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Bolting Encyclopedia

"Bolting" and "Bolt" are terms used in this document to collectively describe fasteners, including screws, nuts, bolts, washers, and studs. The use of the terms "bolt" or "bolting" includes all of the fasteners listed above, unless otherwise specifically noted herein.
Fasteners are a wide ranging classification that includes screws, bolts, nuts, washers, stud bolts, rivets, powder actuated studs, staples, tacks, and pins. Bolting, which is composed of bolting materials, such as rods, bars, flats, and forgings, which are subsequently manufactured into bolting components, are a special subgroup of fasteners. Bolting materials and components have designated compositions and specific properties intended for applications in aggressive service where commercial generic fasteners may not be suitable or have insufficient fitness for purpose under certain conditions. These conditions include cryogenic or high temperature service, or excessive vibration, impact, or shock.



Bolting Specifications

  1. SPECIFICATIONS
      1. ASTM
    1. DIN
      ISO
    2. BS
      SAE
      EN

Bolting Classification

EN 1515-1 Material / strength class EN Rm N/mm2 Reh N/mm2 Allowable stress N/mm2 Material / strength class ASTM Allowable stress Classification
ksi N/mm2
1 4.6 400 240 133 A307 Gr.B 7 48 low
2 5.6 500 300 167 - - - intermediate
4 8.8 800 640 267 A354 Gr.BC 25 172 high
05, 07 25CrMo4 600 440 200 - - - high
06, 08 42CrMo4 860 730 287 B7 25 172 high
9 30CrNiMo8 1 040 940 347 L43 25 172 high
10 42CrMo5-6 860 700 287 - - - high
11 40CrMoV4-6 850 700 283 B16 25 172 high
12 21CrMoV5-7 700 550 233 - - - high
13 20CrMoVTiB4-10 820 660 273 - - - high
14 X6NiCrTiMoVB 25-15-2 900 600 300 A453 Gr.660 21 147 intermediate
15 X7CrNiMoBNb16-16 650 500 217 - - - high
16, 18 A4-50,A2-50 500 210 140 - - - low
17, 19 A4-70, A2-70 700 450 233 - - - high
20 X5CrNiMo17-12-2 500 200 133 B8M 19 130 low
21 X5CrNiMo17-12-2 AT+C 700 350 233 B8M Cl.2 20 138 intermediate
22 X5CrNi18-10 500 190 127 B8 19 130 low
23 X5CrNi18-10 AT+C 700 350 233 B8 CL.2 20 138 intermediate

