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. 2014 by Navistar, Inc. APRIL 2014 Page 1 of 10 NAVISTAR, INC. Material, Parts, and Process Specification
2、s (MPAPS) NUMBER: MPAPS A-1037 Former Designation: TMS-1037 TITLE: Multi-Leaf Springs CURRENT REV No.: 1404 DATE: April 2014 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: TMS-1037 Dec. 2013 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISIO
3、N This specification may involve hazardous materials, equipment, and procedures. This specification does not purport to address all of the safety issues associated with its use. The user is responsible to consult appropriate safety and health practices and to determine the applicability of regulator
4、y limits prior to use. Change Notice: Changed to new MPAPS format; revised Section 4.5; editorial changes. 1.0 APPLICATION This specification covers flat rolled multi-leaf springs used in truck suspension/mounting systems 2.0 SCOPE This specification covers the requirements for material, heat treatm
5、ent, microstructure, quality, post hardening treatments, tolerances, KCC, source approval, and shipping and identification. 2.1 Restricted Chemical Substances Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the MPAPS B-50
6、 specification. 3.0 REFERENCE) Unless otherwise specified the latest issue of all referenced standards shall apply. The following specifications, standards, and regulations are referenced in this specification. Quality System Standard ISO 9001 or TS-16949 NAVISTAR CEMS A-39 ASTM A29 NAVISTAR Manufac
7、turing Standard MS-D-13 NAVISTAR CEMS GT-5A SAE J400 NAVISTAR Engineering Design Std. A-16 NAVISTAR CEMS GT-14C SAE J788 CFR Title 29, Part 1910 NAVISTAR TMS-4516 SAE J510 NAVISTAR MPAPS A-0, Part I; Part III ASTM E1077 NAVISTAR MPAPS B-50 ASTM E10 4.0 REQUIREMENTS 4.1 Material Open hearth, basic ox
8、ygen or electric furnace, ingot cast or strand cast, steel may be used. Unless otherwise specified, the general requirements for steel as described in ASTM A 29 shall be applicable. Steel supplied shall be fully killed, made to fine grain practice, and shall meet the minimum Steel Cleanliness Requir
9、ements of Class I per MPAPS A-0, Part I. 4.2 Chemical Composition Carbon 0.66% max Silicon 0.35% max Phosphorous 0.040% max Sulfur 0.050% max Alloying Elements - As Required (refer to Section A.1 for guidance in steel selection) NUMBER: MPAPS A-1037 TITLE: Multi-Leaf Springs REVISION: 1404 This docu
10、ment 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. 2014 by Navistar, Inc. APRIL 2014 Page 2 of 10 4.3 Dimensional Tolerances 4.3.1 Thickness and Width Shall be as sp
11、ecified in SAE J510, Leaf Springs for Motor Vehicle Suspension. In addition, SAE J788, Design and Application of Leaf Springs, shall govern areas not covered in SAE J510, and shall supersede drawing tolerances where conflicts exist. 4.3.2 Camber Height The leaf spring drawing must specify the method
12、 being employed to manage camber height variation and vertical rate variation and any sorting to manage that variation (either Method A or Method B per section 4.5.2.1). Options include: A. Method A- Sorted by free camber height. B. Method B- Sorted by loaded camber height. C. Method C- Alternative
13、sorting including a secondary operation to correct or pre-set loaded camber prior to sorting. Note: Pre-setting may be preferred as it reduces both the geometric and vertical rate variations. This is particularly recommended for “softer” springs (rated spring load 5,400 lb.) or for applications that
14、 are insensitive to ride height variation or leaning. Springs are non-corrected and sorted in free-state (“free-camber sorted”). Sort into two or more categories and identify the category with stripes on the front spring eye/wrap per the chart below. A typical industry standard for free height toler
15、ance on a non-corrected spring is 12.8mm or +/-6.4mm. A table such as the one below must be published on the drawing to define the free camber height range for each stripe marking condition. Method A Used for Variation Management- Free Camber Sorted Number of Vertical Stripes Mark ID (on front of sp
16、ring eye or wrap) Free Height Tolerance, H (mm) 1 I -6.4 H 0 2 II 0 6.4 are to be rejected Method B - A more stringent camber height sorting method B is recommended for front and rear springs coupled with axle ratings of 12,000 lb or less (rated spring load 5,400 lb). Springs are sorted in the 1g lo
17、aded-state (“loaded-camber sorted”). This is being practiced on our ProStar front springs. Sort into two or more categories and identify the category with stripes on the front spring eye/wrap. A table such as the one above must be published on the drawing to define the loaded camber height range for
