1、This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. MAY 2008 Page 1 of 7 NAVISTAR, INC. Engineering Standard Parts NUMBER: ESP-EM-56.1
2、01-GS TITLE: Prevailing Torque Hex Nuts All Metal General Specifications Metric Series (Noun Code 5780)CURRENT ISSUE DATE: May 2008 WRITTEN/REVIEWED BY: Corporate Technical Standards APPROVED BY: Corporate Technical StandardsSUPERSEDES ISSUE OF: August 2006PRINTED COPIES OF THIS DOCUMENT MUST BE VER
3、IFIED FOR CURRENT REVISION Change Notice: Eliminated Zinc Trivalent plus Sealer (ZN8F) finish specification. Added Zinc Aluminum Clear (ZACLR) finish specification. Replaced International Truck and Engine Corporation with Navistar, Inc. per corporate directive. GENERAL: This specification contains e
4、lements of the following standards: American National Standards Institute: B 18.16.3M International Organization for Standardization: ISO 2320, 7042, 7719 Prevailing torque type is a nut which is frictionally resistant to rotation due to a self-contained prevailing torque feature, and not because of
5、 a compressive load developed against the bearing surface of the nut. Prevailing torque is the torque necessary to rotate the nut on its mating externally threaded component, with the torque being measured while the nut is in motion, and with no axial load in the mating component. Inch series prevai
6、ling torque hex nuts - all metal, may be found in ESP-E-56.101-GS. Letter symbols designating dimensional characteristics are in accord with those used in ANSI and ISO standards. PREFERRED PARTS POLICY: Preferred parts are so designated to reduce variety of parts and assure maximum availability and
7、cost savings: Nominal Sizes: M6, M8, M10, M12, M16, M20, M24, M30, and M36 Material: Class 10 Finish: Phosphate Coating (PHC) WIDTH ACROSS FLATS: The width across flats will be distance, measured perpendicular to the axis of the nut, between two opposite wrenching flats. The maximum width across fla
8、ts may be exceeded by 0.05 mm to allow for nut deformation caused by introduction of the prevailing-torque feature. The width across flats may be less than the specified minimum in the deformed portion of the nut containing the prevailing-torque feature. THICKNESS: The nut thickness will be the over
9、all distance, measured parallel to the axis of the nut, from the top of the nut to the bearing surface of hex nuts. Raised identification markings, if present, will be excluded. WRENCHING HEIGHT: The wrenching height is the distance, measured at a corner of the hex, from the bearing surface of hex n
10、uts, to the last plane of full formed hex, i.e., the plane perpendicular to the nut axis which is closest to the top of the nut and at which the width across corners is within its specified limits. Wrenching height for hex nuts is dimension M, in Table 1, and is subject to measurement. BEARING SURFA
11、CE: Hex nuts will have a chamfered bearing surface. The diameter of the bearing surface will not exceed the width across flats nor be less than the bearing face diameter specified on Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction o
12、r networking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General SpecificationsCURRENT ISSUE DATE: May 2008 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technic
13、al Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. MAY 2008 Page 2 of 7 the page. The bearing surface will be flat and perpendicular to the axis of the thread within the total runout limit specified on the last page. TRUE POSITION OF TAPPED HOLE: The axis of
14、tapped hole will be located at true position with respect to the axis of nut body within a tolerance zone having a diameter equivalent to 3 percent of the maximum width across flats, regardless of feature size. COUNTERSINK: The tapped hole will be countersunk on the bearing face, and may be counters
15、unk on the top face. The countersink included reference angle will be 90 deg to 120 deg. The maximum countersink diameter will be 1.15 times the nominal thread diameter (major diameter) for nuts M4 and smaller, the nominal thread diameter plus 0.75 mm for M5 through M8 nuts, and 1.08 times the nomin
16、al thread diameter for M10 and larger nuts. The minimum countersink diameter will be the nominal thread diameter. THREADS: Threads, prior to introduction of the prevailing-torque feature, will be metric coarse threads with class 6H tolerances in accordance with ANSI B1.13M. Nuts M10 and smaller will
