as 1252 - high strength steel bolts
TRANSCRIPT
AS/NZS 1252:1996
Australian/New Zealand Standard
High-strength steel bolts withassociated nuts and washers forstructural engineering
AS/NZS 1252:1996
This Joint Australian/New Zealand Standard was prepared by Joint TechnicalCommittee ME/29, Fasteners. It was approved on behalf of the Council of StandardsAustralia on 2 April 1996 and on behalf of the Council of Standards New Zealand on11 March 1996. It was published on 5 October 1996.
The following interests are represented on Committee ME/29:
Australian Chamber of Commerce and IndustryBureau of Steel Manufacturers of AustraliaElectricity Supply Association of AustraliaFasteners Institute of AustraliaFederal Chamber of Automotive Industries AustraliaMetal Building Products Manufacturers Association AustraliaMetal Trades Industry Association of AustraliaNew Zealand Manufacturers Federation
Review of Standards. To keep abreast of progress in industry, Joint Australian/New Zealand Standards are subject to periodic review and are kept up to date by the issueof amendments or new editions as necessary.It is important therefore that Standards usersensure that they are in possession of the latest edition, and any amendments thereto.Full details of all Joint Standards and related publications will be found in the StandardsAustralia and Standards New Zealand Catalogue of Publications; this information issupplemented each month by the magazines ‘The Australian Standard’ and ‘StandardsNew Zealand’, which subscribing members receive, and which give details of newpublications, new editions and amendments, and of withdrawn Standards.Suggestions for improvements to Joint Standards, addressed to the head office of eitherStandards Australia or Standards New Zealand, are welcomed. Notification of anyinaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should be madewithout delay in order that the matter may be investigated and appropriate action taken.
This Standard was issued in draft form for comment as DR 94272.
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AS/NZS 1252:1996
Australian/New Zealand Standard
High-strength steel bolts withassociated nuts and washers forstructural engineering
PUBLISHED JOINTLY BY:
STANDARDS AUSTRALIA1 The Crescent,Homebush NSW 2140 Australia
STANDARDS NEW ZEALANDLevel 10, Standards House,155 The Terrace,Wellington 6001 New Zealand
ISBN 0 7337 0541 3
AS / NZS 1252:1996 2
PREFACE
This Standard was prepared by the Joint Standards Australia/Standards New ZealandCommittee ME/29 on Fasteners to supersede AS 1252—1983,High strength steel bolts withassociated nuts and washers for structural engineering.
Major technical changes incorporated in this edition relate to the mechanical properties andtesting requirements in order to align with the relevant ISO requirements. Other changesinclude the following:
(a) Updating of reference documents.
(b) Inclusion of a reference to SAA HB18.22/SANZ HB18.22 in relation to amanufacturer’s declaration of conformity. The Handbook contains a definition ofmanufacturer and includes an example of a declaration of conformity which may beprovided to a customer.
(c) Revision of dimensions to align with ISO requirements.
(d) Replacement of detailed requirements for materials, mechanical properties and testprocedures with reference to separate Standards.
(e) Modification of hardness requirements for hot-dip galvanized washers.
(f) Editorial changes in accordance with current policy.
The identification marking on a fastener may now include that of a distributor or importer,this being a departure from the previously accepted practice of the marking being that of thefabricator of the product.
This Standard is based on and, except for the marking requirements for the nuts and bolts,is technically equivalent to the following ISO Standards for the relevant property class:
ISO4775:1984 Hexagon nuts for high-strength structural bolting with large width across
flats—Product grade B—Property classes 8 and 10
7411:1984 Hexagon bolts for high-strength structural bolting with large width across flats(thread lengths according to ISO 888)—Product grade C—Property classes 8.8and 10.9
7415:1984 Plain washers for high-strength structural bolting, hardened and tempered
The dimensions of M12 products have not been included because the demand for this sizeis small.
The marking requirements given in AS 1252—1983 have been retained because the use ofthe letter ‘S’ used in conjunction with the property class symbol could be confused with thesnug tight bolting category 8.8/S given in AS 4100—1990,Steel structures.
Statements expressed in mandatory terms in notes to tables are deemed to be requirementsto this Standard.
The term ‘informative’ has been used in this Standard to define the application of theappendix to which it applies. An ‘informative’ appendix is only for information and guidance.
