定价： 819元 / 折扣价： 697 元

定价： 975元 / 折扣价： 829 元

定价： 345元 / 折扣价： 294 元

定价： 260元 / 折扣价： 221 元 加购物车

This specification covers higher strength chromium-molybdenum-tungsten alloy steel forgings intended primarily for use in boilers and pressure vessels for elevated temperature service. Materials shall be manufactured by melting processes, except that the open hearth process shall not be used, and that the molten steel shall be vacuum degassed prior to or during teeming of the ingot. The alloy steels may then be given an intermediate heat treatment such as normalizing and tempering or a subcrititcal anneal prior to rough machining. Heat analysis shall be obtained from samples to ensure chemical composition requirements are met. The steel forgings shall also undergo tension and Charpy impact tests and shall conform to the following required mechanical properties: tensile strength, yield strength, elongation, reduction of area, lateral expansion, minimum average absorbed energy, and minimum single value. Nondestructive examination procedures, such as straight-beam and angle-beam ultrasonic examination, and magnetic particle examination, shall also be executed.1.1 This specification covers chromium-molybdenum-tungsten alloy steel forgings intended primarily for use in boilers and pressure vessels for elevated temperature service.1.1.1 Elevated temperatures are temperatures in the range where creep and stress rupture properties are important for the alloy steels in this specification.1.2 Supplementary requirements are provided both in this specification and in the General Requirements Specification A788/A788M for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the purchase order or contract.1.3 Unless the order specifies the applicable “M” specification designation, the forgings shall be supplied to the inch-pound units.1.4 The values stated in either inch-pound or SI (metric) units are to be regarded separately as standard. Within the text and tables, the SI units are shown in brackets. 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 nonconformance with the specification.

定价： 0元 / 折扣价： 0 元

5.1 Continuous fiber-reinforced ceramic composites are candidate materials for structural applications requiring high degrees of wear, erosion, corrosion resistance, and damage tolerance at high temperatures.5.2 The 1D and 2D CFCCs are highly anisotropic and their transthickness tensile and interlaminar shear strength are lower than their in-plane tensile and in-plane shear strength, respectively.5.3 Shear tests provide information on the strength and deformation of materials under shear stresses.5.4 This test method may be used for material development, material comparison, quality assurance, characterization, and design data generation.5.5 For quality control purposes, results derived from standardized shear test specimens may be considered indicative of the response of the material from which they were taken for given primary processing conditions and post-processing heat treatments.1.1 This test method addresses the uniaxial compression of a double-notched test specimen to determine interlaminar shear strength of continuous fiber-reinforced ceramic composites (CFCCs) at elevated temperatures. Failure of the test specimen occurs by interlaminar shear between two centrally located notches machined halfway through the thickness of the test specimen and spaced a fixed distance apart on opposing faces (see Fig. 1). Test specimen preparation methods and requirements, testing modes (force or displacement control), testing rates (force rate or displacement rate), data collection, and reporting procedures are addressed.FIG. 1 Schematic of Uniaxial Compression of Double-Notched Test Specimen for the Determination of Interlaminar Shear Strength of CFCCs1.2 This test method is used for testing advanced ceramic or glass matrix composites with continuous fiber reinforcement having a laminated structure such as in unidirectional (1D) or bidirectional (2D) fiber architecture (lay-ups of unidirectional plies or stacked fabric). This test method does not address composites with nonlaminated structures, such as (3D) fiber architecture or discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics.1.3 Values expressed in this test method are in accordance with the International System of Units (SI) and IEEE/ASTM SI 10.1.4 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. Specific precautionary statements are noted in 8.1 and 8.2.1.5 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

This specification covers hot-wrought, ferritic alloy steel bars for elevated temperature or pressure-containing parts suitable for fusion welding or both. The bars are furnished in two grades: Grade B 11 and Grade B 22. The steel shall be made by on or more of the following primary processes: open-hearth, basic-oxygen, or electric furnace. The bars shall be normalized and tempered. The heat analysis shall conform to the limits for chemical composition specified. The bars as represented by the test specimen shall conform to the tensile requirements specified.1.1 This specification2 covers hot-wrought, ferritic alloy steel bars for elevated temperature or pressure-containing parts suitable for fusion welding or both.1.2 The bars are furnished in the following grades:Grade B 11: 1.25 % chromium, 0.55 % molybdenumGrade B 22: 2.25 % chromium, 1.00 % molybdenum1.3 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.1.4 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： 515元 / 折扣价： 438 元 加购物车

