BRITISH STANDARD AEROSPACE SERIES BS A 301 1989 ISO 8168 1988 Specification for Procurement of corrosion and heat resisting steel bolts with strength classification 1100 MPa and MJ threads Reproduced[.]
BRITISH STANDARD AEROSPAC E SERIES BS A 301 :1 989 ISO 81 68:1 988 Specification for Procurement of corrosion and heat-resisting steel bolts with strength classification 1 00 MPa and MJ threads Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS A 301:1989 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Aerospace Standards Policy Committee (ACE/- ) to Technical Committee ACE/1 upon which the following bodies were represented: Civil Aviation Authority (Airworthiness Division) Electronic Engineering Association Ministry of Defence Society of British Aerospace Companies Limited This British Standard, having been prepared under the direction of the Aerospace Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on Amendments issued since publication 31 October 989 Amd No © BSI 01 - 2000 The following BSI references relate to the work on this standard: Committee reference ACE/1 Draft for comment 86/74336 DC ISBN 580 17461 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Date of issue Comments BS A 301:1989 Contents Page Committees responsible Inside front cover National foreword ii Scope and field of application References Definitions Quality assurance Requirements Figure — Head structure and grain flow 14 Figure — Distortion in fillet area 15 Figure — Grain flow in thread 15 Figure — Non- permissible laps, seams and surface irregularities 16 Figure — Permissible laps, seams and surface irregularities 16 Figure — Metallurgical specimens 17 Table — Technical requirements and test methods Table — Qualification testing requirements for bolt samples Table — Summary of qualification and acceptance tests Table — Surface discontinuities and contamination Table — Minimum tensile and double shear loads for qualification and acceptance tests 10 Table — Qualification and acceptance values for tension fatigue test 10 Table — Thread discontinuities — Maximum depth of permissible faults 10 Table — Classification of defects 11 Table — Sampling plans for visual inspection and inspection of dimensional characteristics 12 Table — Sampling plans for the inspection of mechanical and metallurgical characteristics 12 Table 1 — Variable sampling for tensile and shear tests (alternative method) Publications referred to © BSI 01 - 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy 13 Inside back cover i BS A 301 :1 989 National foreword This British Standard, which has been prepared under the direction of the Aerospace Standards Policy Committee, is identical with ISO 81 68: 988 “Aerospace — Corrosion- and heat-resisting steel bolts with strength classification 1 00 MPa and MJ threads — Procurement specification ” published by the International Organization for Standardization (ISO) Cross-references International Standard C orresponding British Standard ISO 2859- : 974 BS 6001 Sampling procedures for inspection by attributes Part : 972 Specification for sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection (Technically equivalent) ISO 3534: 977 Statistical terminology Glossary of terms relating to probability and general terms relating to statistics BS 5532 Part : 978 (Identical) ISO 5855- 2: 981 BS 6293 MJ threads for aerospace construction Specification for dimensions for bolts Part 2: 982 and nuts (Identical) The Technical Committee has reviewed the provisions of ISO 3452, ISO 3453 and ASTM E 1 2- 84 to which reference is made in the text, and has decided that they are acceptable for use in conj unction with this standard It is envisaged that a British Standard corresponding to ISO 7961 will be published A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application 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, pages i and ii, pages to 8, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover ii Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy © BSI 01 - 2000 BS A : 989 S cop e and fie ld of ap p lication This International Standard specifies the characteristics and quality assurance requirements for bolts with normal heads, made of corrosion- and heat- resisting steel, having a tensile strength classification of 1 00 MPa and MJ threads, and intended for use in aerospace construction This International Standard applies to bolts as defined above, provided that reference is made to this International Standard in the product standard or definition document Re fe re nce s Sampling procedures for inspection by attributes — Part 1: Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection1 ) ISO 2859- , ISO 3452, Non-destructive testing — Penetrant inspection — General principles ISO 3453, Non-destructive testing — Liquid penetrant inspection — Means of