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CONTENTS
Page
SECTION 1 SCOPE AND GENERAL1.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.2 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 MARKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.6 DESIGNATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SECTION 2 HIGH-STRENGTH STEEL BOLTS2.1 METHOD OF MANUFACTURE . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 82.2 SHAPE, DIMENSIONS AND FINISH . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.3 MATERIALS AND MECHANICAL PROPERTIES . . . . . . . . . . . . . .. . . . 92.4 TEST METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
SECTION 3 HIGH-STRENGTH STEEL NUTS3.1 METHOD OF MANUFACTURE . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 163.2 SHAPE, DIMENSIONS AND FINISH . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.3 MATERIAL AND MECHANICAL PROPERTIES . . . . . . . . . . . . . .. . . . . 173.4 TEST METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SECTION 4 FLAT ROUND WASHERS4.1 SHAPE, DIMENSIONS AND FINISH . . . . . . . . . . . . . . . . . . . . . . . . . . . 204.2 MATERIAL AND HEAT TREATMENT . . . . . . . . . . . . . . . . . . . . . . . . . . 204.3 HARDNESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
APPENDICESA SUGGESTED SAMPLING PLAN FOR MECHANICAL PROPERTIES . . . . . 22B RECOMMENDED GAUGE AND METHOD FOR CHECKING THE
SQUARENESS OF THE THREAD TO THE FACE OF THE NUT . . . . . . . . . 23C ASSEMBLY TEST FOR COATED FASTENERS . . . . . . . . . . . . . .. . . . . . . 24D SQUARE TAPER WASHERS . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 25
Originated in Australia as AS B157 — 1960.Previous edition in Australia AS 1252— 1983.Jointly revised and designated AS/NZS 1252:1996.
AS / NZS 1252:1996 4
STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND
Australian/New Zealand Standard
High-strength steel bolts with associated nuts and washers forstructural engineering
S E C T I O N 1 S C O P E A N D G E N E R A L
1.1 SCOPE This Standard specifies the dimensional, material and marking requirementsfor steel bolts of property class 8.8 and steel nuts of property class 8 with ISO metric coarsepitch series threads in diameters from 16 mm to 36 mm and associated hardened andtempered steel washers intended for use in steel structures.
1.2 APPLICATION Bolts, nuts and washers shall comply with the requirements ofSection 1 and the following Sections as applicable:
(a) Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section 2.
(b) Nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section 3.
(c) Washers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section 4.
1.3 REFERENCED DOCUMENTS The following documents are referred to in thisStandard:
AS1014 Gauging of metric screw threads
1214 Hot-dip galvanized coatings on threaded fasteners (ISO metric coarse threadseries)
1275 Metric screw threads for fasteners
1650 Hot-dipped galvanized coatings on ferrous articles
1789 Electroplated coatings—Zinc on iron or steel
1815 Metallic materials—Rockwell hardness test
1817 Metallic materials—Vickers hardness test
1897 Electroplated coatings on threaded components (metric coarse series)
AS/NZS4291 Mechanical properties of fasteners4291.1 Part 1: Bolts, screws and studs4291.2 Part 2: Nuts with specified proof load values —Coarse thread
SAA/SNZHB18 Guidelines for third-party certification and accreditationHB18.22 Guide 22: Information on manufacturers’ declaration of conformity with
standards or other technical specifications
ISO6157 Fasteners—Surface discontinuities6157.1 Part 1: Bolts, screws and studs for general requirements
SAEJ122a Surface discontinuities on nuts
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1.4 DEFINITIONS For the purpose of this Standard, the definitions below apply.
1.4.1 Concentricity tolerance—of a bolt, is the allowable deviation of the shank withrespect to the pitch diameter of the screw thread.
1.4.2 Grip length (lg)—of a bolt, is the minimum thickness of materials which can beclamped.
1.4.3 May—indicates the existence of an option.
1.4.4 Nominal length (l)—of a bolt, is the distance from the bearing surface of the headto the extreme end.
1.4.5 Shall—indicates that a statement is mandatory.
1.4.6 Should—indicates a recommendation.
1.4.7 Symmetry tolerance
1.4.7.1 Of a bolt—the allowable deviation of the across-flats dimension with respect to theshank or the pitch diameter of the screw thread.
1.4.7.2 Of a nut—the allowable deviation of the across-flats dimension with respect to thepitch diameter of the screw thread.
1.4.8 Thread length (b)—of a bolt, is the difference between the nominal length of the boltand the distance between the bearing surface of the head and the nearest face of a 6g GOscrew ring gauge, screwed as far as practicable on to the bolt by hand.
1.4.9 Thread runout
1.4.9.1 Bolts with rolled threads—the distance from the top of the extrusion angle to thenearest face of a 6g GO screw ring gauge, screwed on as far as practicable by hand.
1.4.9.2 Bolts with cut threads—the distance from the last witness of thread to the nearestface of a 6g GO screw ring gauge, screwed on as far as practicable by hand.
1.4.10 Transition diameter (da)—the diameter of a circle formed at the transition betweenthe fillet radius and the bearing surface of the head.
1.4.11 Unthreaded shank length (ls)—of a bolt, is the distance from the bearing surfaceof the bolt head to the last scratch of thread, or top of the extrusion angle, whichever iscloser to the head.
1.5 MARKING (see Figure 1.1)
1.5.1 Bolts High-strength steel bolts shall be marked with the following information:
(a) The property class symbol with or without the separating point embossed or indentedon top of the head or indented or rolled into one of the hexagon flats.
(b) Three radial lines approximately 120 degrees apart embossed or indented on top of thehead.