5.1 This specification is intended to provide information on the properties of adhesives, and the test methods required to evaluate adhesives to be used in the production bonding of aluminum alloys to foam core materials for the manufacture of tactical shelters.AbstractThis specification covers two-part adhesives for bonding aluminum alloy facing to foam core, inserts, edge attachments, and other components of a Type II foam cored sandwich panels. The adhesive should be suitable for forming bonds that can withstand long-term exposure at specified temperatures, and different combinations of stress, temperature, and humidity expected to be encountered in service. The adhesive may be used for new production or depot maintenance. The adhesive shall be a two-part thermosetting epoxy paste containing no asbestos and, when tested, shall meet the following physical and mechanical property requirements: curing time, temperature, and pressure; mix ratio; storage life; adhesive life; room-, low-, and high-temperature shear; hot humidity exposure shear; and room-temperature salt spray exposure shear.1.1 This specification covers two-part adhesives for bonding foam core sandwich panels. The adhesive may be used for new production or depot maintenance. The adhesive should be suitable for forming bonds that can withstand long-term exposure to temperatures from −55 °C  to 93 °C  (−67 °F to 200 °F) and also withstand combinations of stress, temperature, and humidity expected to be encountered in service. The adhesives shall be used for bonding aluminum alloy facing to foam core, inserts, internal aluminum framing members, and other components of a foam cored sandwich panel.1.2 The values stated in SI units are to be regarded as the standard where only SI units are given or where SI units are given first followed by inch-pound units; where inch-pound units are given first followed by SI units, the inch-pound units are to be regarded as the 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： 515元 / 折扣价： 438 元 加购物车

5.1 The flexural properties evaluated by this test method are intended to provide any one or all of the following:5.1.1 Data on the comparative effects of fire-retardant chemical formulations and environmental conditions on the flexural properties of plywood.5.1.2 Data for use in developing modification factors for the allowable design properties of treated plywood when exposed to elevated temperatures and humidities.5.1.3 Data comparing variables, such as other plywood species and dimensions.5.2 Results obtained from tests conducted and analyzed in accordance with the procedures of this test method are suitable for use with other information to establish recommended roof sheathing spans for fire-retardant treated plywood.NOTE 1: Temperatures lower than the test temperature specified in this test method and the cumulative effects of the elevated temperatures and humidity exposures expected to be encountered in service should be taken into account when recommended roof sheathing spans are established.NOTE 2: Practice D6305 can be used to extend the laboratory strength data obtained by this test method to design value recommendations. The test data determined by this test method are used to develop adjustment factors for fire-retardant treatments to apply to untreated plywood design values. The test data are used in conjunction with climate models and other factors.1.1 This test method is designed to determine the effect of exposure to high temperatures and humidities on the flexure properties of fire-retardant treated softwood plywood. In this test method, plywood is exposed to a temperature of 77°C (170°F).1.2 The purpose of the test method is to compare the flexural properties of fire-retardant treated plywood relative to untreated plywood. The results of tests conducted in accordance with this test method provide a reference point for estimating strength temperature relationships. This test method is intended to provide an accelerated test at elevated temperatures and controlled humidities of plywood sheathing treated with the same chemical formulation(s) and processing conditions as plywood used commercially.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that 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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 This specification is intended to provide information on the properties of adhesives, and the test methods required to evaluate adhesives to be used in the production bonding of aluminum alloys to foam core materials for the manufacture of tactical shelters.AbstractThis specification covers two-part paste adhesives for bonding foam core sandwich panels. The adhesive may be used for new production or depot maintenance. The adhesive should be suitable for forming bonds that can withstand long-term exposure to temperatures, and also withstand combinations of stress, temperature, and humidity. The adhesives shall be used for bonding aluminum alloy facing to foam core, inserts, edge attachments, and other components of a foam cored sandwich panel. Materials shall be tested and shall conform to the material requirements, working characteristics; and to the specified values of curing time, temperature, and pressure; mix ratio, storage life, adhesive life, humidity exposure, and salt spray exposure.1.1 This specification covers two-part paste adhesives for bonding foam core sandwich panels. The adhesive may be used for new production or depot maintenance. The adhesive should be suitable for forming bonds that can withstand long term exposure to temperatures from −55 °C to 71 °C (−67 °F to 160 °F) and also withstand combinations of stress, temperature, and humidity expected to be encountered in service. The adhesives shall be used for bonding aluminum alloy facing to foam core, inserts, internal aluminum framing members, and other components of a foam cored sandwich panel.1.2 The values stated in SI units are to be regarded as the standard where only SI units are given or where SI units are given first followed by inch-pound units; where inch-pound units are given first followed by SI units, the inch-pound units are to be regarded as the 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： 515元 / 折扣价： 438 元 加购物车

