1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards TEST METHOD FOR THE IMPACT STRENGTH OF PLASTIC STANDARD TEST PIECE EDS-T-7514 ISSUED DATE: 1994. 08. 31 REVISED DATE: 2006. 06. 19 VERSION: 5 EDS-T-7514TEST METHOD FOR THE IMPACT STRENGTH OF PLASTIC STANDARD TEST PIEC
2、E PAGE: 1/5 ISSUED DATE: 1994. 08. 31 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 1. SCOPE This standard is used to determine the IZOD impact strength of plastic standard test pieces 2. DEFINITION 2.1. Unnotched impact strength : The unnotched impact strength is the striking en
3、ergy absorbed by the unnotched test piece relative to the width of the test piece. 2.2. Notch impact strength : The notch impact strength is the striking energy absorbed by the notched test piece relative to the width of the test piece. 2.3. Relative notch impact strength : The relative notch impact
4、 strength is the ratio obtained from the notch impact strength and the impact strength. 2.4. Estimated net IZOD impact strength : For the specimen of less than 2.7kgfcm/cm of notch, the estimated impact strength to correct the toss energy 3. TEST PIECES 3.1. Dimensions of unnotched and notched test
5、pieces to determine impact strength are as shown in Table 1 and Fig. 1. Table 1. Dimensions for unnotched and notched test pieces(mm) Test pieces Length (C) Width (W) Thickness of unnotched test pieces (E) Residual thickness of notched test pieces (A) Dimension 60.363.5 312.7 12.70.15 10.160.05 3.2.
6、 Dimensions of notch of the notched test pieces are described as follows. Angle of the notch : 451 Radius of curvature : 0.250.05 mm 3.3. Unless otherwise specified, at least 5 pieces are tested and record the thickness of test pieces. 4. CONDITIONING 4.1. Follow the conditioning requirements specif
7、ied in the drawing or material standard. Unless otherwise specified, leave the test pieces under the condition of (232) in temperature and (505)% in relative humidity for minimum 40 hours prior to the test. 4.2. For some hygroscopic materials, such as nylons, it requires sealing the specimens in wat
8、er vapor-impermeable containers as soon as molded and not removing them until ready for testing. EDS-T-7514TEST METHOD FOR THE IMPACT STRENGTH OF PLASTIC STANDARD TEST PIECE PAGE: 2/5 ISSUED DATE: 1994. 08. 31 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 5. APPARATUS 5.1. Pendul
9、um IZOD impact testing machine. 5.1.1. Pendulum IZOD impact testing machine is shown in Fig. 2. 5.1.2. The machine shall consist of a machine base on which is mounted a vise for holding the test piece and to which is connected, through a rigid frame and anti-friction bearing, one of a number of pend
10、ulum-type hammers, plus a pendulum holding and releasing mechanism for indicating the excess energy remaining in the pendulum after breaking the specimen. 5.2. Vernier Calipers 6. PROCEDURE 6.1. This test method is used to test for materials of more than 2.7kgfcm/cm of notch, and for materials of le
11、ss than the value, it is stated in clause 8. 6.2. In a range of pendulums having energies from 2.710 to 21.680 J, it is selected the one that shall be such that not less than 10% and not more than 85% of its maximum striking energy is absorbed by the test piece. 6.3. Check the length and width of te
12、st piece for conformity with the requirements of Table 1, it is described in clause 3.1 Measure the thickness of each test piece with a vernier calipers. 6.4. Notching shall be done on a milling machine. (During notching to the test piece, the blade speed and feeding speed of the milling machine sha
13、ll be maintained constant. To reduce heat generated during notching, use of gas or liquid refrigerant is recommended.) 6.5. With the excess energy indicating pointer in its normal starting position but without a specimen in the vise, release the pendulum from its normal position and note the positio
14、n the pointer attains after the swing as one reading of factor A. 6.6. Without resetting the pointer, raise the pendulum and release again. The pointer should move up the scale an additional amount. Repeat until a swing as one reading of factor B. 6.7. Repeat the above two operations several times a