(c) The trade (identification) mark of the manufacturer embossed or indented on top of thehead.
1.5.2 Nuts High-strength steel nuts shall be marked with the following information:
(a) The property class symbol indented or rolled into a hexagon flat or the bearing surface,or embossed or indented on the external chamfer.
(b) Three circumferential arcs approximately 120 degrees apart embossed or indented onthe non-bearing face, or for double-chamfered nuts, indented on one or both bearingfaces.
(c) The trade (identification) mark of the manufacturer embossed or indented on anexternal chamfer or indented on the bearing face.
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1.5.3 Washers Flat round washers for use with high-strength steel bolts and nuts forstructural engineering shall be identified by the provision of three nibs as shown inFigure 1.1(c).
NOTES:
1 Manufacturers making a statement of compliance with this Australian Standard on a product,packaging, or promotional material related to that product are advised to ensure that suchcompliance is capable of being verified.
2 Guidance on the manufacturer’s declaration of conformity with this Standard is given inSAA HB18.22/SANZ HB18.22.
(a) Bolt marking (b) Nut marking (c) Washer marking
FIGURE 1.1 IDENTIFICATION MARKING
1.6 DESIGNATION
1.6.1 Bolts The designation of high-strength steel bolts for structural engineering shall becomposed of the following:
(a) General product description.
(b) The number of this Joint Australian/New Zealand Standard, i.e. AS/NZS 1252.
(c) The letter ‘M’ indicating that the product has a metric coarse pitch series threadfollowed by the nominal size (thread diameter), in millimetres.
(d) The nominal length, in millimetres.
(e) The property class symbol.
(f) The coating, where applicable in accordance with the appropriate Standard.
(g) Any other features.
Example:
Hot-dip galvanized high-strength steel bolts, 20 mm diameter and 100 mm long aredesignated—
High-strength steel bolts for structural engineering to AS/NZS 1252—M20× 100 —8.8(hot dip galvanized to AS 1214).
1.6.2 Nuts The designation of high-strength steel nuts for structural engineering shall becomposed of the following:
(a) General product description.
(b) The number of this Joint Australian/New Zealand Standard, i.e. AS/NZS 1252.
(c) The letter ‘M’ indicating that the product has a metric coarse pitch series threadfollowed by the nominal size (thread diameter), in millimetres.
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(d) The property class symbol.
(e) The coating, where applicable, in accordance with the appropriate Standard.
(f) Any other features.
Example:
Uncoated high-strength steel nuts with 20 mm threads are designated—
High strength steel nuts for structural engineering to AS/NZS 1252—M20—8.
1.6.3 Washers The designation of hardened and tempered washers for structural boltingshall be composed of the following:
(a) General product description.
(b) The number of the Joint Australian/New Zealand Standard, i.e. AS/NZS 1252.
(c) The nominal size (nominal bolt diameter), in millimetres.
(d) The coating, where applicable, in accordance with the appropriate Standard.
(e) Any other features.
Example:
20 mm hot-dip galvanized hardened and tempered steel washers for structural engineering aredesignated—
Steel washers for structural bolting to AS/NZS 1252—20 (hot-dip galvanized toAS 1650).
NOTE: Bolts, nuts and washers may be supplied as assemblies.
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S E C T I O N 2 H I G H - S T R E N G T H S T E E L B O L T S
2.1 METHOD OF MANUFACTURE High-strength steel bolts shall be—
(a) hot or cold forged with or without secondary machining; or
(b) machined from bar stock.
2.2 SHAPE, DIMENSIONS AND FINISH
2.2.1 Head The heads of high-strength steel bolts shall be in accordance with Figure 2.1and Table 2.1. The dimensions given in Table 2.1 apply before hot-dip galvanizing.
2.2.2 Length The length of high-strength steel bolts shall be as given in Table 2.2.
2.2.3 Ends The ends of high-strength steel bolts shall be finished with a 45-degreechamfer to a depth slightly exceeding the depth of thread (see Figure 2.1).
2.2.4 Screw threads
2.2.4.1 General The form of thread, diameters and associated pitches of high-strength steelbolts shall be the ISO coarse pitch series in accordance with AS 1275.
Screw threads shall be formed by thread rolling or thread cutting.
2.2.4.2 Tolerances The screw threads shall be made to tolerance class 6g in accordancewith AS 1275.
Where bolts are to be hot-dip galvanized, the 6g tolerance class applies before hot-dipgalvanizing.
2.2.5 Thread length (b) The nominal thread lengths for high-strength steel bolts shall beas given in Table 2.3.
The tolerances on the thread length shall be such that the grip lengths (lg) and unthreadedshank lengths (l s) given in Table 2.2 are maintained.
The grip length (l g) shall be determined as the distance between the bearing surface of thehead and the nearest face of a 6g GO screw ring gauge, screwed as far as practicable on tothe bolt by hand. This dimension applies before hot-dip galvanizing.
