GOST 8.398-80
GOST 8.398−80 State system of ensuring unity of measurements (GSI). Instruments for measuring the hardness of metals and alloys. Methods and means of verification (Change No. 1)
GOST 8.398−80
Group Т88.1*
___________________________
* In The «Index State
standards 2001"
the group Т88.2.
Note the «CODE"
STATE STANDARD OF THE USSR
State system for ensuring the uniformity of measurements
INSTRUMENTS FOR MEASURING THE HARDNESS OF METALS AND ALLOYS
Methods and means of verification
State system for ensuring the uniformity of measurements.
Hardness testing machines for metals and alloys.
Methods and means of verification
Date of introduction 1981−07−01
The decision of the State Committee USSR on standards on August 28, 1980 No. 4479 term introduction installed with 01.07.81
INSTEAD of the User 235−66, GOST 8.043−72 and GOST 17191−71
REPRINT (April 1985) Change 1, approved in January 1983 (ICS 5−83).
This standard applies to devices for measuring the hardness — hardness Brinell (TB), Vickers (TV), Rockwell (TP) and Super-Rockwell (TCP) and combined fixed and universal hardness corresponding to GOST 23677−79, and portable, relevant GOST 9030−75, and establishes the methods and means of their initial and periodic verifications.
The standard fully conforms to the recommendations of the CMEA 28−74 PC, PC 293−74, PC 294−74, ISO recommendations R 146−68, R 156−67, R 716−68, OIML recommendations N 37, 38, 39.
(Changed edition, Rev. N 1).
1. OPERATIONS AND MEANS OF VERIFICATION
1.1. During the verification you should perform the operation and use of calibration instruments listed in the table.
| The commitment of operation in | ||||
| The name of the operation verification | Rooms points of the standard |
The name means testing and regulatory specifications | manufacture and repair |
handling and storage |
| External examination |
3.1 | - | Yes | Yes |
| Verification of interaction of parts of the device |
3.2 | Level squared 100−0,2 according to GOST 9392−75 | Yes | Yes |
| Check mismatch the axis of the working table of the device with the axis of the tip |
3.3 | Microscope according to GOST 8074−82 | Yes | No |
| Determination of metrological parameters of hardness of the type of TB |
3.4 | |||
| Visual inspection of the ball | 3.4.1 | Magnifying glass according to GOST 25706−83 with magnification 5x |
Yes | Yes |
| The measurement of the diameter of the ball | 3.4.2 | OPTIMER S-200−1 according to GOST 5405−75 |
Yes | Yes |
| The hardness of the ball | 3.4.3 | The hardness of types of TV according to GOST 23677−79, load of 98.1 N (10 kgf) |
Yes | No |
| Verification of optical measuring device | 3.4.4 | Stage micrometer-type OMO GOST 7513−75; | Yes | No |
| bar is a measure of length according to GOST 12069−78 type II accuracy class 0.2 s division value 1 mm |
||||
| Determine the relative error of the instrument loads |
3.4.5 | Model portable dynamometers types of DOS and DOS of 0.1−3 according to GOST 9500−84; | Yes | Yes |
| Determine the relative error of the instrument for hardness |
3.4.6 | Exemplary measures hardness 2nd class MTB type according to GOST 9031−75 | Yes | Yes |
| Determination of metrological parameters of the hardness testers of the type of TV |
3.5 | |||
| Visual inspection of the tip of the diamond |
3.5.1 | Microscope according to GOST 8074−82 | Yes | Yes |
| Verification of optical measuring device | 3.5.2 | Exemplary scale 2-d level, object-micrometer type OMO GOST 7513−75 |
Yes | No |
| Determine the relative error of the instrument loads |
3.5.3 | Model portable dynamometers types of DOS and DOS of 0.05−0.1 in GOST 9500−84 | Yes | No |
| the relative error of the instrument for hardness | 3.5.4 | Exemplary measures hardness 2nd class MTB types according to GOST 9031−75 |
Yes | Yes |
| Determination of metrological parameters of hardness of type TP and TCP |
3.6 | |||
| Visual inspection of the tip | 3.6.1 | Magnifying glass according to GOST 25706−83 with 5x magnification, microscope according to GOST 8074−82 |
Yes | Yes |
| The hardness of the ball | 3.6.2 | The hardness of types of TV according to GOST 23677−79 with a load of 98.1 N (10 kgf) |
Yes | Yes |
| Determine the relative error of the instrument loads |
3.6.3 | Model portable dynamometers types of DOS and DOS 0,05−0,2 GOST 9500−84 | Yes | No |
| Determining the absolute error of the instrument for hardness |
3.6.4 | Exemplary measures hardness 2nd discharge types and MTR MTSR according to GOST 9031−75 | Yes | Yes |
Notes:
1. Allowed to use other means of verification, with similar legal characteristics.
2. When replacing bulbs appliance bulb of the group, not included in his kit when repair and maintenance is carried out checking at the PP. 3.4.2, 3.4.3;
3. After repair of the optical measuring device is carried out verification by the PP. 3.4.4 and
Optical measuring device of hardness testers, having built-in optical system, can be believed in the laboratory of linear measurements, they issue the verification certificate.
4. In the operation of the verification device according to claim 3.4.6 carried out at least once a year, and also during the extraordinary calibration. In this case, it is allowed not to perform verification at PP. 3.4.2 and
(Changed edition, Rev. N 1).
2. CONDITIONS OF VERIFICATION AND PREPARATION FOR IT
2.1. Stationary devices being checked at the place of operation. Portable devices to check in the laboratory the appropriate metrological service.
2.2. Verified devices must be installed on tables, protecting the device from exposure to vibrations transmitted through the walls and floor of the building. Electrical appliances must be grounded.
2.3. The temperature of the air in the room is from 15 to 28 °C. the relative humidity of the indoor air of 65± 5%.
2.4. The surface of the desktop and boarding portion of the screw must be clean, the surface of the working table and the working part of the tip needs to be degreased.
3. VERIFICATION
3.1. External examination
3.1.1. Verified device should be equipped with the GOST and GOST 23677−79 9030−75.
3.1.2. All the parts of the device and its accessories must not be corrosion and signs of any mechanical damage. The color of the device should be uniform, with no gaps, stains and peeling.
3.2. Verification of interaction of parts of the device
3.2.1. The plane of the working table should be horizontal according to the testimony of the squared level set in two mutually perpendicular directions. The deviation from the horizontal should not exceed 6 smallest divisions of the level.
3.2.2. If the handwheel lifting screw needs to be lowered and raised smoothly without jerking, jamming and should not have a radial backlash.
3.2.3. The load end should be made smoothly, without jerks and jamming.
3.3. Check mismatch the axis of the working table of the device with the axis of the tip
3.3.1. Check mismatch axis desktop device type TB carried out on the soft standard measure of hardness (HB 100±25). Ball tip is replaced by a steel cone with an apex angle of 90 °. Measure the hardness of lying on the desktop, press the lifting screw to the cone and applied the prints. When applying each subsequent imprint Desk with a measure turn. The diameter of the circle formed by the centers of the prints is measured using a microscope type MMI-2.
The discrepancy between the axis of the working table with the axis of the tip equal to half the measured diameter must not exceed 0,4 mm.
3.3.2. Check mismatch axis desktop device type TP (TCP) is performed on a standard measure of hardness of type MTR (MTSR). Diamond tip apply a pre-load applied to the prints. When applying each subsequent imprint Desk with a measure turn. The diameter of the circle formed by the centers of the prints is measured using a microscope type MMI-2.
The discrepancy between the axis of the working table with the axis of the tip shall not exceed 0,3 mm.
3.3.3. Check mismatch axis desktop device type of TV carried out on a standard measure of hardness of the type of MTV. The tip of the instrument under the action of the smallest load is applied as a thumbprint, each time turning Desk. The diameter of the circle formed by the centers of the prints is measured using a microscope type MMI-2.
The discrepancy between the axis of the working table with the axis of the tip must not exceed 0,2 mm.
3.4. Determination of metrological parameters of hardness of the type of TB
3.4.1. Visual inspection of the ball
On the ball surface should be free of dents, scratches, corrosion and other mechanical damage.
3.4.2. The measurement of the diameter of the ball
The diameter of the ball measured in three directions corresponding to the directions of the axes of the three-dimensional rectangular coordinate system. The deviation of the measurements in each direction and the arithmetic mean deviation of these results from the nominal diameter should correspond to GOST 9012−59 (ST SEV 468−77).
