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定价： 689元 / 折扣价： 586 元

5.1 Erosion Environments—This test method may be used for evaluating the erosion resistance of materials for service environments where solid surfaces are subjected to repeated impacts by liquid drops or jets. Occasionally, liquid impact tests have also been used to evaluate materials exposed to a cavitating liquid environment. The test method is not intended nor applicable for evaluating or predicting the resistance of materials against erosion due to solid particle impingement, due to “impingement corrosion” in bubbly flows, due to liquids or slurries “washing” over a surface, or due to continuous high-velocity liquid jets aimed at a surface. For background on various forms of erosion and erosion tests, see Refs (1) through (2).4 Ref (3) is an excellent comprehensive treatise.5.2 Discussion of Erosion Resistance—Liquid impingement erosion and cavitation erosion are, broadly speaking, similar processes and the relative resistance of materials to them is similar. In both, the damage is associated with repeated, small-scale, high-intensity pressure pulses acting on the solid surface. The precise failure mechanisms in the solid have been shown to differ depending on the material, and on the detailed nature, scale, and intensity of the fluid-solid interactions (Note 1). Thus, “erosion resistance” should not be regarded as one precisely-definable property of a material, but rather as a complex of properties whose relative importance may differ depending on the variables just mentioned. (It has not yet been possible to successfully correlate erosion resistance with any independently measurable material property.) For these reasons, the consistency between relative erosion resistance as measured in different facilities or under different conditions is not very good. Differences between two materials of say 20 % or less are probably not significant: another test might well show them ranked in reverse order. For bulk materials such as metals and structural plastics, the range of erosion resistances is much greater than that of typical strength properties: On a normalized scale on which Type 316 stainless steel is given a value of unity, the most resistant materials (some Stellites and tool steels) may have values greater than 10, and the least resistant (soft aluminum, some plastics) values less than 0.1 (see Refs (2) and (4)).NOTE 1: On failure mechanisms in particular, see in Ref (3) under “The Mechanics of Liquid Impact” by W. F. Adler, “Erosion of Solid Surfaces by the Impact of Liquid Drops” by J. H. Brunton and M. C. Rochester, and “Cavitation Erosion” by C. M. Preece.5.3 Significance of the Variation of Erosion Rate with Time: 5.3.1 The rate of erosion due to liquid impact or cavitation is not constant with time, but exhibits one of several “erosion rate-time patterns” discussed more fully in 10.3.3. The most common pattern consists of an “incubation period” during which material loss is slight or absent, followed by an acceleration of erosion rate to a maximum value, in turn followed by a declining erosion rate which may or may not tend to a “terminal” steady-state rate. The significance of the various stages in this history can differ according to the intended service applications of the materials being tested. In almost no case, however, are significant results obtained by simply testing all materials for the same length of time and comparing their cumulative mass loss.5.3.2 The “incubation period” may be the most significant test result for window materials, coatings, and other applications for which the useful service life is terminated by initial surface damage even though mass loss is slight.5.3.3 For bulk materials, this test method provides for determination of the “nominal incubation period” as well as the “maximum erosion rate,” and material ratings based on each. Empirical relationships are given in Annex A2 by which the nominal incubation period and the maximum erosion rate can then be estimated for any liquid impingement conditions in which the principal impingement variables are known. It must be emphasized, however, that because of the previously described variation of erosion rate with exposure time, the above-mentioned parameters do not suffice to predict erosion for long exposure durations. Extrapolation based on the maximum erosion rate could overestimate the absolute magnitude of long-term cumulative erosion by a factor exceeding an order of magnitude. In addition, it could incorrectly predict the relative difference between long-term results for different materials.5.3.4 Because of these considerations, some experimenters concerned with long-life components may wish to base material ratings not on the maximum erosion rate, but on the lower “terminal erosion rate” if such is exhibited in the tests. This can be done while still following this test method in many respects, but it should be recognized that the terminal erosion rate is probably more strongly affected by secondary variables such as test specimen shape, “repetitive” versus “distributed” impact conditions, drop size distributions, and so forth, than is the maximum erosion rate. Thus, between-laboratories variability may be even poorer for results based on terminal erosion rate, and the test time required will be much greater.5.4 This test method is applicable for impact velocities ranging roughly from 60 m/s to 600 m/s; it should not be assumed that results obtained in that range are valid at much higher or lower velocities. At very low impact velocities, corrosion effects become increasingly important. At very high velocities the material removal processes can change markedly, and specimen temperature may also become a significant factor; testing should then be done at the velocities corresponding to the service environment.5.5 Related Test Methods—Since the resistances of materials to liquid impingement erosion and to cavitation erosion have been considered related properties, cavitation erosion Test Methods G32 and G134 may be considered as alternative tests to this test method for some applications. For metals, the relative results from Test Method G32 or G134 should be similar but not necessarily identical to those from a liquid impact test (see 5.2). Either Test Method G32 or G134 may be less expensive than an impingement test, and provides for standardized specimens and test conditions, but may not match the characteristics of the impingement environment to be simulated. The advantages of a liquid impingement test are that droplet or jet sizes and impact velocities can be selected and it can simulate more closely a specific liquid impingement environment. A well-designed liquid impingement test is to be preferred for elastomers, coatings, and brittle materials, for which size effects may be quite important.1.1 This test method covers tests in which solid specimens are eroded or otherwise damaged by repeated discrete impacts of liquid drops or jets. Among the collateral forms of damage considered are degradation of optical properties of window materials, and penetration, separation, or destruction of coatings. The objective of the tests may be to determine the resistance to erosion or other damage of the materials or coatings under test, or to investigate the damage mechanisms and the effect of test variables. Because of the specialized nature of these tests and the desire in many cases to simulate to some degree the expected service environment, the specification of a standard apparatus is not deemed practicable. This test method gives guidance in setting up a test, and specifies test and analysis procedures and reporting requirements that can be followed even with quite widely differing materials, test facilities, and test conditions. It also provides a standardized scale of erosion resistance numbers applicable to metals and other structural materials. It serves, to some degree, as a tutorial on liquid impingement erosion.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.