2.2.6 Squareness, concentricity and symmetry
2.2.6.1 Squareness of bearing faceWhen determined as shown in Figure 2.2(a), thebearing face of the head shall be square, within the values given in Table 2.1, to the shank.The values are based on an angle of two degrees.
2.2.6.2 Concentricity of shank to screw threadWhen determined as shown in Figure 2.2(b)the shank for a distance of 1.5 diameters from the nearest face of a 6g GO screw ring gaugescrewed as far as practicable on to the thread by hand shall be concentric, within the valuesgiven in Table 2.1, to the pitch diameter of the screw thread.
2.2.6.3 Symmetry of head to shankWhen determined as shown in Figure 2.2(c), the headshall be symmetric, within the values given in Table 2.1, to the shank.
2.2.7 Chamfering and washer facing High-strength steel bolts shall have heads with achamfer of 15 to 30 degrees on their upper faces. The diameter of the circle formed by thischamfer shall be not less than 90 percent of the minimum width across-flats of the bolts.
Bolts shall have a washer face on the underside of the head (see Figure 2.1). the diameter anddepth of washer faces shall be as given in Table 2.1.
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2.2.8 Shank
2.2.8.1 Diameter The diameter (ds) of the shank of high-strength steel bolts shall be asgiven in Table 2.1.
2.2.8.2 Straightness High-strength steel bolts shall be straight within the tolerance shownin Figure 2.3.
2.2.9 Underhead fillet The fillet junction of the head and shank shall be a smoothconcave curve lying within an envelope defined by the minimum radius under the head (r )and a maximum profile defined by a tangent to a radius equal to the minimum value ofrblending to the maximum transition diameter on the underside of the head and the filletlength (l f) on the shank as shown in Figure 2.1. The minimum values ofr and the maximumvalues ofl f are given in Table 2.1.
2.2.10 Finish
2.2.10.1 General High-strength steel bolts shall be cleanly finished, sound, and free fromdefects detrimental to their end use. The surface discontinuities on high-strength steel boltsshall be not greater than the limits given in ISO 6157.1.
2.2.10.2 Surface roughness All surfaces of high-strength steel bolts, except screw threads,may be in the as-forged or machined condition. Screw threads shall be machined or have asurface quality equivalent to machining.
2.2.10.3 Surface finish Unless otherwise specified, high-strength steel bolts shall besupplied, hot-dip galvanized in accordance with AS 1214. Uncoated bolts shall be in the dullblack as heat-treated condition.
2.2.10.4 Coatings High-strength steel bolts may be supplied with either decorative orcorrosion-resistant coatings.
NOTE: Where the purchaser requires coated products other than hot-dip galvanized, coatings shouldbe specified to the relevant coating specification e.g. AS 1897, and indicated in the enquiry ororder.
2.3 MATERIALS AND MECHANICAL PROPERTIES The materials and mechanicalproperties of high-strength steel bolts shall be as given in AS/NZS 4291.1 for propertyclass 8.8.
2.4 TEST METHODS The test methods for determining the mechanical properties ofhigh-strength steel bolts shall be as given in AS/NZS 4291.1.
NOTE: A suggested audit sampling plan is given in Appendix A.
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TABLE 2.1
GENERAL DIMENSIONS OF HIGH-STRENGTH STEEL BOLTS
millimetres
Th
rea
d(s
ee
No
te1
)
Pitch
Shankdiameter
Widthacross flats
Widthacross
corners
Washer facedia.
Depth ofwasher face
Fillet details
Height ofhead
Symmetryof head to
body(see Note 3)
Concentricitytolerance
(see Note 3)
Squarenessbearingface toshank
Trans-itiondia.
Radiusunderhead
Filletlength
(ds) (s) (e) (dw) (c) (da) (r) (lf ) (k)
(p) Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. (max.) (min.) (max.) Max. Min. (max.) (max.) (max.)
M16 2.0 16.70 15.30 27 26.16 31.2 29.56
Actualsize
acrossflats
24.9 0.8 0.4 18.7 0.6 3.0 10.75 9.25 1.68 1.40 0.76
M20 2.5 20.84 19.16 34 33.00 39.26 37.29 31.4 0.8 0.4 23.24 0.8 4.0 13.40 11.60 2.00 1.68 0.90
(M22) 2.5 22.84 21.16 36 35.00 41.6 39.55 33.3 0.8 0.4 25.24 0.8 4.5 14.90 13.10 2.00 1.68 1.00
M24 3.0 24.84 23.16 41 40.00 47.3 45.20 38.0 0.8 0.4 27.64 1.0 5.0 15.90 14.10 2.00 1.68 1.04
(M27) 3.0 27.84 26.16 46 45.00 53.1 50.85 42.8 0.8 0.4 31.24 1.2 6.0 17.90 16.10 2.00 1.68 1.28
M30 3.5 30.84 29.16 50 49.00 57.7 55.37 46.5 0.8 0.4 34.24 1.2 6.0 19.75 17.65 2.00 1.68 1.40
M36 4.0 37.00 35.00 60 58.80 69.3 66.44 55.9 0.8 0.4 41.00 1.5 7.5 23.55 21.45 2.40 2.00 1.68
NOTES:
