SPECIFICATION FOR HIGH STRENGTH …

1 UDC 621 882 211 [ 669 14 018 291 ] - ( First Reprint JULY 1990) IS : 3757 - 1985 Indian Standard SPECIFICATION FOR high STRENGTH STRUCTURAL BOLTS ( Second Revision ) I. Scope and Field of Application - Covers the requirements for large series hexagon, high STRENGTH structural steel bolts in property classes 8 8 and 10 9 and in the size range Ml 8 to M36 with short thread lengths suitable for use in both friction-type and bearing-type structural steel joints. Bolts to this standard when matched with the appropriate nuts have been designed to provide an assembly with a high level of assurance against failure by thread stripping on overtightening. Note - Attention is drawn to the importance of ensuring that the bolts arecorrectly used if satisfactory results are to be obtained. 2. Dimensions and Tolerances The dimensions or the bolts shall be as given in Table 1. The recommended length-size combinations shall be as given in Table 2. 23 ~Threads shall conform to tolerance class 6g of IS : 4218 ( Part 6 )-1978 ISO.

2 Metric screw threads: Part 6 Limits of sizes for commercial bolts and nuts ( diameter range 1 to 52 mm) ( first revision ) . In case of hot-dip galvanized bolts, the specified tolerance class shall apply before hot-dip galvanizing. 3. Grade - Unless otherwise specified, the bolts shall be of product grade C as specified~in IS : 1367 ( Part 2 )-1979 Technical supply conditions for threaded steel fasteners: Part 2 Product grades and tolerarans ( second revision ) . 4. p~~chanicat Properties - The bolts shall be of property class 8 8 or 10 9 as specified in IS : 1367 ( Part 3 )-1979 Technical supply conditions for threaded steel fasteners: Part 3 Mechanical properties and test methods for bolts, screws and studs with full loadability ( second revision ) . For tensile, proof load and wedge loading test on full size bolts only four threads shall be exposed between the grips. This is obtained by freely running the nut or fixture to the fullest extent and then unscrewing the specimen four full turns.

3 For test purposes, the screw threads on hot-dip galvanized bolts shall be chemically stripped to permit assembly with a standard threaded grip or nut, that is, thread class 6H. 5. Finish Unless specified otherwise; the bolts shall be supplied in the dull black heat-treated condition with a residual coating of light oil. Where property class 88 bolts are required to be hot-dip galvanized, they shall be galvanized in accordance with the requirements of IS : 1367 ( Part 13)-1983 Technical supply conditions for thread- ed steel fasteners: Part 13 Hot-dip galvanized coatings on threaded fasteners ( second revision) . For fasteners with hot-dip galvanized coatings, the bolts or the mating nuts shall be provided with a suitable lubricant which shall be clean and dry to the touch to ensure that seizure shall not take place in assembly. The hot-dip galvanized bolts shall be subjected to the anti-seizing test as specified in Appendix A. Note - Bolts or property class 10 9 should not be hot-dip galvanized since this may cause hydrogen embrittlement.

4 6. General Requirements !n regard to permissible surface discontinuities, the bolts shall conform to IS : 1367 ( Pari 9 )- 1979 Technical supply conditions for threaded steel fasteners: Part 9 Surface discontinuities on bolts, screws and studs ( second revision ).. In regard to requirements not covered in the standard, the bolts shall conform to IS : 1367 -( Part 1 J-1 980 Technical supplv conditions for threaded steel fasteners: Part 1 Introduction and general information ( second revision ) . Adopted 26 July 1985 I 0 December 1985,,kIS I Gr 3 BUREAU OF INDIAN SlAPiDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 . IS : 3757 - 1985 TABLE 1 DlMiNSlONS FOR high STRENGTH ?TRUCTURAL BOLTS ( Clause ) All dimensions in millimetres. DETAIL X DETAIL Y ROUNDED BOLT END HEAD TYPE FOR BOLTS OF THREAD SIZE d >20 ALTERNATIVES DIFFERENCE BETWEEN IS, Min AND la, Max SHALL NOT BE LESS THAN I tip Thread Size d I Ml6 M20 (M27) M30 3 3 5 M36 4 (M22)* M24 P Pitch of thread I 2 I 2 5 2 5 I 3 36 38 1 41 43 45 1 48 I 56 63 braf For length I Nom%1 ii Max Min Max Max Min 0 8 -2% 0 4 23 24 A- 20 84 --_- 15 30 19 16.)