This specification covers standard requirements for ductile iron castings for pressure-retaining parts for use at elevated temperatures. Castings are classified by grades based on mechanical property requirements. These iron castings shall meet the specified values of tensile strength, yield strength, elongation and hardness. Chemical analysis shall be performed wherein the casting shall conform to the required chemical composition for carbon, silicon, and phosphorous. The material shall meet the required tensile properties, hardness, and microstructure. The iron casting shall undergo pressure test after machining. The thickness of any repaired section in relation to the size of the plug used shall be indicated. The minimum radius of repaired sections of cylinders or cones in relation to the size of plug used shall not exceed the prescribed limit. Other defective areas may also be repaired by plugging provided the minimum ligament between plugs in adjacent areas shall not be less than twice the distance from the nearest plug. Three Y-blocks shall be utilized as test coupons. The material shall undergo the following test methods: tension test, chemical analysis, yield strength test, and hardness test.1.1 This specification covers ductile iron castings for pressure-retaining parts for use at elevated temperatures. Castings of all grades are suitable for use up to 450 °F. For temperatures above 450 °F and up to 650 °F, only Grade 60-40-18 castings are suitable (Note 1).1.2 Valves, flanges, pipe fittings, pumps, and other piping components are generally manufactured in advance and supplied from stock by the manufacturer, jobber, or dealer.1.3 For supplemental casting requirements, Specification A834 may be utilized.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 may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.NOTE 1: For service other than as specified in this section, reference should be made to Specification A536 for Ductile Iron Castings.21.5 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

5.1 End-jointed lumber studs used in fire resistance-rated assemblies shall be able to support the superimposed design load for the specified time under an elevated temperature exposure, when a wall assembly is exposed to a standard fire specified in Test Methods E119. Light-weight wood assemblies utilize gypsum wallboard or other types of membrane protection to accomplish a requisite fire resistance rating for the assembly. However, wood studs and the end joints in the studs shall resist the developed elevated temperature environment for the duration of the rating. This practice provides a method for evaluating the elevated temperature performance of an adhesive used in end-jointed lumber as compared with the elevated temperature performance of solid wood.1.1 This practice is to be used to evaluate the elevated temperature performance of adhesives used in end-jointed lumber.1.2 A symmetric wall assembly containing end-jointed lumber studs is exposed to a standard fire exposure specified in Test Methods E119.1.3 The wall assembly shall sustain the applied load during a standard fire exposure specified in Test Methods E119 for a period of 60 min or more.1.4 This practice is used to evaluate the performance of adhesives used in end-jointed lumber to heat and flame under controlled conditions, but it does not by itself incorporate all factors required for fire hazard or fire risk assessment under actual fire conditions.1.5 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.1.6 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： 515元 / 折扣价： 438 元 加购物车

This specification covers carbon and low-alloy steel and cobalt alloy castings made by the investment casting process. Fifteen grades of steel and two cobalt alloy grades are covered. Steel castings shall be heat treated either by full annealing, normalizing, normalizing and tempering, or quenching and tempering to obtain the specified properties or other properties that have been agreed upon within each grade. The castings shall conform to the requirements for chemical composition specified.1.1 This specification covers carbon and low-alloy steel and cobalt alloy castings made by the investment casting process.1.2 Fifteen grades of steel and two cobalt alloy grades are covered.1.3 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or contract.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 may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.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