1 Threads in parentheses are non-preferred.
2 For hot-dip galvanized bolts, the dimensions apply before galvanizing.
3 Values equal to FIM (Full Indicator Movement).
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TABLE 2.2
LENGTH OF HIGH-STRENGTH STEEL BOLTSmill imetres
Overall lengthThread
M16 M20 (M22) M24 (M27) M30 M36Unthreaded shank lengths (l s) and grip lengths (l g)
(l) ls l g ls lg ls lg ls lg ls lg ls lg ls lg
Nom. Min. Max. (min.) (max.) (min.) (max.) (min.) (max.) (min.) (max.) (min.) (max.) (min.) (max.) (min.) (max.)
40 38.75 41.25 8 14 — — — — — — — — — — — —45 43.75 46.25 8 14 10 17.5 — — — — — — — — — —50 48.75 51.25 8 14 10 17.5 11 18.5 — — — — — — — —
55 53.5 56.5 11 17 10 17.5 11 18.5 12 21 — — — — — —60 58.5 61.5 16 22 10 17.5 11 18.5 12 21 — — — — — —65 63.5 66.5 21 27 11.5 19 11 18.5 12 21 13.5 22.5 — — — —
70 68.5 71.5 26 32 16.5 24 12.5 20 12 21 13.5 22.5 15 25.5 — —75 73.5 76.5 31 37 21.5 29 17.5 25 12 21 13.5 22.5 15 25.5 — —
80 78.5 81.5 36 42 26.5 34 22.5 30 17 26 13.5 22.5 15 25.5 — —
85 83.25 86.75 41 47 31.5 39 27.5 35 22 31 16 25 15 25.5 18 3090 88.25 91.75 46 52 36.5 44 32.5 40 27 36 21 30 15 25.5 18 3095 93.25 96.75 51 57 41.5 49 37.5 45 32 41 26 3518.5 29 18 30
100 98.25 101.75 56 62 46.5 54 42.5 50 37 46 31 40 23.5 34 18 30110 108.25 111.75 66 72 56.5 64 52.5 60 47 56 41 50 33.5 4420 32120 118.25 121.75 76 82 66.5 74 62.5 70 57 66 51 60 43.5 54 30 42
130 128 132 80 86 70.5 78 66.5 74 61 70 55 64 47.5 58 34 46140 138 142 90 96 80.5 88 76.5 84 71 80 65 74 57.5 68 44 56150 148 152 100 106 90.5 98 86.5 94 81 90 75 84 67.5 78 54 66
160 156 164 — — — — — — 91 100 85 94 77.5 88 64 76170 166 174 — — — — — — 101 110 95 104 87.5 98 74 86180 176 184 — — — — — — 111 120 105 114 97.5 108 84 96
190 186 194 — — — — — — 121 130 115 124 107.5 118 94 106200 196 204 — — — — — — 131 140 125 134 117.5 128 104 116220 216 224 — — — — — — 138 147 132 141 124.5 135 111 123
240 236 244 — — — — — — 158 167 152 161 144.5 155 131 143
NOTES:1 Threads in parentheses are non-preferred.2 For bolts below the dotted line—
lg = l − b; andl s = lg − 3pFor bolts above the dotted line—l s = 0.5d; andlg = l s + 3pwhere
lg = maximum grip length, in millimetresl = nominal length of bolt, in millimetres (see Table 2.2)b = nominal thread length, in millimetresl s = minimum unthreaded shank length, in millimetresp = pitch of thread, in millimetresd = nominal diameter of thread, in millimetres
3 Bolts above the dotted line have shortened thread lengths.4 The difference betweenls (min.) and lg (max.) shall be not less than 1.5p.5 Inclusion of the diameter/length combinations given in this table does not necessarily imply that these are stock
items. The purchaser should refer to the manufacturer’s listings for stock availability.
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TABLE 2.3
NOMINAL THREAD LENGTHSmillimetres
Nominalbolt
length
(l)
Basis forthreadlength*
Nominal length of thread (b)
M16 M20 (M22) M24 (M27) M30 M36
≤125>125 ≤200>200
2d + 62d + 122d + 25
3844—
465265
505669
546073
606679
667285
788497
* d = nominal thread diameter, in millimetres.
NOTES:
1 Threads in parenthesis are non-preferred.
2 These thread lengths are not applicable to bolts above the dotted line in Table 2.2.
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FIGURE 2.1 HIGH-STRENGTH STEEL BOLTS
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FIGURE 2.2 SQUARENESS, CONCENTRICITY AND SYMMETRYOF HIGH-STRENGTH STEEL BOLTS
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DIMENSIONS IN MILLIMETRES
FIGURE 2.3 TOLERANCE ON STRAIGHTNESS OF HIGH-STRENGTH STEEL BOLTS
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S E C T I O N 3 H I G H - S T R E N G T H S T E E L N U T S
3.1 METHOD OF MANUFACTURE High-strength steel nuts shall be—
(a) hot or cold formed with or without subsequent machining; or
(b) machined from bar stock.
