BS A 305-1994 Bolts - Test methods《螺栓 试验方法》.pdf

1、BRITISH STANDARD BS A305:1994 ISO7961:1994 Bolts Test methodsBSA305:1994 This BritishStandard, having been prepared under the directionof the Aerospace Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15August1994 BSI12-1999 The following BSI

2、 references relate to the work on this standard: Committee reference ACE/12 Draft for comment91/82709 DC ISBN 0 580 23219 0 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Aerospace Standards Policy Committee (ACE/-) to Technical Committee

3、 ACE/12, upon which the following bodies were represented: The Association of Electronics, Telecommunications and Business Equipment Industries British Industrial Fasteners Federation Ministry of Defence Society of British Aerospace Companies Ltd. Amendments issued since publication Amd. No. Date Co

4、mmentsBSA305:1994 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Tests 1 4 Test validity 10 5 Test reports 10 Annex A (normative) Calibration of apparatus 11 Annex B (normative) Test reports 11 Annex C (informative) For

5、mulae 12 Figure 1 Tensile test Test device 2 Figure 2 Tensile test Position of the nut in relation to the complete threads (shank side) 2 Figure 3 Tensile test Upper and lower cup details 3 Figure 4 Double shear test Test device 4 Figure 5 Double shear test Upper and lower blocks 5 Figure 6 Stress c

6、orrosion test Test cylinder (principle) 10 Table 1 Rates of load application Tensile test 4 Table 2 Rates of load application Double shear test 6 Table B.1 Information to appear in test report 11 List of references Inside back coverBSA305:1994 ii BSI 12-1999 National foreword This BritishStandard ha

7、s been prepared under the direction of the Aerospace Standards Policy Committee. It is identical with ISO7961:1994 Aerospace Bolts Test methods, published by the International Organization for Standardization (ISO). Cross-reference. The Technical Committee has reviewed the provisions of ISO7500-1:19

8、86, to which normative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct applicatio

9、n. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to12, an inside back cover and a back cover. This standard has been updated (see copyright date) and ma

10、y have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BSA305:1994 BSI 12-1999 1 1 Scope This International Standard specifies test methods for bolts for aerospace constructions. It is applicable whenever quoted in reference. 2 Normative reference

11、 The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard

12、are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO7500-1:1986, Metallic materials Verification of static uniaxial testing machines Part1: Tensile

13、testing machines. 3 Tests 3.1 Tensile test at ambient temperature 3.1.1 Apparatus 3.1.1.1 Test device (seeFigure 1). The test device shall be centred such that the stress at four equi-spaced points around the test sample is uniform within1%, or such that the coaxiality between the bolt and the clear

14、ance holes is less than or equal to0,025mm to ensure the application of the tensile load along the axis of the bolt 1) . Other types of device may be used provided they respect the requirements of Figure 3. 3.1.1.1.1 Cups, fixed or removable, in conformity with Figure 3, which specifies only functio

15、nal requirements. 3.1.1.1.2 Test nut (free-running or self-locking) or threaded part (assuming the role of a nut), of sufficient strength to guarantee bolt failure. 3.1.1.2 Tapered spacer, placed under the head during the test, when required by the procurement specification or definition document to

16、 evaluate the effect of angularity. The minimum clearance between the hole and the bolt shank shall be0,13mm. At least90% of the bolt bearing area shall be supported by the spacer which shall have a diameter sufficient to support the width across the corners of the bolt. The tolerance on the hole di

17、ameter in the spacer shall bemm. 3.1.1.3 Washers, used under bolt heads or nuts only in the case outlined in3.1.1.2. 3.1.1.4 Tensile or compressive test machine, depending on the fixture, capable of applying the test loads. 3.1.2 Procedure 3.1.2.1 Assemble the bolt in the test device(3.1.1.1) as sho

18、wn in Figure 1. Install the nut(3.1.1.1.2) as shown in Figure 2. Place the complete assembly between the loading platens of the machine. 3.1.2.2 Apply the load specified in the procurement specification or definition document at the rate specified in Table 1 1) , in a controlled way. 3.2 Double shea

19、r test 3.2.1 Apparatus SeeFigure 4 andFigure 5, the latter only defining functional requirements. NOTE 1Totally enclosed top and bottom blades may be used as an alternative. 3.2.2 Procedure 3.2.2.1 Assemble the bolt into the lower part of the guillotine. The blend radius under the head and the threa

20、ded portion shall not be in contact with the lower part of the guillotine (seeFigure 4). 3.2.2.2 Apply the load required in the procurement specification or definition document at the rate specified in Table 2, in a controlled way. If this load is attained without breakage of the bolt, the test may

