in Practice A of Practices A262.FIG. 2 Schematic Microstructures After EPR Testing for Method A—Single LoopNOTE 1: The calculation of Pa is based on the assumptions illustrated at left. Mild cases of sensitization usually result in a combination of intergranular attack and pitting as illustrated at right (6).1.1 These test methods cover a laboratory procedure for conducting an electrochemical reactivation (EPR) test on AISI Type 304 and 304L (UNS No. S30400 and S30403, respectively) stainless steels. These test methods can provide a nondestructive means of quantifying the degree of sensitization in Type 304 stainless steels (1, 2, 3).2 These EPR test methods have found wide acceptance in studies of the effects of sensitization on intergranular corrosion and intergranular stress corrosion cracking behavior (see Terminology G193). The EPR technique has been successfully used to evaluate other stainless steels and nickel base alloys (4), but the test conditions and evaluation criteria used were modified in each case from those cited in the current test methods. This standard test covers two tests, (1) Test Method A or Single Loop, and (2) Test Method B or Double Loop.1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 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.

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4.1 The critical level of hydrogen in steels is that hydrogen which can build up to high concentrations at points of high triaxial stress causing embrittlement of the steel which can lead to catastrophic damage. This hydrogen can enter by various means, such as during pickling and electroplating. Means of reducing this hydrogen during processing are given in Specification B766 and Practices B183 and B242. It is still necessary, however, to know how effective these methods are. Though the ultimate reason for measuring this hydrogen is to relate it to embrittlement, this is not within the scope of this test method. As susceptibility to hydrogen embrittlement is a function of alloy type, heat treatment, intended use,and so forth, the tolerance for hydrogen must be determined by the user according to Method F519.4.2 Though the actual hydrogen concentration is not determined in this test method, the current densities have been shown to be useful as an indication of relative hydrogen concentrations (1-3),3 and therefore the degree of hydrogen embrittlement (1,2). Thus, measurements can be compared to one another (see 4.1 and 7.1).4.3 This test method is applicable as a quality control tool for processing (such as to monitor plating and baking) or to measure hydrogen uptake caused by corrosion.4.4 This test method is nondestructive; however, if there is a coating, it must be removed by a method which has been demonstrated to neither damage the steel nor introduce hydrogen to make the measurement.4.5 This test method is also applicable to situations producing continuous hydrogen permeation, such as high pressure hydrogen cylinders or corrosion processes. The results, however, would require a different treatment and interpretation (4).4.6 This test method is also applicable to small parts, such as fasteners. The technique, procedure, and interpretation would, however, have to be altered.4.7 Use of this test method on austenitic stainless steels and other face centered cubic (FCC) alloys would require different measurement times and interpretation of results because of differing kinetics.4.8 This test method can be used on slightly curved surfaces as long as the gasket defines a reproducible area. The area calculation must, however, be changed.1.1 This test method covers the procedure for measuring diffusible hydrogen in steels by an electrochemical method.1.2 This test method is limited to carbon or alloy steels, excluding austenitic stainless steels.1.3 This test method is limited to flat specimens to which the cell can be attached (see 4.6 and 4.8).1.4 This test method describes testing on bare or plated steel after the plate has been removed (see 4.4).1.5 This test method is limited to measurements at room temperature, 20 to 25°C (68 to 77°F).1.6 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.1.7 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.

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