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ISO 898-1 Specification

Fasteners, Boltings, Stud Bolts, Screws

ISO 898-1 Scope

ISO 898 specification concludes mechanical and physical properties of bolts, screws and studbolts made of carbon steel and alloy steel when tested at an ambient temperature range of 10 °C to 35 °C. Fasteners conforming to the requirements of ISO 898-1 are used in applications ranging from −50 °C to +150 °C. ISO 898-1 specification is applicable for bolts, screws & studbolts with coarse pitch thread M1,6 to M39, and fine pitch thread M8×1 to M39×3 with diameter/pitch combinations in accordance with ISO 261 and ISO 262 and having thread tolerances in accordance with ISO 965-1, ISO 965-2 and ISO 965-4.

Related Specifications of ISO 898-1 Bolting

EN 10269 F2281 A320 SAE J429 SAE J995 DIN 267 BS EN 1515 ISO 898-2 ISO 898-3 ISO 898-5

ISO 898-1 Chemical Compositions

Property class Material and heat treatment Chemical composition limit (cast analysis, %) a Tempering temperature °C min.
C P max. S max. Bb max.
min. max.
4.6 c d Carbon steel or carbon steel with additives - 0,55 0,050 0,060 Not specified -
4.8 d
5.6 c 0,13 0,55 0,050 0,060
5.8 d - 0,55 0,050 0,060
6.8 d 0,15 0,55 0,050 0,060
8.8 f Carbon steel with additives (e.g. Boron or Mn or Cr) quenched and tempered 0,15e 0,40 0,025 0,025 0,003 425
Carbon steel quenched and tempered 0,25 0,55 0,025 0,025
Alloy steel quenched and temperedg 0,20 0,55 0,025 0,025
9.8 f Carbon steel with additives (e.g. Boron or Mn or Cr) quenched and tempered 0,15 e 0,40 0,025 0,025 0,003 425
Carbon steel quenched and tempered 0,25 0,55 0,025 0,025
Alloy steel quenched and temperedg 0,20 0,55 0,025 0,025
10.9 f Carbon steel with additives (e.g. Boron or Mn or Cr) quenched and tempered 0,20 e 0,55 0,025 0,025 0,003 425
Carbon steel quenched and tempered 0,25 0,55 0,025 0,025
Alloy steel quenched and temperedg 0,20 0,55 0,025 0,025
12.9 f h i Alloy steel quenched and temperedg 0,30 0,50 0,025 0,025 0,003 425
12.9 f h i Carbon steel with additives (e.g. Boron or Mn
or Cr or Molybdenum) quenched and tempered		 0,28 0,50 0,025 0,025 0,003 380
  • a In case of dispute, the product analysis applies.
  • b Boron content can reach 0,005 %, provided non-effective boron is controlled by the addition of titanium and/or aluminium.
  • c For cold forged fasteners of property classes 4.6 and 5.6, heat treatment of the wire used for cold forging or of the cold forged fastener itself may be necessary to achieve required ductility.
  • d Free cutting steel is allowed for these property classes with the following maximum sulfur, phosphorus and lead contents: S: 0,34 %; P: 0,11 %; Pb: 0,35 %.
  • e In case of plain carbon boron steel with a carbon content below 0,25 % (cast analysis), the minimum manganese content shall be 0,6 % for property class 8.8 and 0,7 % for property classes 9.8 and 10.9.
  • f For the materials of these property classes, there shall be a sufficient hardenability to ensure a structure consisting of approximately 90 % martensite in the core of the threaded sections for the fasteners in the “as-hardened” condition before tempering.
  • g This alloy steel shall contain at least one of the following elements in the minimum quantity given: chromium 0,30 %, nickel 0,30 %, molybdenum 0,20 %, vanadium 0,10 %. Where elements are specified in combinations of two, three or four and have alloy contents less than those given above, the limit value to be applied for steel class determination is 70 % of the sum of the individual limit values specified above for the two, three or four elements concerned.
  • h Fasteners manufactured from phosphated raw material shall be dephosphated before heat treatment; the absence of white phosphorus enriched layer shall be detected by a suitable test method.
  • i Caution is advised when the use of property class 12.9/12.9 is considered. The capability of the fastener manufacturer, the service conditions and the wrenching methods should be considered. Environments can cause stress corrosion cracking of fasteners as processed as well as those coated

