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. 2015 by Navistar, Inc. JUNE 2015 Page 1 of 4 NAVISTAR, INC. Material, Parts, and Process Specifications (
2、MPAPS) NUMBER: MPAPS-S-D-100.101-GS/PL Former Designation: ESP-D-100.101-GS TITLE: Mechanical and Quality Requirements for Tapping Screws English Series (Noun Code 7450) CURRENT REV No.: 1506 DATE: June 2015 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: ESP-
3、D-100.101-GS - March 2002 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISION 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 c
4、onsult appropriate safety and health practices and to determine the applicability of regulatory limits prior to use. Change Notice: Changed to New MPAPS format. 1.0 GENERAL: This specification covers the mechanical and quality requirements for carbon steel tapping screws as used in automotive and re
5、lated industries. It does not apply to corrosion resistant (stainless) steel screws. The primary objective of the specification is to insure that screws form or cut mating threads in materials of construction into which they are normally driven, without deforming their own thread and without breakin
6、g during assembly or service. Note: Certain limitations on basic material and manufacturing processes have been incorporated because the size and configuration of the parts under consideration make them vulnerable to relatively small variations in chemistry, heat treatment, etc.; and because experie
7、nce has shown that in processing it is difficult to keep these variables consistently “in balance.“ Until improved performance tests are developed these limitations will supplement the “performance“ features of the specifications. 2.0 RESTRICTED CHEMICAL SUBSTANCES: Effective January 1, 2007, all pr
8、oduct supplied to the requirements of this specification must comply with the requirements of the MPAPS B-50 specification. 3.0 PERFORMANCE REQUIREMENTS: 3.1 Drive Test: Sample screws (coated or uncoated, as received) will, without deforming their own, form a mating thread in test plate described be
9、low until a thread of full diameter is completely through the test plate. In cases where screws are plated subsequent to delivery to the purchasers (or where plating of screws is otherwise under the control of the purchaser), the screw producer is not responsible for failures due to plating. Additio
10、nal screws from the same lot will be stripped of plating, baked, lubricated with machine oil and retested in the plain finish condition. The test plate will be made of low carbon cold rolled steel, having hardness of Rockwell B70-85 (Vickers 125-169), or equivalent, and thickness as specified in Tab
11、le 1. Test holes will be drilled or punched and redrilled, or reamed, to plus and minus .0010 inch (.0254 mm) or nominal diameters specified in Table 1 for the type and size of screw being tested. NUMBER: MPAPS-S-D-100.101-GS/PL TITLE: Mechanical and Quality Requirements for Tapping Screws REVISION:
12、 1506 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. 2015 by Navistar, Inc. JUNE 2015 Page 2 of 4 3.2 Torsional Strength Test: Shank of sample screw (co
13、ated or uncoated, as received) will be clamped in a mating, split, blind-hole die (see Figure 1), or other means, such that the clamped portion of the thread is not damaged and that at least two full form threads project above the clamping device, and at least two full form threads exclusive of poin
14、t, flutes or end slots are held within the clamping device. (A blind hole may be used in place of a threaded clamping device, providing the hole depth is such as to insure that breakage will occur beyond the point, or the full length of the flutes or end slot.) By means of a suitably calibrated torq
15、ue measuring device, apply torque to the screw until failure occurs. The torque required to cause failure will equal or exceed the minimum value shown in Table 2 for the type and size of screw being tested. 4.0 MATERIAL REQUIREMENTS: Screws will be made from cold heading quality, killed steel wire.
16、Chemical composition (percent by weight) will conform to the following: Tapping Screw Size Analysis % Carbon % Manganese No. 4 or Smaller Ladle2 .13 - .25 .60 - 1.65 Check .11 - .27 .57 - 1.71 No. 6 or Larger Ladle2 .15 - .25 .70 - 1.65 (3.5 mm) Check .13 - .27 .64 - 1.71 4.1 Core Hardness: Types AB
17、 B, BP, BT, C, D, F, T, and TT will be Rockwell C28-383(Vickers 286-372); Type BSD (self drilling point) will be Rockwell C32-40 (Vickers 318-392). Core hardness will be determined at mid-radius of a transverse section through the screw taken at a distance sufficiently behind the point of the screw
18、 to be through the full minor diameter. Drive test does not apply to Types BT screws. 2Ladle analyses are shown for informational purposes. Check analyses are mandatory and refer to individual determinations on uncarburized or core portion of screws. 3Core hardness will not exceed maximum shown and