3.2 SHAPE, DIMENSIONS AND FINISH
3.2.1 General The shape of nuts shall be in accordance with Figure 3.1.
For hot-dip galvanized nuts, the dimensions apply before hot-dip galvanizing (seeClause 3.2.2.2).
3.2.2 Screw threads
3.2.2.1 General The thread form, diameters and associated pitches of nuts shall be thoseof the ISO coarse pitch series in accordance with AS 1275.
3.2.2.2 Tolerances Hot-dip galvanized nuts shall be tapped oversize in accordance withAS 1214 after galvanizing. The screw threads of uncoated nuts shall be made to toleranceclass 6H in accordance with AS 1275.
3.2.3 Chamfering, washer facing and countersinking
3.2.3.1 Chamfering and washer facingNuts shall have a chamfer of 15 to 30 degrees onboth faces, or a chamfer of 15 to 30 degrees on their upper face and a washer face on thebearing surface. The bearing faces shall be smooth and flat. The minimum washer face orchamfer diameter (dw) shall be not less than that given in Figure 3.1.
3.2.3.2 Countersinking Nuts shall be radiused or countersunk on the bearing face or faces.The maximum countersink diameter (da) shall be not greater than the value given inFigure 3.1.
3.2.4 Squareness and symmetry
3.2.4.1 Squareness of thread to bearing face(s)When determined as shown inFigure 3.2(a) the bearing face(s) of the nut shall be square, within the values given inFigure 3.1, to the pitch diameter of the screw thread.
NOTE: A recommended method of checking this feature in conjunction with an appropriate gaugedesign is described and illustrated in Appendix B.
3.2.4.2 Symmetry of hexagonWhen determined as shown in Figure 3.2(b), the hexagonshall be symmetrical, within the values given in Figure 3.1, to the pitch diameter of the screwthread.
3.2.5 Finish
3.2.5.1 General High-strength steel nuts shall be cleanly finished, sound and free fromdefects detrimental for their end use. The surface discontinuities shall be not greater than thelimits given in SAE J122a.
3.2.5.2 Surface roughness All surfaces of high-strength steel nuts, except screw threads,may be in the as-forged or machined condition. Screw threads shall be machined or have asurface quality equivalent to machining.
3.2.5.3 Surface finish Unless otherwise specified, high-strength steel nuts shall be suppliedhot-dip galvanized in accordance with AS 1214. Uncoated nuts shall be in the dull black as-heat-treated condition.
3.2.5.4 Coated nuts Nuts may be supplied with either decorative or corrosion-resistantcoatings.
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All hot-dip galvanized and zinc-plated nuts shall be provided with an additional lubricantcoating to prevent seizure on assembly. The coating shall be clean and dry to the touch.
NOTES:
1 Information on a suitable test for the effectiveness of the lubricant coating is given inAppendix C.
2 Where the purchaser requires coated products other than hot-dip galvanized, coatings shouldbe specified to the relevant coating specification e.g. AS 1897, and indicated in the enquiry ororder.
3.3 MATERIAL AND MECHANICAL PROPERTIES The material of high-strengthsteel nuts shall be as given in AS/NZS 4291.2 for property class 8 and the mechanicalproperties shall be as given in Table 3.1.
3.4 TEST METHODS The test methods for determining the mechanical properties ofhigh-strength steel nuts shall be as given in AS/NZS 4291.2. The proof load values for high-strength steel nuts are given in Table 3.2.
NOTES:
1 A suggested audit sampling plan is given in Appendix A.
2 In the event of a dispute as to the results of tests, referee testing should be carried out by anindependent laboratory mutually acceptable to the purchaser and the supplier.
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Thread*
Pitchof
thread
Widthacross
flat(s)
Widthacrosscorners
(e)
Nut height
(m)
Square-ness
tolerance†
Symmetrytolerance†
Washer-faceor chamfer
dia.(dw)
Depth ofwasher-face
(c)
Countersinkdiameter
(da)
(p) Max. Min. Max. Min. Max. Min. (max.) (max.) Max. Min. Max. Min. Max. Min.
M16 2.0 27.0 26.16 31.2 29.56 17.1 16.4 0.76 1.04 Actualsize
acrossflats
24.90 0.8 0.4 17.30 16.00
M20 2.5 34.0 33.00 39.26 37.29 20.7 19.4 0.90 1.24 31.40 0.8 0.4 21.60 20.00
(M22) 2.5 36.0 35.00 41.6 39.55 23.6 22.3 1.00 1.24 33.30 0.8 0.4 23.80 22.00
M24 3.0 41.0 40.00 47.3 45.20 24.2 22.9 1.04 1.24 38.00 0.8 0.4 25.90 24.00
(M27) 3.0 46.0 45.00 53.1 50.85 27.6 26.3 1.28 1.24 42.80 0.8 0.4 29.20 27.00
M30 3.5 50.0 49.00 57.7 55.37 30.7 29.1 1.40 1.24 46.50 0.8 0.4 32.40 30.00
M36 4.0 60.0 58.80 69.3 66.44 36.6 35.0 1.68 1.48 55.90 0.8 0.4 38.90 36.00
* Threads in parentheses are non-preferred.† Values equal to FIM (Full indicator movement).