ISO 898-1 Mechanical and physical properties of bolts, screws and studs

Mechanical or physical property Property class
4.6 4.8 5.6 5.8 6.8 8.8 9.8 d ≤ 16 mm 10.9 12.9/ 12.9
d ≤16 mm a d > 16 mm b
Tensile strength, Rm, MPa nom.c 400 500 600 800 900 1000 1200
min. 400 420 500 520 600 800 830 900 1040 1220
Lower yield strength, ReLd, MPa nom.c 240 - 300 - - - - - - -
min. 240 - 300 - - - - - - -
Stress at 0,2 % non-proportional elongation, Rp0,2, MPa nom.c - - - - - 640 640 720 900 1080
min. - - - - - 640 660 720 940 1100
Stress at 0,0048d non-proportional elongation for full-size fasteners, Rpf, MPa nom.c - 320 - 400 480 - - - - -
min. - 340 e - 420 e 480 e - - - - -
Stress under proof load, Spf, MPa nom. 225 310 280 380 440 580 600 650 830 970
Proof strength ratio
Sp,nom/ReL,min
or Sp,nom/Rp0,2 min or
Sp,nom/Rpf,min		 0,94 0,91 0,93 0,90 0,92 0,91 0,91 0,90 0,88 0,88
Percentage elongation after fracture for machined test pieces, A, % min. 22 - 20 - - 12 12 10 9 8
Percentage reduction of area after fracture for machined test pieces, Z, % min. - 52 48 48 44
Elongation after fracture for full-size fasteners, Af (see also Annex C) min. - 0,24 - 0,22 0,20 - - - - -
Head soundness No fracture
Vickers hardness, HV F ≥ 98 N min. 120 130 155 160 190 250 255 290 320 385
max. 220 g 250 320 335 360 380 435
Brinell hardness, HBW F = 30 D2 min. 114 124 147 152 181 245 250 286 316 380
max. 209 g 238 316 331 355 375 429
Rockwell hardness, HRB min. 67 71 79 82 89 -
max. 95,0 g 99,5 -
Rockwell hardness, HRC min. - 22 23 28 32 39
max. - 32 34 37 39 44
Surface hardness, HV 0,3 max. - - 390 435
Non-carburization, HV 0,3 max. - h h h
Height of non-decarburized thread zone, E, mm min. - 1/2 H1 2/3 H1 3/4 H1
Depth of complete decarburization in the thread, G, mm max. - 15
Reduction of hardness after retempering, HV max. - 20
Breaking torque, MB, Nm min. - in accordance with ISO 898-7
Impact strength, KV i j, J min. - 27 - 27 27 27 27 k
Surface integrity in accordance with ISO 6157-1l ISO 6157-3
  • a Values do not apply to structural bolting.
  • b For structural bolting d ≥ M12.
  • c Nominal values are specified only for the purpose of the designation system for property classes. See Clause 5.
  • d In cases where the lower yield strength, ReL, cannot be determined, it is permissible to measure the stress at 0,2 % nonproportional elongation Rp0,2.
  • e For the property classes 4.8, 5.8 and 6.8, the values for Rpf,min are under investigation. The values at the time of publication of this part of ISO 898 are given for calculation of the proof stress ratio only. They are not test values.
  • f Proof loads are specified in Tables 5 and 7.
  • g Hardness determined at the end of a fastener shall be 250 HV, 238 HB or 99,5 HRB maximum.
  • h Surface hardness shall not be more than 30 Vickers points above the measured base metal hardness of the fastener when determination of both surface hardness and base metal hardness are carried out with HV 0,3 (see 9.11).
  • i Values are determined at a test temperature of −20 °C (see 9.14).
  • j Applies to d ≥ 16 mm.
  • k Value for KV is under investigation.
  • l Instead of ISO 6157-1, ISO 6157-3 may apply by agreement between the manufacturer and the purchaser.