Bolting Materials & Service Limits

PN Class up to Temperature range oC Type of material Steel designation name or property class Steel designation number Material standard
bolts nuts bolts nuts
PN 40 Cl. 300 -10 to 120 C-St C-St 4.6 - EN 20898-1 5 - EN 20898-2
PN 40 1) Cl. 300 -10 to 300 C-St C-St 5.6 - EN 20898-1 5 - EN 20898-2
PN 40 1) Cl. 300 -10 to 300 C-St C-St 6.8 - EN 20898-1 6 - EN 20898-2
PN 40 1) Cl. 300 -10 to 300 C-St C-St 8.8 - EN 20898-1 8 - EN 20898-2
All -10 to 450 0,25C-1Cr-Mo C-St elev. temp. 25CrMo4 1.7218 EN 10269 C35E 1.1181 EN 10269
All -10 to 450 0,42C-1Cr-Mo C-St elev. temp. 42CrMo4 1.7225 EN 10269 C45E 1.1191 EN 10269
All -60 to 400 0,25C-1Cr-Mo 18Cr-9Ni 25CrMo4 1.7218 EN 10269 A2-50, A2-70 - EN ISO 3506-2
All -100 to 450 0,42C-1Cr-Mo 0,42C-1Cr-Mo 42CrMo4 1.7225 EN 10269 42CrMo4 1.7225 EN 10269
All -40 to 300 0,3C-2Cr-Ni-Mo 0,42C-1Cr-Mo 30CrNiMo8 1.6580 EN 10269 42CrMo4 1.7225 EN 10269
All -10 to 500 0,42C-1,3Cr- 0,6Mo 0,42C-1Cr-Mo 42CrMo5-6 - EN 10269 42CrMo4 1.7225 EN 10269
All -10 to 500 0,40C-1Cr- 0,6Mo-V 0,42C-1Cr-Mo 40CrMoV4-6 1.7711 EN 10269 42CrMo4 1.7225 EN 10269
All -10 to 540 0,21C-1,3Cr- 0,7Mo-V 0,21C-1,3Cr- 0,7Mo-V 21CrMoV5-7 1.7709 EN 10269 21CrMoV5-7 1.7709 EN 10269
All -10 to 600 0,2C-1Cr-1Mo- V-Ti-B 0,2C-1Cr-1Mo- V-Ti-B 20CrMoVTiB4-10 - EN 10269 20CrMoVTiB4-10 - EN 10269
All -200 to 550 25Ni-15Cr-0,2Ti- Mo-V-B 25Ni-15Cr-0,2Ti- Mo-V-B X6NiCrTiMoVB 25-15-2 1.4980 EN 10269 X6NiCrTiMoVB 25-15-2 1.4980 EN 10269
All -10 to 550 16Cr-16Ni-Mo- B-Nb 16Cr-16Ni-Mo- B-Nb X7CrNiMoBNb16-16 1.4986 EN 10269 X7CrNiMoBNb16-16 1.4986 EN 10269
PN 40 Cl. 300 -200 to 400 18Cr-9Ni-Mo 18Cr-9Ni-Mo A4-50 - EN ISO 3506-1 A4-50 - EN ISO 3506-2
PN 100 Cl. 600 -200 to 400 18Cr-9Ni-Mo 18Cr-9Ni-Mo A4-70 - EN ISO 3506-1 A4-70 - EN ISO 3506-2
PN 40 Cl. 300 -200 to 400 18Cr-9Ni 18Cr-9Ni A2-50 - EN ISO 3506-1 A2-50 - EN ISO 3506-2
PN 100 Cl. 600 -200 to 400 18Cr-9Ni 18Cr-9Ni A2-70 - EN ISO 3506-1 A2-70 - EN ISO 3506-2
PN 40 Cl. 300 -200 to 550 17Cr-12Ni-2Mo 17Cr-12Ni-2Mo X5CrNiMo17-12-2 1.4401 EN 10269 X5CrNiMo17-12-2 1.4401 EN 10269
PN 100 Cl. 600 -200 to 200 2) 17Cr-12Ni-2Mo AT+C 17Cr-12Ni-2Mo X5CrNiMo17-12-2 AT+C 1.4401 EN 10269 X5CrNiMo17-12-2 1.4401 EN 10269
PN 40 Cl. 300 -200 to 550 18Cr-10Ni 18Cr-10Ni X5CrNi18-10 1.4301 EN 10269 X5CrNi18-10 1.4301 EN 10269
PN 100 Cl. 600 -200 to 200 2) 18Cr-10Ni AT+C 18Cr-10Ni X5CrNi18-10 AT+C 1.4301 EN 10269 X5CrNi18-10 1.4301 EN 10269
  • 1) Up to PN 63 for temperature up to 120 oC.
  • 2) Allowable stresses for elevated temperatures may be taken from the material in AT condition, as no stresses exist for the cold worked condition

