Decree No. 68 / 2004 Coll.
Order setting out requirements for metal hardness meters
Valid
Effective from 01.03.2004
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68
DECLARATION
of 3 February 2004
laying down requirements for metal hardness meters
The Ministry of Industry and Trade provides pursuant to Section 27 of Act No. 505 / 1990 Coll., on Metrology, as amended by Act No. 119 / 2000 Coll. and Act No. 137 / 2002 Coll., ("the Act") for the implementation of Sections 6 (2) and 9 (1) of the Act:
This Decree sets out requirements for metal hardness meters (hereinafter referred to as "hardness meters'), the type approval procedure and the procedure for their verification.
For the purposes of this decree, the following shall be considered as hardness meters:
(a) Rockwell-type hardness meters;
(b) Vickers-type hardness meters;
(c) Brinell-type hardness meters.
The terminology, the hardness requirements and the type-approval procedure and the verification procedure are set out in the Annex.
This Decree shall take effect on 1 March 2004.
Minister:
Ing. Urban v. r.
Annex to Decree No. 68 / 2004 Coll.
1. TERMINOLOGY
1.1 A hard gauge is a device used to measure the hardness of materials.
1.2 The intrusion is a body of the specified shape and of the prescribed material, which enters the material and creates a permanent printing. The printing shall be measured using the prescribed method and the hardness of the material shall be calculated from its size.
1.3 A hard plate is a plate with prescribed parameters, which serves as an etalon and transfers the hardness value.
1.4 A force gauge is a device to measure the force.
1.5 Preliminary load is the force load applied to the Rockwell method, which sets zero value. After the delay on the total load, the force is again transferred to the preliminary load and here the constant depth of the printing is measured.
1.6 The total load is the force at which permanent printing is produced in the material.
2 DURATION REQUIREMENTS
2.1. METHOLOGICAL REQUIREMENTS
2.1.1 Rockwell hardness meters
2.1.1.1. The permitted preload tolerance (before and after removal of the total load) shall be ± 2,0%.
2.1.1.2. The permissible tolerance of the total load shall be ± 1,0 per cent.
2.1.1.3. Intruder body with diamond cone:
Angle of cone (120 ± 0,35) °.
The differences of equality forming the lines of the diamond cone adjacent to the connection shall not exceed 0,002 mm at a minimum length of 0,4 mm.
The angle between the centreline of the diamond cone and the centreline of the entanglement holder shall not exceed 0,5 °.
The peak of the intrusion system must be nothing. Its radius shall be determined from the individual values measured in axis sections. The distance of the concentrated circles shall not exceed 0,004 mm. Each individual value of radius shall be 0,200 ± 0,015 mm. The average value calculated from at least four individual values shall be 0,20 ± 0,01 mm.
Indirect verification of the impactor shall be carried out on four reference plates which are calibrated for the values given in Table 1. The average hardness of the three prints carried out by the verified intrusion body shall not differ from the average of the three prints carried out by the reference intrusion body by more than ± 0,8 units of Rockwell.
Table 1
| Stupnice | Tvrdost | Mezní úchylka |
|---|---|---|
| HRC | 23 | ± 3 |
| HRC | 55 | |
| HR45N | 43 | |
| HR15n | 91 |
2.1.1.4. Intruder ball:
The balls must be polished and have no surface defects.
Steel balls shall have a hardness of not less than 700 HV 10
Hard metal balls shall have a hardness of not less than 1500 HV 10
The diameter of the ball measured at three locations shall not differ from the nominal diameter more than the limit deviations given in Table 2.
Table 2
| Stupnice tvrdosti podle Rockwella | Průměr kuličky mm | Mezní úchylky mm |
|---|---|---|
| B | 1,587 5 | ± 0,0035 |
| F | 1,587 5 | ± 0,0035 |
| G | 1,587 5 | ± 0,0035 |
| T | 1,587 5 | ± 0,0035 |
| E | 3,175 | ± 0,004 |
| H | 3,175 | ± 0,004 |
| K | 3,175 | ± 0,004 |
2.1.1.5. Depth meter
The depth meter shall show an accuracy of ± 0,001 mm for scales A to K and 0,0005 mm for scales N and T.