FIGURE 3.1 HIGH-STRENGTH STEEL NUTS
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FIGURE 3.2 SQUARENESS AND SYMMETRY OF HIGH-STRENGTH STEEL NUTS
TABLE 3.1
MECHANICAL PROPERTIES OF HIGH-STRENGTH STEEL NUTS
Nut finish
Proofstress
Hardness
VickersRockwell
HRC HRB
MPa Max. Min. Max. Min. Min.
Hot-dip galvanized 1165 353 260 36 24 —
Other than hot-dipgalvanized
1075 353 188 36 — 89
TABLE 3.2
PROOF LOADS FOR HIGH-STRENGTH STEEL NUTS
Thread
Tensile stress area of threadedtest mandrel
(As)
Proof load, kN
Hot-dipgalvanized nuts
Other than hot-dip galvanized
nutsmm2
M16M20M22
157245303
182.9285.4353.0
168.9263.4325.7
M24M27M30
353459561
411.2534.7653.6
379.5493.4603.1
M36 817 951.8 878.3
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S E C T I O N 4 F L A T R O U N D W A S H E R S
4.1 SHAPE, DIMENSIONS AND FINISH
4.1.1 Shape and dimensions The shape and dimensions of washers for high-strengthstructural bolting shall be in accordance with Figure 4.1. For coated washers the dimensionsapply before coating.
NOTE: Dimensions of square taper washers are given in Appendix D.
4.1.2 Flatness When a straight edge is placed along a line passing through the centre ofthe hole, the departure from flatness determined by inserting thickness gauges at a pointmidway between the edge of the hole and the edge of the washer shall be not greater than0.25 mm.
4.1.3 Finish
4.1.3.1 General Washers for high-strength steel bolts shall be cleanly finished, sound andfree from defects detrimental to the end use.
4.1.3.2 Surface roughness All surfaces of washers for high-strength structural bolting maybe in the as-rolled or machined condition.
4.1.3.3 Surface finish Unless otherwise specified washers shall be supplied hot-dipgalvanized. Uncoated washers shall be in the dull black as heat-treated condition.
4.1.3.4 Coatings Washers may be supplied with either decorative or corrosion-resistantcoatings.
The coating on hot-dip galvanized washers shall comply with AS 1650.
NOTE: Where the purchaser requires coated products other than hot-dip galvanized, coatings shouldbe specified to the relevant coating specification, e.g. AS 1789, and indicated in the enquiry ororder.
4.2 MATERIAL AND HEAT TREATMENT
4.2.1 Material Steel used for the manufacture of washers shall be produced by an openhearth, a basic oxygen or an electric process.
4.2.2 Heat treatment All washers shall be hardened and tempered and the hardness shallbe as given in Clause 4.3.
4.3 HARDNESS
4.3.1 General The hardness of washers other than hot-dip galvanized shall be345—445 HV (35—45 HRC). The hardness of hot-dip galvanized washers shall be270—445 HV (26—45 HRC).
4.3.2 Hardness tests The hardness shall be determined on a transverse section of thewasher and the result shall be reported without conversion to any other scale.
When the Vickers method is used, the preparation of test specimens and the method of testshall be in accordance with AS 1817.
When the Rockwell method is used, the preparation of test specimens and the method of testshall be in accordance with AS 1815.
The Vickers method shall be used for any referee tests.
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millimetres
Nominaldiameter of bolt
Inside dia. Outside dia. Thickness
(d1) (d2) (h)
(d)* Max. Min. Max. Min. Max. Min.
16 18.43 18.0 34.0 32.4 4.6 3.120 22.52 22.0 42.0 40.4 4.6 3.1
(22) 24.52 24.0 44.0 42.4 4.6 3.4
24 26.52 26.0 50.0 48.4 4.6 3.4
(27) 30.52 30.0 56.0 54.1 4.6 3.4
30 33.62 33.0 60.0 58.1 4.6 3.4
36 39.62 39.0 72.0 70.1 4.6 3.4
* Values in parentheses are non-preferred.
FIGURE 4.1 FLAT ROUND WASHERS FOR HIGH-STRENGTH STRUCTURAL BOLTING
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APPENDIX A
SUGGESTED SAMPLING PLAN FOR MECHANICAL PROPERTIES
(Informative)
Where tests are required for audit inspection purposes, a lot should consist of all items (bolts,nuts or washers) of the same heat of steel and size (diameter and length) made essentiallyunder the same conditions in accordance with this Standard. From each lot, the number oftest specimens for each required property should be in accordance with Table A1.
