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定价： 590元 加购物车

4.1 The use of this practice presupposes that the failure criteria selected to evaluate materials (that is, the property or properties being measured as a function of exposure time) and the duration of the exposure can be shown to relate to the intended use of the materials.4.2 Plastic materials exposed to heat are subject to many types of physical and chemical changes. The severity of the exposures in both time and temperature determines the extent and type of change that takes place. A plastic material is not necessarily degraded by exposure to elevated temperatures. However, extended periods of exposure of plastics to elevated temperatures will generally cause some degradation, with progressive changes in physical properties. Specific properties and failure (or lifetime) criteria for these properties are typically chosen for the evaluation of thermal endurance.4.3 Generally, short exposures at elevated temperatures drive out volatiles such as moisture, solvents, or plasticizers, relieve molding stresses, advance the cure of thermosets, and may cause some change in color of the plastic or coloring agent, or both. Normally, additional shrinkage should be expected with loss of volatiles or advance in polymerization.4.4 Some plastic materials become brittle due to loss of plasticizers after exposure at elevated temperatures. Other types of plastics become soft and sticky, either due to sorption of volatilized plasticizer or due to breakdown of the polymer.4.5 The degree of change observed will depend on the property measured. Different properties, mechanical or electrical, may not change at the same rate. For instance, the arc resistance of thermosetting compounds improves up to the carbonization point of the material. Mechanical properties, such as flexural properties, are sensitive to heat degradation and may change at a more rapid rate. Ultimate properties such as strength or elongation are more sensitive to degradation than bulk properties such as modulus, in most cases.4.6 The material studied can change inherent behavior with change in temperature as for example when crossing α, β, and γ transitions. These transitions should be avoided both in the range of aging temperatures used, as well as in extrapolation of the lifeline. Arrhenius principles may only be used to accelerate a chemical mechanism if there are no fundamental changes in the material properties. With semi-crystalline and highly crystalline polymers, elevated temperatures may cause significant changes to the morphology of the material, invalidating or compromising that assumption.NOTE 2: Caution should be exercised in using the Arrhenius relation and knowledge of physical changes in the material at elevated temperatures is important. Guidance given in ISO 9080 for characterizing lifetime of plastic materials in pipe form by extrapolation suggests that the highest oven aging temperature should be at least 15°C lower than the Vicat softening temperature for glassy amorphous polymers, and at least 15°C lower than the melting point for semi-crystalline polymers.4.7 Effects of exposure can be quite variable, especially when specimens are exposed for long intervals of time. Factors that affect the reproducibility of data are the degree of temperature control of the enclosure, humidity of the oven, air velocity over the specimen, and period of exposure. Errors in exposure are cumulative with time. Certain materials are susceptible to the influence of humidity.4.8 It is not to be inferred that comparative material ranking is undesirable or unworkable. On the contrary, this practice is designed to provide data which can be used for such comparative purposes. However, the data obtained from this practice, since it does not account for the influence of stress or environment that is involved in most real life applications, must be used cautiously by the designer, who must inevitably make material choices using additional data such as creep and creep rupture that are consistent with the requirements of the specific application.4.9 It is possible for many CUT and TI values to exist. Therefore, for any application of the CUT or the TI (temperature index) to be valid, either the thermal aging program must duplicate the intended thermal exposure conditions of the end product, or the Arrhenius relation must apply.4.10 There can be very large errors when Arrhenius plots or equations based on data from experiments at a series of temperatures are used to estimate time to produce a defined property change at some lower temperature. This estimate of time to produce the property change or “failure” at the lower temperature is often called the “service life;” however, using this term should be avoided as this implies the tester has information on specific failure criteria in end-use, while numerous factors are not under the scope of this test. It is preferable to use terms such as “end point,” “thermal endurance time,” and such. Because of the errors associated with these calculations, this endurance time should be considered as “maximum expected” rather than “typical.”1.1 This practice is intended to define the exposure conditions for evaluating the thermal endurance of plastics when exposed solely to hot air for extended periods of time. Only the procedure for heat exposure is specified. The effect of elevated temperature on any particular property is determined by selection of the appropriate test method and test specimens for that property.1.2 This practice can be used as a guide to compare thermal aging characteristics of materials as measured by the change in some property of interest. The property of interest is measured at room temperature.1.3 This practice recommends procedures for comparing the thermal aging characteristics of materials at a single temperature. Recommended procedures for determining the thermal aging characteristics of a material using a series of elevated temperatures for the purpose of estimating endurance time to a defined property change at a lower temperature are also described; the applicability of the Arrhenius relation for making predictions to other temperatures, is assumed in this case.1.4 This practice does not predict thermal aging characteristics where interactions between stress, environment, temperature, and time control failure occur.1.5 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.NOTE 1: This standard and ISO-2578 address the same subject matter but differ in technical content.1.6 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 加购物车