2.1.1.6. Error and reliability
The permitted errors and the reliability of the hardometer are given in Table 3.
Table 3
| Stupnice tvrdosti podle Rockwella | Rozsah tvrdosti podle referenční destičky | Dovolená chyba v jednotkách Rockwella | Dovolená spolehlivost tvrdoměrua) |
|---|---|---|---|
| A | 20 HRA až ≤ 75 HRA > 75 HRA až ≤ 88 HRA | ± 2 HRA ± 1,5 HRA | ≤ 0,02 (100-) nebo 0,8 jednotky Rockwellab) |
| B | 20 HRB až ≤ 45 HRB > 45 HRB až ≤ 80 HRB > 80 HRB až ≤ 100 HRB | ± 4 HRB ± 3 HRB ± 2 HRB | ≤ 0,04 (130-) nebo 1,2 jednotky Rockwellab) |
| C | 20 HRC až ≤ 70 HRC | ± 1,5 HRC | ≤ 0,02 (100-) nebo 0,8 jednotky Rockwellab) |
| D | 40 HRD až < 70 HRD > 70 HRD až ≤ 77 HRD | ± 2 HRD ±1,5 HRD | ≤ 0,02 (100-) nebo 0,8 jednotky Rockwellab) |
| E | 70 HRE až ≤ 90 HRE > 90 HRE až ≤ 100 HRE | ± 2,5 HRE ± 2 HRE | ≤ 0,04 (130-) nebo 1,2 jednotky Rockwellab) |
| F | 60 HRF až ≤ 90 HRF > 90 HRF až ≤ 100 HRF | ± 3 HRF ± 2 HRF | ≤ 0,04 (130-) nebo 1,2 jednotky Rockwellab) |
| G | 30 HRG až ≤ 50 HRG > 50 HRG až ≤ 75 HRG > 75 HRG až ≤ 94 HRG | ± 6 HRG ± 4,5 HRG ± 3 HRG | ≤ 0,04 (130-) nebo 1,2 jednotky Rockwellab) |
| H | 80 HRH až ≤ 100 HRH | ± 2 HRH | ≤ 0,04 (130-) nebo 1,2 jednotky Rockwellab) |
| K | 40 HRK až ≤ 60 HRK > 60 HRK až ≤ 80 HRK > 80 HRK až ≤ 100 HRK | ± 4 HRK ± 3 HRK ± 2 HRK | ≤ 0,04 (130-) nebo 1,2 jednotky Rockwellab) |
| N | ± 2 HRN | ≤ 0,04 (100-) nebo 1,2 jednotky Rockwellab) | |
| K | ± 3 HRT | ≤ 0,06 (100-) nebo 2,4 jednotky Rockwellab) | |
| a) kde je průměrná hodnota tvrdosti | |||
| b) která je větší | |||
2.1.2 Vickers type hardness meters
2.1.2.1. The permissible limit deviation of the total load is given in Table 4.
Table 4
| Rozsah zkušebního zatížení F N | Tolerance% |
|---|---|
| F ≥ 1,961 | ± 1,0 |
| 0,098 07 ≤ F < 1,961 | ± 1,5 |
2.1.2.2. Intruder body - diamond needle:
Angle of opposite walls (136 ± 0,5) °.
The angle between the centreline of the diamond needle and the centreline of the entanglement holder shall not exceed 0,5 °.
The four walls of the needle must meet at the top; the maximum permissible length of the roof between the opposite walls is given in Table 5.