verification ISO 3534, Statistics — Vocabulary and symbols ISO 5855- 2, ISO 7961 , Aerospace construction — MJ threads — Part 2: Dimensions for bolts and nuts Aerospace — Bolts — Test methods 2) ASTM E 1 2- 84, Standard methods for determining average grain size D e finitions 3.1 p ro ducti on b atch quantity of finished bolts manufactured, using the same process, from a single material cast (single heat of alloy) , having the same basic part number and diameter, heat- treated together to the same specified condition and produced as one continuous run 3.2 insp e ction lot quantity of bolts from a single production batch with the same part number which completely defines the bolt D iscontinuitie s 3.3.1 crack rupture in the material which may extend in any direction and which may be intercrystalline or transcrystalline in character 3.3.2 se am open surface defect resulting from extension of the material 3.3.3 lap surface defect caused by folding over metal fins or sharp corners and then rolling or forging them into the surface 3.3.4 inclusions non- metallic particles originating from the material manufacturing process These particles may be isolated or arranged in strings 1) 2) At present at the stage of draft (Revision, in part, of ISO 2859: 974 ) At present at the stage of draft © BSI 01 - 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS A 301 :1 989 3.4 simple random sampling the taking of items from a population of items in such a way that all possible combinations of items have the same probability of being chosen3) n N n 3.5 critical defect a defect that, according to judgement and experience, is likely to result in hazardous or unsafe conditions for individuals using, maintaining or depending3)upon the considered product, or that is likely to prevent performance of the function of a major end item 3.6 maj or defect a defect, other than critical, that is likely to3)result in a failure or to reduce materially the usability of the considered product for its intended purpose 3.7 minor defect a defect that is not likely to reduce materially the usability of the considered product for its intended purpose, or that is a departure from established specification having little bearing on the effective use or operation of this product3) 3.8 sampling plan a plan according3)to which one or more samples are taken in order to obtain information and possibly to reach a decision 3.9 limiting quality (LQ) in a sampling plan, a quality level which corresponds to a specified and relatively low probability of acceptance: for the purposes of this International Standard, a 10 % probability of acceptance (LQ10) It is the limiting lot quality characteristic that the consumer is willing to accept with a low probability that a lot of this quality would occur3) 3.1 acceptable quality level (AQL) a quality level which in a sampling plan corresponds to a specified but relatively high probability of acceptance it is the maximum percent defective (or the maximum number of defects per hundred units) that, for purposes of sampling inspection, can be considered satisfactory as a process average3) Quality assurance 4.1 General 4.1 Approval of manufacturers 4.1 Qualification of bolts The manufacturer shall conform to the quality assurance and approval procedures in effect in the purchaser’s country: the purpose of these procedures is to ensure that a manufacturer has a quality system and the capability for continuous production of bolts complying with the specified quality requirements The granting of an approval of the manufacturer is a function of the Certification Authorities, or their appointed representative, who may be the prime contractor The purpose of qualification inspections and tests of bolts is to check that the design and manufacturing conditions of a bolt allow it to satisfy the requirements of this International Standard The granting of qualification of a bolt is a function of the Certification Authorities in the purchaser’s country, or their appointed representative, who may be the prime contractor 3) Definition taken from ISO 3534:1977 (ISO 3534 is currently being revised by ISO/TC 69, Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Ap p lication o f s tatis tical m eth ods ) © BSI 01-2000 BS A : 989 4.1 Acceptance of bolts The purpose of acceptance inspections and tests of bolts is to check, as simply as possible, using a method which is inexpensive and representative of actual conditions of use, with the uncertainty inherent in statistical sampling, that the bolts satisfy the requirements of this International Standard Acceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility The manufacturer is responsible for the quality of the bolts manufactured Qualification insp e ction and te st conditions Qualification inspections and tests (requirements, methods, numbers