5.1 The thickness of a geotextile decreases with increase in the normal compressive stress. This decrease in thickness may result in the partial closing or the opening of the voids of geotextile depending on its initial structure and the boundary conditions.5.2 This test method measures the permittivity due to a change of void structure of a geotextile as a result of an applied compressive stress.1.1 This test method covers the determination of the water permittivity behavior of geotextiles in a direction normal to the plane of the geotextile when subjected to specific normal compressive loads.1.2 Use of this test method is limited to geotextiles. This test method is not intended for application with geotextile-related products such as geogrids, geonets, geomembranes, and other geocomposites.1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.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 加购物车

定价： 646元 加购物车

This specification covers externally threaded bolts, studs, and cap screws called fasteners, capable of indicating clamping forces up to yield strength during the tightening process or post installation residual tension, or both. Load-indicating fasteners utilize mechanical, electronic, or ultrasonic means to indicate fastener tension. These fasteners provide a means to verify the desired clamp load in critical applications upon installation and in service. This specification covers the following four different types of load-indicating fasteners: mechanical dial type (MT); electronic type (ET); strain gauge type (ST); and ultrasonic type (UT). Tension test shall be performed to conform to the chemical and mechanical requirements specified.1.1 This specification covers externally threaded bolts, studs, and cap screws, herein called fasteners, capable of indicating clamping forces up to yield strength during the tightening process or post installation residual tension, or both. Load-indicating fasteners utilize a variety of sensor types to indicate fastener tension. This specification outlines the various types of load indication technologies available and defines their performance requirements.1.2 This specification covers fastener diameters 1/4 to 7 in. [M6 to M180] inclusive. Fasteners are manufactured from a variety of material types and grades. All fastener materials shall be defined by a governing engineering standard or specification for strength and performance values (see 6.1). Fasteners governed by this specification shall maintain traceability of material test records throughout the manufacturing process to verify conformance with the applicable fastener standards.1.3 These fasteners provide a means to verify the desired clamp load in critical applications upon installation and in service.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.1.5 The following precautionary statement pertains only to the test method portion, Section 11, of the specification: 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.1.6 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 加购物车