Table 5
| Rozsah zkušebního zatížení N | Největší přípustná délka stříšky mm |
|---|---|
| F ≥ 49,03 | 0,002 |
| 1,961 ≤ F < 49,03 | 0,001 |
| 0,098 07 ≤ F < 1,961 | 0,0005 |
2.1.2.3. Measuring equipment
The scale of the measuring device shall be so divided as to permit the determination of the diagonals of the printing and the maximum error shall not exceed the values given in Table 6. The measuring equipment shall be verified by measurements carried out on an objective micrometer at at least five intervals for each operating range.
Table 6
| Úhlopříčka, d Mm | Schopnost stanovení měřicího zařízení | Maximální dovolená chyba |
|---|---|---|
| d ≤ 0,040 | 0,0002 mm | 0,0004 mm |
| d > 0,040 | 0,5% z d | 1,0% z d |
2.1.2.4 Reliability of the test gauge
The permissible hardness of the test gauge is given in Table 7.
Table 7
| Tvrdost tvrdoměrné destičky | Spolehlivost tvrdoměru max | ||||||
|---|---|---|---|---|---|---|---|
| 1) | HV | ||||||
| HV5 až HV100 | HV0,2 až < HV5 | < HV0,2 | HV5 až HV100 | HV0,2 až < HV5 | |||
| Tvrdost tvrdoměrné destičky | HV | Tvrdost tvrdoměrné destičky | HV | ||||
| < 225HV | 0,03 | 0,06 | 0,06 | 100 200 | 6 12 | 100 200 | 12 24 |
| 225HV | 0,02 | 0,04 | 0,05 | 250 350 600 750 | 10 14 24 30 | 250 350 600 750 | 20 28 48 60 |
| 1) | |||||||
2.1.2.5. Inertia error
Allowed hardness errors are shown in Table 8.
Table 8
| Značka tvrdosti | Maximální dovolená chyba tvrdoměru v procentech tvrdosti tvrdoměrné destričky | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tvrdost, HV | ||||||||||||||||
| 50 | 100 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 600 | 700 | 800 | 900 | 1000 | 1500 | |
| HV0,01 | ||||||||||||||||
| HV0,015 | 10 | |||||||||||||||
| HV0,02 | 8 | |||||||||||||||
| HV0,025 | 8 | 10 | ||||||||||||||
| HV0,05 | 6 | 8 | 9 | 10 | ||||||||||||
| HV0,1 | 5 | 6 | 7 | 8 | 8 | 9 | 10 | 10 | 11 | |||||||
| HV0,2 | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 12 | 12 | |||||||
| HV0,3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 10 | 11 | 11 | ||||||
| HV0,5 | 3 | 5 | 5 | 6 | 6 | 7 | 7 | 8 | 8 | 9 | 11 | |||||
| HV1 | 3 | 4 | 4 | 4 | 5 | 5 | 5 | 6 | 6 | 6 | 8 | |||||
| HV2 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 6 | |||||
| HV3 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 5 | |||||
| HV5 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | |||||
| HV10 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | |||||
| HV20 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | |||||
| HV30 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | |||||
| HV50 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | |||||
| HV100 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | ||||||
| 1 – Pro úhlopříčku vtisku menší než 0,020 mm se hodnoty neuvádějí. | ||||||||||||||||
| 2 – Pro mezilehlé hodnoty může být maximální dovolená chyba stanovena interpolací. | ||||||||||||||||
| 3 – Hodnoty pro mikrotvrdoměry jsou založeny na maximální dovolené chybě 0,001 mm nebo 2 % délky střední úhlopříčky vtisku v závislosti na tom, která je větší. | ||||||||||||||||
2.1.3. Brinell hardness meters
2.1.3.1. The permissible tolerance of the total load shall be ± 1,0 per cent.
2.1.3.2. Intruder ball:
The balls must be polished and have no surface defects.
The balls are only hardmetal and must have a hardness of at least 1500 HV 10.
The diameter of the ball measured in three places shall not differ from the nominal diameter more than the limit deviations given in Table 9.