19、preferably should be no higher than C36 (Vickers 354) to insure against failure in assembly and service. 4.2 Surface Hardness After Tempering: Types AB, B, BP, BT, C, D, F, T, and TT will be Rockwell 15N 83 (C45 Vickers 446) minimum. Type BSD will be Rockwell 15N 86 (C52 Vickers 544) minimum. Surfac
20、e hardness will be determined by a microhardness instrument at “root of thread profile“ as exposed by removal of enough material to form a “flat“ along length of screw. For routine quality control purposes, it is common practice to measure surface hardness on end, shank, or head. 4.3 Case Depth: wil
21、l conform to following, as measured at thread flank, mid-point between crest and root: Inch Metric Nominal Size Case Depth Nominal Size Case Depth Min Max Min Max #4 thru #6 #8 thru #12 1/4 and Larger .002 .004 .006 .007 .009 .011 3.5 4.2 and 4.8 6.3 and 8 0.05 0.1 0.15 0.18 0.23 0.28 4.4 Microstruc
22、ture: Will show no band of free ferrite between case and core as determined by metallographic examination. NUMBER: MPAPS-S-D-100.101-GS/PL TITLE: Mechanical and Quality Requirements for Tapping Screws REVISION: 1506 This document is restricted and may not be sent outside Navistar, Inc. or reproduced
23、 without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2015 by Navistar, Inc. JUNE 2015 Page 3 of 4 5.0 PROCESSING REQUIREMENTS: To insure the above requirements the following additional details will be observed by the screw manufacturer 4A. He
24、at Treatment will be in carbonitriding or gas carburizing system. Cyaniding systems may be approved by specific purchaser when it is shown that continuous flow (not batch) quenching processes are employed which consistently produce uniform case and core. B. Quenching Media for Types AB, B, BP, BT, C
25、 D, F, T, and TT (1/4 inch diameter and larger) will be water. Oil may be used by agreement between supplier and purchaser. For these same types (numbered sizes only), for Type BSD (all sizes) and for Sems (all types and sizes), water or oil will be used. C. Tempering Temperature for Type BSD (self
26、driller) will be 625F (329C) min; for all other types will be 650F (343C) min. 4See MPAPS-S-A-1.301 for requirements for relief of hydrogen embrittlement after plating, phosphate coating, etc. Dimensions in inches: Table 1 - Standard Test Plate Thicknesses and Hole Sizes for Drive Test Inspection o
27、f Tapping Screws Thickness Hole Size Nominal Screw Size Types AB, B, BP, and C Types D, F, T, and TT Types AB, B, and BP Type C Type D, F, G, T, and TT Coarse Thread Fine Thread Coarse Thread Fine Thread Gage Max Min Max Min Drill Size Hole Size Drill Size Hole Size Drill Size Hole Size Drill Size H
28、ole Size Drill Size Hole Size 2 18 .0500 .0460 .0800 .0760 No.48 .0760 No.48 .0760 No. 48 .0760 No. 49 .0730 3 18 .0500 .0460 .0960 .0920 No.46 .0810 No. 44 .0860 No.43 .0890 No. 46 .0810 4 18 .0500 .0460 .1110 .1070 No.44 .0860 No. 41 .0960 No. 40 .0980 No. 41 .0960 - - 5 18 .0500 .0460 .1110 .1070
29、 No. 36 .1065 No. 35 .1100 No. 35 .1100 No. 37 .1040 - - 6 14 .0770 .0730 .1425 .1385 No. 32 .1160 No. 31 .1200 1/8 .1250 No. 31 .1200 - - 7 14 .0770 .0730 - - No. 30 .1285 - - - - - - - - 8 14 .0770 .0730 .1420 .1380 No.29 .1360 No.27 .1440 No.26 .1470 No.26 .1470 - - 10 1/8 .1270 .1230 .1905 .1845
30、 No.21 .1590 No. 19 .1660 11/64 .1719 No. 17 .1730 No. 16 1770 12 1/8 .1270 .1230 .1905 .1845 3/16 .1875 No.11 .1910 No. 10 .1935 No. 8 .1990 - - 1/4 3/16 .1905 .1845 .2530 .2470 5.5 mm .2165 7/32 .2188 I .2280 I .2280 A .2340 5/16 3/16 .1905 .1845 .3155 .3095 I .2720 J .2770 L .2900 L .2900 M .2950
31、 3/8 3/16 .1905 .1845 .3780 .3720 21/64 .3281 R .3390 11/32 .3438 T .3580 T .3580 7/16 3/16 .1905 .1845 - - 13/32 .4062 - - - - - - - - 1/2 3/16 .1905 .1845 - - 15/32 .4688 - - - - - - - - NUMBER: MPAPS-S-D-100.101-GS/PL TITLE: Mechanical and Quality Requirements for Tapping Screws REVISION: 1506 Th
32、is 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. 2015 by Navistar, Inc. JUNE 2015 Page 4 of 4 Table 2 - Torsional Strength Requirements for Tapping Screws N
33、ominal Screw Size Minimum Torsional Strength (pound - inches) Types AB, B, BP, and BT Type C Types D, F, T, and TT Coarse Thread Fine Thread Coarse Thread Fine Thread 2 4 5 6 5 6 3 9 9 10 9 10 4 13 13 15 13 15 5 18 18 20 18 20 6 24 23 27 23 27 7 30 - - - - 8 39 42 47 42 47 10 56 56 74 56 74 12 88 93
34、 108 93 108 1/4 142 140 179 140 179 5/16 290 306 370 306 370 3/8 590 560 710 560 710 7/16 - - - - - 1/2 - - - - - 6.0 TECHNICAL INFORMATION: For further information related to the technical content of this specification, contact: Suppliers may purchase controlled copies of this specification by contacting: Materials Engineering and Technology Dept. 10400 W. North Avenue Melrose Park, IL 60160 E-mail: MaterialsEngineeringN IHS Global Inc. 15 Inverness Way East Englewood CO 80112-5776 Phone: 1-800-854-7179 E-mail: AutomotiveIHS.com Website: http:/
