1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards EVALUATION OF INDUCTION OR FLAME HARDENING IN STEEL EDS-T-7110 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 EDS-T-7110EVALUATION OF INDUCTION OR FLAME HARDENING IN STEEL PAGE: 1/6 ISSUED DATE: 1990.
2、 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 GM DAEWOO Auto & Technology 1. PURPOSE This standard aims at establishing appropriate test method for GMDAT by specifying method of measuring case depth of steel hardness by flame or indication hardening process. 2. SCOPE This standard specifies the meth
3、ods of measuring case depth (hereinafter referred to as the case depth) of steel hardened by flame or induction hardening process. 3. DEFINITIONS 3.1. Effective case depth The distance from the surface of a case, as quenched or as quenched and tempered, to the position of critical hardness as specif
4、ied in Table 1. For special purpose, the critical hardness other than Table 1 may be designated. Fig. 1. Definition of effective case depth Table 1. Critical Hardness of the Effective Case Depth Carbon content of steel (%) Critical hardness (Hv) 0.23 0.33 0.33 0.43 0.43 0.53 0.53 min. 350 400 450 50
5、0 Note: The carbon content of steel shall apply to the midpoint of range specified for the steel grade to be tested. 3.2. Total case depth The distance from the surface of the hardness case to the point where the difference in physical and chemical properties between the case and the core material i
6、s no longer determinable. Physical properties shall be determined by the hardness and chemical properties by the macro-structure. EDS-T-7110EVALUATION OF INDUCTION OR FLAME HARDENING IN STEEL PAGE: 2/6 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 GM DAEWOO Auto & Technology 4. TES
7、T PIECE In principle, for the test piece, the product itself, hardened by flame or induction hardening process, shall be used. If impossible, a separate test specimen of the same material quality and processed under the same heat treatment conditions as the product may be used as an alternative. 4.1
8、. Measuring point of sample When the measuring points are not specified in the drawing, the test piece shall be prepared along either transverse or longitudinal direction as the hardening pattern and effective hardening depth measurement differ according to the shape and function of parts. The measu
9、ring points for components are as follows: 4.1.1. Gear Teeth : PCD 4.1.2. Thrust faces : two radial planes perpendicular to the surface 4.1.3. SHAFT & JOURNAL (1) Transverse plane passing through the hardening center point and perpendicular to the shaft (2) One or more radial planes passing through
10、the pattern run-out and hardening center axis 5. KIND OF MEASURING METHOD 5.1. Measuring method by hardness test 5.1.1. The test piece shall be cut at right angle to the hardened case, and the surface shall be finished by polishing for testing. Care shall be taken in cutting and polishing that these
11、 processes may not affect the hardness and not blunt the edges of the surface to be tested. 5.1.2. The case depth shall be measured by means of vickers hardness test to the test surface. In this case, vickers hardness test load shall be 0.3 kgf or 1 kgf but if necessary, it shall be selected as 0.1
12、1 kgf. 5.1.3. Hardness transition curve shall be made according to the following 2 methods. (1) Method A 1) The hardness transition curve shall be made by measuring the hardness along the straight line at right angle to the test plane. If necessary, after selecting 2 to 5 points within a 1.5 mm span
13、 on the plane, one hardness transition curve shall be made by measuring the hardness on each point along the straight line at right angle to the plane (See Fig. 2). 2) In the case of marking the hardness transition curve by vickers hardness test, the space between the measuring points shall be, in p
14、rinciple, not more than 0.1 mm. 3) For the vickers hardness test, the space between the center of the adjacent indentation shall be not less than 2.5 times the diagonal length of the indentation. (2) Method B(Only for effective case depth) 1) Only in case effective case depth is 0.3 max.(See Fig. 3)
15、. 2) Effective case depth shall exist between t1 and t2 on the surface, distance between t1 and t2 shall be 0.3 EDS-T-7110EVALUATION OF INDUCTION OR FLAME HARDENING IN STEEL PAGE: 3/6 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 GM DAEWOO Auto & Technology max. Effective case dept