Table 9
| Průměr kuličky | Mezní úchylky |
|---|---|
| 10 mm | ± 0,005 mm |
| 5 mm | ± 0,004 mm |
| 2,5 mm | ± 0,003 mm |
| 1 mm | ± 0,003 mm |
2.1.3.3 Measuring equipment
The scale of the measuring device shall be divided in such a way as to allow the measurement of the diameter of the plate to be determined with an accuracy of ± 0,5 per cent.
The measuring equipment shall be verified by measurements carried out on an objective micrometer at at least five intervals for each operating range. The maximum error shall not exceed 0,5 per cent.
When measuring the projected area, the maximum error shall not exceed 1%.
2.1.3.4. Error and reliability
The permitted errors and the reliability of the hardometer are given in Table 10.
Table 10
| Tvrdost referenční destičky HBW | Dovolená spolehlivost tvrdoměru mm | Dovolená chyba tvrdoměru % z H |
|---|---|---|
| ≤ 125 | 0,030 | 3 |
| 125 < HBW ≤ 225 | 0,025 | 2,5 |
| > 225 | 0,020 | 2 |
2.2 TECHNICAL REQUIREMENTS
2.2.1. Labels and marks
The special inscriptions and markings on the hardometer outside the normal marking shall be replaced by a technical document containing:
(a) a list of all accessories belonging to the hardness meter, indicating the manufacturers and the production or other identification numbers;
(b) the number of certificates for each installation (e.g. measuring equipment, hardworking plates), if their calibration or verification has been carried out; and
(c) the methods and scales that can be measured by the hardness meter.
3. APPROVAL
3.1. Procedure for type approval
The approval procedure shall consist of:
(a) an assessment of the documents1) on the gauge which the applicant is required to submit to the assessor;
(b) preliminary assessment;
(c) roadworthiness tests;
(d) tests by direct and indirect measurement;
(e) drawing up type-approval documents and issuing certificates; if applicable, the stopping of the type-approval procedure if the hardness gauge does not comply with all the requirements of this Regulation.
3.1.1 Rockwell hardness meters
3.1.1.1 General conditions
Before measuring a Rockwell-type hardness gauge, check to ensure that:
(a) the hardness gauge is correctly established;
b) the push pin holding the intrusion body may move in its guidance,
c) the inside holder is firmly connected to the push pin,
d) the test load may be applied and relieved without impact, shaking and in such a way as not to affect reading;
(e) the reading shall not be affected by the movements of the test body or by the deformation of the stand.
3.1.1.2. Direct measurement method
3.1.1.2.1. Direct measurement should be performed at (23 ± 5) ° C. If measurements are made at a different temperature, the temperature shall be indicated in the measurement report.
3.1.1.2.1. The instruments used in the measurement shall be connected to state etalons.
3.1.1.2.2. Direct measurement shall include:
(a) measuring the test load;
(b) the measurement of the impactor;
(c) measurement of depth measuring equipment.
3.1.1.2.3. Test load measurement:
The preliminary test load and each total test load to be applied shall be measured and, whenever possible, measurements shall be made in at least three positions of the pressure pin evenly distributed within the range of its movement during testing. The delay of the test load shall be at least two seconds.
The load shall be measured either by measuring either the class 1 load gauge or by balancing the counterforce to an accuracy of ± 2,0% applied by means of an etalon mass and by using a mechanical transmission.
Three readings shall be made for each load and each position of the push pin. The measurement shall be carried out in such a way that, at each measurement, the reading of the preliminary load value, then the total load, and again after the relief, the second reading of the preliminary load is carried out.
3.1.1.2.4. Intruder measurement:
In order to ensure reliable measurement of conical intrusions, both direct and indirect measurements must be made.
3.1.1.2.4.1 Direct measurement of conical intrusions
Check the surface of the intrusion panel. To be performed visually using a suitable microscope. The body must be polished and have no surface defects.
Measurement of the geometry of the conical impactor may be performed by direct measurement or by measuring its projection on the projection surface. The measurements shall be made in at least four evenly spaced sections.