5 __ 0 0 -- 04 I 0 8 0 4 0 4 0 8 0 8 0 4 0 4 31 24 34 24 _ --- 30 84 26 16 29 16 4: 8 I?&- -- 50 85 55 37 - --- 17 -- .._- 17 90 19 75 __ .- -- 16 10 17 65 I 25 24 1 27 64 41 00 22 84 i 24 84 21 16 1 23 16 37 00 ---- t 55 9 dw Max I t I t Min 24 9 31 4 t t 33 3 38 0 39 55 46 20 86 44 -. -- e Min I 29 @6 1 -- - 21 45 15 0 k k Nom 10 12 5 Max 10 75 13 40 Min 9 25 11 60 Min 6 6 8 1 14 15 --p 14 90 15 90 13 10 14 10 I I 9'9 11 3 1 .I 12 4 1 2 i 1 5 60 - --__ 58 8 6 I Min 0 6 0 8 s 27 34 Min 26 16 33 0 8 1 0 -- 36 41 -35- -- 40 46 1 50 45 I 49 4 5 ( 5 3 Chamfer length 2 Msx 1 3 1 3 8 _. 3 8 4 5 Note - Sizes shown in brackets are at second preference. *For galvanized bolts, dimensions apply before galvanitin& t dw, Max = s actual. I.. 2 TABLE 2 RECOMMENDED LENGTH-SIZE COMBINATIONS FOR high STRENGTH STRUCTURAL BOLTS ( Clause ) All dimefisions in millimetres. - I Ml6 M20 (M22) M24 M30 M36 Thread Size d -_ Length I Nom Min Max 43 Max Is Min 1s Min - -. - - . - - -- i- - _- Ja Max 16 5 ; XT, 4; :: 64 344 1% 114 124 134 144 i: 184 $4 114 !)

6 24 !34 !44 Min Max -- : :8 5; 38 43 :: :: ;: 9 : 106 116 126 136 146 156 166 176 186 196 206 216 t3t 246 256 9 ::: $94 :t 2 E z 72 t22 ::: 122 132 142 152 162 :Zf 192 202 212 t:3 242 262 262 Min 1s B Min Max Min Max 2 2294 % 44 49 E E 9 : 102 112 122 132 142 152 162 172 182 192 % :23t 22:; Ma;l ;: 2 $fi 46 :: :: 79 :Zt 109 119 129 139 149 159 169 179 189 199 209 219 229 239 249 Max :84 :: 39 44 6:: 7677 87 lo93 :;; 137 147 167 167 177 187 197 g; 237 11 5 :72 Z :2 :; 6 ; $6 9855 105 115 125 135 145 155 165 I75 185 195 !05 !15 !25 !35 !35 !46 4: 50 55 :: 55 8 : 90 109: 110 120 130 140 150 160 170 % 200 210 220 230 240 ts6: :3x % 5 i 5 i , , ; 1 i I i I : : : l! $! $ 22; :! i . , . 41 2! 46 21 51 2! 56 5 x::: 76 5 81 5 86 75 91 75 KY 11:7: % :; ;: :: 04 :44 34 :4 !t !84 294 304 I- - 38 7! 43 71 48 7! 53 5 58 5 63 5 73 5 78 5 83 2E 88 25 93 25 98 25 108 25 : Z 138 148 156 166, 176 186 196 206 216 226 ;:; 156 !66 !76 :: - 4 16 5 26 5 31 5 36% 41 6 51 9 56 5 59 5 69 5 99 6 K6 29 5 39 5 t::: 69 5 79 5 89 6 19 5 3tB.

