5 Apparatus
5.1 Testing Machines—Machines used for tension testing shall conform to the requirements of Practices E 4. The forces used in determining tensile strength and yield strength shall be within the verified force application range of the testing machine as defined in Practices E 4.
5.2 Gripping Devices:
5.2.1 General—Various types of gripping devices may be used to transmit the measured force applied by the testing machine to the test specimens. To ensure axial tensile stress within the gage length, the axis of the test specimen should coincide with the center line of the heads of the testing machine. Any departure from this requirement may introduce bending stresses that are not included in the usual stress computation (force divided by cross-sectional area).
NOTE 1—The effect of this eccentric force application may be illustrated by calculating the bending moment and stress thus added. For a standard 12.5-mm [0.500-in.] diameter specimen, the stress increase is 1.5 percentage points for each 0.025 mm [0.001 in.] of eccentricity. This error increases to 2.5 percentage points/ 0.025 mm [0.001 in.] for a 9 mm [0.350-in.] diameter specimen and to 3.2 percentage points/ 0.025 mm [0.001 in.] for a 6-mm [0.250-in.] diameter specimen. NOTE 2—Alignment methods are given in Practice E 1012.
5.2.2 Wedge Grips—Testing machines usually are equipped with wedge grips. These wedge grips generally furnish a satisfactory means of gripping long specimens of ductile metal and flat plate test specimens such as those shown in Fig. 1. If, however, for any reason, one grip of a pair advances farther than the other as the grips tighten, an undesirable bending stress may be introduced. When liners are used behind the wedges, they must be of the same thickness and their faces must be flat and parallel. For best results, the wedges should be supported over their entire lengths by the heads of the testing machine. This requires that liners of several thicknesses be available to cover the range of specimen thickness. For proper gripping, it is desirable that the entire length of the serrated face of each wedge be in contact with the specimen. Proper alignment of wedge grips and liners is illustrated in Fig. 2. For short specimens and for specimens of many materials it is generally necessary to use machined test specimens and to use a special means of gripping to ensure that the specimens, when under load, shall be as nearly as possible in uniformly distributed pure axial tension (see 5.2.3, 5.2.4, and 5.2.5).
5.2.3 Grips for Threaded and Shouldered Specimens and Brittle Materials—A schematic diagram of a gripping device for threaded-end specimens is shown in Fig. 3, while Fig. 4 shows a device for gripping specimens with shouldered ends. Both of these gripping devices should be attached to the heads of the testing machine through properly lubricated sphericalseated bearings. The distance between spherical bearings should be as great as feasible.
5.2.4 Grips for Sheet Materials—The self-adjusting grips shown in Fig. 5 have proven satisfactory for testing sheet materials that cannot be tested satisfactorily in the usual type of wedge grips.
5.2.5 Grips for Wire—Grips of either the wedge or snubbing types as shown in Figs. 5 and 6 or flat wedge grips may be used.
5.3 Dimension-Measuring Devices—Micrometers and other devices used for measuring linear dimensions shall be accurate and precise to at least one half the smallest unit to which the individual dimension is required to be measured.
5.4 Extensometers—Extensometers used in tension testing shall conform to the requirements of Practice E 83 for the classifications specified by the procedure section of this test method. Extensometers shall be used and verified to include the strains corresponding to the yield strength and elongation at fracture (if determined).
5.4.1 Extensometers with gage lengths equal to or shorter than the nominal gage length of the specimen (dimension shown as “G-Gage Length” in the accompanying figures) may be used to determine the yield behavior. For specimens without a reduced section (for example, full cross sectional area specimens of wire, rod, or bar), the extensometer gage length for the determination of yield behavior shall not exceed 80 % of the distance between grips. For measuring elongation at fracture with an appropriate extensometer, the gage length of the extensometer shall be equal to the nominal gage length
required for the specimen being tested.
6 Test Specimens
6.1 General:
6.1.1 Specimen Size—Test specimens shall be either substantially full size or machined, as prescribed in the product specifications for the material being tested.
6.1.2 Location—Unless otherwise specified, the axis of the test specimen shall be located within the parent material as follows:
6.1.2.1 At the center for products 40 mm [1.500 in.] or less in thickness, diameter, or distance between flats.
6.1.2.2 Midway from the center to the surface for products over 40 mm [1.500 in.] in thickness, diameter, or distance between flats.