Measurements shall be made of the vertical angle, radius of curvature, differences of equality forming the lines of the diamond cone and angle between the axis of the diamond cone and the axis of the holder of the intrusion body. Four measurements shall be made each time and the value of the individual surface parameters shall be calculated as the arithmetic mean of the individual measurements. The measured results shall not exceed the tolerances specified in paragraph 2.1.1.
3.1.1.2.4.2 Indirect measurement of conical impactor
The measurements shall be carried out on four hardening plates by first carrying out at least three measurements of the reference intrusion body and then being carried out in the vicinity of such plates under the same conditions by means of a printed intrusion body. The average hardness values of individual wafers measured by individual intruders shall be calculated and compared. The tolerances of the measured hardness between the measurements made by the reference intrusion body and the measured intrusion are given in paragraph 2.1.1.
3.1.1.2.4.3 Measurement of balls
For the purpose of measuring the size and hardness of balls, a random ball shall be considered as sufficient test. The ball on which the hardness was measured must be eliminated.
The balls shall be polished and free from surface defects, the inspection shall be carried out using a suitable microscope.
The user must either measure the balls to ensure that they meet all the requirements or obtain from the supplier a certificate that the balls meet all the requirements.
The diameter of the ball shall be determined by calculating the mean from at least three individual values of the diameters measured in the different positions of the ball.
All requirements are given in paragraph 2.1.1.
3.1.1.2.5.
In most cases, the measurement of the intruders of both balls and cones is carried out by the designated workplace of the Czech Metrology Institute, or by other calibration laboratories, which are suitably equipped for these measurements. When conducting the tests for type approval of a hardometer, the calibration sheets, for ball certificates from manufacturers, shall be checked for individual intruders which are part of the test hardometer.
3.1.1.2.6. Measurement of depth measuring devices
The device for measuring the depth of the printing shall be measured in at least three positions, including positions corresponding to the smallest and greatest hardness for which scales are normally used, during the displacement of the intrusion body in the direction of increasing hardness.
The apparatus used for measuring depth meters shall have an accuracy of 0,0002 mm.
If it is not possible to measure the depth measurement device directly, the modified indirect measurement may be made by testing hardness with reference plates and reference intrusion bodies. It is necessary to know the corrections for the reference entry body. At least three prints shall be made on the three Rockwell C scale reference plates. Calculate the mean hardness on each plate and add the correction of the reference impactor to that hardness. The hardness thus calculated on each plate shall not differ by more than 0,8 HRC from the face value of the hardening plate.
3.1.1.3. Indirect measurement method
3.1.1.3.1. Indirect measurements shall be made at (23 ± 5) ° C using calibration reference hardness plates. These plates must be calibrated at the Czech Metroloic Institute.
3.1.1.3.2. The hard gauge shall be measured for each scale the hard gauge allows to measure. The reference plates of the three ranges given in Table 3 in paragraph 2.1.1 shall be used for each scale measured.
On each reference plate, five prints evenly distributed over the test surface shall be carried out and each hardness value shall be determined in the range of 0,2 units of scale. Before such printing, at least two pre-printing marks shall be carried out to ensure that the reference plate, intrusion pad and pad are correctly established. The results of these preliminary prints shall not be included. The measured results shall then calculate the reliability and error of the hardness meter. The permissible errors and reliability values are given in point 2.1.1.
3.1.1.3.3 Reliability
For each hard plate H1, H2, H3, H4, H5, the hardness values are measured by increasing size. The reliability of the hardometer under selected conditions is determined by the difference:
H5 - H1
The average H-value of five prints is defined as follows:
H H1 + H2 + H3 + H4 + H55
where H1, H2, H3, H4, H5 are the hardness values corresponding to five printed prints.