3.4.3. The hardness of the ball
The hardness of the ball is determined by sampling for the two balls from the group consisting of up to 10 units, and 5% (but not less than 2) from the group of greater size. All the balls of the group take from the same factory batch. The whole group recognize valid if the hardness of each bulb not less than 850 HV 10, i.e. the average diagonal imprints of the pyramid do not exceed the following values:
0,143 mm for balls with a diameter of 2.5 mm;
0,145 mm «"" 5 mm;
Of 0.146 mm «"" 10 mm.
Beads coated with fingerprints to the operation is not allowed.
3.4.4. Verification of optical measuring device
3.4.4.1. Determination of the error of the millimetre divisions on the scale.
To determine the error of the optical microscope with a scale division of not more than 0.05 mm under the ocular scale set the stage micrometer so that the initial touch of his scales coincide with the initial bar check millimetric divisions of the ocular scale of the microscope. The mismatch between the end bar calibratable millimeter division of the ocular scale and the final touch of the object micrometer evaluate on the eye on the object micrometer. The true length of the millimeter divisions of the ocular scale of the microscope is determined in the intervals 0−1; 2−3; 3−4; 5−6 mm. the Microscope is mounted on the tripod over the coordinate table.
To determine the error projection device on the object table of the device is placed stage micrometer so that the image of primary stroke coincided with the initial stroke scale screen, check the corresponding millimeter division. The mismatch between the end bar calibratable scale division of screen image for the final stroke scale object-micrometer, determine the measuring micrometer head of the device, after checking the position of the zero mark of the micrometer screw. The length of the scale divisions of the screen is defined in the interval 0−1; 2−3; 3−4; 5−6 mm. If the screen consists of two movable halves, digitized in the opposite direction, then measure the length of the tick marks in intervals 3−2; 1−0 in the right half of the screen.
The accuracy of millimeter scale division shall not exceed the values specified in GOST and GOST 23677−79 9030−75.
3.4.4.2. Determination of the error of the length scale
To determine the error of a measuring microscope the microscope is placed a bar so that the end bar of the ocular scale of the microscope was combined with one of the strokes of the action, and the initial ocular scale bar was inside the first mm bar measure divided into tenths of a millimeter. The mismatch between the initial touch verified the ocular scale of the microscope and the closest bar bar measures are evaluated on the eye. The microscope is mounted on the tripod over the coordinate table.
To determine the error projection device to the desktop device is placed bar measure so that the image of the initial stroke, the stroke measures coincided with the initial (leftmost) stroke scale screen. The mismatch between the final (rightmost) stroke scale screen and the closest bar bar measures should be defined micrometer measuring head of the device. If the screen consists of two movable halves, the pre-measurement should be aligned the zero mark of both halves, and checked the correct position of the bullet mark of the measuring micrometer head.
Error full length of the scale must not exceed the values specified in GOST and GOST 23677−79 9030−75.
3.4.4.3. The pricing division
The price of division of the measuring microscope with an ocular screw micrometer with a scale division of not more than 0.01 mm is determined at the beginning, middle and end of the measurement range. Carry out five measurements of the length of the scale object-micrometer graduations in the ocular micrometer. The price of division determine the ratio of the length of the scale object-micrometer for the average path length dimensions of the scale object-micrometer graduations in the ocular micrometer.
3.4.5. Determine the relative error of the instrument loads
The relative error of the device load determine the standard dynamometers: DOS of 0.1 at loads 153; 613 N (15,6; 62,5 kgf) and DOS-3 with loads of 1839; 2452; 7357; 9810; 29430 N (187,5; 250; 750; 1000; 3000 kgf) in the sequence given below:
remove the tip from the device;
establish exemplary dynamometer on the desktop of the device;
set the readout device of the dynamometer in the position taken as zero;
three times load the load cell the maximum load developed by the device;
unload the dynamometer and set it to a readout device to zero. Failure to return the arrows to position zero must not exceed 0.5 of the smallest division of the scale;
load the dynamometer three times for each load. The indicator of the dynamometer read ,
,
and calculate the mean value
in the scale graduation;
the relative error of the device load in percents is calculated by the formula
where — the indicator of the dynamometer, taken from its certificate for the test load in scale divisions;
— the reading of the indicator, the unloaded dynamometer, taken as zero, the scale divisions.