6.1.3 Specimen Machining—Improperly prepared test specimens often are the reason for unsatisfactory and incorrect test results. It is important, therefore, that care be exercised in the preparation of specimens, particularly in the machining, to maximize precision and minimize bias in test results.
6.1.3.1 The reduced sections of prepared specimens should be free of cold work, notches, chatter marks, grooves, gouges, burrs, rough surfaces or edges, overheating, or any other condition which can deleteriously affect the properties to be measured.
NOTE 3—Punching or blanking of the reduced section may produce significant cold work or shear burrs, or both, along the edges which should be removed by machining.
6.1.3.2 Within the reduced section of rectangular specimens, edges or corners should not be ground or abraded in a manner which could cause the actual cross-sectional area of the specimen to be significantly different from the calculated area.
6.1.3.3 For brittle materials, large radius fillets at the ends of the gage length should be used.
6.1.3.4 The cross-sectional area of the specimen should be smallest at the center of the reduced section to ensure fracture within the gage length. For this reason, a small taper is permitted in the reduced section of each of the specimens described in the following sections.
6.1.4 Specimen Surface Finish—When materials are tested with surface conditions other than as manufactured, the surface finish of the test specimens should be as provided in the applicable product specifications.
NOTE 4—Particular attention should be given to the uniformity and quality of surface finish of specimens for high strength and very low ductility materials since this has been shown to be a factor in the variability of test results.
6.2 Plate-Type Specimens—The standard plate-type test specimen is shown in Fig. 1. This specimen is used for testing metallic materials in the form of plate, shapes, and flat material having a nominal thickness of 5 mm [0.188 in.] or over. When product specifications so permit, other types of specimens may be used, as provided in 6.3, 6.4, and 6.5.
6.3 Sheet-Type Specimens:
6.3.1 The standard sheet-type test specimen is shown in Fig.1 This specimen is used for testing metallic materials in the form of sheet, plate, flat wire, strip, band, hoop, rectangles, and shapes ranging in nominal thickness from 0.13 to 19 mm [0.005 to 0.750 in.]. When product specifications so permit, other types of specimens may be used, as provided in 6.2, 6.4, and 6.5.
NOTE 5—Test Methods E 345 may be used for tension testing of materials in thicknesses up to 0.15 mm [0.0059 in.].
6.3.2 Pin ends as shown in Fig. 7 may be used. In order to avoid buckling in tests of thin and high-strength materials, it may be necessary to use stiffening plates at the grip ends. 6.4 Round Specimens:
6.4.1 The standard 12.5-mm [0.500-in.] diameter round test specimen shown in Fig. 8 is used quite generally for testing metallic materials, both cast and wrought.
6.4.2 Fig. 8 also shows small-size specimens proportional to the standard specimen. These may be used when it is necessary to test material from which the standard specimen or specimens shown in Fig. 1 cannot be prepared. Other sizes of small round specimens may be used. In any such small-size specimen it is important that the gage length for measurement of elongation be four times the diameter of the specimen when following E 8 and five times the diameter of the specimen when following E 8M.
6.4.3 The shape of the ends of the specimen outside of the gage length shall be suitable to the material and of a shape to fit the holders or grips of the testing machine so that the forces may be applied axially. Fig. 9 shows specimens with various types of ends that have given satisfactory results.
6.5 Specimens for Sheet, Strip, Flat Wire, and Plate—In testing sheet, strip, flat wire, and plate, use a specimen type appropriate for the nominal thickness of the material, as described in the following:
6.5.1 For material with a nominal thickness of 0.13 to 5 mm [0.005 to 0.1875 in.], use the sheet-type specimen described in 6.3.
6.5.2 For material with a nominal thickness of 5 to 12.5 mm [0.1875 to 0.500 in.], use either the sheet-type specimen of 6.3 or the plate-type specimen of 6.2.
6.5.3 For material with a nominal thickness of 12.5 to 19 mm [0.500 to 0.750 in.], use either the sheet-type specimen of 6.3, the plate-type specimen of 6.2, or the largest practical size of round specimen described in 6.4.
6.5.4 For material with a nominal thickness of 19 mm [0.750 in.], or greater, use the plate-type specimen of 6.2 or the largest practical size of round specimen described in 6.4.6.5.4.1 If the product specifications permit, material of a thickness of 19 mm [ 0.750 in.], or greater may be tested using a modified sheet-type specimen conforming to the configuration shown by Fig. 1. The thickness of this modified specimen must be machined to 10 6 0.5 mm [0.400 6 0.020 in.], and must be uniform within 0.1 mm [0.004 in.] throughout the reduced section. In the event of disagreement, a round specimen shall be used as the referee (comparison) specimen.