7 49 5 :94 24 4 19 5 24 5 29 6 34 5 39 5 44 5 54 5 57 5 67 5 77 6 37 5 D7 B :3:5 37 5 ;;:; 37 9 77 5 )7 5 ! 17 S 5 :: i: 33: 40 2: s533 Z ;; 123 133 143 153 163 173 183 193 % 223 2234x 1:.5 15 5 52::: 30 5 35 6 ZX . 53 5 63 5 73 5 g : . 03 5 13 5 23 5 33 6 :::5 63 5 73 5 83 5 93 5 K5 f$6 6 :; 22 Z :x Z 75 2 :E 12s :Z :.Z 175 185 195 206 21s 225 w 117 117 127 4 ; 157 67 77 Note 1 - Recommended lengths are below the bold stepped line. Note 2 - Sizes shown in brackets are of second preference. Formulae: lu, Max - lnom - bref Is, Min = lg. Max - 3 P I For bolts with lengths above the bold line, IS. hfin e 1 5 P and 10, Max = Is, Min + 3 P Is : 3757 - 1985 The high STRENGTH structural nuts to be used with these bolts shall conform to the requirements of lS : 8623-l 985 high STRENGTH structural nuts ( first reViSiOfJ 1 . 1 These nuts shall be of the property class and finish for each type of bolt as follows: Bolt Property Chess and Finish Nut Property Class and Finish 8 8S, dull black 8s or lOS, dull black 8 8S, hot-dip galvanized 1 OS, hot-dip galvanized 10 9S, dull black \ lOS, dull black Hardened and tempered washers to be used with these bolts shall conform to the requirements of lS : 6649-1985 Hardened and tempered washers for high STRENGTH structural bolts and nuts ( firsr revision ).

8 7. Designation - high STRENGTH structural bolts shall be designated by ,name, size, nominal lenqth, the number of this standard and the property class identification symbol 8 8s or 10 9S-the sl:ffix letter S denotes a high STRENGTH structural bolt with a larga series hexagon head. In case of hot dip galvanized bolts, the word galvanized shall be added to the designation. Example : A high STRENGTH structural bolt of size M24, length 140 mm, property class 8 8 and galvanized shall be designated as: high STRENGTH Structural Bolt M24 x 140 IS : 3757-8 8s galvanized If the bolt in the above example is required with a hot-dip galvanized high STRENGTH structural nut ( see IS : 6623-1985 ), the letter N shall be added to the designation as follows: high STRENGTH Structural Bolt M24 ;: 140 N IS : 3757-8 88 galvanized 8. Sampling - Sampling ,and criteria of acceptance shall be in accordance with IS : 2814-1959 Methods for sampling of fasteners ( first reV/SiOn 1 . 9. Marking - high STRENGTH structural bolts shall be marked with the following symbols on the top surface of the bolt head, either embossed or indented, as shown below: a) The manufacturer s identification symbol, and b) The property class indetification symbol 8s for 8 8s or 10s for 10 9s.

9 Minimum height of markings shall be 4 0 mm. When embossed, marking shall project not less than 0 3 mm above the surface of the head and total head height ( head plus markings ) shall not exceed the specified maximum head height plus 0 4 mm. XYZ 0 8S 10. Mode of Delivery - The bolts shall be delivered in accordance with IS : 1367 ( Part 18 )-I 979 Technical supply conditions for threaded steel fasteners: Part 18 Marking and mode of delivery ( second revision ) . 11. Certification Marking a- Details available with the Bureau of Indian Standards. 4 c IS : 3757 - 1985 APPENDIX A ( Clause ) ANTI-SEIZING TEST FOR HOT-DIP GALVANIZED FASTENERS A-l. Where bolts and the mating nuts and washers with hot-dip galvanized coating are specified, these shall be subject to the following anti-seizing test for testing the effectiveness of the lubricant coating applied to the hot-dip galvanized bolts or nuts: a) b) cl The test shall be carried out on bolts, nuts and washers in the condition as supplied by the manufacturer and shall be in accordance with, and include a lubricant coating as required by There shall be no other lubricant applied for the purpose of this test.

10 If the test is performed by the user it s ? II be carried out immediately after receipt of the bolts, nuts and washers from the manufact, rer. The bolt with nut and washer selected for testing shall be placed with the washer directly under the nut in a steel joint with total thickness sothat three to five full threads of the bolt are located between the bearing surfaces of the bolt head and nut. The diameter of the holes in the assembly shall have the same nominal diameter as the hole in the washer. The nut shall be initially tightened to produce a load in the bolt not less than 10 percent of the specified proof load. After this initial tightening, the bolt and the nut position shall be marked to provide the starting point for the rotational movement to be measured. During nut rotation the bolt head shall be restrained from turning, and the final tensioning shall be com- pleted without stopping the motion of the nut. The nut shall be rotated in accordance with the requirements of Table 3 from the initial tightening position without fracture of the bolt, or stripping of the bolt or nut thread.