1、) I i ! I I I i I : MILITARY SPECIFICATION SPRINGS; HELICAL, AIRCRAFT MIL-S-6715 12 June 1950 ThlS speclflcation was approved by the Departments of the Army, the Navy, and the Air Force for use of procurement services of the respective Departments. 1. SCOPE 1.1 Scope. This specification establishes
2、the requirements for forming helical sprlngs from wire or rod, and heat treatment after coiling. 1.2 .L.3 . The springs shall be of the followlng types: Type I - Compression Type II - Extension Clase. Classes of helical prings shall be as shown in table I. Class Speciflcation A AN-S-58 B AN-S-S C MI
3、L-W-6101 D AN-W-23 E I MIL-W-6713 F ! AN-N-4 G QQ-W-401 TABLE I Material Description Chrome-Vanadium Steel Rod and Wire Carbon Steel Rod Spring Steel Wlre Corroslon-Resisting Steel Wue Corrosion-Reslsting Steel Wire Nickel-Chromium-Iron Allo Y I Spring Wire I I Wire Phosphor-Bronze 1/ Value to De us
4、ed ln test calculatlons. Shear Modulus of Elasticity “G“ psi 1) 11,500.000 11.500.000 11,500.000 11.000.000 11,000,000 11,000,000 6.250.000 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-671S 2. APPLICABLE SPECIFICATIONS AND OTHER PUBLICATIONS
5、 2.1 The following publications of the issue, in effect on date of nvitaton for bids, shall form a part of this specif1cation to the extent spec1f1ed herin: 2.1.1 Federal QQ-M-1S1 QQ-P-416 QQ-.J-401 M1litary MIL-S-S002 MIL-.J-6101 MIL-.J-6713 JAN-STD-I05 JAN-B-121 JAN-P-I05 JAN-P-I06 JAN-P-I08 JAN-P
6、-125 JAN-P-130 JAN-P-133 Specificat1ons. Metals; General Specification for Inspection of Plating; Cadm1um (Electrodeposited) Wire; Phosphor-Bronze, Spr1ng Surface Treatments (Except Pr1ming and Painting) for Metal and Metal Parts in Aircraft .Jre; Spr1ng Steel (for Aircraft Applications) Wire; Corro
7、sion-Resisting (Grade G) Steel Sampling Inspection Table for Inspection by Attributes Barrier-Materials. Greaseproof Packaging and Packing for Overseas Shipment - Boxes, Wood. Cleated. Plywood Packaging and Packing for Overseas Shipment - Boxes; Wood, Nailed Packag1ng and Packing for Overseas Shipme
8、nt - Boxes, F1berboard (V-Board and .J-Board). Exterior and Interior Packaging and Packing for Overseas Shipment -Barrier-Materials, Waterproof. Flexible Packaging and Packing for Overseas Ship.ent -RarierHaterial; Utility. Noncorrosive, Paper Packaging and Packing for Overseas Shipment - Boxes. Set
9、-Up. Paperboard 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-“-) MIL-S-671S Military (Continued) JAN-P-139 JAN-P-140 Packaging and Packing for Overseas Shipment - Ply wood, Container Grade Packaging and Packing for Overseas Shipment -Adhesives,
10、Water-Resistant, Case-Liner Air Force-Navy Aeronautical AN-H-201 AN-I-30 AN-I-32 AN-N-4 AN-P-13 AN-S-5 AN-S-58 AN-lol-23 U. S. Arm;! 94-40645 2.1. 2 Heat Treatment of Steels (Aircraft); Process for Inspection; Fluorescent Penetrant, Method of Inspection Process; Magnetic Particle Nickel-Chromium-Iro
11、n Alloy; Wire and Welding Rod Preservation and Packaging; Parts and Equipment (General Specification For) Steel; Carbon (1095) Bar and Rod Steel; Chrome-Vanadium (61S0) Rod and Wire Marking; Exterior, Domestic and Export Shipment by Contractors Other publications. Air Force-Nav;! Aeronautical Bullet
12、in No. 143 Specifications and Standards; Use of Bureau of Supplles and Accounts Navy Shipment Marking Handbook (Copies of this specification and copies of other publications referenced herein or required for Government procurement, and the Index of Military Aeronaut1cal (AN or MIL) Standards. may be
13、 obtained upon application to the Commandlng General, Air Materiel Command, Wright Patterson A1r Force Base, Dayton. OH; or the Commanding Offlcer. U S. Naval A1r Statlon, Johnsville. PA.) 3 . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-671
14、5 3. REQUIREMENTS 3.1 Selection of materials. Specificatons and standards for all materals. parts. and Government certif1cation and approval of processe and equipment. WhlCh are not specif1cdlly deslgnated here1n and which are necessary for the execution of this specificatlon, shall be selected in a
15、ccordance with ANA Bulletin No. 143. 3.2 Forming. The springs shall be cold formed from wire or rod uniform n quallty and free from seams. except that class A and class B springs may be hot formed unless otherwise specified. 3.3 Maximum allowable working stress. The maximum allowable stress at full
16、deflecton shall not exceed 100,000 pounds per square lnch as determ1ned by the following formula: S FGd K 3.14ND2 (for round wire) (for square wire) where: S Maximum allowable stress. in pounds per square inch F - Total deflection under load. in inches G Shear modulus of elasticity, 1n pounds per sq