The relative error of the device loads must not exceed the values specified in GOST and GOST 23677−79 9030−75.
(Changed edition, Rev. N 1).
3.4.6. Determine the relative error of the instrument for hardness
To determine the error model as selected depending on the device used in balls and loads. An exemplary measure is applied to five prints, arranging them evenly across the working surface measures. With loads and 29430 9810 N (1000 kgf and 3000) may be applied to measure scanned three times. Measurement of the diameters of the prints is carried out in two mutually perpendicular directions by using the measuring device metrologically approved instrument. If the difference of the diameters of the prints does not exceed 2% of the smallest diameter, calculate the average value of the diameter, which find the hardness. If the difference of the diameters exceeds 2%, then instead of this new imprint is applied. According to the average values of the diameters of five prints calculated arithmetic average value that find hardness according to GOST 9012−59.
The absolute error of the instrument in units of Brinell calculated as the difference between the found hardness value and the hardness value indicated on a standard measure.
Relative error of the instrument is calculated as the ratio of the absolute error of the instrument to the value of the hardness is a good measure in percent.
Relative error of the instrument shall not exceed values specified in GOST and GOST 23677−79 9030−75.
3.5. Determination of metrological parameters of the hardness testers of the type of TV
3.5.1. External examination of the diamond tip
External examination of the diamond tip is performed using microscope in reflected light.
For inspection of the working part of the surface of the diamond adjacent to its top, tip top set up so that the axis of the tip was a continuation of the optical axis of the microscope. Microscope focus at first on the top of the diamond, then, slowly changing the focus, visiting the adjacent surface of the diamond.
The working part of the tip must not have scratches, cracks, chips and other defects.
3.5.2. Verification of optical measuring device
3.5.2.1. Determination of the error of the measuring device
The error projection of a measuring device designed to measure the diagonal of the print size more than 0.2 mm, determined using a model scale. An exemplary scale is placed on a Desk so that the image of primary stroke coincided with the initial stroke scale screen, check the corresponding millimeter division. The mismatch between the end bar calibratable scale division of the screen and the image a final touch of the appropriate division of the scale model is determined by the measuring micrometer head of the device. The length of the scale divisions of the screen is determined in the intervals 0−1, 2−3, 3−4, 5−6. If the screen consists of two movable halves, digitized in the opposite direction, then measure the length of the tick marks in intervals of 3−2, 1−0 mm in the right half of the screen.
To determine the error projection measuring device designed to measure the diagonal of the print size up to 0.2 mm, the desktop device is placed as a model to the initial stroke coincided with the initial stroke scale screen. The mismatch between the scale division of the screen and the image stroke model scale is determined by the measuring micrometer head of the device.
The error of the measuring device must not exceed the values specified in GOST 23677−79.
3.5.2.2. The pricing division
The price of division of the measuring microscope with an ocular screw micrometer determined by the object micrometer, which is placed on the desktop of the device so that in the field of view of the measuring device has got the largest number of divisions. Conduct measurement of the three intervals of the object micrometer. The interval is measured five times, each measurement interval includes six combination of barcode eyepiece with the first stroke and six combined with the final touch of the measured interval. The difference between the counts set the number of divisions on the scale of the measuring device enclosed between the first and last strokes of the measured interval of the object micrometer, and calculate the price of division of the measuring device. The arithmetic mean of three values obtained when testing the three intervals of the object micrometer is a scale measuring device.
3.5.3. Determine the relative error of the instrument loads
The relative error of the device loads determine the same p 3.4.5 with exemplary dynamometers: DOS 0,05 with loads of 49.0; of 98.1 N (5,10 kgs) and DOS of 0.1 at loads of 98.1; of 196.2; 294,3; 490,5; 981,0 N (10; 20; 30; 50 and 100 kgs).
The relative error of the device loads must not exceed the values specified in GOST and GOST 23677−79 9030−75.
(Changed edition, Rev. N 1).
An exemplary measure is applied to five of the prints, placing them evenly across the surface of the action. The measurement of the diagonals of the prints is performed using the measuring device metrologically approved instrument. If the difference of the diagonals of the prints does not exceed 2% of the least of these, calculate the average value of the diagonal, which find the hardness. If the difference between the diagonals exceeds 2%, then applied a new imprint. On the average of the diagonals of five prints calculated arithmetic mean, which determine the hardness according to GOST 2999−75.
