1、 _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising ther
2、efrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this
3、publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-49
4、70 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/ARP6156 AEROSPACE RECOMMENDED PRACTICE ARP6156 Issued 2017-04 WAM High Speed Load Capacity Tes
5、t Method RATIONALE ARP6156 serves to document the conditions and procedures required for the user of a WAM ball-on-disc test machine to run a standard protocol scuffing load capacity test. The continuous measurement of the traction coefficient provides insight into the anti-wear and extreme pressure
6、 properties of the lubricant. The WAM scuffing load stage is a report item in AS5780 and the measurement method is currently described in the appendix to determine if limits can be assigned for aviation turbine oil qualification. The SAE E-34 committee has made a recommendation for the test method t
7、o be documented as recommended practice. SAE INTERNATIONAL ARP6156 Page 2 of 18 TABLE OF CONTENTS 1. SCOPE 3 1.1 Purpose . 3 2. APPLICABLE DOCUMENTS 3 2.1 SAE Publications . 3 3. APPROACH 4 4. SPECIMEN SPECIFICATIONS. 6 4.1 Ball Specification . 6 4.2 Disc Specification 6 4.3 Slinger Washer Specifica
8、tion 7 4.3.1 WAI Part Number W21125-2 7 4.3.2 Storage and Handling 7 5. TEST PROCEDURE . 7 5.1 Clean Specimens 8 5.2 Rig Set Up . 8 5.3 Software Set Up 9 5.4 Find Pure Rolling . 10 5.5 Set Skew and Track Diameter 11 5.6 Run Test 11 5.7 Perform Repeat Tests . 12 5.8 Track Diameter Spacing 12 6. PRECI
9、SION STATEMENT 13 7. REPORT ITEMS FOR AS5780 . 13 8. RECOMMENDATIONS . 13 9. DATA PROCESSING 14 10. NOTES 18 10.1 Revision Indicator 18 FIGURE 1 WAM TEST MACHINE . 4 FIGURE 2 FLOW CHART FOR TEST METHOD . 7 FIGURE 3 TWENTY REPEAT TESTS WITH A STANDARD MIL-PRF-23699 OIL . 13 FIGURE 4 TEST PLOT FOR 5 c
10、St REFERENCE OIL WITH MACRO SCUFF FAILURE. 14 FIGURE 5 TEST PLOT FOR 5 cSt REFERENCE OIL WITH MICRO-SCUFF FAILURE 15 FIGURE 6 AVERAGE TRACTION COEFFICIENT FOR TEST OIL C AND 5 cSt STD REFERENCE OIL . 16 FIGURE 7 HEIGHT OF EACH BAR IS THE AVERAGE SCUFF STAGE OF (4) REPEAT TESTS 16 FIGURE 8 SCUFFING P
11、ERFORMANCE OF A TEST OIL AS A PERCENTAGE OF A REFERENCE OIL TESTED ON THE SAME SURFACE . 17 FIGURE 9 MAXIMUM TRACTION COEFFICIENT VERSUS SCUFFING RELATIVE TO 5 cSt STD REFERENCE OIL . 17 FIGURE 10 TEST PLOT WITH TOTAL CONTACT TEMPERATURE, Tc . 18 TABLE 1 LOAD CAPACITY TEST LOAD STAGES AND THE CORRES
12、PONDING CONTACT STRESS . 5 SAE INTERNATIONAL ARP6156 Page 3 of 18 1. SCOPE The lubricant performance capability for aero propulsion drive systems is derived from the physical properties of the oil and the chemical attributes associated with the oil formulation. All properties, such as viscosity, pre
13、ssure-viscosity coefficient and full-film traction coefficient are inherent properties of the lubricating fluid. Chemical attributes are critical for the formation of protective boundary lubricating films on the surfaces to prevent wear and scuffing. To assure performance and to provide needed infor
14、mation for engineering design, test methodologies for at least five oil properties or attributes are being addressed: (1) pressure-viscosity coefficient, (2) full-film traction coefficient, (3) scuffing resistance, (4) wear resistance, and (5) micropitting propensity. While viscosity versus temperat
15、ure data are readily available, the above five properties or attributes must be measured under relevant conditions for aero propulsion hardware systems. This document (ARP6156) describes the test method for scuffing and wear resistance. It should be noted that the test method results are limited to
16、the selected test conditions, which may not be representative of the broad scope of conditions encountered in service. 1.1 Purpose The purpose of this test method is to provide the scuffing performance of aviation oil formulations under a defined set of engineering parameters and with gear materials
17、 (AISI 9310) and surface processing representative of that used in aero propulsion. The test method also provides anti-wear (AW) behavior. Anti-wear is associated with the polishing or wear protection of roughness features similar to what is experienced in critical aviation bearing and gear hardware
18、. The degree of wear experienced by roughness features is reflected in the measured traction (friction) coefficient during a scuffing load capacity test. ARP6156 serves to document the conditions and procedures required for the user of a WAM ball-on-disc test machine to run a standard protocol scuff
