1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards METHOD OF ERICHSEN CUPPING TEST EDS-T-7125 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 2 EDS-T-7125METHOD OF ERICHSEN CUPPING TEST PAGE: 1/2 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSI
2、ON: 2 GM DAEWOO Auto & Technology 1. PURPOSE The standard aims at evaluating the formability of steel sheets, or how much the sheets can be formed to the required shape without generating crack, by measuring ERICHSEN number of steel sheets used for outside and inside plates of automobiles manufactur
3、ed by GMDAT. 2. SCOPE This standard specifies the measuring method of ERICHSEN numbers of sheet metals of 0.1 to 2.0mm in thickness and 70mm and over in width. 3. DEFINITIONS 3.1. ERICHSEN test method: The ERICHSEN test method to be performed by the use of the die and the stretching ring with a cons
4、tant fastening load of approximately 1000kg applied to the test piece. 3.2. ERICHSEN number: The value indicated in millimeters for the distance which the top of the punch have moved from the surface clamped by the stretching ring by the time when the crack is produced at least at a part in the ERIC
5、HSEN test. 4. TEST PIECES The test piece shall be classified into three kinds of No. 1 to No. 3 by shape, and the dimensions shall be as given in Table 1. However, where the dimensions of materials are less than 90mm, the dimension 90mm given in Table shall be changed to 70mm. In this case, the abov
6、e shall be clearly stated in the test result. Table 1. Dimensions of Test Pieces Unit : mm Test pieces Dimensions No. 1 test piece Strip of 90 2 in width No. 2 test piece Square of 90 2 in side No. 3 test piece Circle of 90 2 in diameter 5. TESTING MACHINE 5.1.1. The testing machine shall be so cons
7、tructed that the clamping pressure of more than 1000 kgf(9.8066 kN) shall be constantly applied and in this state the test piece shall be uniformly pressed to the surface of the die by the stretching ring. 5.1.2. In the range of clamping pressure of more than 1000 kgf, the error of the load indicato
8、r shall be within 5%. EDS-T-7125METHOD OF ERICHSEN CUPPING TEST PAGE: 2/2 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 2 GM DAEWOO Auto & Technology 6. TEST 6.1. The test piece shall be greased, and graphite grease shall generally be used. 6.2. The test piece shall be so placed that
9、 the center line of the width or the center of the square or the circle is in accordance with the centers of the punch or die. In the case of strips, the distance between the centers of dents shall be 90mm or over. 6.3. The indication of the micrometer shall be set to zero at the position where the
10、top of the punch stands on the same plane surface as the stretching ring, or the difference shall be used for the purpose of correction. 6.4. The indenting speed of the punch shall be generally at a rate of 5 to 20mm/min and at first applied as uniformly as possible, then gradually decreased toward
11、the end of the testing, and made minimum of the above range when a crack may be produced. 6.5. The testing temperature shall generally be within the range of 5 to 35 and if necessary the testing temperatures shall be recorded. However, the testing temperatures shall be 202 for the materials sensitiv
12、e to the variation of temperatures and the application shall comply with the requirements of the material standard. 7. INDICATION METHOD The ERICHSEN number shall conform to KS A 0021(termination method of number) and shall be rounded off to one decimal place. Remark: The graphite grease used for the ERICHSEN test shall be composed of calcium soap, refined mineral oil and graphite. It shall be free from corrosive matters, resin powder and other ingredients. 8. REFERENCE KS B 0812 Method of ERICHSEN cupping test JIS Z 2247 Method of ERICHSEN cupping test
