FORD FLTM EU-BA 050-3-2001 EVALUATION OF THE INDUCTION OR FLAME HARDENING OF COMPONENTS.pdf

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1、 FORD LABORATORY TEST METHOD EU-BA 050-03 Date Action Revisions 2001 03 02 Revised Editorial no technical change A. Cockman 1993 01 04 Printed copies are uncontrolled Page 1 of 6 Copyright 2001, Ford Global Technologies, Inc. EVALUATION OF THE INDUCTION OR FLAME HARDENING OF COMPONENTS 1. Scope This

2、 procedure defines the methods to be used for evaluating induction or flame hardened steel or cast iron components relative to specified requirements. 2. Principle of Methods Induction or flame hardening requirements are normally specified by a combination of the following methods: (a) Surface hardn

3、ess in specified areas of the component (b) A hardening pattern to be effective in specific areas to a specific depth (c) Hardness requirements at specific depths below the surface Methods detailed in this procedure are for determining conformance with these specifications and include interpretation

4、 of surface hardness requirements, a macroscopic method for determining the hardening pattern, and a hardness traverse method for determining the depth of effective hardening. 3. Apparatus Required 1. Cut-off machine 2. Linishing machine 3. Metallurgical hand grinders or equivalent 4. Hardness test

5、machines 5. 5 % Nital etch solution 6. Low-powered metallurgical microscope with calibrated graticule Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidity for not less than 24 h p

6、rior to testing and tested under the same conditions unless otherwise specified. FORD LABORATORY TEST METHOD EU-BA 050-03 Page 2 of 6 Copyright 2001, Ford Global Technologies, Inc. 4. Selection of Sample Unless specified on the component print, selection of the position for determining the hardening

7、 pattern or depth of effective hardening is dependent on the geometry and function of the component. Components shall be sectioned in such a manner as to permit measurement in the following positions, a transverse and longitudinal section generally being necessary. Gear Teeth 1. In a plane midway al

8、ong and normal to the tooth flank face. 2. In a radial plane through the centre line of the tooth. Thurst Faces Two radial planes at 90 and normal to the face. Shafts and Journals 1. In a transverse plane, normal to the axis and through the centre of the hardened zone. 2. One or more radial planes t

9、hrough the axis to show the centre of the hardened zone and areas of pattern run-out. 5. Preparation of Sample The surface of the sample on which the hardening pattern or depth of effective hardening is to be determined, must be ground to a sufficiently fine finish to permit etching and distinct for

10、mation of hardness test impressions. All precautions must be taken to prevent rounding of edges and overheating of the sample. 6. Determination of Surface Hardness 1. The surface hardness should be determined using standardised methods and practices, the actual method used being as specified on the

11、component print with due regard to corrections for surface curvature. 2. Sufficient hardness tests should be made to ensure compliance with specification over the total area and to define the periphery of the hardened zone. 3. Acceptance of hardening in sections not normally accessible to hardness t

12、esting, e.g., fillet radii, groove roots, etc., may be determined by ensuring satisfactory extension of the hardening pattern using the method detailed in para 7. FORD LABORATORY TEST METHOD EU-BA 050-03 Page 3 of 6 Copyright 2001, Ford Global Technologies, Inc. 7. Determination of Hardening Pattern

13、 1. The ground surface should be etched in 5 % nital solution, the time of etching being controlled to develop maximum distinction between the hardened zone and the heat affected zone or core. 2. The extremity of the hardening is defined as the demarcation line between the differentially etched hard

14、ened zone and core. 3. Some induction hardening techniques and most flame hardening techniques do not give sharp and clear demarcation lines due to blending of hardened zone, heat affected zone and core. In these cases the extremity of the hardening pattern must be determined by using the hardness t

15、raverse method detailed in para 8. 4. The depth or extent of the hardening pattern from specified reference points should be measured by microscope at X10 magnification. 5. Through hardening is permissible only when specified on the component drawing. 8. Determination of Depth of Effective Hardening

16、 1. The specimen, preferably in the unetched condition. should be suitably jigged or mounted to permit accurate hardness determinations. 2. Hardness determination should be made using standardised methods and practices at intervals from the surface of the component. A minimum of five impressions are

17、 necessary and these should span the depth of effective hardening. A minimum distance between impressions should not be less than 2 1/2 times the diameter/diagonal of the impression. 3. A curve should be plotted representing the hardness variation in relation to the distance from the surface and the

18、 depth of effective hardening obtained by determining the depth at which the effective hardness value occurs. 4. The effective hardness value is defined at 80 % of the minimum specified surface hardness. Effective hardness values for a range of surface hardness may only be used if specified on the c

19、omponent print. FORD LABORATORY TEST METHOD EU-BA 050-03 Page 4 of 6 Copyright 2001, Ford Global Technologies, Inc. 9. Position for Determining Effective Depth of Hardening or Pattern Due to the nature of the process and component configuration, the hardened zone resulting from flame or induction ha

20、rdening will not necessarily be constant and parallel to the component surface. The following define the position for measurement of depth of hardening pattern or depth of effective hardening unless otherwise stated on the component print. 1. The hardening zone on bearing journals, cams, thrust face

21、s and similar applications of localised hardening, is of a convex form. This form may be displaced from a central position due to adjacent heat soaks, internal bores, etc., therefore evaluation should be the ensure correct hardness over the specified area, with measurement of depth at the deepest pa

22、rt of the zone (see Figure 1a). 2. When the hardening zone contour pattern is not shown on the drawing but is required to extend over sections having stepped surfaces (see Figure 1b), the depth of hardening requirement shall apply to the main functional section of the component which can be determin

23、ed, if necessary, by reference to the responsible engineer. 3. The depth of hardening of splines should be determined from the spline root diameter unless otherwise stated. 4. The hardening pattern at the run-out should approximate to that shown on the drawing. If no pattern is shown the length of t

24、he run-out should not exceed twice the depth of the actual hardened zone. 5. Run-out of the hardening pattern adjacent to a fillet radius should show a gradual, but constant reduction in the depth of hardening. A localised reduction in depth at the fillet radius indicates an adverse condition (see F

25、igure 1d). 6. Where minimum and/or maximum depths are specified the hardening pattern should be maintained with these limits over the entire specified length with the exceptions as stated under 7.5, 9.2 and 9.4. Chemicals, materials, parts, and equipment referenced in this document must be used and

26、handled properly. Each party is responsible for determining proper use and handling in its facilities. FORD LABORATORY TEST METHOD EU-BA 050-03 Page 5 of 6 Copyright 2001, Ford Global Technologies, Inc. EVALUATION OF THE INDUCTION OR FLAME HARDENING OF COMPONENTS Table 1 Effective Hardness Values Mi

27、nimum Surface Hardness Effective Hardness Value HRC HV HV 45 445 355 46 460 365 47 470 375 48 485 390 49 500 400 50 515 410 51 530 425 52 545 435 53 560 450 54 580 465 55 595 475 56 615 490 57 635 510 58 655 525 59 695 560 60 695 560 FORD LABORATORY TEST METHOD EU-BA 050-03 Page 6 of 6 Copyright 2001, Ford Global Technologies, Inc. Position for Determining Effective Depth of Hardening or Pattern