4.1 For many structural ceramic components in service, their use is often limited by lifetimes that are controlled by a process of slow crack growth. This test method provides the empirical parameters for appraising the relative slow crack growth susceptibility of ceramic materials under specified environments at elevated temperatures. This test method is similar to Test Method C1368 with the exception that provisions for testing at elevated temperatures are given. Furthermore, this test method may establish the influences of processing variables and composition on slow crack growth as well as on strength behavior of newly developed or existing materials, thus allowing tailoring and optimizing material processing for further modification. In summary, this test method may be used for material development, quality control, characterization, and limited design data generation purposes.NOTE 3: Data generated by this test method do not necessarily correspond to crack velocities that may be encountered in service conditions. The use of data generated by this test method for design purposes may entail considerable extrapolation and loss of accuracy.4.2 In this test method, the flexural stress computation is based on simple beam theory, with the assumptions that the material is isotropic and homogeneous, the moduli of elasticity in tension and compression are identical, and the material is linearly elastic. The average grain size should be no greater than one fiftieth (1/50) of the beam thickness.4.3 In this test method, the test specimen sizes and test fixtures were chosen in accordance with Test Method C1211, which provides a balance between practical configurations and resulting errors, as discussed in Refs (5, 6). Only the four-point test configuration is used in this test method.4.4 In this test method, the slow crack growth parameters (n and D) are determined based on the mathematical relationship between flexural strength and applied stress rate, log σf = [1/(n + 1)] log σ˙ + log D, together with the measured experimental data. The basic underlying assumption on the derivation of this relationship is that slow crack growth is governed by an empirical power-law crack velocity, v = A[KI /KIC]n (see Appendix X1).NOTE 4: There are various other forms of crack velocity laws which are usually more complex or less convenient mathematically, or both, but may be physically more realistic (7). The mathematical analysis in this test method does not cover such alternative crack velocity formulations.4.5 In this test method, the mathematical relationship between flexural strength and stress rate was derived based on the assumption that the slow crack growth parameter is at least n ≥ 5 (1, 8). Therefore, if a material exhibits a very high susceptibility to slow crack growth, that is, n < 5, special care should be taken when interpreting the results.4.6 The mathematical analysis of test results according to the method in 4.4 assumes that the material displays no rising R-curve behavior, that is, no increasing fracture resistance (or crack-extension resistance) with increasing crack length. It should be noted that the existence of such behavior cannot be determined from this test method. The analysis further assumes that the same flaw types control strength over the entire test range. That is, no new flaws are created, and the flaws that control the strength at the highest stress rate control the strength at the lowest stress rate.4.7 Slow crack growth behavior of ceramic materials can vary as a function of mechanical, material, thermal, and environmental variables. Therefore, it is essential that test results accurately reflect the effects of specific variables under study. Only then can data be compared from one investigation to another on a valid basis, or serve as a valid basis for characterizing materials and assessing structural behavior.4.8 The strength of advanced ceramics is probabilistic in nature. Therefore, slow crack growth that is determined from the flexural strengths of a ceramic material is also a probabilistic phenomenon. Hence, a proper range and number of test rates in conjunction with an appropriate number of specimens at each test rate are required for statistical reproducibility and design (2). Guidance is provided in this test method.NOTE 5: For a given ceramic material/environment system, the SCG parameter n is independent of specimen size, although its reproducibility is dependent on the variables previously mentioned. By contrast, the SCG parameter D depends significantly on strength, and thus on specimen size (see Eq X1.7).4.9 The elevated-temperature strength of a ceramic material for a given test specimen and test fixture configuration is dependent on its inherent resistance to fracture, the presence of flaws, test rate, and environmental effects. Analysis of a fracture surface, fractography, though beyond the scope of this test method, is highly recommended for all purposes, especially to verify the mechanism(s) associated with failure (refer to Practice C1322).1.1 This test method covers the determination of slow crack growth (SCG) parameters of advanced ceramics by using constant stress-rate flexural testing in which flexural strength is determined as a function of applied stress rate in a given environment at elevated temperatures. The strength degradation exhibited with decreasing applied stress rate in a specified environment is the basis of this test method which enables the evaluation of slow crack growth parameters of a material.NOTE 1: This test method is frequently referred to as “dynamic fatigue” testing (1-3)2 in which the term “fatigue” is used interchangeably with the term “slow crack growth.” To avoid possible confusion with the “fatigue” phenomenon of a material which occurs exclusively under cyclic loading, as defined in Terminology E1823, this test method uses the term “constant stress-rate testing” rather than “dynamic fatigue” testing.NOTE 2: In glass and ceramics technology, static tests of considerable duration are called “static fatigue” tests, a type of test designated as stress-rupture (Terminology E1823).1.2 This test method is intended primarily to be used for negligible creep of test specimens, with specific limits on creep imposed in this test method.1.3 This test method applies primarily to advanced ceramics that are macroscopically homogeneous and isotropic. This test method may also be applied to certain whisker- or particle-reinforced ceramics that exhibit macroscopically homogeneous behavior.1.4 This test method is intended for use with various test environments such as air, vacuum, inert, and any other gaseous environments.1.5 Values expressed in this standard test are in accordance with the International System of Units (SI) and IEEE/ASTM SI 10.1.6 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： 646元 / 折扣价： 550 元 加购物车