16、h shall be obtained by means of the following formula. 3IU UUU)-)=+ Fig. 2. Definition of Hardness Measuring Location(a) and Effective Case Depth on Hardness Transition Curve 5.2. Measuring method by macro-structure test 5.2.1. The test piece shall be cut at right angle to the hardened case and the
17、surface shall be finished by polishing for testing. Care shall be taken in cutting and polishing that these processes may not affect the structure of the surface to be tested. The test surface shall be used by polishing until it becomes polished surface 5.2.2. The test surface shall be etched for se
18、veral seconds in a 5% nitric acid alcoholic solution (Nital 95 ml ethyl alcohol + 5 ml nitric alcohol). After washing the surface in alcohol or water, measure the distance to the point different from the internal structure by examining the colored condition according to the etching, under a magnifyi
19、ng glass of a proper magnification. 5.3. Measuring point for effective hardening depth and pattern 5.3.1. Bearing journal, cam, thrust face and partially hardened parts : Maximum hardening portion (See Fig 3-1a) 5.3.2. Parts with setoff in the hardened portion: Section representing the main function
20、 of the part (See Fig 3-1b) 5.3.3. Spline : Spline root diameter 5.3.4. Unless the hardening pattern of run-out is specified in drawings, the actual run-out length shall not be larger than twice the actual hardening depth. 5.3.5. Hardening run-out of fillet radius shall diminish at a constant reduct
21、ion rate of hardening depth. (See Fig 3-1d) EDS-T-7110EVALUATION OF INDUCTION OR FLAME HARDENING IN STEEL PAGE: 4/6 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 GM DAEWOO Auto & Technology Fig. 3. Positions for effective hardening depth and pattern EDS-T-7110EVALUATION OF INDUCTIO
22、N OR FLAME HARDENING IN STEEL PAGE: 5/6 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 GM DAEWOO Auto & Technology 6. INDICATION 6.1. Method A 6.1.1. The meaning of the indication symbol shall be as follows. HD (HARDING DEPTH) : Induction hardened case depth FD (FLAME DEPTH) : Flame
23、 hardened case depth H (HARDNESS) : Measurement by hardness test M (MICROSTRUCTURE) : Measurement by structure test E (EFFECTIVE) : Effective case depth T (TOTAL) : Total case depth 6.1.2. The case depth shall be given in mm. Table 2. Classification of Indication Method Measuring method Case depth M
24、easuring method by hardness test Measuring method by structure testEffective case depth by induction hardening HD - H - E() = - Effective case depth by flame hardening FD - H - E() = - Total case depth by induction hardening HD - H - T = HD - M - T = Total case depth by flame hardening FD - H - T =
25、FD - M - T = Remark 1. In , test load shall be indicated with the unit of kgf(N) 2. When test load is 1 kgf(9.8N) record of may be omitted 3. indicates critical hardness value. 4. In , record case depth. 6.1.3. Examples (1) HD(FD)-H1-E(450)= 2.5 : In case effective case depth by induction hardening
26、which is measured by hardness test method under a test load of 1 kgf(9.8N) is 2.5 mm to the critical hardness of HV 450. (2) HD(FD)-H0.3-T = 1.5 : In case total case depth by induction hardening which is measured by hardness test method under a test load of 0.3 kgf(2.9N) is 1.5 mm. (3) HD(FD)-M-T=2.
27、0 : In case total case depth by induction hardening which is measured by microstructure test method is 2.0 mm. EDS-T-7110EVALUATION OF INDUCTION OR FLAME HARDENING IN STEEL PAGE: 6/6 ISSUED DATE: 1990. 12. 29 REVISED DATE: 2006. 06. 19 VERSION: 3 GM DAEWOO Auto & Technology 6.2. Method B 6.2.1. Effe
28、ctive case depth (1) Indication Rht Hv = Effective case depth Critical hardness Load(kgf or N) Case depth (2) Examples Rht 450 HV1= 0.5 : In case effective case depth by induction(flame) hardening, which is measured by hardness test method under a test load of 1 kgf(9.8N), is 0.5 mm to the critical
29、hardness of HV 450. 6.2.2. Total hardening depth (1) Indication TCD = Total hardening depth Hardening depth (2) Examples THD = 0.2 : In case total case depth by microstructure test is 0.2 mm. 7. RELATED SPECS KS D 0027 Methods of measuring case depth for steel hardened by flame or induction hardening process JIS G 0559 Methods of measuring case depth for steel hardened by flame or induction hardening process DIN 50190 Hardening depth of heat treated pieces EU-BA 50-3 Evaluation of induction or flame hardening of components
