A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. Scope 1. Final indentation diameter in both the comparative test bar and material tested shall be within the range of the comparator used for the instrument. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use.
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A number in parentheses indicates the year of last reapproval. Scope 1. L5 Rebound Velocity 3 Impact Velocity 1. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 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.
Referenced Documents 2. Terminology 3. Current edition approved Nov. Published December Originally approved in Last previous edition approved in as A — Leeb and Equotip are registered trademarks used with permission of Proceq SA. DOI: The ratio of the rebound velocity to the impact velocity of the impact body is a measure of the hardness of the material under test. Summary of Test Method 4. The impact and rebound velocities are measured when the impact body is approximately 1 mm from the test surface.
This is accomplished by means of a permanent magnet mounted in the impact body which, during the test, moves through a coil in the impact device and induces an electric voltage on both the impact and rebound movements. These induced voltages are proportional to the respective impact and rebound velocities. The quotient of these measured voltage values derived from the impact and rebound velocities, multiplied by the factor produces a number which constitutes the Leeb hardness value.
Brief descriptions of the types of devices and their common applications are given in Appendix X1. Calibration using a single standard test block may indicate acceptable results. It is recommended that this test be performed with the test piece at rest. At temperatures outside this range. The results generated at that location do not represent the part at any other surface location and yield no information about the material at subsurface locations. The results obtained are indicative of the strength and dependent on the heat treatment of the material tested.
Failure to provide adequate support and coupling will produce test results lower than the true hardness value. Impact Device D. The Leeb hardness value is read on the indicator device. Any instrument not meeting the requirements of Part B shall not be employed for the acceptance testing of product. The impact device. The following guidelines are offered as minimum weights and sizes of test pieces for selecting the proper test equipment..
Any paint. The surfaces to be tested shall be smooth. The charging tube is allowed to slowly return to the starting position. Procedure 9. If replacement. In addition. Test Piece 7. Apparatus 6.
After placing the impact device on the test surface. These are the D. The impact body is now in its loaded or locked position. Test pieces of weights less than the minimum or pieces of any weight with sections less than the minimum thickness require rigid support and coupling to a thick.
If the material being tested is considered to be nonhomogeneous for example. All such conversions are. The indicated value is automatically replaced with the next test impact result. HB HLG. Calculation of Hardness Result Some newer models automatically compensate for test direction.
No point shall be impacted more than once Precision and Bias The distance between the impact point and a specimen edge shall not be less than three diameters edge-to-edge.
This compensation value can be determined in accordance with Tables Report Scope Each laboratory measured the hardness of each block 25 times. The respective standard deviations among test results. Manufacture Uniformity of Hardness Standardizing Procedure General Requirements The two opposite end plane surfaces shall be parallel.. If they are too near. In order to reproduce the standard direction dependency.
The results are. The main reasons for this are: X1. Equotip hardness test. For more details. Each of the standard probes has its own characteristic direction dependency. Keywords The other types have been added with the time for applications with special requirements. The impact and rebound velocities are assumed to be proportional to the extreme values A and B of the signal curve. Marking Instruments containing some means for determining the impact angle can make a fully automatic direction compensation.
Applications on steel and cast steel. With microprocessor controlled instruments. Impact bodies tend to wear out at the high end of hardness range. Impact Device G max. Same materials to be tested like standard D unit but at extended hardness range. Applications on surface hardened components.. Applications for measurement in the high end range.
Probe C LE LE -7 -7 -7 -6 -6 -6 -5 -5 -4 -4 -4 -3 -2 -5 -4 -3 -3 -2 -2 -9 -7 -6 -5 -4 -3 -9 -7 -6 -6 -3 -5 -7 -3 -6 -8 -9 LD -2 -2 -2 -2 -2 -5 -9 -5 -9 -5 -5 -5 TABLE X1. Impact Device C max.. Application in the Brinell-range on heavy coarse grained castings and forgings. Measurements on steel and cast steel. Impact Device DL max. Applications on walled or impact sensitive components small measuring indentation too. Impact bodies show no wear even at high hardness levels when compared to D device.
Probe G. Same materials to be tested like standard D unit but at extended hardness range.. The measurement readings determined by the latter method are erroneous due to gravitational acceleration and are not independent of direction. Impact bodies show minimal wear even at high hardness levels when compared to D device. The moments t It is of advantage to arrange the impact body magnets and the coil so that the impact signal as well as the rebound signal uses at least two zero transitions in this case 3 of the induced voltage as support points for the evaluation of the curve.
The results must therefore be correspondingly corrected.. This disadvantage is not apparent in instruments which operate according to the Krautkramer rebound method.
Probe S LS -4 -4 -4 -4 -3 -3 -3 -3 -3 -2 -2 -5 -7 -5 -8 -5 -9 -6 -6 -7 -7 -7 -8 -8 -9 max. The complete reproduction law is obtained by interpolation between these curve points so that the corresponding amplitude value u t1 can be allocated to each voltage value u t0 enabling the velocity ratio except at the zero positions themselves to be calculated. Only the mass must be kept within narrow tolerances.
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A number in parentheses indicates the year of last reapproval. Scope 1. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. Terminology 3. Current edition approved Nov. Published December
A number in parentheses indicates the year of last reapproval. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Referenced Documents2. L 5Rebound VelocityImpact VelocityThe Leeb hardness number is followed by the symbol HLwith one or more suffix characters representing the type ofimpact device.