17、 assemble a minimum of one-half turn, and nuts M12 and larger will assemble a minimum of one full turn by hand on a basic GO thread plug gage. The plug gage will be without a chip groove, and will have a point with dimensions conforming to those for the point on metric hex head bolts given in ESP-BM
18、-1.101-GS. MATERIAL: Steel, Class 10 per CEMS A-31, Part II. FINISHES: In accordance with the International Engineering Material Specification and class listed below: Plain (PLN) Free from dirt and rust and coated with a light oil film. Phosphate Coated (PHC) CEMS G-1, Class B-2. Zinc Aluminum Clear
19、 (ZACLR) TMS-4518, Type II. All nuts will be provided with a supplementary lubricant following plating which will be clean and dry to the touch. Lubricant will not deteriorate due to temperature and humidity variations so as to affect nut performance for a period of one year when nuts are stored, sh
20、ipped, or handled in a normal manner. RESTRICTED CHEMICAL SUBSTANCES: Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the CEMS B-50 specification. WORKMANSHIP: Nuts will not contain an excess of surface imperfections whic
21、h might affect their serviceability, such as burrs, seams, laps, loose scale, and other irregularities. PERFORMANCE REQUIREMENTS: The prevailing torque developed by nuts during their first installation or any subsequent installation or removal, will not exceed the maximum first installation torque a
22、s specified in Table 1 when tested as specified in this standard. In addition, the prevailing torque developed by nuts during their first and fifth removals will not be less than those specified in Table 1. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for
23、 ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General SpecificationsCURRENT ISSUE DATE: May 2008 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permissio
24、n from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. MAY 2008 Page 3 of 7 Table 1 - Proof Loads, Clamp Loads and Prevailing Torques for Nuts Proof Load, kN Clamp Load, kN Prevailing Torque, NmNominal Size Class 9 Class 10 Class 10First I
25、nstallation MaxFirst Removal MinFifth Removal MinM6 18.1 20.9 12.5 4 0.55 0.4 M8 34.4 38.1 22.8 8 1.15 0.8 M10 54.5 60.3 36.1 14 2 1.4 M12 80.1 88.5 52.5 21 3.1 2.1 M14 109 121 71.6 31 4.4 3 M16 149 165 97.5 42 6 4.2 M20 - 260 152 72 10.5 7 M24 - 374 220 106 15 10.5 M30 - 595 350 140 19 14 M36 - 866
26、 509 180 24 17 5 Note: The clamp loads for class 10 nuts are equal to 75 percent of the proof load of property class 10.9 bolts. Proof loads are given in CEMS A-31, Part I. TEST METHODS: Proof Load Test: The test sample nut will be assembled on a test bolt or on a hardened mandrel with a minimum of
27、three threads projecting through the nut. For referee test purposes, the hardened mandrel will be used. The maximum torque occurring during the assembly of the nut on the test bolt or mandrel will be recorded. A tensile load equal to the specified proof load for the nut, as given in Table 1, will be
28、 applied through the test bolt or mandrel against the nut bearing surface in an axial direction. The nut will resist this load without thread stripping or rupture. The torque necessary to remove the nut from the test bolt or mandrel will not exceed the maximum torque occurring during assembly. Test
29、Bolt: The bolt used for proof load testing nuts will have threads conforming to ISO 965, Part I, Class 6g tolerances. The test bolt will have a proof load capability strength in excess of the specified proof load of the nut being tested. Hardened Mandrel: The mandrel used for proof load testing nuts
30、 will have threads conforming to ISO 965, Part I, Class 5h tolerances, except that the tolerance of the major diameter will be the lowest quarter of the 6g range on the minimum material side. The mandrel will be heat treated to a hardness of Rockwell C45 to C50. Hardness Test: Either Vickers or Rock
31、well hardness may be determined. Vickers testing will be in accordance with ISO R81, and Rockwell testing in accordance with ISO R80. For referee purposes, Vickers hardness will be determined. The hardness of the sample nut will be determined on the top or bottom face of the nut. The top or bottom s
32、urface of the nut will be prepared by grinding, removing sufficient material from the surface to eliminate the effects of plating, coating or other surface condition. Material removal will also be such as to provide a flat area large enough to allow a hardness test to be made midway between the hex
33、corner and the major diameter of the thread. The opposite surface (i.e., top or bottom of nut) will be prepared parallel to the test surface with removal of plating or coating. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or netw