17、uare inch, from table 1 d Rod or wire dameter. in inches N Number of active coils D Mean coil diameter. in inches K Stress correction factor which allows for non-unlform distrlbution of shearing stress due to the finite ratio of DId Values of this factor are obtained from figure 1. 3.4 Taper of the
18、end COlIs of type I sprlngs. The spring wire shall be tapered uniformly at each end for a length equal to 270 degrees, plus or minus 20 degrees of the circular coil and shall have a thickness at the tip 1/4 the diameter of the unground section. The shoulders between the tapered end and the Circular
19、sect10ns shall be rounded to avo1d sharp edges. 3.5 Free length tolerances. The free overall length tolerance of the spring shall be as specified on the applicable drawing. after the maximum work1ng load has been released as specified 1n para graph 4.3.2.1. 1. 3.6 Concentricity. The coil shall be co
20、ncentric with tfte axis of the load. as specified on the applicable drawing. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-) a: 18 16 14 a: 12 cs: -w o .ICS: oZS U 0 10 zO cs:a: u o cs: a: 8 6 4 2 o 10 MIL-S-6715 , , !, “ “-“.,.,. 12 14 16 18 2.0
21、 2.2 K= STRESS CORRECTION FACTOR FIGURE 1. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-6715 3.7 Opening between coils. The opening between cols for type 1 springs shall not vary more than plus or minus 5 percent of the opening specified o
22、n the applicable drawings. The opening between coils at the ends shall taper uniformly to full opening within 360 degrees and not less than 270 degrees from the coil ends. 3.8 Spring ends. The spring ends shall be ground as shown on the applicable drawings. 3.9 Heat treatment. Springs of class A and
23、 class B shall be heat treated in accordance with Specification AN-H-201. if necessary. to obtain the required physical characteristics. and shall have a smooth fin1sh when cleaned. Care shall be exercised while heat treating to prevent internal or surface cracks. The springs shall be given a set af
24、ter heat treatment to prevent any change in operation under normal loadlng. 3.9.1 Decarburization. The surface of heat-treated springs shall not be decarburized. except that sprlngs having a total decarbu r1zation of 0.001 inch or less .ay be furnished at the discretion of the Procuring Service. 3.1
25、0 Cleaning and descaling. All springs of classes A. B. and C shall be thoroughly cleaned and descaled by a process suitable for the purpo intndd. 3.11 Bending. The wire in a finished spring shall with-stand the Bend test specified herein. 3.12 Strain relief. After forming. ferrous alloy springs shal
26、l be given a suitable strain-relieving treatment. Suggested treat o ments are baking for 1 hour at 350 F or baking for not more than 10 o minutes at 600 F. Copper base alloy springs shall be strain-relieved by bakng at 3750F for 1 hour. 3.13 Cleaning. All springs of classes D and E shall be passlvat
27、ed immediately after treatment for strain relief in accordance with Speclfication MIL-S-5002. The entire sprlng shall be immersed at one time. 3.14 Plating. Springs shall be cadmium plated. when speclfied by contract or purchase order. in accordance with Speclfication .P-416. 3.15 Embrittlement reli
28、ef after plating. Springs which have been cadmium plated shall be baked at the temperature and the time 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-) MIL-S-671S specified in Specification QQ-P-416 to relieve embrittlement. The baking. treatment
29、 shall be the last operation before oiling or coating with rust-preventive. 3.16 Rust preventive. All springs of classes A. B. and C which are not to be painted shall be coated with a suitable rust preventive. 3.17 Workmanship. Workmanship aha II be in accordance with high-grade commercial practice
30、covering this class of work. The coils of the finished springs shall be entirely free from cracks. seams. nicks. dents, or other surface imperfections. 4. SAMPLING, INSPECTION, AND TEST PROCEDURES 4.1 General. All the tests required for the testing of helical springs are classified as Inspection tes
31、ts, for which necessary sampling techniques and methods of testing are specified in this section. The contractor shall furnish all samples and shall be responsible for acomplishing the required tests. When inspection is conducted at the contractors plant. all inspection and testing shall be under th
32、e superv1s1on of the Government Inspector. Contractors not having laboratory testing facilities satisfactory to the Government shall engage the services of a commercial testing laboratory acceptable to the Inspector. The contractor shall furnish test reports, in duplicate, shoWing quantitative resul
33、ts for all tests required by this specification. and Signed by an authorized representative of the contractor or laboratory. as applicable. Acceptance or approval of material during course of manufacture shall in no case be construed 8S a guaranty of the acceptance of the finished product. 4.2 Sampl