of bolts) are specified in Table They shall be carried out on — each type and diameter of bolt, — 25 bolts selected from a single inspection lot by simple random sampling The test programme may possibly be reduced, or the qualification of a bolt be granted, without inspection or testing: any such decision shall be based on the results obtained on similar types and diameters of bolts provided that the design and manufacturing conditions are identical The inspections and tests shall be repeated on any bolt if the manufacturing conditions have changed Table indicates the allocation of bolt specimens for the inspections and tests Qualification inspections and tests are summarized in Table Acce p tance insp e ction and te st conditions Acceptance inspections and tests (requirements, methods, numbers of bolts) are specified in Table ; they shall be carried out on each production batch or inspection lot Bolts from the batch or lot to be tested shall be selected by simple random sampling Each bolt may be submitted to several inspections or tests The bolts to be subj ected to destructive inspections or tests may be those on which non- destructive inspections or tests have been carried out If a more stringent inspection is deemed necessary, all or part of the qualification inspections and tests may be performed during the acceptance inspection and testing In this case, the number of bolts submitted to these inspections and tests is the same as that submitted for qualification inspections and tests Production batches or inspection lots declared unacceptable after the acceptance inspections and tests shall be submitted for re- inspection or re- testing only after all defective units have been removed and/or defects have been corrected Twice the normal sample size shall be used for re- inspecting or re- testing the attributes causing initial rej ection; the same acceptance level shall be used Acceptance inspections and tests are summarized in Table Require me nts The requirements of this International Standard are given in Table and, unless otherwise specified, they apply to bolts ready for use Unless otherwise specified, the test temperature shall be the ambient temperature These requirements complement the requirements of all other standards or specifications referenced in the product standard or in the definition document of the bolt © BSI 01 - 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS A : 989 Tab le — Te chnical re quire me nts and te st me thod s Insp e ctio n and te st C lau se No 5.1 5.2 C haracte risti c Mate rials D ime nsio ns Te chni cal re qui re me nt me tho d In accordance with the product As stated in the standard or definition document material specification In accordance with the Standard gauging requirements of the product standard or definition document 5.3 5.3.1 Q/A a S amp le siz e Q 22 A Table and Table Manufacturing Forging The heads of the bolts shall be The equipment used formed by a hot or cold forging shall be approved process before heat treatment In the case of hot forging, the equipment shall be such that a constant temperature of less than 090 ° C is guaranteed 5.3.2 Heat treatment throughout the production batch The forged blanks shall be heat treated to produce the properties required by the product standard or definition document No blank shall be heat treated more than twice The heat treatment media or atmosphere shall not cause any surface contamination except as 5.3.3 Machining permitted by 5.5.3 The amount of material removed See 5.5.1 See 5.5.1 from the bearing surface of the head and the shank of the heat- treated blanks shall be as little as practicable consistent with the removal of surface contamination, production of a smooth surface and maintenance of optimum grain flow around the under- head fillet radius 5.3.4 Cold rolling as shown in Figure The fillet radius shall be cold rolled after heat treatment and machining so as to remove all visual signs of machining and to create superficial cold working; this may cause distortion which shall not exceed the values shown in Figure 2; this requirement is not applicable to fully threaded screws or bolts with 5.3.5 5.3.6 a Threads Surface roughness a nominal diameter less than MJ5 To be formed by a single rolling process after all heat treatment In accordance with the product Visual comparison standard or definition document method or thumbnail comparison method Q = qualification inspection and test conditions (see A = production acceptance test conditions (see Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Q A Table and Table 4.2) 4.3) © BSI 01 - 2000 BS A : 989 Tab le — Te chnical re quire me nts and te st me thod s C lause No 5.3.7 C haracte ri stic Surface coating Insp e cti o n and te st Te chnical re qu i re me nt me tho d In accordance with the product standard See