34、orking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General SpecificationsCURRENT ISSUE DATE: May 2008 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Sta
35、ndards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. MAY 2008 Page 4 of 7 Prevailing Torque Test: Two test programs are included in this standard. The first, program A, is intended for the routine acceptance of lots of prevailing torque nuts as produced by the manufa
36、cturer and received by the user. It is generally considered that products meeting program B in qualification, may ordinarily be accepted by the routine test procedure of program A. Program A: Program A is recommended for routine inspection for lot acceptance. The prevailing torque test will be condu
37、cted at room temperature using a load measuring device. A test bolt will be inserted in the load measuring device, a test washer placed on the bolt and the sample nut then assembled on the bolt. The nut will be advanced on the bolt until a minimum of two full bolt threads protrude through the nut. N
38、ut tightening may be either manually with a torque wrench or with an equivalent torque-sensing power device. The maximum torque occurring while the nut is being advanced through the next 360 of nut rotation will be measured. For the nut to be acceptable, this torque will not exceed the first install
39、ation prevailing torque value as specified for the applicable nut in Table 1. Tightening will be continued until the nut is seated against the test washer. The length of the test bolt should be such that seating of the nut occurs when a length equivalent to four to seven thread pitches of the test b
40、olt protrude through the top of the nut, measured from the end of the bolt. The nut will then be tightened until a tensile load equal to the clamp load, as specified in Table 1, is developed in the bolt. The test washer will be prevented from turning during nut tightening. The nut will then be backe
41、d off by the application of reverse torque until the tensile load in the bolt has been reduced to zero. The maximum torque occurring while the nut is being backed off through the next 360 of rotation will be measured. For the nut to be acceptable, this torque will not be less than the first removal
42、prevailing torque value specified for the applicable nut in Table 1. Program B: Program B will be used when qualifying nuts, and also for referee inspection for lot acceptance. The Program A test procedure will be conducted. After the first removal prevailing torque has been measured, the nut will b
43、e backed off until the prevailing torque element is disengaged from the bolt thread. The nut will then be reassembled and removed four more times. On each assembly, the nut will be advanced sufficiently to allow a length equivalent to four to seven thread pitches to protrude through the nut. On each
44、 removal, the prevailing torque element will be disengaged from the bolt thread. This portion of the test need not be carried out in the load measuring device. During the fifth removal, the maximum torque occurring while the nut is being backed off through the first 360 of rotation will be measured.
45、 For the nut to be acceptable, this torque will not be less than the fifth removal prevailing torque value as specified in Table 1. In addition, at no time during these four additional installations and removals will the torque exceed the maximum first installation prevailing torque value as specifi
46、ed in Table 1. Sufficient time will elapse between cycles of application of the torque to prevent overheating of the test assembly. The speed of application and removal of the torque will not exceed 30 rev/min, and will be continuous and uniform. Copyright Navistar International Corporation Provided
47、 by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General SpecificationsCURRENT ISSUE DATE: May 2008 This document is restricted and may not be sent outside Navist
48、ar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. MAY 2008 Page 5 of 7 Torque Measuring Device: The torque measuring device (torque wrench or power device) will be accurate within plus or minus
49、2 percent of the maximum of the specified torque range of the device. For referee purposes, all readings taken must fall within the upper 50 percent of the torque range of the measuring device. Load Measuring Device: The load measuring device used in the prevailing torque test will be an instrument capable of measuring the actual tension induced in the test bolt as the nut is tightened. The device will be accurate within pl