34、ing. 4.2.1 Lot. A lot shall consist of all the springs of the same type. design, adimensions made from the same material, and submitted for inspection at the same time. 4.2.2 Sampling for workmanship and drawing conformance. Samples shall be randomly selected in accordance with table I, Inspection L
35、evel III, Acceptable Quality Level (AQL) class 2.2 to 3.2 of JAN-STO-10S. Sampling Inspection Table for Inspection by Attributes. A random sample is defined in Specification JAN-STO-10S. 4.2.3 Sampling for mechanical tests. Unless otherwise specified samples shall consist of random samples selected
36、1n accordance with table II. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Lot Size in Springs 1 - 20 21 - 100 101 - 300 301 - 500 501 - 1000 1001 - 2000 2001 - 4000 Over 4000 4.3 MlL-S-671S TABLE II Sampling for Mechanical Tests Single Plans Sam
37、ple Size Maximum Allowable Number of Defective Items First 13 Second 26 First 20 Second 40 First 35 Second 70 First 50 Second 100 Tests. 1 3 7 10 Double Plans Accumulative Acceptance No. o 1 0 1 1 2 1 3 o o o o Accumulative Rejection No. 2 2 2 2 3 3 4 4 4.3.1 Workmanship or draw1ng conformance. Rand
38、om samples selected in accordance with paragraph 4.2.2 shall be examined to determine 1f they conform to their detail drawings and the standard or workmanship specified in Section 3. 4.3.2 Hechan1cal tests. 4.3.2.1 Compression and extension. 4.3.2.1.1 Free length. Measure the length of the spring af
39、ter the maximum work1ng load specified on the applicable drawing, has been aplied and released. This length measurement shall conform to the length measurement specified on the applicable drawing. Free length measurements shall be made at the approximate center of the spring. The minimum value obtai
40、ned from three loadings shall apply. 8 -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-) MIL-S-671S 4.3.2.1.2 Rate of deflection. Measure the deflection under 80 percent and under 10 percent of the maximum working load and apply the following formul
41、a: Rate of deflection - 0.80g - 0.10Q where A at 0.80Q - A at 0.10Q Q Maximum working load. in pounds A Measured deflection under applied load. in inches 4.3.2.1.3 Maximum deflection. The maximum deflection of the spring shall be determined by applying 1-1/4 times the working load and measuring the
42、perpendicular distance between the plates of the testing machine. The difference between this measurement and the free length is the maximum deflection. 4.3.2.2 Hardness. Hardness tests shall be made in accordance with Specification QQ-M-1S1. 4.3.2.3 Bend. The wire in a finished spring shall withsta
43、nd bending 180 degrees around a diameter equal to twice the diameter of the wire. 4.3.2.4 Magnetic particle inspection. Springs of classes A. B. and C shall be inspected in accordance with the requirements of Specification AN-I-32. 4.3.2.5 The sample shall be sectioned. shall be given a metallograph
44、ic polish. etched vith 5 percent nital and examined by a competent metallographist. 4.4 Rejection and retest. 4.4.1 Workmanship and draving conformance. Any item of any given sample which does not pass inspection (paragraph 4.3) shall be called a defective. If a lot has been rejected according to th
45、e sampling plan specified in paragraph 4.2.2, t may be resubmitted for reinspection after havng been screened by the manufacturer for such defectiveness. 4.4.2 Mechanical tests. Any item of any given sample which-does not pass all of the Mechanical tests shall be called a defective. A lot shall be r
46、ejected if the sample fails to meet the acceptance require ments of table II. 5. PREPARATION FOR DELIVERY 5.1 Application. The packaging. packing and mark1ng requirements specified herein apply only to direct purchase by or direct shipments to the Government. 9 Provided by IHSNot for ResaleNo reprod
47、uction or networking permitted without license from IHS-,-,-MIL-S-671S 5.2 Preservation. Unpainted class A. B. and C springs shall be preserved in accordance w1th method I of Specif1cation AN-P-13. All springs shall be wrapped in barrier material conforming to Specifi cation JAN-B-121, grade A. 5.3
48、Packaging. Wrapped springs in quantit1es specified bv the Procuring Service shall be snugly packaged in cartons or boxse conforming to Specification JAN-P-130 or JAR-P-133. respectively. S.4 Pack1ng. Unless otherw1se specified. all items shall be afforded domest1c packing. ShipP1ng containers shall contain the same number of packages. shall be uniform 1n size and snugly packed. The gross weight. when packed for shipment, shall not exceed approx1aately 200 pounds. 5.4.1 Domestic packing. Unless otherwise specified. the packages shall be placed in substantial e