Minimum ultimate tensile loads - ISO metric coarse pitch thread

Threada d Nominal stress area As,nomb mm2 Property class
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
Minimum ultimate tensile load, Fm,min (As,nom x Rm,min), N
M3 5,03 2010 2110 2510 2620 3020 4020 4530 5230 6140
M3,5 6,78 2710 2850 3390 3530 4070 5420 6100 7050 8270
M4 8,78 3510 3690 4390 4570 5270 7020 7900 9130 10700
M5 14,2 5680 5960 7100 7380 8520 11350 12800 14800 17300
M6 20,1 8040 8440 10000 10400 12100 16100 18100 20900 24500
M7 28,9 11600 12100 14400 15000 17300 23100 26000 30100 35300
M8 36,6 14600 c 15400 18300 c 19000 22000 29200 c 32900 38100 c 44600
M10 58 23200 c 24400 29000 c 30200 34800 46400 c 52200 60300 c 70800
M12 84,3 33700 35400 42200 43800 50600 67400 d 75900 87700 103000
M14 115 46000 48300 57500 59800 69000 92000 d 104000 120000 140000
M16 157 62800 65900 78500 81600 94000 125000 d 141000 163000 192000
M18 192 76800 80600 96000 99800 115000 159000 - 200000 234000
M20 245 98000 103000 122000 127000 147000 203000 - 255000 299000
M22 303 121000 127000 152000 158000 182000 252000 - 315000 370000
M24 353 141000 148000 176000 184000 212000 293000 - 367000 431000
M27 459 184000 193000 230000 239000 275000 381000 - 477000 560000
M30 561 224000 236000 280000 292000 337000 466000 - 583000 684000
M33 694 278000 292000 347000 361000 416000 576000 - 722000 847000
M36 817 327000 343000 408000 425000 490000 678000 - 850000 997000
M39 976 390000 410000 488000 508000 586000 810000 - 1020000 1200000
  • a Where no thread pitch is indicated in a thread designation, coarse pitch is specified.
  • b To calculate As,nom.
  • c For fasteners with thread tolerance 6az in accordance with ISO 965-4 subject to hot dip galvanizing, reduced values in accordance with ISO 10684:2004, Annex A, apply.
  • d For structural bolting 70 000 N (for M12), 95 500 N (for M14) and 130 000 N (for M16).

Proof loads - ISO metric coarse pitch thread

Threada d Nominal stress area As,nomb mm2 Property class
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
Proof load, Fp (As,nom x Sp,nom), N
M3 5,03 1130 1560 1410 1910 2210 2920 3270 4180 4880
M3,5 6,78 1530 2100 1900 2580 2980 3940 4410 5630 6580
M4 8,78 1980 2720 2460 3340 3860 5100 5710 7290 8520
M5 14,2 3200 4400 3980 5400 6250 8230 9230 11800 13800
M6 20,1 4520 6230 5630 7640 8840 11600 13100 16700 19500
M7 28,9 6500 8960 8090 11000 12700 16800 18800 24000 28000
M8 36,6 8240 c 11400 10200 c 13900 16100 21200 c 23800 30400 c 35500
M10 58 13000 c 18000 16200 c 22000 25500 33700 c 37700 48100 c 56300
M12 84,3 19000 26100 23600 32000 37100 48900 d 54800 70000 81800
M14 115 25900 35600 32200 43700 50600 66700 d 74800 95500 112000
M16 157 35300 48700 44000 59700 69100 91000 d 102000 130000 152000
M18 192 43200 59500 53800 73000 84500 115000 - 159000 186000
M20 245 55100 76000 68600 93100 108000 147000 - 203000 238000
M22 303 68200 93900 84800 115000 133000 182000 - 252000 294000
M24 353 79400 109000 98800 134000 155000 212000 - 293000 342000
M27 459 103000 142000 128000 174000 202000 275000 - 381000 445000
M30 561 126000 174000 157000 213000 247000 337000 - 466000 544000
M33 694 156000 215000 194000 264000 305000 416000 - 576000 673000
M36 817 184000 253000 229000 310000 359000 490000 - 678000 792000
M39 976 220000 303000 273000 371000 429000 586000 - 810000 947000
  • a Where no thread pitch is indicated in a thread designation, coarse pitch is specified.
  • b To calculate As,nom
  • c For fasteners with thread tolerance 6az in accordance with ISO 965-4 subject to hot dip galvanizing, reduced values in accordance with ISO 10684:2004, Annex A, apply.
  • d For structural bolting 50 700 N (for M12), 68 800 N (for M14) and 94 500 N (for M16).