applicable or definition document coating specification 5.4 Q/A S amp le si z e Q A Table and Table Me chanical p rop e rtie s 5.4.1 Tensile strength In accordance with the minimum tensile See ISO 7961 loads specified in Table Q A Table 0, Tensile tests are not applicable to the column B, following: or Table 1 a) protruding head bolts of grip length less than D ; b) countersunk head bolts of grip length less than , D ; c) threaded- to- head b olts of overall length less than D or bolts having an overall length less than mm In such cases, acceptance shall be based on the results from tests bars of the same material, heat- treated with the same 5.4.2 Double shear strength process cycle In accordance with the values specified See ISO 7961 in Table Q A Table 0, The grip length shall not be shorter than column B twice the nominal shank diameter for or Table 1 protruding head b olts or shorter than , times the nominal shank diameter for 5.4.3 Tension fatigue strength countersunk heads Life: See ISO 7961 — mean value 65 000 cycles — individual value 45 000 cycles Q 10 A Table 0, column B 30 000 cycles max Frequency: Loads: 40 Hz see Tab le Unb roken bolts shall b e rendered unusable Unless otherwise specified, fatigue tests shall not b e carried out on the following: a) bolts with drilled shanks; b) b olts of thread size smaller than mm; c) bolts having a grip length of less than twice the diameter 5.5 Me tallurgical p rop e rtie s © BSI 01 - 000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS A : 989 Tab le — Te chnical re quire me nts and te st me thod s C lause No 5.5.1 C haracte risti c Te chni cal re qui re me nt Insp e cti o n and te st me tho d Head-to-shank Flow lines in the fillet area Specimens shall be taken grain flow and immediately below the from the finished bolt fillet work surface shall closely conform (see Figure 6) The sections effect to the fillet contour to be examined shall be (see Figure ) subj ected to an appropriate See Figure for breaks in flow macroscopic etchant lines Macroscopic examination If there is doubt about the of a longitudinal section at acceptability of the grain flow a suitable magnification or fillet work effect, the (X1 to X20) Q/A S amp le siz e Q A A Table 0, column B acceptability shall be decided by the results of the acceptance fatigue test 5.5.2 Thread grain The grain flow shall be flow and work continuous and shall follow effect the general thread contour Macroscopic examination Q A Table 0, column B with the maximum density at the bottom of the root radius (see Figure 3) 5.5.3 5.5.4 Microstructure Grain size The microstructure shall be The sections to be free from overheating and examined shall be alloy segregation which is subj ected to an appropriate likely to affect the mechanical microscopic etchant or physical properties of the Microscopic examination at bolt a magnification of X1 00 The grain size of the finished Microscopic examination bolts when compared with at a magnification of X1 00 plate II in ASTM E 1 2- 84 Q A Table 0, column B Q A Table 0, column B shall not be coarser than Isolated grains not exceeding a mean diameter a of 0, 23 mm are acceptable 5.5.5 Surface See Table contamination Microscopic examination at a magnification of X1 00 Q A Table 0, column B 5.5.6 Discontinuities The bolts shall not show any Penetrant flaw detection in discontinuity equal to or accordance with ISO 3452 greater than the limitations and ISO 3453 specified in this International In cases of doubt, Standard (see Table 4) Care microscopic examination at shall be exercised to avoid confusing cracks with other a magnification of X1 00 shall be carried out discontinuities Cracked bolts and those Q 25 A Penetrant: Table and Table Microscopic examination: Table 0, column B having discontinuities transverse to the axis (i e at an angle of more than ° to the longitudinal axis) shall be rej ected and destroyed a Mean diameter = average of the maj or and minor axes of an individual grain Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy © BSI 01 - 2000 BS A : 989 Tab le — Te chnical re quire me nts and te st me thod s C lau se No 5 6.1 5 6.2 5.6 C haracte ri sti c Te chni cal re qu i re me nt Insp e cti o n and te st me tho d Q/A S amp le si z e Head and shank See Table for the limits of Thread Prod uct ide ntification acceptance Acceptance limits (see Figure and Figure 5): — in the unloaded part of the fillet, above the pitch diameter, see Table 7; — at the crest of the threads, see Table — values to be increased by half the difference between the actual measured diameter and the minimum external thread diameter (see ISO 5855-2); — a slight irregularity in the form of the crests in relation to the basic profile is acceptable (see Figure 5) Marking in accordance with Visual inspection the product standard or definition document