18、 each stripe marking condition. Alternative Method - An alternative (“Method C”) camber height sorting method may be approved by the Suspension Technical Specialist on a case-by-case basis and must be clearly specified with a table on the drawing. For example springs may be corrected or pre-set to a
19、chieve the desired tolerance. This is being practiced on our TerraStar front springs. A typical industry standard for the loaded height tolerance on a corrected spring is 8mm or +/-4mm. A table such as the one below must be published on the drawing to define the loaded camber height range for each s
20、tripe marking condition. Please note that NUMBER: MPAPS A-1037 TITLE: Multi-Leaf Springs REVISION: 1404 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. 2
21、014 by Navistar, Inc. APRIL 2014 Page 3 of 10 correcting or pre-setting springs may impact the fatigue life of the spring. As such careful validation is required prior to adopting this capability. Method C Example (Loaded Camber Sorted) Number of Vertical Stripes Mark ID (on front of spring eye or w
22、rap) Loaded Height Tolerance, H (mm) 1 I -4.0 H 0 2 II 0 4.0 are to be rejected 4.3.2.2 Camber Height Variation Calculation To define the 1g loaded camber range use the following equations: o Maximum loaded camber = xmax = f + f P/(k + k) o Minimum loaded camber = xmin = f - f P/(k - k) o Loaded cam
23、ber range = R = xmax - xmin o Where: x = Loaded camber (mm or in) R = Loaded camber range (mm or in) f = Free camber (mm or in) f = Free camber tolerance typically = 6.4 mm or 0.25 in. for uncorrected spring P = 1g rated spring load (lb or N) k = Vertical spring rate (lb/in or N/mm) k = Vertical rat
24、e tolerance typically = 7% * k Example: Let f = 4.04 in f = 0.25 in Let P = 5,350 lb Let k = 1,425 lb/in Thus k = 100 lb/in xmax = f + f P/(k + k) = 0.78 in xmin = -f - f P/(k - k) = -0.25 in R = 0.78 in - (-0.25 in) = 1.03 in o Another Way To Calculate Loaded Camber Range: Loaded camber range = R =
25、 Free Camber Tolerance +Rate Tolerance For an uncorrected spring R = 0.5 in. + (P/ (0.93 * k) (P / (1.07 * k) Example: Let P = 5,350 lb Let k = 1,425 lb/in R = 0.5 in + (P(0.93 * k) (P/ (1.07 * k) = 1.03 in NUMBER: MPAPS A-1037 TITLE: Multi-Leaf Springs REVISION: 1404 This document is restricted and
26、 may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2014 by Navistar, Inc. APRIL 2014 Page 4 of 10 4.4 Heat Treatment Spring leaves shall be hardened and tempered at 425C (800F) minimum. B
27、rinell hardness (ASTM E-10) shall be 388-461 HB (42-48 HRC). To obtain the hardness reading, a light grind of the surface on the compression side of the leaf is permissible. 4.5 Microstructure The microstructure shall consist of 90% minimum tempered martensite throughout the cross section. Intergran
28、ular oxidation on the surface shall not exceed 0.05 mm (0.002 in). The depth of decarburization (ASTM E1077) shall be controlled within the following limits: Bar Thickness Decarburization* Up to 12.67 mm (0.499 in) 0.38 mm (0.015 in) Over 12.67 mm (0.499 in) 0.64 mm (0.025 in) 4.6 Post Hardening Tre
29、atment Shot peening is required to improve fatigue strength of leaf springs. The treatment shall consist of shot peening the tension side of all leaves to Class IND 6-10C, 90% minimum coverage, per CEMS A-39. 4.6.1 Corrosion Protective Compound After heat treatment, shot peening, and assembly, all s
30、prings shall be coated with an approved black paint meeting the requirements of TMS-4516, Type IV, and having a minimum dry film thickness of 1 mil. The coating will also meet the additional requirements specified in Table 1 below. Table 1. Additional Coating Requirements Property Required Test Meth
31、od* Adhesion %, min 90 GT-5A Gravelometer % retained, min 80 SAE J400 Cold Cracking Pass GT-14C * Navistar test method, unless otherwise specified. Section of spring shall be used as the sample in place of the test panel(s) specified in the test methods. 4.7 Spring Eye Bushing (Applicable to both ru
32、bber and threaded bushings) Bushings shall be bonded or welded into the spring eye such that the bushing will withstand a minimum push-out force, for each suspension rating, as shown in Table 2, without movement or loosening. Table 2. Minimum Bushing Push-Out Force Suspension Rating (lbs) Corner Loa
33、d at Ground (lbs) Push-Out Force (min. pounds) 6,000 3,000 2,400 7,000 3,500 2,800 8,000 4,000 3,200 10,000 5,000 4,000 12,000 6,000 4,800 14,000 7,000 5,600 16,000 8,000 6,400 18,000 and above 9000 7,200 * Only Partial Decarburization Allowed NUMBER: MPAPS A-1037 TITLE: Multi-Leaf Springs REVISION:
34、 1404 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. 2014 by Navistar, Inc. APRIL 2014 Page 5 of 10 4.8 Vertical suspend at 250,000 cycles. 4.8.2 Combin
35、ed Vertical suspend at 250,000 cycles. Furthermore the cumulative measured free camber loss must be less than 12mm after the completion of Stage II relative to the pre-test measurement. 4.8.2.3 Combined Vertical & Braking Sample Size For new parts, 6 samples shall be tested for initial qualification
36、, unless validated under similar design. For parts with prior production history, 3 samples shall be tested. 5.0 QUALITY Surface of the leaves shall exhibit no visual evidence of significant discontinuities such as laps, scale, scabs, and slivers, and shall exhibit no transverse tool marks or gouges
37、. (Transverse is defined as being perpendicular to the length of the leaf within an angle of 15 from the perpendicular). Surface discontinuities such as pits, longitudinal tool marks or gouges and other depressions are permissible provided they are no deeper than 0.25 mm (0.010 in) and that they do
38、not have a sharp radius - root radius less than 0.75 mm (0.030 in). Leaves shall also be free from pipe, bursts, and laminations. Maximum depth of seams shall be 0.02 mm (0.001 in) per 1.6 mm (0.06 in) thickness. 6.0 QUALIFICATION Engineering qualification of sources is required in advance of produc
39、tion shipments. Suppliers shall submit samples for approval of finish, luster, color and appearance to the Navistar Industrial Design Group. Samples shall be accompanied by test data certifying that all requirements of the specification NUMBER: MPAPS A-1037 TITLE: Multi-Leaf Springs REVISION: 1404 T
40、his 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. 2014 by Navistar, Inc. APRIL 2014 Page 8 of 10 have been met. Upon approval, styling master samples denoti
41、ng the minimum level of acceptable appearance quality shall be developed and retained by the supplier and the quality department of each using NAVISTAR facility. 6.1 Quality Control Plan A Quality Control Plan for this product will be established by mutual agreement between Navistar and the supplier
42、. The following five (5) characteristics, where applicable*, shall be included in the plan as features for management by statistical process control*. (1) Width at the Leaf Ends (2) Pack width at points 3.0 0.1 inch on either side of the spring center. (3) Center bolt height above the main leaf (4)
43、Finished bushing ID or thread pitch diameter (5) Spring free height * Other characteristics for inclusion in the control plan may be specified on the engineering drawing and/or purchase order. * See NAVISTAR Engineering Design Standard A-16 7.0 SOURCE APPROVAL AND QUALITY CONTROL 7.1 Supplier Requir
44、ements All suppliers to NAVISTAR are required to be registered to ISO 9001 Quality System Requirements. NAVISTAR will also accept TS-16949 registration as long as the supplier can also fulfill all AIAG PPAP (Production Part Approval Process) documentation and approval requirements. Suppliers must ma
45、intain their certification with an accredited registrar and must furnish copies of registration certificates to their Corporate Buyer upon request. 7.2 Approval Parts supplied against contracts or purchase orders citing this specification shall be equivalent in all respects to those samples which we
46、re approved by the purchaser. No changes in formulation or processing practices are permitted without approval. In the event that changes in material, properties, processing practices, construction, color, or labeling of the product are required, the supplier shall notify NAVISTAR Materials Engineer
47、ing and Purchasing and Supplier Development of the proposed change(s). Test data indicating conformance to all requirements of this specification, test samples, and new or amended or updated Material Safety Data Sheet(s) (MSDS), in accordance with CFR Title 29, Part 1910 shall be submitted with the
48、request for change. 7.3 Process Control The supplier shall either perform and report results of tests on specific lots of parts produced using ISO 9001 or TS-16949 guidelines, or provide statistical evidence of the lot having been produced in a state of statistical control and with a process capable of providing all required properties. The part supplier and the quality control manager of the using NAVISTAR plant may determine testing and reporting requirements on specific products. 8.0 SHIPPING AND HANDLING Loading, packing and identification shall be in accordance with Manufacturing Std
