AS 833-2017 pdf free.Standard Test Method for Indentation Hardness of Metallic Materials by Comparison Hardness Testers.
6. Test Parts
6.1 Test parts by this hardness testing test method vary greatly in form since it is frequently desirable to make the impression upon a test part to he used in the finished product rather than upon a sample test specimen.
6. 1. 1 1)i,ne,z.s’io,,s—The thickness of the tested part shall be such that no bulge or other marking showing the etb.ct ot the load appears on the side of the piece opposite the impression. In any event, the thickness of the test part shall be at least ten times the depth of the indentation. The minimum width shall be at least Iwo and one half times the diameter of the indentation.
6. 1.2 Fi,si.h—When necessary. the surface on which the impression is to be made shall be liled. ground. machined, or polished with abrasive material so that the edge of the impression shall be defined clearly enough to permit the measurement of the diameter to the specified accuracy. Take care to avoid overheating or cold working the surface. Suflicient metal shall be removed to eliminate decarburized metal.
6.2 Suppori—All test parts shall he adequately supported to prevent any movement or deflection during application of the impact load.
7. eritication of Apparatus and Calibration of Test Bars
7. I V’rijicuiioii ofAflparulux—The hardness-testing appara— ftis (including test bars) shall be verified by performing tests on Brinell blocks that have been standardized according to the requirements of Test Method ElO.
7.1. I Full verification of the apparatus shall be performed prior to use when new, and upon replacement of the impression ball. The full verification shall include testing at least one Brinell test block 3 times. The average of the three measurements shall be within ±5 % of the Hnnell value of the test block.
7.12 Periodic verilications are recommended at the beginning of each day the comparative esIer is use. or during usage as deemed necessary. Periodic verifications should be performed using Brinell test blocks within IS % of the expected Brinell hardness of the test parts being tested. One measurement is satisfactory for periodic testing. The result of the periodic tcst measurement should be within ±5 ‘f of the Brinell value of the test block to he considered to be in compliance with this test method.
7.2 calibration of Test Bars—The lirinell hardness of the test bars shall be detennined by the test bar manufacturer using a 10 mm diameter ball and a 341(X) kg load according in Test Method ElO on each of the four faces of the test bar at approximately the mid-length of the bar. If the test bar is too soft to permit the use of a 30(X) kg load, then a 15(X) kg load shall be used. The hardness values obtained shall not vary from each other by more than ±2 . The ends of the bar shall be permanently marked with the average hardness value, as well as the applied load if the 15(X) kg load was uses) by the rnaiiufacturer prior to shipment.
8. Procedure
8.1 Assemble the tcsl bar into the apparatus making sure a minimum distance of no less than 5 mm will exist between diameter of the impression to be made and any other indentations on the face. Minimum distance of the indentation diameter from the edge of the test part shall be 12.5 mm. If the apparatus is equipped with a presetting bar stop. ensure the fixture is properly in place. Place the apparatus on the surface of the component to be tested and apply the impact load using a I to 2¼ kg hammer. It is essential to apply a well guided. short blow in order to avoid a rebound and thus a double blow that may produce an erroneous result by damaging the sharp edge of the ball impression.
Non I—A hinimcr eighi ol 2 to S lb ina be used instead ni the kilogram niung.
8.2 im,nrssitni Diameter—In order to achieve the published precision level (see Section It)). impression diameters on test part should fall between 3.0 and 4.0 mm. If a larger impression is produced, the test h-ar may give way laterally and the test result may be in error.
8.3 Mea.su,wne,its—Each impression shall be measured twice with the measurements taken at right angles to each other. The two diameters, determined with equipment in accordance with 5.2. shail be within 0.05 mm of each other. If the two measured diameters are not within 0.05 mm of each other, then the test impression is deemed to he invalid and a retest must be performed. The mean value of the two diameter measurements (taken at right angles) is then used as the basis for subsequent calculation as discussed in 8.4.
8.3.1 If the two diameter measurements differ by more than
0,1 mm. the readings shall be discarded in accordance with Test Methods and Definitions A370. and the test repeated.AS 833 pdf download.