15、nd calculate and record the average factor A and B reading. 6.8. For notched test specimen, it is essential that notched surface be machined parallel to its opposite surface within 0.025 mm, Other test pieces shall be placed at the correct positions on the fixture jig and fastened securely. 6.9. Rel
16、ease the pendulum and note and record the excess energy remaining in the pendulum after breaking the specimen, together with a description of the appearance of the broken specimen. EDS-T-7514TEST METHOD FOR THE IMPACT STRENGTH OF PLASTIC STANDARD TEST PIECE PAGE: 3/5 ISSUED DATE: 1994. 08. 31 REVISE
17、D DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology CB : Completed Break - a break in which the specimen separates into two or more pieces HB : Hinge Break - an incomplete break such that one part of the specimen cannot support itself above the horizontal when the other part is held vertical
18、ly (less than 90oincluded angle). PB : Partial Break - an incomplete break that does not meet the definition for a hinge break but has fractured at least 90% of the distance between the vertex of the notch and the opposite side. NB : Non Break - an incomplete break where the fracture extends less th
19、an 90% of the distance between the vertex of notch and the opposite side. 7. EVALUATION 7.1. Obtain the net value to consider a air resistance and friction from the indicated angle and factors A and B (see 6.7) using the Angle to Energy Table. 7.2. Compare the net value so found with the energy requ
20、irement of the hammer specified in 6.2. If a hammer of a improper energy was used, discard the result and make additional test on new test specimen with the proper hammer. If the proper hammer was used, divide the net value so found by the measured width of the particular specimen to obtain its impa
21、ct strength in kgfcm per of width. 8. TEST METHOD FOR MATERIALS OF LESS THAN 2.7 kgfcm/cm OF NOTCH 8.1. For relatively brittle materials for which fracture propagation energy is small in comparison with the fracture initiation energy, the indicated impact energy absorbed is the sum of the energies r
22、equired to initiate fracture of the specimen, and to throw free end of the broken specimen (“toss correction“). 8.2. The procedure shall be the same as in section 6 with the addition of a procedure for estimating the energy to toss the broken specimen part. 8.3. To correct the toss energy, this is d
23、one by repositioning the free end of the broken specimen on the clamped portion and striking it a second time with the pendulum released in such a way as to impart to the specimen approximately the same velocity it had attained during the test. This is done by releasing the pendulum from a height co
24、rresponding to that to which it rose following the breakage of the test specimen. 8.4. The energy to toss is then considered to be the difference between the reading described above and the free swing reading obtained from this height. 8.5. The difference between the IZOD impact strength and the tos
25、s correction reported as the estimated net IZOD impact strength. 9. EXPRESSION OF RESULTS Impact strength shall be the arithmetical mean of each test results and presented in kgfcm/cm. EDS-T-7514TEST METHOD FOR THE IMPACT STRENGTH OF PLASTIC STANDARD TEST PIECE PAGE: 4/5 ISSUED DATE: 1994. 08. 31 RE
26、VISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 10. CODING SYSTEM Impact strength shall be specified on the drawing or material specification as follows. IZOD Impact strength to EDS-T-7514 - min 30 5 kgfcm/cm Requirements Test method Test item 11. DEVIATIONS Deviations from the above
27、 test conditions shall be agreed upon and specified on the drawing or material standard and also in the test certificates or reports, etc. 12. REFERENCE ASTM D 256 Standard test method for impact resistance of plastic and electrical insulating materials. EDS-T-7514TEST METHOD FOR THE IMPACT STRENGTH OF PLASTIC STANDARD TEST PIECE PAGE: 5/5 ISSUED DATE: 1994. 08. 31 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology FIG 1. Dimension of IZOD Type Test Specimen FIG 2. Cantilever Beam (IZOD-Type) Impact Machine
