JJG 944-1999 Metal Webster Hardness Tester (Trial) JJG944-1999 Standard download decompression password: www.bzxz.net
This procedure is applicable to the calibration of metal Webster hardness testers with a measuring range of (0~20) HW that are newly manufactured, in use, and after repair.

National Metrology Verification Regulation of the People's Republic of China JJG 944--1999
Metallic Webster Hardness
Testirrg Machine
1999-05--06 Issued
199909-01 Implementation
Issued by the State Administration of Quality and Technical Supervision
JG 944—1999
Verification Regulation of MetalicWehsterHardnessTestingMlachineJJG 944-
This regulation was approved by the State Administration of Quality and Technical Supervision on May 6, 1999, and came into effect on September 1, 1999.
Responsible for: National Technical Committee on Force and Hardness Metrology Drafting Unit: Ordnance Industry 423 Regional Metrology Station China Institute of Metrology
This regulation entrusts the National Technical Committee on Force and Hardness Metrology to be responsible for interpreting the main drafters of this regulation:
J.JG944—1999
Yang Huiqi (China Institute of Metrology) Gu Yuqi {Ordnance Industry 423 Regional Metrology Station Liang Jianwei [Ordnance Industry 423 Regional Metrology Station Participating Drafters:
Peng Yu Shan [Ordnance Industry 423 Regional Metrology Station Zhang Hongyun (National Defense Science and Technology Commission First Metrology and Testing Research Center) Zhang Jinling (China National Institute of Metrology) Liu Yubo [Ordnance Industry 43 Lan Regional Metrology Station) 1
Technical requirements
Verification of buried and verified parts
Aging case implementation method
5 Verification multiplication and verification cycle
JJG944—1999
Appendix A Technical requirements and verification of standard gold Weiss hard chase block Appendix B Aluminum and aluminum alloy HW Conversion table with HRE... Conversion table with IIW and HRE for C soft steel and hard aluminum
JJG 944—1999
Verification procedure for metal Webster hardness tester
This procedure is applicable to the verification of metal Webster hardness (hereinafter referred to as hardness tester) with a measuring range of (020) W that is newly manufactured, in use and repaired.
1 Overview
1.1 The hardness tester is mainly composed of a needle, a test force spring, an indicator and other parts. 1.2 The hardness tester is used to measure the hardness of plates and pipes with a thickness of [-6) mH. It is suitable for aluminum, lead alloys, ferrous metals and relatively soft ferrous metals.
1.3 The basic principle of the hardness test is to use a certain shape of the indenter to press into the sample surface under the action of the standard elastic test force. The indentation depth of 0.01 mm is one indentation hardness unit, and HW is the symbol of the indentation value.
The indentation value is calculated according to the formula (): HW =
In the formula: HW——indentation hardness value:
L—indenter protrusion length (mm).
2 Technical requirements
2.1 The hardness tester should have a chrome plate indicating the instrument name, model, manufacturer name, number, manufacturing license mark and manufacturing date.
2.2 When the hardness tester applies the test force, the indicating part should be flexible, without friction and jamming. 2.3 The bottom of the indenter of the hardness tester is located at the center of the small hole of the buttress and the plane of the circular boss, without visible inclination. 2.4 The allowable error of the upward movement of the indenter for measuring these mechanisms is ±0.5HW. The number of pressure needles, their rigidity, and the main uses are shown in Table 1: Table 1 Types of pressure needles Cone cone Pressure needle Round shape Overall dimensions Cone angle (G) 0.35 Precision Plane diameter (0.4±0.05) Top plane diameter (0.4+0.05) Surface thickness Needle hardness Applicable range Aluminum and aluminum alloy Mild steel and hard aluminum 2.5 Value-added bills and value-added copies JJG 944—1999
Use the standard Webster hardness tester (hereinafter referred to as the tester) to carry out the indication verification. The overall indication and repeatability of the hardness meter should meet the requirements of Table 2:
Hardness range
(5.--18) HW
Verification items and verification conditions
Jingbo difference
Verification items and verification conditions of hardness tester are shown in Table 3
Light items
Cone angle
Extension items and point diameter
Pressure surface sweeping trend
Needle degree
Pressure new model displacement
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Projection or engineering design flow
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High precision two The test standard of the instrument is as follows: The ambient temperature is (1035): 3.2 4 Test method 4.1 Perform an appearance inspection according to 2.1-2.3. 4.2 Test accuracy 1rm 2-199 micrometer 13 Test procedure (.) Accuracy 1TC 100g (Hum) A)
When checking the pressure needle chain angle, the pressure needle should be fixed horizontally and measured on two mutually perpendicular axes. Each side should be measured at least 3 times, and the average value should be taken. The test result should meet the requirements of Table 1. 4.3 Diameter of the end face of the pressure needle
When checking the diameter of the top plane of the pressure needle, fix the needle vertically upward on a special clamp, measure on two mutually perpendicular axes, measure 3 times on each side, and take the average value. The test result should meet the requirements of Table 1. 3
G944—1990||t 4.4 The surface roughness of the positive needle is measured by four-dimensional interference ratio micromirror, and its verification result shall meet the requirements of Table 1. 4.5 The external hardness is verified on the microhardness tester, and its verification result shall meet the requirements of Table 1: 4.G Verification of three-position gauge
Use the block for verification. During the verification, when the pin moves up by 0.5r, 15r, the gauge head indicates 5W, 10HW and 15HW: When the small needle is completely moved up into the needle sleeve, the output value is zero, and the gauge head reading is 20HW. The tolerance shall meet the requirements of 2.4. 4. Hardness tester indication
4.7.1 Zero point accuracy
In the case of placing the standard block, apply the test force, the pressure needle contacts the surface of the test table, and the gauge needle indication shall be (20_0.2)FW.