4.1 This test method may be used for material development, quality control, characterization, and design data generation purposes. This test method is intended to be used with ceramics whose flexural strength is ∼50 MPa (∼7 ksi) or greater.4.2 The flexure stress is computed based on simple beam theory, with assumptions that the material is isotropic and homogeneous, the moduli of elasticity in tension and compression are identical, and the material is linearly elastic. The average grain size should be no greater than 1/50 of the beam thickness. The homogeneity and isotropy assumptions in the test method rule out the use of it for continuous fiber-reinforced composites for which Test Method C1341 is more appropriate.4.3 The flexural strength of a group of test specimens is influenced by several parameters associated with the test procedure. Such factors include the testing rate, test environment, specimen size, specimen preparation, and test fixtures. Specimen and fixture sizes were chosen to provide a balance between the practical configurations and resulting errors as discussed in Test Method C1161, and Refs (1-3).4 Specific fixture and specimen configurations were designated in order to permit the ready comparison of data without the need for Weibull size scaling.4.4 The flexural strength of a ceramic material is dependent on both its inherent resistance to fracture and the size and severity of flaws. Variations in these cause a natural scatter in test results for a sample of test specimens. Fractographic analysis of fracture surfaces, although beyond the scope of this test method, is highly recommended for all purposes, especially if the data will be used for design as discussed in Ref (4) and Practices C1322 and C1239.4.5 This method determines the flexural strength at elevated temperature and ambient environmental conditions at a nominal, moderately fast testing rate. The flexural strength under these conditions may or may not necessarily be the inert flexural strength. Flexure strength at elevated temperature may be strongly dependent on testing rate, a consequence of creep, stress corrosion, or slow crack growth. If the purpose of the test is to measure the inert flexural strength, then extra precautions are required and faster testing rates may be necessary.NOTE 6: Many ceramics are susceptible to either environmentally assisted slow crack growth or thermally activated slow crack growth. Oxide ceramics, glasses, glass ceramics, and ceramics containing boundary phase glass are particularly susceptible to slow crack growth. Time-dependent effects that are caused by environmental factors (for example, water as humidity in air) may be minimized through the use of inert testing atmosphere such as dry nitrogen gas or vacuum. Alternatively, testing rates faster than specified in this standard may be used if the goal is to measure the inert strength. Thermally activated slow crack growth may occur at elevated temperature even in inert atmospheres. Testing rates faster than specified in this standard should be used if the goal is to measure the inert flexural strength. On the other hand, many ceramics such as boron carbide, silicon carbide, aluminum nitride, and many silicon nitrides have no sensitivity to slow crack growth at room or moderately elevated temperatures and for such materials, the flexural strength measured under laboratory ambient conditions at the nominal testing rate is the inert flexural strength.4.6 The three-point test configuration exposes only a very small portion of the specimen to the maximum stress. Therefore, three-point flexural strengths are likely to be much greater than four-point flexural strengths. Three-point flexure has some advantages. It uses simpler test fixtures, it is easier to adapt to high temperature, and it is sometimes helpful in Weibull statistical studies. However, four-point flexure is preferred and recommended for most characterization purposes.4.7 The three-point test configuration exposes only a very small portion of the specimen to the maximum stress. Therefore, three-point flexural strengths are likely to be much greater than four-point flexural strengths. Three-point flexure has some advantages. It uses simpler test fixtures, it is easier to adapt to high temperature, and it is sometimes helpful in Weibull statistical studies. However, four-point flexure is preferred and recommended for most characterization purposes.1.1 This test method covers determination of the flexural strength of advanced ceramics at elevated temperatures.2 Four-point-1/4-point and three-point loadings with prescribed spans are the standard as shown in Fig. 1. Rectangular specimens of prescribed cross-section are used with specified features in prescribed specimen-fixture combinations. Test specimens may be 3 by 4 by 45 to 50 mm in size that are tested on 40-mm outer span four-point or three-point fixtures. Alternatively, test specimens and fixture spans half or twice these sizes may be used. The test method permits testing of machined or as-fired test specimens. Several options for machining preparation are included: application matched machining, customary procedures, or a specified standard procedure. This test method describes the apparatus, specimen requirements, test procedure, calculations, and reporting requirements. The test method is applicable to monolithic or particulate- or whisker-reinforced ceramics. It may also be used for glasses. It is not applicable to continuous fiber-reinforced ceramic composites.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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