6.6 Specimens for Wire, Rod, and Bar:
6.6.1 For round wire, rod, and bar, test specimens having the full cross-sectional area of the wire, rod, or bar shall be used wherever practicable. The gage length for the measurement of elongation of wire less than 4 mm [0.125 in.] in diameter shall be as prescribed in product specifications. When testing wire, rod, or bar having a diameter of 4-mm [0.125-in.] or larger diameter, a gage length equal to four times the diameter shall be used when following E 8 and a gage length equal to five times the diameter shall be used when following E 8M unless otherwise specified. The total length of the specimens shall be at least equal to the gage length plus the length of material required for the full use of the grips employed.
6.6.2 For wire of octagonal, hexagonal, or square cross section, for rod or bar of round cross section where the specimen required in 6.6.1 is not practicable, and for rod or bar of octagonal, hexagonal, or square cross section, one of the following types of specimens shall be used:
6.6.2.1 Full Cross Section (Note 6)—It is permissible to reduce the test section slightly with abrasive cloth or paper, or machine it sufficiently to ensure fracture within the gage marks. For material not exceeding 5 mm [0.188 in.] in diameter or distance between flats, the cross-sectional area may be reduced to not less than 90 % of the original area without changing the shape of the cross section. For material over 5 mm [0.188 in.] in diameter or distance between flats, the diameter or distance between flats may be reduced by not more than 0.25 mm [0.010 in.] without changing the shape of the cross section. Square, hexagonal, or octagonal wire or rod not exceeding 5 mm [0.188 in.] between flats may be turned to a round having a cross-sectional area not smaller than 90 % of the area of the maximum inscribed circle. Fillets, preferably with a radius of 10 mm [0.375 in.], but not less than 3 mm [0.125 in.], shall be used at the ends of the reduced sections. Square, hexagonal, or octagonal rod over 5 mm [0.188 in.] between flats may be turned to a round having a diameter no smaller than 0.25 mm [0.010 in.] less than the original distance between flats.
NOTE 6—The ends of copper or copper alloy specimens may be flattened 10 to 50 % from the original dimension in a jig similar to that shown in Fig. 10, to facilitate fracture within the gage marks. In flattening the opposite ends of the test specimen, care shall be taken to ensure that the four flattened surfaces are parallel and that the two parallel surfaces on the same side of the axis of the test specimen lie in the same plane. 6.6.2.2 For rod and bar, the largest practical size of round specimen as described in 6.4 may be used in place of a test specimen of full cross section. Unless otherwise specified in the product specification, specimens shall be parallel to the direction of rolling or extrusion.
6.7 Specimens for Rectangular Bar—In testing rectangular bar one of the following types of specimens shall be used:
6.7.1 Full Cross Section—It is permissible to reduce the width of the specimen throughout the test section with abrasive cloth or paper, or by machining sufficiently to facilitate fracture within the gage marks, but in no case shall the reduced width be less than 90 % of the original. The edges of the midlength of the reduced section not less than 20 mm [3⁄4 in.] in length shall be parallel to each other and to the longitudinal axis of the specimen within 0.05 mm [0.002 in.]. Fillets, preferably with a radius of 10 mm [3⁄8 in.] but not less than 3 mm [1⁄8 in.] shall be used at the ends of the reduced sections.
6.7.2 Rectangular bar of thickness small enough to fit the grips of the testing machine but of too great width may be reduced in width by cutting to fit the grips, after which the cut surfaces shall be machined or cut and smoothed to ensure failure within the desired section. The reduced width shall not be less than the original bar thickness. Also, one of the types of specimens described in 6.2, 6.3, and 6.4 may be used.
6.8 Shapes, Structural and Other—In testing shapes other than those covered by the preceding sections, one of the types of specimens described in 6.2, 6.3, and 6.4 shall be used. 6.9 Specimens for Pipe and Tube (Note 7): 6.9.1 For all small tube (Note 7), particularly sizes 25 mm [1 in.] and under in nominal outside diameter, and frequently for larger sizes, except as limited by the testing equipment, it is standard practice to use tension test specimens of full-size tubular sections. Snug-fitting metal plugs shall be inserted far enough into the ends of such tubular specimens to permit the testing machine jaws to grip the specimens properly. The plugs shall not extend into that part of the specimen on which the elongation is measured. Elongation is measured over a length of four times the diameter when following E 8 or five times the diameter when following E 8M unless otherwise stated in the product specification. Fig. 11 shows a suitable form of plug, the location of the plugs in the specimen, and the location of the specimen in the grips of the testing machine.