Minimum ultimate tensile loads - ISO metric fine pitch thread

Thread d x P Nominal stress area As,noma mm2 Property class
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
Minimum ultimate tensile load, Fm,min (As,nom ´ Rm,min), N
M8x1 39,2 15700 16500 19600 20400 23500 31360 35300 40800 47800
M10x1,25 61,2 24500 25700 30600 31800 36700 49000 55100 63600 74700
M10x1 64,5 25800 27100 32300 33500 38700 51600 58100 67100 78700
M12x1,5 88,1 35200 37000 44100 45800 52900 70500 79300 91600 107000
M12x1,25 92,1 36800 38700 46100 47900 55300 73700 82900 95800 112000
M14x1,5 125 50000 52500 62500 65000 75000 100000 112000 130000 152000
M16x1,5 167 66800 70100 83500 86800 100000 134000 150000 174000 204000
M18x1,5 216 86400 90700 108000 112000 130000 179000 - 225000 264000
M20x1,5 272 109000 114000 136000 141000 163000 226000 - 283000 332000
M22x1,5 333 133000 140000 166000 173000 200000 276000 - 346000 406000
M24x2 384 154000 161000 192000 200000 230000 319000 - 399000 469000
M27x2 496 198000 208000 248000 258000 298000 412000 - 516000 605000
M30x2 621 248000 261000 310000 323000 373000 515000 - 646000 758000
M33x2 761 304000 320000 380000 396000 457000 632000 - 791000 928000
M36x3 865 346000 363000 432000 450000 519000 718000 - 900000 1055000
M39x3 1030 412000 433000 515000 536000 618000 855000 - 1070000 1260000
  • a To calculate As,nom

Proof loads - ISO metric fine pitch thread

Thread d x P Nominal stress area As,noma mm2 Property class
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
Proof load, Fp (As,nom x Sp,nom), N
M8x1 39,2 8820 12200 11000 14900 17200 22700 25500 32500 38000
M10x1,25 61,2 13800 19000 17100 23300 26900 35500 39800 50800 59400
M10x1 64,5 14500 20000 18100 24500 28400 37400 41900 53500 62700
M12x1,5 88,1 19800 27300 24700 33500 38800 51100 57300 73100 85500
M12x1,25 92,1 20700 28600 25800 35000 40500 53400 59900 76400 89300
M14x1,5 125 28100 38800 35000 47500 55000 72500 81200 104000 121000
M16x1,5 167 37600 51800 46800 63500 73500 96900 109000 139000 162000
M18x1,5 216 48600 67000 60500 82100 95000 130000 - 179000 210000
M20x1,5 272 61200 84300 76200 103000 120000 163000 - 226000 264000
M22x1,5 333 74900 103000 93200 126000 146000 200000 - 276000 323000
M24x2 384 86400 119000 108000 146000 169000 230000 - 319000 372000
M27x2 496 112000 154000 139000 188000 218000 298000 - 412000 481000
M30x2 621 140000 192000 174000 236000 273000 373000 - 515000 602000
M33x2 761 171000 236000 213000 289000 335000 457000 - 632000 738000
M36x3 865 195000 268000 242000 329000 381000 519000 - 718000 839000
M39x3 1030 232000 319000 288000 391000 453000 618000 - 855000 999000
  • a To calculate As,nom.

Thread tolerance classes of internally threaded adaptors

Finish of fastener Thread tolerance class
Thread tolerance class of fastener before any surface coating Thread tolerance class of internally threaded adaptor
As processed 6h or 6g 6H
Electroplating to ISO 4042 6g or 6e or 6f 6H
Zinc flake coating to ISO 10683 6g or 6e or 6f 6H
Hot dip galvanizing to ISO 10684 in order to mate with nuts tapped to thread tolerance classes:
- 6H
- 6AZ
- 6AX		 6az
6g or 6h
6g or 6h		 6H
6AZ
6AX