5.1 The grab method is applicable whenever it is desired to determine the “effective strength” of the fabric in use, that is, the strength of the material in a specific width, together with the additional strength contributed by adjacent material. There is no simple relationship between grab tests and strip tests since the amount of fabric assistance depends on the construction of the fabric. It is useful as a quality control or acceptance test.5.2 The procedure in Test Method D4632/D4632M for the determination of grab strength of geotextiles may be used for acceptance testing of commercial shipments, but caution is advised since information about between-laboratory precision is incomplete. Comparative tests as directed in 5.2.1 are advisable.5.2.1 In case of a dispute arising from differences in reported test results when using the procedures in Test Method D4632/D4632M for acceptance testing of commercial shipments, the purchaser and the manufacturer should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and which are from a lot of material of the type in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using the appropriate Student's t-test and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the manufacturer must agree to interpret future test results in the light of the known bias.5.3 Most geotextile fabrics can be tested by this test method. Some modification of clamping techniques may be necessary for a given fabric, depending upon its structure. Special adaptation may be necessary with strong fabrics, or fabrics made from glass fibers, to prevent them from slipping in the clamps or being damaged as a result of being gripped in the clamps, such as cushioning the clamp or boarding the specimen within the clamp.5.4 This test method is applicable for testing fabrics either dry or wet. It may be used with constant-rate-of-traverse (CRT) or constant-rate-of-extension (CRE) type tension machines. However, there may be no overall correlation between the results obtained with the CRT machine and the CRE machine. Consequently, these two tension testers cannot be used interchangeably. In case of controversy, the CRE machine shall prevail.1.1 This test method is an index test which provides a procedure for determining the breaking load (grab strength) and elongation (grab elongation) of geotextiles using the grab method. This test method is not suitable for knitted fabrics and alternate test methods should be used. While useful for quality control and acceptance testing for a specific fabric structure, the results can only be used comparatively between fabrics with very similar structures because each different fabric structure performs in a unique and characteristic manner in this test. The grab test method does not provide all the information needed for all design applications and other test methods should be used.1.2 Procedures for measuring the breaking load and elongation by the grab method in both the dry and wet state are included; however, testing is normally done in the dry condition unless specified otherwise in an agreement or specification.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.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 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 646元 加购物车

定价： 590元 加购物车

定价： 515元 加购物车

5.1 The load versus thickness properties of a gasket material are an important factor with regard to the selection of a given material for use in a particular sealing application. Additionally, compression/load behavior data are a common request from users. The test allows comparison of materials at room temperature or elevated temperatures or both. Additionally, properties can be evaluated while loading and unloading the material at room temperature or elevated temperatures or both. The significance of the test method is based, in part, on the assumption that, if a material exhibits too much compression at either room temperatures or elevated temperatures, it will no longer function as effectively as a seal. The results may be used in certain flange design methods to characterize properties for design such as finite element analysis (FEA). The results may be used to confirm adequate assembly loading based on measured gasket compression in the field. Two or more materials can be compared to determine differences in their compression properties. A sample of material can be compared to an established standard or previously determined characteristics on original lots of the same material for quality assurance purposes.5.2 If desired, samples may be tested with a raised profile flange, insert, or calibration ring described in 6.3 and Fig. 1 so that the area (2042 mm2 [3.18 in.2]) remains constant during the test.FIG. 1 Test Assembly for Determining Load versus Compression1.1 This practice measures the compression properties of a gasket material by measuring gasket deflection while it is subjected to an increasing compressive load until a target load is reached. The load and change in thickness are recorded at a defined loading rate as a function of time for the duration of the test.1.2 Suggested loading rates are 0.5 MPa/s [72.52 psi/s] for all types of gaskets except for expanded polytetrafluoroethylene (PTFE), elastomer, and cork/elastomer gaskets when 0.1 MPa/s [14.5 psi/s] is used.1.3 The Part A test is performed that measures the compression properties of a gasket material by measuring gasket thickness while it is subjected to an increasing compressive load until a target load is reached. This test is performed at room temperature but may be performed at an elevated temperature if desired or when agreed upon by producer and user.1.4 The Part B test may be performed that measures the compression properties of a gasket material by measuring gasket thickness while it is subjected to increasing compressive loads that includes a sequence or sequences in which the gasket is unloaded followed by a resumption of the compressive load until a target load is reached. The unloading rate is the same as the loading rate unless different loading and unloading rates are desired or when agreed upon by producer and user. This test is performed at room temperature but may be performed at an elevated temperature if desired or when agreed upon by producer and user.1.5 The testing parameters for both Parts A and B including the gasket material type, gasket dimensions, platen type (RF or FF), target load, loading time, recording interval used during the test, loading and unloading rates, and temperature are to be reported with the results.1.6 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.7 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.1.8 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 is intended for quality assurance and production control purposes.1.1 This test method covers the determination of the static load capacity of hunting saddles and bridge in terms of a factor of safety relative to the manufacturer’s rated capacity.1.2 The values shared are in inch-pound units and are to be regarded as the 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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定价： 646元 加购物车

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