Bolts to be “package-marked” shall be packed and identified in accordance with and Q A 25 Table and Table A 100 % A 100 % 5.7 7.1 7.2 D e live ry Packaging Labelling © BSI 01-2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy The bolts shall be packed in Visual inspection such a way as to prevent any damage or corrosion occurring in the course of handling, transportation and storage Each basic package shall only contain bolts with the same part number and the same inspection lot number Visual inspection Each basic package shall carry a label on which the complete part number, quantity, production batch number and inspector’s stamp have been legibly recorded BS A 301 :1 989 Table — Qualification testing requirements for bolt samples Bolt sample number Type of test Defined in 10 11 12 Uncoated 13 14 15 16 17 18 19 20 21 22 23 24 25 C oated Non-destructive D imensions Surface roughness × × × × × × × × × × × × × × × × × × × × × × 5.2 5.3.6 × × × × × × Surface coating 5.3.7 D iscontinuities 5.5.6 × × × × × × × × × × × × × × × × × × × × × × × × × 5.6 × × × × × × × × × × × × × × × × × × × × × × × × × Product identification Destructive Tensile strength D oub le shear strength Tension fatigue strength × × × × × 5.4.1 5.4.2 × × × × × × × × × × × × × × × 5.4.3 Head- to- shank 5.5.1 × × × × 5.5.2 × × × × Microstructure 5.5.3 × × × × Grain size 5.5.4 × × × × 5.5.5 × × × × grain flow and fillet work effect Thread grain flow and work effect Surface contamination Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy © BSI 01 - 000 BS A 301 :1 989 Table — Summary of qualification and acceptance tests Sample size for Type of test Defined in Dimensions Surface roughness Surface coating Tensile strength 5 3.6 3.7 4.1 Double shear strength Tension fatigue strength Head-to-shank grain flow and fillet work effect Thread grain flow and work effect Microstructure Grain size Surface contamination Discontinuities 4.2 4.3 5 5 5 5 5 5 Product identification Packaging Labelling 7.1 7.2 qualification 22 3 5 10 4 4 25 25 — — tests acceptance tests Table and Table Table and Table Table and Table Table 10, column B or Table 11 Table 10, column B or Table 11 Table 10, column B Table 10, column B Table 10, column B Table 10, column B Table 10, column B Table 10, column B Penetrant: Table and Table Microscopic examination: Table 10, column B Table and Table 100 % 100 % Table — Surface discontinuities and contamination Dimensions in millimetres Maximum depth normal to surface for bolts having a Location Permissible discontinuity nominal diameter up to mm Heat-to-shank fillet and root of thread Shank diameter and bearing surface of head Non-bearing surface of head Any other location © BSI 01-2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy No discontinuities No surface contamination Seams not extending into head to shank 0,12 fillet or root of thread No surface contamination Laps, seams and inclusions 0,25 Surface contamination 0,025 Surface contamination 0,025 mm and above 0,15 0,3 0,025 0,025 BS A :1 989 Tab le — Minimum te nsile and doub le shear loads for qualification and acce ptance te sts Thre ad Te nsile stre ngth te st Load, D iame ter Protruding head kN Pitch mm mm 0,5 0,7 0,8 1 1,25 1,25 1,5 1,5 1,5 1,5 1,5 10 12 14 16 18 20 22 24 5,98 10,47 16,83 23,93 34,02 45,85 71,65 107 145 193 249 311 380 442 Countersunk head kN 4,78 8,38 13,46 19,14 27,22 36,68 57,32 85,6 116 154 199 249 304 354 D oub le she ar stre ngth te st Lo ad C ross-se ctional kN are a mm 5,439 9,517 15,296 21,753 30,93 41,682 65,136 97,128 131,562 175,613 225,949 282,571 345,478 401,68 9,33 16,59 25,92 37,32 50,8 66,4 104,3 149 203 266 337 415 502 597 C ross-se ctional are a mm2 7,069 12,566 19,635 28,274 38,484 50,265 78,54 113,1 153,9 201,1 254,5 314,2 380,1 452,4 Tab le — Qualification and acce ptance value s for te nsion fatigue te st Thre ad Protruding he ad H igh load D iame te r mm 10 12 14 16 18 20 22 24 ±2% kN Pitch 0,8 1 1,25 1,25 1,5 1,5 1,5 1,5 1,5 mm 7,74 11,01 15,65 21,09 32,96 49,22 66,7 88,78 114,5 143 174,8 203,3 Lo w lo ad ±2% kN 0,77 1,1 1,56 2,11 3,3 4,92 6,67 8,88 11,45 14,3 17,48 20,33 C ounte rsunk he ad H igh lo ad ±2% kN 6,19 8,8 12,52 16,87 26,37 39,38 53,36 70,84 91,54 114,5 139,8 162,8 Lo w load ±2% kN 0,62 0,88 1,25 1,69 2,64 3,94 5,34 7,08 9,15 11,45 13,98 16,28 Tab le — Thread discontinuitie s — Maximum de pth of pe rmissib le faults (see Thre ad p itch 0,5 0,7 0,8 1,25 1,5 10 5.5.5.2 ) Dimensions in millimetres 0,06 0,08 0,09 0,12 0,15 0,18 0,24 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy D e p th © BSI 01-2000 BS A 301 :1 989 Table — Classification of defects Acceptable Category of quality defect level (AQL) Major “A” 0,065 % Major “B” 1% Minor “A” 2,5 % Minor “B” 4% © BSI 01-2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Characteristics Magnetic flaw detection Thread