Should any test specimen fail to comply with the requirements of any specified test, doublethe number of samples should be taken from the same lot and should be subjected to the sametest, and unless all of these comply with the relevant requirements, the lot should be rejected.
TABLE A1
NUMBER OF TEST SPECIMENS
Number of piecesin lot
Minimum numberof samples
≤50 2>50 ≤500 3
>500 ≤35 000 5
>35 000 8
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APPENDIX B
RECOMMENDED GAUGE AND METHOD FOR CHECKING THESQUARENESS OF THE THREAD TO THE FACE OF THE NUT
(Informative)
The nut should be screwed by hand on to a tapered threaded mandrel as shown in Figure B1,until the thread of the nut is tight on the thread of the mandrel. A sliding sleeve having a facediameter equal to the minimum distance across flats of the nut, square with the axis of themandrel thread, should then be brought into contact with the leading face of the nut. Withthe sleeve in this position it should not be possible for a thickness gauge with a thicknessequal to the squareness tolerance to enter between the leading face of the nut and the faceof the sleeve.
NOTES:
1 Squareness of gauging face of sleeve to be within 10 min of arc with respect to bore axis. The sleeve bore tobe a close-sliding fit on the parallel portion of the mandrel.
2 Thread form, pitch and flank angles of the thread on the mandrel to conform to the requirements of thecorresponding GO screw plug gauge (AS 1014).
FIGURE B1 RECOMMENDED GAUGE FOR CHECKINGSQUARENESS OF THREAD TO FACE OF NUT
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APPENDIX C
ASSEMBLY TEST FOR COATED FASTENERS
(Informative)
A1 SCOPE This Appendix sets out a method of testing the anti-seizing properties of anassembly of high-strength steel bolts and nuts with corrosion-preventive coatings.
A2 ASSEMBLY A test assembly consists of a bolt, nut and washer complying with therelevant requirements of this Standard, supplied with a corrosion-preventive coating.
A3 TEST PROCEDURE The test should be carried out on high-strength steel bolts andnuts in the condition as supplied by the manufacturer and should be in accordance with andinclude a lubricant coating as required by Clause 3.2.5.4. There should be no other lubricantcoating applied for the purpose of this test. Where the two foregoing conditions cannot besatisfied, then the anti-seizing test should be by agreement between the purchaser and themanufacturer, but a lubricant coating should still be applied. If the test is carried out by thepurchaser, then he should ensure that the storage conditions and storage time are such thatthey will not have significantly promoted deterioration of the lubricant coating.
The bolt with nut and washer selected for testing is placed with the washer directly under thenut in a steel joint with a total thickness such that where the thread length permits, there arenot less than six full bolt threads located between the bearing surface of the bolt head andnut. The diameter of the holes in the joint should be 1 to 2 mm larger than the nominaldiameter of the bolts. The nut is initially tightened to produce a load in the bolt of not lessthan 10 percent of the specified proof load. After this initial tightening, the bolt and nutposition is marked to provide the starting point for the rotational movement to be measured.During the rotation, the bolt head is restrained from turning, and the final tensioning iscompleted without stopping the motion of the nut. The nut is rotated in accordance with therequirements of Table C1 from the initial tightening position without fracture of the bolt orstripping of the bolt or nut thread.
TABLE C1
NUT ROTATION REQUIREMENTS
Bolt length (nominal)*Nut rotation (minimum)
degrees
≤2d 180
>2d ≤3d 240
>3d ≤4d 300
>4d ≤8d 360
>8d 420
* d = nominal diameter of bolt
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APPENDIX D
SQUARE TAPER WASHERS
(Informative)
D1 SCOPE This Appendix gives information on a series of hardened and tempered,square taper washers suitable for use with high-strength steel bolts and nuts.
D2 DIMENSIONS The dimensions of square taper washers shall be in accordance withFigure D1.
D3 MATERIAL AND HEAT TREATMENT The material and heat treatment of squaretaper washers should be in accordance with Clause 4.2.
D4 FINISH The finish of square taper washers should be in accordance with Clause 4.1.3.
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millimetres
Nominal diameterof bolt
Inside diameter
(d1)
Width across flats
(d2)
Mean thickness
(t)
Max. Min. Nom. 8° taper
16 18.43 18.0 31.75 6.3520 22.52 22.0 38.10 6.35
(22) 24.52 24.0 38.10 6.35
24 26.52 26.0 44.45 6.35
(27) 30.52 30.0 57.15 6.35
30 33.62 33.0 57.15 6.35
36 39.62 39.0 57.15 6.35
NOTES:
1 Where required, square taper washers may be clipped along the thin edge toprovide clearance. The clipping should be parallel to the opposite edge and notcloser to the centre of the washer than 0.9 of the bolt diameter.
2 Values in parentheses are non-preferred.
FIGURE D1 SQUARE TAPER WASHER
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