19、ing load capacity test. The document also serves to support a “modified” test protocol which operates under more severe conditions for high scuffing performance oils. The original test conditions used in the standard protocol were derived from the Ryder Gear Test Method and described in Appendix D o
20、f AIR4978 “Temporary Methods for Assessing the Load Carrying Capacity of Aircraft Propulsion System Lubricating Oils”. While these test conditions and loading protocol do not actually simulate the Ryder Gear Test, the test conditions and materials have linkage to Ryder Gear and its tribology mechani
21、sms leading to scuffing failures. The continuous measurement of traction coefficient and specimen temperatures that reflect the wear behavior of roughness features throughout the test protocol provide both scientific insight and engineering usefulness. They allow the calculation of the total contact
22、 temperature for additive activation and scuffing limit. 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the da
23、te of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 SAE Publicati
24、ons Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AIR4978 Temporary Methods for Assessing the Load Carrying Capacity of Aircraft Propulsion System Lubricating Oils AIR5433
25、Lubricating Characteristics and Typical Properties of Lubricants Used in Aviation Propulsion and Drive Systems AS5780 Specification for Aero and Aero-Derived Gas Turbine Engine Lubricants SAE INTERNATIONAL ARP6156 Page 4 of 18 3. APPROACH The historical challenge to develop a meaningful and yet cost
26、 effective test for oil lubricating performance is associated with the large range of lubricated contacts and operating conditions that the oil must serve. The original association of this test method with the Ryder Gear Test Method provides some degree of continuity and linkage to historical data.
27、The Ryder Gear Test Method also represents one of the most severe lubricated contacts that the oil must serve. Five key tribology parameters control the severity of the contact: (1) entraining velocity (Ue); (2) sliding velocity (Us); (3) elastohydrodynamic (EHD) oil film thickness-to-surface roughn
28、ess ratio (h/); (4) total contact temperature (Tc); and (5) contact stress (both Hertzian stress and qualitative local asperity stress). To further engineering usefulness and to provide scientific insight for the formulator the WAM High Speed Load Capacity Test Method provides continuous measurement
29、 of specimen temperatures and traction coefficient. These measurements can be used to calculate the total contact temperature (Tc) for gear scuffing prediction and for additive activation. A detailed study of the Ryder Gear Test Method revealed general operating conditions from which a test method w
30、as derived. The test method was designed to operate within the limits of the original prototype WAM (Wedeven Associates Machine) tribology test equipment. While the test method is not a true simulation of the Ryder Gear Test Method, the physical phenomena driven by stress, temperature and sliding ve
31、locity to invoke a scuffing event is similar to the conditions on the Ryder Gear active tooth profile where scuffing is initiated. The test configuration and some of the operating conditions are shown in Figure 1. Angle Z = 75Ue= 5.72 m/secUs= 8.77 m/secStd ProtocolModified Protocol forhigh load-car
32、rying oilsUe= 4.01 m/secAngle Z = 95Us= 8.77 m/secUeUsZUdUbUe= (Ub+ Ud) Us= Ub- Ud)Z = skewFigure 1 - WAM test machine The test machine controls specimen position, contact load and motions of a single contact in space. A computerized run file controls load and contact kinematics between the specimen
33、s. Specimen temperatures are recorded with trailing thermocouples. The scuffing and wear test protocol uses AISI 9310 ball and disc specimens with specifications described in Section 4. A detailed test procedure is given in Section 5. The general operating conditions are given below: Test Conditions
34、: Ball velocity, Ub = 7.214 m/s (284 in/s) Disc velocity, Ud = 7.214 m/s (284 in/s) Skew = 75; skew is the angle between Ub and Ud surface velocity vectors SAE INTERNATIONAL ARP6156 Page 5 of 18 Entraining velocity, Ue = 5.723 m/s (225 in/s), Ue = 1/2(Ub + Ud) Sliding velocity, Us = 8.783 m/s (346 i