定价： 646元 / 折扣价： 550 元 加购物车

This test method covers determination of the fineness of hydraulic cement, using the Blaine air-permeability apparatus, in terms of the specific surface expressed as total surface area in square centimetres per gram, or square metres per kilogram, of cement. Two test methods are given: test method A is the reference test method using the manually operated standard Blaine apparatus, while test method B permits the use of automated apparatus that has in accordance with the qualification requirements of this test method demonstrated acceptable performance. The Blaine air-permeability apparatus consists essentially of a means of drawing a definite quantity of air through a prepared bed of cement of definite porosity. The permeability cell shall consist of a rigid cylinder, constructed of austenitic stainless steel. The disk shall be constructed of noncorroding metal, and shall fit the inside of the cell snugly. The plunger shall be constructed of austenitic stainless steel and shall fit into the cell. The filter paper disks shall be circular, with smooth edges, and shall have the same diameter as the inside of the cell. The U-tube manometer shall be constructed according to the design indicated. The manometer shall be filled to the midpoint line with a nonvolatile, nonhygroscopic liquid of low viscosity and density. The timer shall have a positive starting and stopping mechanism. The calibration of the air permeability apparatus shall be made using the standard reference material. The automated test method shall employ apparatus designed either on the principles of the Blaine air-permeability method or apparatus based on the air-permeability principles of the Lea and Nurse method. When the specific surface values determined by an automated apparatus are to be used for acceptance or rejection of cement, the method used shall comply with the qualification requirements. When standardization is required in order to achieve agreement between test method A and test method B, the apparatus shall be standardized according to the requirements prescribed.1.1 This test method covers determination of the fineness of hydraulic cement, using the Blaine air-permeability apparatus, in terms of the specific surface expressed as total surface area in square centimetres per gram, or square metres per kilogram, of cement. Two test methods are given: Test Method A is the Reference Test Method using the manually operated standard Blaine apparatus, while Test Method B permits the use of automated apparatus that has in accordance with the qualification requirements of this test method demonstrated acceptable performance. Although the test method may be, and has been, used for the determination of the measures of fineness of various other materials, it should be understood that, in general, relative rather than absolute fineness values are obtained.1.1.1 This test method is known to work well for portland cements. However, the user should exercise judgement in determining its suitability with regard to fineness measurements of cements with densities, or porosities that differ from those assigned to Standard Reference Material No. 114 or No. 46h.1.2 The values stated in SI units are to be regarded as the standard.1.3 Warning—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet (SDS) for additional information. Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.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.

定价： 590元 / 折扣价： 502 元 加购物车

1.1 This practice covers a means for calibration of the heat flow meter apparatus in conjunction with Test Method C518. The apparatus shall be calibrated as a unit, with the heat flux transducer(s) installed in the apparatus using either standard reference materials (SRM), calibrated transfer specimens (CTS), or other appropriate reference standards. 1.2 This practice applies to the calibration of a heat flow meter apparatus over a wide range of heat flow rates and temperatures that permits the testing of a wide variety of insulation materials over an extended temperature range. It is applicable to materials with the same requirements and temperature ranges allowed in Test Method C518. 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.

定价： 0元 / 折扣价： 0 元

5.1 Heat flow meter apparatus are being used to measure the center-of-panel portion of a vacuum insulation panel, which typically has a very high value of thermal resistivity (that is, equal to or greater than 90 m-K/W). As described in Specification C1484, the center-of-panel thermal resistivity is used, along with the panel geometry and barrier material thermal conductivity, to determine the effective thermal resistance of the evacuated panel.5.2 Using a heat flow meter apparatus to measure the thermal resistivity of non-homogenous and high thermal resistance specimens is a non-standard application of the equipment, and shall only be performed by qualified personnel with understanding of heat transfer and error propagation. Familiarity with the configuration of both the apparatus and the vacuum insulation panel is necessary.5.3 The center-of-panel thermal transmission properties of evacuated panels vary due to the composition of the materials of construction, mean temperature and temperature difference, and the prior history. The selection of representative values for the thermal transmission properties of an evacuated panel for a particular application must be based on a consideration of these factors and will not apply necessarily without modification to all service conditions.1.1 This test method covers the measurement of steady-state thermal transmission through the center of a flat rectangular vacuum insulation panel using a heat flow meter apparatus.1.2 Total heat transfer through the non-homogenous geometry of a vacuum insulation panel requires the determination of several factors, as discussed in Specification C1484. One of those factors is the center-of-panel thermal resistivity. The center-of-panel thermal resistivity is an approximation of the thermal resistivity of the core evacuated region.1.3 This test method is based upon the technology of Test Method C518 but includes modifications for vacuum insulation panel applications as outlined in this test method.21.4 This test method shall be used in conjunction with Practice C1045 and Practice C1058.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.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, health, and environmental 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.

定价： 590元 / 折扣价： 502 元 加购物车