21、be terminated 1) . 1) Calibration requirements: seeISO7500-1:1986 and Annex A of this International Standard. +0,08 0BSA305:1994 2 BSI 12-1999 Figure 1 Tensile test Test device Figure 2 Tensile test Position of the nut in relation to the complete threads (shank side)BSA305:1994 BSI 12-1999 3 Figure

22、3 Tensile test Upper and lower cup detailsBSA305:1994 4 BSI 12-1999 Table 1 Rates of load application Tensile test Nominal shank diameter a Rate kN/min Nominal shank diameter a Rate kN/min Nominal shank diameter a Rate kN/min 3 4 5 6 7 8 10 5 9 14 20 27 35 55 12 14 16 18 20 22 24 80 110 140 180 220

23、270 320 27 30 33 36 39 400 500 600 700 850 a For other shank diameters, bolts shall be tested at a loading rate, accurate to 10%, of750N per minute per1mm 2of nominal shank cross-section. Figure 4 Double shear test Test deviceBSA305:1994 BSI 12-1999 5 Figure 5 Double shear test Upper and lower block

24、sBSA305:1994 6 BSI 12-1999 Table 2 Rates of load application Double shear test 3.3 Tension fatigue test 3.3.1 Apparatus 3.3.1.1 Test device (seeFigure 1). Universal joints and spherical seats shall not be used in the test column. The test device shall be centred such that the stress at four equi-spa

25、ced points around the test sample shall be uniform within3% of the mean stress value 2) . Other types of device may be used provided they respect the requirements of Figure 3. Test bolts shall not be re-used. 3.3.1.1.1 Cups, fixed or removeable, in conformity with Figure 3, which specifies only func

26、tional requirements. 3.3.1.1.2 Test nut or threaded part (assuming the role of a nut), with a height greater than or equal to0,8D and of sufficient strength to ensure bolt breakage. NOTE 2Test nuts or threaded parts may be re-used provided that it meets the dimensional requirements and has not been

27、damaged by a previous test. For referee purposes, only unused nuts or threaded parts shall be used. 3.3.1.2 Load measuring system, of an accuracy within 2% of the applied maximum load 2) . 3.3.1.3 Automatic load maintaining system 3.3.1.4 Fixtures, designed to incorporate the features indicated in F

28、igure 3. 3.3.2 Procedure 3.3.2.1 Installation Test bolts shall be assembled so that a minimum of two and a maximum of three complete threads are exposed between the nut or threaded part (3.3.1.1.2) bearing face and incomplete threads on the shank side. In the case of flush head bolts, the bearing be

29、tween the bolt head and the loading cup in which it is to be tested shall be uniform. There shall be no contact in the head-shank junction area. 3.3.2.2 Test conditions 3.3.2.2.1 Torque There shall be no tensile stress due to torque or any other installation procedure. 3.3.2.2.2 Load level The fatig

30、ue test loads shall comply with the values specified in the procurement specification or definition document. 3.3.2.2.3 Frequency The frequency of the test shall conform with the requirements of the procurement specification or definition document. The maximum temperature of the bolt during test sha

31、ll not exceed50 C. 3.4 Stress durability test of ambient temperature 3.4.1 Apparatus 3.4.1.1 For torque or elongation loading 3.4.1.1.1 Steel blocks or spacers, heat treated to obtain a minimum Rockwell hardness of45HRC. 3.4.1.1.2 Threaded part, with sufficient strength to withstand the full tensile

32、 strength of the bolt being tested. 3.4.1.2 For external loading 3.4.1.2.1 Test device, as specified in3.1.1.1. 3.4.1.2.2 Adapted fixture 2) 3.4.2 Procedure Assemble the bolt in the test device(3.4.1.2.1) and apply the load specified in the procurement specification or definition document. Nominal s

33、hank diameter a Rate kN/min Nominal shank diameter a Rate kN/min Nominal shank diameter a Rate kN/min 3 4 5 6 7 8 10 10 18 27 40 54 70 110 12 14 16 18 20 22 24 160 215 280 350 440 530 630 27 30 33 36 39 800 990 1200 1400 1700 a For other shank diameters, bolts shall be tested at a loading rate, accu

34、rate to 10%, of750N per minute per1mm 2of double the nominal shank cross-section. 2) Calibration requirements: seeISO7500-1:1986 and Annex A of this International Standard.BSA305:1994 BSI 12-1999 7 For the torque loading method, the load is achieved by torque tightening to a pre-determined torque; t