35、n/s), Us = (Ub - Ud) Load: Exponential increase from 17.9 N (4 pounds) to 627.2 N (140 pounds) in 30 stages over 1800 seconds. Increase in load is accomplished with a computer controlled script file according to the values in Table 1. Table 1 - Load capacity test load stages and the corresponding co
36、ntact stress Test duration: Until a macro-scuffing event or test suspension (no macro-scuffing event). If no macro-scuff occurs, test time is 30 minutes. Failure criteria: Macro-scuff defined by total loss of surface integrity and sudden increase in traction coefficient or a micro-scuff defined by r
37、apid decline in traction coefficient due to local scuffing or smearing confined to the roughness features. Performance: Oil performance is judged by the contact stress (or load stage) at which either a macro or micro scuff occurs. To accommodate test specimen or other operating environmental variati
38、ons, scuffing performance can also be given relative to a reference oil. Additionally, traction coefficient behavior, which reflects wear of roughness features, is used to characterize anti-wear performance. Temperature: The test method allows specimen temperatures to be driven by frictional heating
39、. Surface temperatures increase with load stage from ambient to approximately 200 C. Specimens are required to be at room temperature (23 to 27 C) before the start of a test. Oil supply: Computer controlled peristaltic pump, 15 mL/min. Oil flow rate is selected for adequate lubrication without signi
40、ficant cooling. The oil is wetted and distributed across the disc surface from a central oil slinger. The test oil is not recirculated. SAE INTERNATIONAL ARP6156 Page 6 of 18 Variables recorded during a test include the following: Ball and disc temperatures Traction coefficient Ball and disc surface
41、 velocities Contact load Time 4. SPECIMEN SPECIFICATIONS 4.1 Ball Specification 4.1.1 Material: Carburized case hardened AISI 9310, AMS6265 4.1.2 Diameter: 20.64 mm (0.8125 inch) 4.1.3 ABMA Grade: 10 or better (for geometry) 4.1.4 Through-Hole: 6.48 mm (0.255 inch) 4.1.5 Case Depth: 0.762 to 1.02 mm
42、 (0.030 to 0.040 inch); 58 HRC at approximately 1.0 mm from surface 4.1.6 Hardness: Case hardened surface to be 63 HRC + 1 HRC 4.1.7 Roughness: Ra = 0.274 micrometer + 0.025 micrometer (11 microinches + 1 microinch); “Hard Grind” isotropic finish 4.1.8 0.2 mm (0.008 inch) material removal for final
43、grind after heat treatment 4.1.9 Regrinding is not permissible 4.1.10 Storage and Handling 4.1.10.1 Ball specimen for test should be handled with clean gloves in a work zone free of contaminants that could contaminate or corrode the specimen surface. 4.1.10.2 When not in use, ball specimen is to be
44、coated with a rust preventative oil such as Ferrocote5856 BF T1 and stored in a sealed plastic bag. 4.2 Disc Specification 4.2.1 Material: Carburized case hardened AISI 9310, AMS6265; double vacuum melt (VIM VAR) per OEM spec; grain size 5 or finer 4.2.2 Diameter: 102 mm (4.0 inches) 4.2.3 Thickness
45、: 12.7 mm (0.50 inch) nominal 4.2.4 Through-Hole: 19.05 mm (0.750 inch 0.0005 inch), perpendicular to either face 0.0005 inch; concentricity 0.001 inch 4.2.5 Parallelism of Faces: 0.0002 inch 4.2.6 Flatness: 0.0002 inch 4.2.7 Case Depth: 0.762 to 1.02 mm (0.030 to 0.040 inch); 58 HRC at approximatel
46、y 1.0 mm from surface 4.2.8 Hardness: Case hardened surface to be HRC 63 + 1 SAE INTERNATIONAL ARP6156 Page 7 of 18 4.2.9 Roughness: 0.15 micrometer (6 microinches + 1 microinch) Ra, circumferential grind fine texture finish 4.2.10 0.2 mm (0.008 inch) material removal at initial grind after heat tre
47、atment, no grind burns 4.2.11 Re-grinding a used disc is permissible if no more than 0.356 mm (0.014 inch) total material is removed with respect to the as heat treated thickness; at least 0.051 mm (0.002 inch) is removed from the used surface with no grind burns, the surface hardness remains within
48、 specification and scuffing and traction behavior is within family for a reference oil. 4.3 Slinger Washer Specification 4.3.1 WAI Part Number W21125-2 4.3.2 Storage and Handling 4.3.2.1 Disc specimen for test should be handled with clean gloves in a work zone free of contaminants that could contami
49、nate or corrode the specimen surface. 4.3.2.2 When not in use, disc specimen to be coated with a rust preventative oil such as Ferrocote5856 BF T1 and stored in a sealed plastic bag. 5. TEST PROCEDURE The procedure to run a load capacity test requires a series of steps outlined in the flow chart in Figure 2. The detailed procedure concurs with the U.S. Navy, Patuxent River, MD. Details for each step follow. Figure 2 - Flow chart