size Shank diameter Grip length Fillet radius: distortion and dimensions Drilled holes missing when required Surface roughness Burrs and tool marks Surface coating Identification Depth of lightening hole in head Thread form Incomplete threads Squareness between head-bearing surface and shank Straightness of shank Overall length Head diameter Head angle (countersunk head) Lightening hole diameter Drilled hole location and diameter Wrenching configuration Concentricity of head and shank Coaxiality of shank and thread pitch diameter Chamfer on thread end Hexagon head: chamfer and washer face Collar height Head height 11 BS A 301:1989 Table — Sampling plans for visual inspection and inspection of dimensional characteristics Production batch size 91 to 91 to 151 to 281 to 501 to 201 to 201 to 10 001 to 35 001 to 150 001 to Acceptance number (Ac) and limiting quality (LQ10) in accordance with the acceptable quality level (AQL) AQL 0,065 % AQL % AQL 2,5 % AQL % LQ10 LQ10 LQ10 LQ10 Ac Ac Ac Ac % % % % Sample size 150 150 280 500 200 200 10 000 35 000 150 000 500 000 13 20 32 50 80 125 200 315 500 800 — — 16 G G G G G G G G G G E E G G G E 10 — 1,2 G 0,49 E 7,6 6,5 5,4 4,6 3,7 3,1 — — 10 14 21 — — 18 16 13 11 9,4 7,7 6,4 5,6 — — 10 14 21 — 25 20 18 14 12 10 — — E E Use the sampling plan above (sample size and Ac) Use the sampling plan below (sampling size and Ac) NOTE The data given in Table are based on single sampling plans for a standard inspection, as specified in ISO 2859-1 (Table 2-A and Table 6-A) A 100 % inspection should be performed when the sample size is as large as or larger than the batch size Other sampling plans specified in ISO 2859-1 may be used (double or multiple sampling), but these shall be chosen in such as way as to ensure an equivalent quality level As regards those manufacturers who carry out an inspection during the manufacturing process (inspection on a machine and/or inspection between operations), the sampling plan for the final inspection shall be compiled in such a way that the overall inspection plan shall guarantee an equivalent quality level E G Table 10 — Sampling plans for the inspection of mechanical and metallurgical characteristics Production batch size Up to 500 501 to 200 201 to 35 000 Above 35 000 12 Sample size Non-destructive Destructive tests tests A B 13 20 32 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy 5 Acceptance number 0 0 © BSI 01-2000 BS A 301:1989 Table 11 — Variable sampling for tensile and shear tests (alternative method) Production batch size Sample number Acceptable quality level approximately AQL % First sample Combined sample Sample size Total K K a Under 51 51 to 300 301 to 500 First 4 Second 12 First Second First Second First 501 to 300 Second First 301 to 200 Above 200 5 10 15 6 12 18 7 14 21 K r t 2, 42 , 35 — — — , 72 2, 21 0, 89 — — — , 74 2, 22 0, 94 — — — 1,7 2, 32 1,1 — — — , 78 8 2, 48 0, 99 — Second 16 24 — — , 81 First 10 10 2, 34 , 31 — Second 20 30 — — 1,8 Evaluate each sample by tensile or shear tests as follows: First sample: Accept if X KS WM – a Rej ect if X KS – r < M Take second sample if batch is doubtful; evaluate as follows: X KS WM Second sample: Accept if t – t t Rej ect if X KS M t – t t < Definition of terms: X K K is the average of a, r and K t X individual values in the first sample; are coefficients of S which is the best estimate of standard deviation and which are used to determine acceptance or rej ection of the batch represented by the sample; where N CX is the number of parts in the first sample, M X ( is the sum of squares of C X1)2 X values, is the square of the sum of X values; is the minimum tensile or minimum shear value according to Table 5; is the average of t X t individual values in the combined samples; where N CX t is the number of parts in the combined sample, t ( C Xt)2 is the sum of squares of X t values, is the square of the sum of © BSI 01 - 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy X t values 13 BS A : 989 NOTE Cut grain acceptable in the zone defined by specified in the product standard) ] Z dimensions [Z max = R max (where R max is the minimum fillet radius Figure — H e ad structure and grain flow 14 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy (see 5.5.1 ) © BSI 01 - 2000 BS A : 989 Dimensions in millimetres A B o lt no minal d i ame te r max B C max max 1,5 1,5 1,5 2, 10 2, 12 14 0, 03 0, 025 3, 3, 16 3, 18 4, 20 4, 22 4, 24 4, Figure — D istortion in fille t are a Figure — Grain flow in thre ad © BSI 01 - 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy (see (see 4) 5.5.2) 15 BS A :1 989 Figure — Non-p ermissib le laps, se ams and surface irre gularities Figure — Pe rmissib le laps, seams and surface irre gularitie s 16 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy (see (see 5.5.5.2 ) 5.5.5.2) © BSI 01 - 2000