Hole diameters and radius for the wedge

Nominal thread diameter d dh ab r1 c
min. max.
3 3,4 3,58 0,7
3,5 3,9 4,08 0,7
4 4,5 4,68 0,7
5 5,5 5,68 0,7
6 6,6 6,82 0,7
7 7,6 7,82 0,8
8 9 9,22 0,8
10 11 11,27 0,8
12 13,5 13,77 0,8
14 15,5 15,77 1,3
16 17,5 17,77 1,3
18 20 20,33 1,3
20 22 22,33 1,6
22 24 24,33 1,6
24 26 26,33 1,6
27 30 30,33 1,6
30 33 33,39 1,6
33 36 36,39 1,6
36 39 39,39 1,6
39 42 42,39 1,6
  • a Medium series in accordance with ISO 273.
  • b For square neck bolts, the hole shall be adapted to accommodate the square neck.
  • c For product grade C, a radius, r1, should be used in accordance with the following formula:
    r1 = rmax + 0,2
    where
    r max = da,max- ds,min/2

Wedge angle, α, for tensile test under wedge loading

Nominal thread diameter d mm Property class for
bolts and screws with unthreaded shank length ls ≥ 2d screws threaded to the head and bolts and screws with unthreaded shank length ls < 2d
4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9 12.9/12.9 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9 12.9/12.9
a ± 30'
3 ≤ d ≤ 20 10° 6° 6° 4°
20 < d ≤ 39 6° 4° 4° 4°

Angle of solid block, β, for head soundness test

Property class 4.6 5.6 4.8 5.8 6.8 8.8 9.8 10.9 12.9/12.9
b 60° 80°

Values for height of external thread in maximum material condition, H1, and minimum height of non-decarburized zone in thread, Emin

Pitch of thread P a H1 Property class
8.8, 9.8 10.9 12.9/12.9
Emin b
0,5 307 154 205 230
0,6 368 184 245 276
0,7 429 215 286 322
0,8 491 245 327 368
1 613 307 409 460
1,25 767 384 511 575
1,5 920 460 613 690
1,75 1,074 537 716 806
2 1,227 614 818 920
2,5 1,534 767 1,023 1,151
3 1,840 920 1,227 1,380
3,5 2,147 1,074 1,431 1,610
4 2,454 1,227 1,636 1,841
  • a For P < 1,25 mm, microscopic method only.
  • b Calculated on the basis of the specification

Test series

Test series FF1 - Finished bolts and screws with full loadability

Property Test method Property class
4.6, 4.8, 5.6, 5.8, 6.8 8.8, 9.8, 10.9, 12.9/12.9
d < 3 mm or l < 2,5d or b < 2,0d d ≥ 3 mm and l ≥ 2,5d and b ≥ 2,0 d d < 3 mm or l < 2,5d or b < 2,0d d ≥ 3 mm and l ≥ 2,5d and b ≥ 2,0 d
No. (see Table 3) Subclause
1 Minimum tensile strength, Rm,min Tensile test under wedge loading 9.1 NF a NF a
Tensile test 9.2 NF a NF a
5 Nominal stress under proof load, Sp,nom Proof load test 9.6 NF NF
8 Minimum elongation after fracture, Af,min Tensile test for full-size fasteners 9.3 NF b d c d NF b d
9 Head soundness Head soundness test d ≤ 10 mm 1,5d ≤ l &lt; 3d 9.8
l ≥ 3d
10 or 11 or 12 Hardness Hardness test 9.9
13 Maximum surface hardness Carburization test 9.11 NF NF
14 Non- carburization NF NF
15 Maximum decarburized zone Decarburization test 9.10 NF NF
16 Reduction of hardness after retempering Retempering test 9.12 NF NF e e
17 Minimum breaking torque, MB,min Torsional test 1,6 mm ≤ d ≤ 10 mm, b ≥ 1d + 2Pf 9.13 g g h h
19 Surface integrity Surface discontinuity inspection 9.15
  • a For fasteners with d ≥ 3 mm, l ≥ 2d and b < 2d, see 9.1.5 and 9.2.5.
  • b Values for property classes 4.6, 5.6, 8.8 and 10.9 are given in Annex C.
  • c For property classes 4.8, 5.8 and 6.8.
  • d l ≥ 2,7d and b ≥ 2,2d.
  • e This test is a reference test to be applied in case of dispute.
  • f For the torsional test, these specific dimensional limits apply instead of the limits specified in the header of this table.
  • g For property classes 4.6 to 6.8, no values are specified in ISO 898-7.
  • h May be used instead of tensile test; however, in case of dispute the tensile test applies.