NOTE 7—The term “tube” is used to indicate tubular products in general, and includes pipe, tube, and tubing.
6.9.2 For large-diameter tube that cannot be tested in full section, longitudinal tension test specimens shall be cut as indicated in Fig. 12. Specimens from welded tube shall be located approximately 90° from the weld. If the tube-wall thickness is under 20 mm [0.750 in.], either a specimen of the form and dimensions shown in Fig. 13 or one of the small-size specimens proportional to the standard 12.5-mm [0.500-in.] specimen, as mentioned in 6.4.2 and shown in Fig. 8, shall be used. Specimens of the type shown in Fig. 13 may be tested with grips having a surface contour corresponding to the curvature of the tube. When grips with curved faces are not available, the ends of the specimens may be flattened without heating. If the tube-wall thickness is 20 mm [0.750 in.] or over, the standard specimen shown in Fig. 8 shall be used.
NOTE 8—In clamping of specimens from pipe and tube (as may be done during machining) or in flattening specimen ends (for gripping), care must be taken so as not to subject the reduced section to any deformation or cold work, as this would alter the mechanical properties.
6.9.3 Transverse tension test specimens for tube may be taken from rings cut from the ends of the tube as shown in Fig. 14 Flattening of the specimen may be either after separating as in A, or before separating as in B. Transverse tension test specimens for large tube under 20 mm [0.750 in.] in wall thickness shall be either of the small-size specimens shown in Fig. 8 or of the form and dimensions shown for Specimen 2 in Fig. 13. When using the latter specimen, either or both surfaces of the specimen may be machined to secure a uniform thickness, provided not more than 15 % of the normal wall thickness is removed from each surface. For large tube 20 mm [0.750 in.] and over in wall thickness, the standard specimen shown in Fig. 8 shall be used for transverse tension tests. Specimens for transverse tension tests on large welded tube to determine the strength of welds shall be located perpendicular to the welded seams, with the welds at about the middle of their lengths.
6.10 Specimens for Forgings—For testing forgings, the largest round specimen described in 6.4 shall be used. If round specimens are not feasible, then the largest specimen described in 6.5 shall be used.
6.10.1 For forgings, specimens shall be taken as provided in the applicable product specifications, either from the predominant or thickest part of the forging from which a coupon can be obtained, or from a prolongation of the forging, or from separately forged coupons representative of the forging. When not otherwise specified, the axis of the specimen shall be parallel to the direction of grain flow.
6.11 Specimens for Castings—In testing castings either the standard specimen shown in Fig. 8 or the specimen shown in Fig. 15 shall be used unless otherwise provided in the product specifications.
6.11.1 Test coupons for castings shall be made as shown in Fig. 16 and Table 1.
6.12 Specimen for Malleable Iron—For testing malleable iron the test specimen shown in Fig. 17 shall be used, unless otherwise provided in the product specifications.
6.13 Specimen for Die Castings—For testing die castings the test specimen shown in Fig. 18 shall be used unless otherwise provided in the product specifications.
6.14 Specimens for Powder Metallurgy (P/M) Materials— For testing powder metallurgy (P/M) materials the test specimens shown in Figs. 19 and 20 shall be used, unless otherwise provided in the product specifications. When making test specimens in accordance with Fig. 19, shallow transverse grooves, or ridges, may be pressed in the ends to allow gripping by jaws machined to fit the grooves or ridges. Because of shape and other factors, the flat unmachined tensile test specimen (Fig. 19) in the heat treated condition will have an ultimate tensile strength of 50 % to 85 % of that determined in a machined round tensile test specimen (Fig. 20) of like composition and processing.
Hydraulic Tensile Tester 500 KN
- Load cell 500KN
- Force capacity 500 KN
- Computerized
- USB port to connect to computer
- Pneumatic wedge grip for flat and round bars (Thickness and diameter as per customer request)
- Extensometer input (Extensometer is as option according to customer request)
- Hydraulic unit is included
- Reporting in MS EXCEL
- Graphing of displacement and force data
- Speed is adjustable 0-100 mm/min
- Maximum cylinder stroke 500mm
- Space between columns 500mm
- Manual crosshead lift and clamp
- 2-Column
- Round sample 5-30mm
- Flat samples thickness 5-25mm
- Training video included