4.7.2 When using standard hardness tester for value determination
, the distance between two adjacent positive retreat centers and the pressure decay center and the edge of the standard hardness test block shall not be less than 4nm2ml respectively.
4.7.3 When calibrating, measure 6 points on the working surface of the carbon block, ignore the first point, and the other 5 points are evenly distributed. The hardness tester's value tolerance dynamic indication repeatability R shall be calculated using formula (2), (3) and shall comply with the provisions of 2.5. +HW-HW.
R-HWr-.-HWru.
Wherein:
——indication error;Www.bzxZ.net
R——indication checkability;
HW——5-point average position;
HWstandard——hardness standard value;
W, ·5 points;
Minimum repair time:
4.8 The hardness meter in use shall be calibrated according to the regulations of .1 and 4.7, and other items can also be calibrated according to actual conditions.
5 Calibration auxiliary results processing and calibration period
5, after qualified calibration, hardness card will be issued; large network continuous inspection and completion notice card-52 The calibration cycle of the silicon meter is generally [years, so that the unit can conduct key hardness indication inspection according to actual conditions. 3
Appendix A
JIG 944—1999
Standard Metal Vickers Hardness Block [Hereinafter referred to as the punch-through block! Technical requirements and verification requirements are as follows: The working surface and support shall not have any defects such as scratches, leakage marks, etc. Al
The size, flatness, and surface torsion requirements of the punch-through block are shown in Table 1A2
100--153
20-·25
Table Plasticity Accuracy R:
The above is not required.
A3 The quality specifications and uniformity requirements of the punch-through block are shown in Table A2 Table 2
Probe Hardness Range
(5-18,The pressure of the counter-control under TW
is not greater than half of the pressure of the under-control under TW
! The stability of the A-block does not exceed 0.5HW within 1 year: The stability of the decision is expressed by the difference between the average values ​​of the two chains before and after. In order to ensure the reliability of the products, the newly produced hard products must be subjected to human aging treatment and be effective for more than ≠ years before they can be used. A5 Hardness Quick Test: Standard Luke's Quick Tester b.0 Digit Table Interference Microscope Caliper and other inspection tools Flat Hardness Measuring Instrument A6 Hardness Test Before the establishment of the standard hardness tester, the HRE scale of the standard Luke's hardness tester shall be used for the calibration of the hardness block. The calibration result shall be converted into the standard hardness width value HW according to Appendix B and Appendix C. The calibration When measuring 6 points on the working surface in the late sequence, 1 point is not counted, and the other 5 points are evenly distributed. The distance between the center of the two parts and the edge of the hardness block is not less than 4m and 2u respectively. The average of the 5 points is the hardness value of the hardness block. The difference between the maximum and minimum values ​​is the hardness symbol of the hardness block. A7 qualified hardness block shall be issued its inspection certificate, and its overall position and the edge of the surface of the component shall be engraved on it. The AS qualified hardness block shall be used on the working surface and is valid for 2 years: Appendix B
Book on Hardness Value
Circular Dimension Combination Pressure Needle
J.IG 944-1999
Conversion table of HW and HAE for aluminum and aluminum alloy
Spring stiffness 5 N/um
100.51100.9
Appendix ℃
Book's degree value
Toilet pressure needle
JJG 944—1999
Conversion table of HW and HRE for soft steel and hard aluminum
Spring stiffness 145 N/mLm
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