3.1.1.3.4 Error
The hardometer error in selected conditions is expressed by the difference:
H-H
where H ^ s is the average hardness value
H specific hardness of reference plates used
3.1.2 Vickers hardness meters
3.1.2.1 General conditions
Before measuring a Vickers-type hardness gauge, it shall be checked to ensure that:
(a) the hardness gauge is correctly established;
b) the push pin holding the intrusion body may move in its guidance,
c) the inside holder is firmly connected to the push pin,
(d) the test load may be applied and relieved without impact, shaking and in such a way as not to affect reading.
If the measuring device is part of a hardometer, the change from the relief of the test load to the moment of measurement shall not affect reading. Lighting does not affect reading value. The centre of the printing is preferably in the centre of the field of vision.
3.1.2.2. Direct measurement method
3.1.2.2.1. Direct measurement should be performed at (23 ± 5) ° C. If measurements are made at a different temperature, the temperature shall be indicated in the measurement report.
3.1.2.2.2. The instruments used in the measurement shall be connected to state etalons.
3.1.2.2.3. Direct measurement shall include:
(a) measuring the test load;
(b) the measurement of the impactor;
(c) measuring the measuring device.
3.1.2.2.4. Test load measurement:
Each test load to be applied shall be measured and, whenever possible, measured in at least three positions of the pressure pin evenly distributed within the range of its movement during testing.
The load shall be measured either by measuring either the class 1 load gauge or by balancing the counterforce to an accuracy of ± 2,0% applied by means of an etalon mass and by using a mechanical transmission.
Three readings shall be made for each load and each position of the push pin. The push pin shall move in the same direction as during the test immediately before each reading.
3.1.2.2.5 Measurement of the intrusion system
The intrusion is in the shape of a regular four-sided needle.
Check the surface of the intrusion panel. This should be done visually using a suitable microscope. The body must be polished and have no surface defects.
The measurement of the geometry of the impactor may be done by direct measurement or by measuring its projection on the projection surface.
The measurement of the vertical angle of the opposite walls, the roof, and the angle between the axis of the diamond needle and the axis of the holder of the intrusion body shall be carried out. The value of each surface parameter shall be calculated as the arithmetic mean of each measurement. The measurement of the vertical angle shall be done by measuring the angles of opposite walls and the arithmetic mean of these measurements shall be the resulting peak angle of the intrusion body. Other parameters are measured in four sections. The measured results shall not exceed the permitted limits referred to in paragraph 2.1.2.
3.1.2.2.6 Note
In most cases, the measurement of the intruders is performed by the designated workplace of the Czech Metrology Institute or other calibration laboratories, which are suitably equipped for these measurements. When conducting the tests for the type approval of a hardometer, the calibration sheets shall be checked for the individual intruders which are part of the test hardness gauge.
3.1.2.2.7 Measurement of measuring equipment
The measurement capability depends on the size of the printing material that can be measured on the measuring device.
The measuring equipment shall be measured on an objective micrometer at least five intervals for each operating range.
If it is not possible to measure the measuring device directly, the modified indirect measurement may be made by testing hardness with reference plates. The measurement shall be made by measuring the reference plate on each reference plate, as a general rule on reference plates to be used for indirect measurement of the hardness meter. The measurement device error expressed as a percentage of the middle diagonal of the printing shall not exceed 1%.
3.1.2.3. Indirect measurement method
3.1.2.3.1. Indirect measurements shall be made at (23 ± 5) ° C using calibration reference hardness plates. These plates must be calibrated at the Czech Metrology Institute.
3.1.2.3.2. In the case of measurements of the hardness measures applicable to several test loads, at least two of these loads shall be selected. One of them must be the load most frequently used. At least two hardness plates of two different hardness ranges shall be used for each test load selected. It is recommended to use three hardening plates in the following ranges:
≤ 225 HV
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Regulation Information
| Citation | Decree No. 68 / 2004 Coll. |
|---|---|
| Regulation Type | - |
| Author | - |
| Collection | Code of Laws |
| Date of Promulgation | 24.02.2004 |
|---|---|
| Effective from | 01.03.2004 |
| Effective until | - |
| Status | Valid |
The regulation text is for informational purposes only.
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