The absolute error of the instrument in units of Vickers scale is calculated as a difference was found between the hardness value and the hardness value indicated on a standard measure.
Relative error of the instrument is calculated as the ratio of the absolute error of the instrument to the value of the hardness is a good measure in percent.
Relative error of the instrument shall not exceed values specified in GOST and GOST 23677−79 9030−75.
3.6. Determination of metrological parameters of the hardness testers of the types TP and TCP
3.6.1. Visual inspection of the ball
Visual inspection of the ball is performed using a magnifying glass with five times magnification. On the ball surface should be free of dents, scratches, corrosion and other mechanical damage.
External examination of the diamond tip is carried out analogously to claim
3.6.2. The hardness of the ball
The procedure of selection of ball hardness is according to claim
Beads coated with fingerprints to the operation is not allowed.
3.6.3. Determine the relative error of the instrument loads
The relative error is determined with the aid of exemplary dynamometers: DOS of 0.05 to hardness testers of the type TCP and DOS 0.05, DOS 0.2 for hardness testers of the type TR.
The procedure for determining uncertainties according to claim
3.6.4. Determining the absolute error of the instrument for hardness
The absolute error is determined by exemplary measures the hardness of type MTR (set of five measures 23677−79 GOST and GOST 9030−75) — for the hardness of type TP and type MTSR (set of six measures according to GOST 23677−79) — for the hardness of type TCP.
An exemplary measure is applied to one or two prints for a snug fit to the desktop. Then put five prints all over the work surface measures and measure hardness.
The absolute accuracy of the device is determined as the difference between the arithmetic average of the results of five measurements and the hardness value indicated on a standard measure, which shall not exceed the values specified in GOST and GOST 23677−79 9030−75.
4. THE RESULTS OF THE VERIFICATION
4.1. Positive results of primary testing devices to measure the hardness issue a stamp in the passport.
4.2. The instruments for measuring the hardness, the ones that are suitable when state verification, issue a certificate in the prescribed form indicating the number of the diamond tip, which carried out the verification.
4.3. The results of periodic Agency verification issue a stamp in the passport.
4.4. The results of the verification of the instrument are entered in the Protocol, the form of which is given in mandatory Appendix.
4.5. Devices for measuring hardness does not satisfy the requirements of this standard, and the application is not allowed.
APPLICATION (required) PROTOCOL # _ _ verification of hardness tester type _________, owned by
APP
Mandatory
PROTOCOL № _________
calibration of hardness tester type ___________________, owned by
_________________________________________________________________________________
name of the organization
1. Serial number ________ Year of manufacture _______Manufacturer _____________________
2. The type and number of verified tip of the instrument (the nominal diameter of the ball) ___________
3. Believed __________________ 4. Temperature when testing _________°With
date
5. The results of the external examination and verification of interaction of parts of the device
_________________________________________________________________________________
6. The result of the external inspection of the tip (ball) ___________________________________
7. The result of the determination of hardness of balls (Vickers)
| Ball | Length of diagonal, mm | Conclusion about fitness balls | |
| 1 | 2 | ||
| 1 | |||
| 2 | |||
8. The results of verification of optical measuring device__________________
type
Price smallest division of the scale __________________ mm
The error measuring device of the hardness tester of type of TV
when measuring the diagonal of the print size to 0.2 mm _______mm.
when measuring the diagonal of the print size more than 0.2 mm _______mm.
The error of the length scale ________ mm
Error four millimeter scale intervals:
interval «0−1» _______,
interval «2−3» _______ ,
interval «3−4» _______ ,
interval «5−6» _______ .
9. The results of the determination error of the instrument loads by means of exemplary dynamometer
type _______№ _______
| The nominal value of the load, N (kgf) | Indicator dynamometer | Error loading (%) of the actual value | ||
| 1 | 2 | 3 | ||
10. Determination of the error of the readings for hardness
| Number of exemplary measures hardness | Hardness is a good measure, units TV. |
Check the scale of the instrument | Counts units, TV.; diameters (diagonal) prints mm | The error check tool | |||||
| 1 | 2 | 3 | 4 | 5 | The average arifma — MATIC value | ||||
Conclusion. Based on the results of the calibration device 
Issued certificate number_______from ________19 ___year.
The audit was conducted____________________________
signature