Test series FF2 - Finished studs with full loadability

Property Test method Property class
4.6, 4.8, 5.6, 5.8, 6.8 8.8, 9.8, 10.9, 12.9/12.9
d < 3 mm or lt < 3d or b < 2,0d d ≥ 3 mm and lt ≥ 3d and b ≥ 2,0 d d < 3 mm or lt < 3d or b < 2,0d d ≥ 3 mm and lt ≥ 3d and b ≥ 2,0 d
No. (see Table 3) Subclause
1 Minimum tensile strength, Rm,min Tensile test 9.2 NF a NF a
5 Nominal stress under proof load, Sp,nom Proof load test 9.6 NF NF
8 Minimum elongation after fracture, Af,min Tensile test for full- size fasteners 9.3 NF b c b d NF b c
10 or 11 or 12 Hardness Hardness test 9.9
13 Maximum surface hardness Carburization test 9.11 NF NF
14 Non-carburization NF NF
15 Maximum decarburized zone Decarburization test 9.1 NF NF
16 Reduction of hardness after retempering Retempering test 9.12 NF NF e e
19 Surface integrity Surface discontinuity inspection 9.15
    a If fracture occurs in the threaded length of the stud (metal) end, bm, minimum hardness applies instead of Rm,min. Alternatively, the tensile strength Rm using machined test pieces in accordance with 9.7 may be determined. b lt ≥ 3,2d, b ≥ 2,2d. c Values for property classes 4.6, 5.6, 8.8 and 10.9 are given in Annex C. d For property classes 4.8, 5.8 and 6.8. e This test is a reference test to be applied in case of dispute.

Test series FF3 - Finished screws with reduced loadability due to head design

Property Test method Property class
4.6, 4.8, 5.6, 5.8, 6.8 8.8, 9.8, 10.9, 12.9/12.9
d < 3 mm or lt < 3d or b < 2,0d d ≥ 3 mm and l ≥ 2,5d and b ≥ 2,0 d d < 3 mm or lt < 3d or b < 2,0d d ≥ 3 mm and l ≥ 2,5d and b ≥ 2,0 d
No. (see Table 3) Subclause
a Minimum ultimate tensile load Tensile test for screws which do not break in the free threaded length due to head design 9.4 NF a NF a
10 or 11 or 12 Hardness Hardness test 9.9
13 Maximum surface hardness Carburization test 9.11 NF NF
14 Non-carburization NF NF
15 Maximum decarburized zone Decarburization test 9.1 NF NF
16 Reduction of hardness after retempering Retempering test 9.12 NF NF b b
19 Surface integrity Surface discontinuity inspection 9.15
  • a See relevant product standard for minimum ultimate tensile load.
  • b This test is a reference test to be applied in case of dispute.

Test series FF4 - Finished bolts, screws and studs with reduced loadability due to shank design

Property Test method Property class
4.6, 5.6 8.8, 9.8, 10.9, 12.9/12.9
d < 3 mm or waist length <3ds or b < d d ≥ 3 mm and waist length ≥3ds and b ≥ d d < 3 mm or waist length <3ds or b < d d ≥ 3 mm and waist length ≥3ds and b ≥ d
No. (see Table 3) Subclause
1 Minimum tensile strength, Rm,min Tensile test for bolts and studs with waisted shank 9.5 NF a NF a
10 or 11 or 12 Hardness Hardness test 9.9
13 Maximum surface hardness Carburization test 9.11 NF NF
14 Non-carburization NF NF
15 Maximum decarburized zone Decarburization test 9.10 NF NF
16 Reduction of hardness after retempering Retempering test 9.12 NF NF b b
19 Surface integrity Surface discontinuity inspection 9.15
  • a Rm is related to the cross-sectional area of the waisted shank, Ads = π/4 ds2
  • b This test is a reference test to be applied in case of dispute.

