1、I INTERNATIONAL TRUCK AND ENGINE CORPORATION I TI TL E: WRiTTEN/EDITED BY: APPROVED BY: Gray Cast Iron, Brake Drum Materials Engineering Materials Engineering UMBER: r TMS-2014 TMS (TRUCK MATERIAL SPECIFICATION) REVISION; E - 1 DATE ISSUED August 2000 IChange Notice: Reformatted and Editorial Change
2、s I hefereme: File 04-1 keywords: Brake Drums I 1.0 APPLICATION This specification covers a gray cast iron which is used in automotive brake drums or clutch plates, flywheels and similar applications requiring a high level of strength and resistance to thermal checking or cracking. 2.0 SCOPE This sp
3、ecification covers the manufacture, chemical composition, mechanical properties, microstructure, quality, and qualification. 3.0 REFERENCE DOCUMENTS Unless otherwise specified, the latest issue of all referenced standards shall apply. The following standards, specifications and regulations are refer
4、enced in this specification. Quality System Standard QS-9000 (IS0 9001) INTERNATIONAL IQR Quality Standard INTERNATIONAL Manufacturing Standard D- 13 CFR Title 29, Part 1910 ASTM E 8 ASTM A 247 INTERNATIONAL Drawing AD-339 1 4.0 REOUIREMENTS 4.1 Manufacture The brake drums shall be cast from an elec
5、tric furnace gray iron which has been inoculated during pouring to produce the required mechanical properties and microstructure. The mechanical properties and microstructure shall be the controlling characteristics. 4.2 Chemical Composition The following chemical composition is recommended: Total C
6、arbon 3.40-3.80% Silicon 1.50-2.00% Manganese O. 60-0.90% Phosphorus 0.15 max Sulfur O. 12 max Carbon Equivalent 3.90-4.30% This document is restricted and may not be sent outside International Truck and Engine Corporation or reproduced without permission from Corporate Technical Standards. Supplier
7、s are required to assume all patent liability. 02000 International Truck and Engine Corporation AUGUST 2000 Page i of 5 NUMBER: TMS - 20 14 4.2.1 Deviations from the recommended chemical composition shall be submitted to the using Plant Metallurgist. The deviation shall be approved if the castings a
8、re machinable and the required mechanical properties and microstructure are produced. See Qualification Procedure, 5.1. TITLE: REVISION: Gray Cast Iron, Brake Drum E-1 4.3 Tensile Properties The control of tensile properties shall be primarily by Brinell hardness on a statistical basis. The vendor i
9、s responsible for controlling his processing and sampling shipments of brake drums to assure the following hardness requirements on the braking surface: BHN (3000 kg) f 20 Range f 30 Range 207-255 187-269 4.3.1 If hardness is measured other than on the braking surface, correlation data shall be supp
10、lied to the using Navistar Plant so that the alternate site can be approved for production control. The Brinell hardness control, however, is not intended to circumvent the basic requirement of the drum, which is tensile strength. The tensile strength shall be determined on specimens cut from the br
11、aking surface cross section per ASTM E-8, Figure 16, Specimen 2 preferred. The centerline of the reduced section of the tensile bar shall be at or near the center of the braking surface width. (Sub-size and rectangular specimens may be taken by agreement with the International Plant.) 95% of Drums 1
12、00% of Drums Ultimate Tensile Strength, MPa 215 min 185 min , psi 31 200 min 26 900 min 4.3.2 The BHN values should assure the minimum tensile strength values shown but tensile strength is the controlling or referee value. Vendors shall be required to tensile test drums frequently enough to prove th
13、e tensile-BHN relationship is valid for their foundry. If it is not, then separate correlation values will be established for their product. Records of all hardness-tensile data shall be made available to International personnel when requested. See General Information for further discussion. 4.4 Mic
14、rostructure, Brake Drum Surface 4.4.1 Graphite* Type A 90% min Size 3-5 Type B, D, no more than 2-1/2% will be below 214 MPa (31 O00 psi), and none will be below 190 MPa (27 500 psi). At BHN 187, not more than 5% of the tensile values will be below 215 MPa (31 200 psi); no more than 2-1/2% below 208
15、 MPa (30 200 psi), and none below 185 MPa (26 900 psi). A. 1.3 If these values are not satisfactory for the Designer, other hardnesses or tensile values may be selected by consulting a Materials Engineer. It is urged, however, that the Designer consider adjusting the design to these graphed values,
16、for they represent a statistical analysis of production data from our two principal brake drum suppliers. A. 1.4 If Quality Control tests indicate that BHN 207 does not result in 221 MPa (32 O00 psi) tensile strength min in at least 95% of tests, action to rectify the situation should be taken immed
17、iately. A. 1.5 Suppliers are expected to continually generate statistics on tensile-hardness data to provide the statistics and assure the vast majority of drums are above the 221 MPa (32 O00 psi) tensile strength level. A. 2 Chemical Composition Alloying elements may be used in small amounts to inc
18、rease the tensile strength of the iron, but the effect on the eutectic graphitizing tendency (EGT) should be considered: Si Cr Mo Ni Cu P EGT = T.C. + - - - - - +-+-+- 339 9 10 3 A. 2.1 The graphitizing tendency is an extension of the carbon equivalent. The overall alloying additions should be balan
19、ced to maintain the EGT in the specified carbon equivalent range. Tin, up to 0.10%, does not affect the EGT. A. 3 Thermal Conductivitv The heat transfer characteristics of a gray cast iron will be decreased by the addition of alloying elements, especially carbide formers. This document is restricted
20、 and may not be sent outside International Truck and Engine Corporation or reproduced without permission from Corporate Technical Standards. 02000 International Truck and Engine Corporation Suppliers are required to assume all patent liability. AUGUST 2000 Page 4 of 5 NUMBER: TMS - 20 14 FIGURE 1 TI
21、TLE: REVISION: Gray Cast Iron, Brake Drum E-1 50 45 40 35 30 25 160 180 200 220 240 260 280 BRINELL HARDNESS This document is restricted and may not be sent outside International Truck and Engine Corporation or reproduced without permission from Corporate Technical Standards. 02000 International Truck and Engine Corporation Suppliers are required to assume all patent liability. AUGUST 2000 Page 5 of 5