35、his torque may be determined by formula or by calibrating torque against a load cell assimilating the test assembly 3) . For the elongation loading method, the load is achieved by measuring bolt extension; this extension may be determined by formula or by calibrating extension against a load cell as

36、similating the test assembly 3) . During the test, the loaded portion of the bolt shank shall have two full threads exposed between the incomplete threads on the shank side and the bearing face of the threaded part. Keep the bolt at ambient temperature in the loaded condition for the period of time

37、specified in the procurement specification or definition document. At the end of this time, disassemble and examine the bolt for the presence of cracks. Bolts suspected of having cracks shall be sectioned and microscopically examined using 100 magnification. Cracked or fractured test bolts constitut

38、e failure of the bolt. 3.5 Inspection for grinding burns 3.5.1 Procedure 3.5.1.1 Clean Remove all foreign matter from the bolts such as grease, dirt or oxide film. 3.5.1.2 Wetting test Rinse the bolts in cold water. If water breaks occur, reclean the bolts. 3.5.1.3 “Nital” etch Immerse the bolts for

39、2min to2,5min in a3% (V/V) solution of nitric acid (relativedensity1,38) in ethanol, at ambient temperature. Agitate the bath. 3.5.1.4 Rinse Rinse the bolts for at least2min in running water at a temperature below25 C. 3.5.1.5 Bleaching Immerse the bolts for2min to2,5min in a5% (V/V) solution of hyd

40、rochloric acid (relativedensity1,18) in ethanol, at ambient temperature. Agitate the bath. 3.5.1.6 Rinse Rinse the bolts for10s to30s in running water at a temperature below25 C. 3.5.1.7 Neutralization Neutralization may be performed with either of the following baths: 3.5.1.7.1 Ammonia solution Imm

41、erse the bolts for30s to60s in a solution of50g/l of ammonia (relative density0,90), at ambient temperature. 3.5.1.7.2 Soda solution Immerse the bolts for30s to60s in a solution of50g/l of soda at ambient temperature. 3.5.1.8 Rinse Rinse the bolts for10s to30s in running water at a temperature below

42、25 C. 3.5.1.9 Dry Dry the bolts with filtered compressed air at ambient temperature. 3.5.1.10 Examine for grinding burns These burns appear as either white streaks (untempered martensite) or dark grey (zone of overtempering) on an even light grey background on the surface of the bolts. 3.5.1.11 De-e

43、mbrittle Carry out a maximum of12h of “Nital” etch(3.5.1.3) de-embrittlement treatment on the bolts at a temperature of130 C 10 C or190 C 10 C for at least2h, depending on whether the tempering temperature of the parts is less than or equal to200 C or greater than200 C. NOTE 3After bleaching (3.5.1.

44、5) and up to drying (3.5.1.9), operations should be carried out quickly to avoid oxidation. This oxidation builds up a chamois colour reducing contrast at a defect. Rinsing in running water at a temperature below25 C produces a uniform light grey colour on bolts without grinding defects, instead of

45、a chamois colour for higher temperatures. 3.6 Tensile test at elevated temperature 3.6.1 Apparatus 3.6.1.1 Test device, as specified in3.1.1.1. Materials and dimensional tolerances shall be consistent with the temperature. 3.6.1.2 Furnace, in which regulation and thermocouples used shall determine,

46、indicate and control the temperature of the bolt over its entire length within 3 C to1260 C 4) . Thermocouples shall have the following accuracy: 1 C from18 C to276 C, 0,4% from277 C to1260 C; 3) Formulae: seeAnnex C. 4) Calibration requirements: seeISO7500-1:1986 and Annex A of this International S

47、tandard.BSA305:1994 8 BSI 12-1999 be fitted with ceramic insulators from10mm from the junction to300mm outside the furnace, and after, with an insulating material; have their hot spot clamped against the bolt so as not to be affected by the ambient conditions; be attached to each end of the bolt and

48、, if possible, in the middle. 3.6.1.3 Tensile or compressive test machine, depending on the fixture, capable of applying the test loads. 3.6.2 Procedure 3.6.2.1 Mount the bolt to be tested, fitted with its thermocouples, in the test device(3.6.1.1), and place this, with the furnace between the plate

49、ns of the machine. 3.6.2.2 Heat the furnace to the temperature specified in the procurement specification or definition document. The minimum time to reach this temperature shall be60min per25mm of bolt diameter. 3.6.2.3 Maintain this temperature for30min before applying the load, then throughout the test. 3.6.2.4 Apply the load specified in the procurement specification or definition document at the rate specified in Table 1, in a controlled way. 3.6.2.5 Record