Test series MP1 - Material properties determined on machined test pieces

Property Test method Property class
4.6, 5.6 8.8, 9.8, 10.9, 12.9/12.9
3 ≤ d < 4,5 mm and d0 < d3,min and b ≥ d and l ≥ 6,5da d ≥ 4,5 mm and d0 ≥ 3 mm and b ≥ d and l ≥ d + 26 mma 3 ≤ d < 4,5 mm and d0 < d3,min and b ≥ d and l ≥ 6,5d abc 4,5 ≤ d ≤ 16 mm and d0 ≥ 3 mm and b ≥ d and l ≥ d + 26 mm ade d > 16 mm and d0 ≥ 0,75ds and b ≥ d and l ≥ 5,5d + 8 mm afg
No. (see Table 3) Sub clause
1 Minimum tensile strength, Rm,min Tensile test for machined test pieces 9.7
2 Minimum lower yield strength, ReL,min h h NF NF NF
3 Minimum stress at 0,2 % non-proportional elongation, Rp0,2 min NFh NFh
6 Minimum elongation after fracture, Amin
7 Minimum reduction of area after fracture, Zmin NF NF
10 or 11 or 12 Hardness Hardness test 9.9
13 Maximum surface hardness Carburization test 9.11 NF NF
14 Non-carburization NF NF
15 Maximum decarburized zone Decarburization test 9.1 NF NF
18 Minimum impact strength, Kv,min Impact test d ≥ 16 mm and li or lt ≥ 55 mmj 9.14 NF k NF
19 Surface integrityl Surface discontinuity inspection 9.15
  • a To determine the minimum total length, lt, for studs, add 1d to the length formula.
  • b For bolts and screws l ≥ 5d to determine Zmin.
  • c For studs lt ≥ 6d to determine Zmin.
  • d For bolts and screws l ≥ d + 20 mm to determine Zmin.
  • e For studs lt ≥ 2d + 20 mm to determine Zmin.
  • f For bolts and screws l ≥ 4d + 8 mm to determine Zmin.
  • g For studs lt ≥ 5d + 8 mm to determine Zmin.
  • h In cases where the lower yield strength, ReL, cannot be determined, it is permissible to measure the stress at 0,2 % nonproportional elongation Rp0,2.
  • i The solid part of the head may be included.
  • j For the impact test, these specific dimensional limits apply instead of the limits specified in the header of this table.
  • k Only for property class 5.6.
  • l To be evaluated before machining.

Test series MP2 - Material properties determined on finished fasteners with full loadability

Property Test method Property class
4.6, 5.6 4.8, 5.8, 6.8 8.8, 9.8, 10.9, 12.9/12.9
No. (see Table 3) Subclause d ≥ 3 mm and l ≥ 2,7da and b ≥ 2,2d
1 Minimum tensile strength, Rm,min Tensile test for finished fasteners 9.2 d d d
4 Minimum stress at 0,0048d non-proportional elongation, Rpf,min Tensile test for full-size fasteners 9.3 d d
5 Nominal stress under proof load, Sp,nom Proof load test for finished fasteners 9.6 d d d
8 Minimum elongation after fracture, Af,min Tensile test for full-size fasteners 9.3 d d
10 or 11 or 12 Hardness Hardness test 9.9
13 Maximum surface hardness Carburization test 9.11 NF NF
14 Non-carburization NF NF
15 Maximum decarburized zone Decarburization test 9.10 NF NF
16 Reduction of hardness after retempering Retempering test 9.12 NF NF f
19 Surface integrity Surface discontinuity inspection 9.15
  • a For studs with metal end stronger than the nut end, or for fully threaded studs with lt ≥ 3,2d.
  • b For property classes 4.6 and 5.6, the stress at 0,0048d non-proportional elongation, Rpf, is not specified in Table 3.
  • c No values available.
  • d l ≥ 2,5d and b ≥ 2,0d.
  • e Values for Af are given in Annex C for information.
  • f This test is a reference test to be applied in case of dispute

ISO 898-1 Bolting Marking

Property class 4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9 12.9
Marking symbola 4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9 12.9
  • a The dot in the marking symbol may be omitted.

ISO 898-1 Bolting Surface Treatment Specifications