1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology. Standards ROCKWELL HARDNESS TEST OF PLASTICS EDS-T-7517 ISSUED DATE: 1995. 09. 06 REVISED DATE: 2006. 05. 23 VERSION: 4 EDS-T-7517 ROCKWELL HARDNESS TEST OF PLASTICS PAGE: 1/4 ISSUED DATE: 1995. 09. 06 REVISED DATE: 2006. 05.
2、23 VERSION: 4 GM DAEWOO Auto & Technology 1. PURPOSE This standard aims at specifying the method of measuring Rockwell M, L and R hardness of plastics. In principle, the range of M, L and R hardness shall be 50150. Plastic film tapes and plastic foam are excluded. 2. DEFINITION 2.1. Rockwell hardnes
3、s When the ball indenter is preliminary pressed under the minor load, additionally under the major load and then under the minor load again, the hardness is determined by the difference between the depth “h“ of indentation under those two minor loads mentioned above. The type of the indenter, minor
4、load, major load and hardness defining formula are as shown in the Table. 2.2. Scale of hardness In case of Rockwell hardness, the “scale“ is so defined as a combination of indenters, major load and hardness defining formula, with an inherent symbol. The content is as shown in the Table. Table Scale
5、 Rockwell hardness Indenter diameterMinor load (Kgf) Major load (Kgf) Hardness defining formulaR HRR 12.70.0025 mm(1/2 In) 60 130500h L HRL 6.350.0025 10 (h in mm) M HRM (1/4 In) 100 3. CONDITIONING Conditioning shall be done in accordance with pre-processing requirements specified in drawings or ma
6、terial specification. When not specified, test sample shall be soaked for 24 hours or longer at temperature of 232 and relative humidity of 505%. 3.1. Test temperature and humidity Test shall be conducted at temperature of (232) and relative humidity of (505)%. 4. APPARATUS 4.1. Construction The app
7、aratus shall be composed of the stand, specimen support, loading device, hardness indicator and indenter. EDS-T-7517 ROCKWELL HARDNESS TEST OF PLASTICS PAGE: 2/4 ISSUED DATE: 1995. 09. 06 REVISED DATE: 2006. 05. 23 VERSION: 4 GM DAEWOO Auto & Technology 4.2. Stand and specimen support 4.2.1. The sta
8、nd and specimen support shall have sufficient rigidity and stability to withstand max. load. 4.2.2. The specimen stage plane shall be set perpendicular to the mounting axis of the indenter in principle. 4.2.3. Each measured return displacement shall be within 0.5 of hardness. Distribution of five re
9、petition (Max. - Min.) shall not exceed 0.4 from hardness value. Measurement of return displacement shall be made following two times of preliminary operation. 4.2.4. The return displacement shall be the difference of displacement in loading direction of the stand and specimen support under two stan
10、dard loads when the load changes in the order of initial standard load, test load and standard load again as in ordinary hardness test, with the indenter mounting axis directly contacting the specimen stage or with a supplementary jig placed between the indenter mounting axis and specimen stage. The
11、 calculation formula is as follows: Return displacement = second reading under standard load - first reading under standard load 4.3. Loading device It shall be of a structure that will not generate shock or vibration at a time of application, keeping and removal of the minor and major load. 4.4. Ha
12、rdness indicator 4.4.1. The scale or reading of the hardness indicator shall be the hardness value. 4.4.2. Permissible deviation of the hardness indicator shall be 0.5 of hardness value. 4.5. Indenter 4.5.1. The indenter consists of the steel ball, holder and cap. 4.5.2. The holder and cap shall ens
13、ure both revolution of the ball without resistance when it is mounted and normal measurement of hardness. 4.5.3. Each measured return displacement, including indenter, shall be within 0.7 of hardness and distribution of five repetition (Max. - Min.) shall not exceed 0.5 from hardness value. 5. TEST
14、SPECIMEN 5.1. The test specimen shall have a minimum thickness of 6mm and minimum width of 13mm. 5.2. As a rule, the test surface and opposite one of the specimen has parallel flat surfaces to ensure good seating on the anvil and thus avoid the deflection that may be caused by poor contact. 5.3. The
15、 test surface and opposite one of the specimen shall be smooth and clean. 5.4. The test specimen shall be at least 25mm square if cut from sheet stock, or at least 6cm2in area if from EDS-T-7517 ROCKWELL HARDNESS TEST OF PLASTICS PAGE: 3/4 ISSUED DATE: 1995. 09. 06 REVISED DATE: 2006. 05. 23 VERSION
16、: 4 GM DAEWOO Auto & Technology other shapes. 5.5. The diameter of solid rod test specimens shall be not less than 3 times the diameter of the steel ball indenter. 6. TEST METHOD 6.1. Scale shall be properly selected according to the specimen hardness, test purpose, etc. It is desirable to select sc
17、ale so that hardness obtained is 100 or less. 6.2. The steel ball shall rotate freely when placed on the holder and be clean and free of flaws. 6.3. The specimen stage plane shall be clean. 6.4. When the indenter, specimen stage and etc. are assembled or replaced, or when the elevating screw for the
18、 specimen stage is moved to align with a large stroke, or when test starts, conduct preliminary operation, which is the same as the measuring procedure, twice or more. 6.5. The test specimen shall be placed so that the mounting axis of the indenter is perpendicular to the test surface. The back surf
19、ace of indented portion of the specimen shall be placed as close to the specimen stage as possible. 6.6. The distance between the centers of two adjacent indentations shall preferably be at least 4 d (d is the diameter of the indentation) and the distance from the center any indentation to an edge o
20、f the test specimen shall preferably be at least 2.5 d 6.7. The lifting position of the indenter axis to apply the minor load shall be so determined as to range 5 in hardness to the standard position. Then the zero point of the indicator and scale shall be set. 6.8. Increase of the minor load shall
21、start as soon as possible upon completion of clause 6.7. The duration of applying major load shall generally be 24 seconds. 6.9. The keeping time of the major load shall be 15 seconds from its application. 6.10. After 15 seconds is elapsed, the load shall be reduced to return to the minor load condi
22、tion. 6.11. Read the hardness value up to first place of integer after 15 seconds from starting load reduction, 6.12. Throughout the loading operation, the indenter shall be protected from shock or vibration and the test load shall be increased or decreased smoothly. 6.13. Repeat test for the same s
23、pecimen 3 times or more. and for the other-type piece by each direction. For the anisotropic specimen, conduct test 3 times or more for each direction. 7. CODING SYSTEM EDS-T-7517 ROCKWELL HARDNESS TEST OF PLASTICS PAGE: 4/4 ISSUED DATE: 1995. 09. 06 REVISED DATE: 2006. 05. 23 VERSION: 4 GM DAEWOO A
24、uto & Technology Rockwell hardness shall be indicated as follows in drawings and material specifications: 7.1 Rockwell hardness to EDS-T-7517 83 R Scale Requirements Test method Designation 8. DEVIATIONS Deviations from this test method shall have been agreed upon. These requirements shall be specified on drawings or material specifications and shall be defined on test certification, report etc. 9. REFERENCE ASTM D 785, Standard Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials KS M 3037 , Standard Test Method for Rockwell Hardness of Plastics