Bolting Material Combinations

PN Class up to Suitable temperature range °C Type of bolting and description of material groups Steel designation name or property class Steel designation number Material standard
Bolts, screws, studs Nuts Bolts, screws, studs Nuts
PN 40a Cl. 300 - 10 to 300 C-St C-St 5.6g - EN ISO 898-1 5e - EN 20898-2
PN 40a Cl. 300 - 10 to 300 C-St C-St 8.8g - EN ISO 898-1 8 - EN 20898-2
all - 10 to 400 0,25C-1Cr-Mo C-St elev. temp. 25CrMo4 1.7218 EN 10269 C35E 1.1181 EN 10269
all - 10 to 350 0,42C-1Cr-Mo C-St elev. temp. 42CrMo4 1.7225 EN 10269 C45E 1.1191 EN 10269
all - 60 to 400 0,25C-1Cr-Mo 18Cr-9Ni 25CrMo4 1.7218 EN 10269 A2-50, A2-70 g - EN ISO 3506-2
all - 60 to 500 0,25C-1Cr-Mo 0,25C-1Cr-Mo 25CrMo4h 1.7218 EN 10269 25CrMo4 1.7218 EN 10269
all - 100 to 500 0,42C-1Cr-Mo 0,42C-1Cr-Mo 42CrMo4h 1.7225 EN 10269 42CrMo4 1.7225 EN 10269
all - 10 to 500 0,42C-1,3Cr- 0,6Mo 0,42C-1Cr-Mo 42CrMo5-6h 1.7233 EN 10269 42CrMo4 1.7225 EN 10269
all - 10 to 500 0,40C-1Cr- 0,6Mo-V 0,42C-1Cr-Mo 40CrMoV4-6h 1.7711 EN 10269 42CrMo4 1.7225 EN 10269
allc - 10 to 500 0,21C-1,3Cr- 0,7Mo-V 0,21C-1,3Cr- 0,7Mo-V 21CrMoV5-7h 1.7709 EN 10269 21CrMoV5-7 1.7709 EN 10269
all - 10 to 500 0,2C-1Cr-1Mo- V-Ti-B 0,2C-1Cr-1Mo- V-Ti-B 20CrMoVTiB4-10h 1.7729 EN 10269 20CrMoVTiB4-10 1.7729 EN 10269
allc - 196j to 650 25Ni-15Cr-0,2Ti- Mo-V-B 25Ni-15Cr- 0,2Ti-Mo-V-B X6NiCrTiMoVBh 25-15-2 1.4980 EN 10269 X6NiCrTiMoVB 25-15-2 1.4980 EN 10269
allc - 10 to 500 12Cr-1Mo-V 12Cr-1Mo-V X22CrMoV12-1h 1.4923 EN 10269 X22CrMoV12-1 1.4923 EN 10269
all - 10 to 650 16Cr-16Ni-Mo- B-Nb 16Cr-16Ni-Mo- B-Nb X7CrNiMoBNb16-16h 1.4986 EN 10269 X7CrNiMoBNb16-16 1.4986 EN 10269
PN 40d Cl. 300 - 196 to 400 18Cr-9Ni 18Cr-9Ni A2-50g - EN ISO 3506-1 A2-50g - EN ISO 3506-2
PN 100 Cl. 600 - 196 to 400 18Cr-9Ni 18Cr-9Ni A2-70g - EN ISO 3506-1 A2-70g - EN ISO 3506-2
PN 40d Cl. 300 - 60f to 400 18Cr-9Ni-Mo 18Cr-9Ni-Mo A4-50g - EN ISO 3506-1 A4-50g - EN ISO 3506-2
PN 100 Cl. 600 - 60f to 400 18Cr-9Ni-Mo 18Cr-9Ni-Mo A4-70g - EN ISO 3506-1 A4-70g - EN ISO 3506-2
PN 40d Cl. 300 - 196 to 550 17Cr-12Ni-2Mo 17Cr-12Ni-2Mo X5CrNiMo17-12-2 AT 1.4401 EN 10269 X5CrNiMo17-12-2 1.4401 EN 10269
PN 100 Cl. 600 - 196 to 200b 17Cr-12Ni-2Mo AT+C 17Cr-12Ni-2Mo X5CrNiMo17-12-2 AT+C 1.4401 EN 10269 X5CrNiMo17-12-2 1.4401 EN 10269
PN 40d Cl. 300 - 196 to 550 18Cr-10Ni 18Cr-10Ni X5CrNi18-10 1.4301 EN 10269 X5CrNi18-10 1.4301 EN 10269
PN 100 Cl. 600 - 196 to 200b 18Cr-10Ni AT+C 18Cr-10Ni X5CrNi18-10 AT+C 1.4301 EN 10269 X5CrNi18-10 1.4301 EN 10269
  • a Up to PN 63 for temperature up to 120 °C.
  • b Allowable stresses for elevated temperatures may be taken from the material in AT condition, as no stresses exist for the cold worked condition.
  • c Commonly used for PN 160 up to PN 400.
  • d Is limited to be used for max. PN 40/Cl. 300 (low strength bolting).
  • e The use of free-cutting steel is not permitted.
  • f - 196 °C for studs.
  • g Starting material shall comply with EN 10269 (see 6.1).
  • h May be used in the creep range. For maximum suitable temperature see EN 10269.
  • j When intended to be used down to - 273 °C, for additional requirements see Table 5, footnote a.

Equivalent Bolting Materials

Product Material designation name or property class or grade Material standard for materials in accordance with Remarks 1)
EN BS NF DIN ASTM
Bolt 4.6 EN 20898-1 4.6 BS EN 20898: Part 1:1992 4.6 NF EN 20898-1 4.6 DIN ISO 898: Teil 1 Gr. B ASTM A307 1)
Nut 5 EN 20898-2 5 BS EN 20898: Part 2:1994 5 NF EN 20898-2 5 DIN EN 20898: Teil 2 1/2 ASTM A194 2)
Bolt 5.6 EN 20898-1 5.6 BS EN 20898: Part 1:1992 5.6 NF EN 20898-1 5.6 DIN ISO 898: Teil 1 - - 2)
Nut 6 EN 20898-2 6 BS EN 20898: Part 2:1994 6 NF EN 20898-2 6 DIN EN 20898: Teil 2 - - 2)
Bolt 6.8 EN 20898-1 6.8 BS EN 20898: Part 1:1992 6.8 NF EN 20898-1 6.8 DIN ISO 898: Teil 1 - - 2)
Nut 8 EN 20898-2 8 BS EN 20898: Part 2:1994 8 .NF EN 20898-2 8 DIN EN 20898: Teil 2 - - 2)
Bolt 8.8 EN 20898-1 8.8 BS EN 20898: Part 1:1992 8.8 NF EN 20898-1 8.8 DIN ISO 898: Teil 1 - - 2)
Nut C35E EN 10269 - - - - Ck35 DIN 17240 - - -
Nut C45E EN 10269 162 BS 1506 AF65C45 NF E29-043 Ck45 - 2H ASTM A194 -
Bolt 25CrMo4 EN 10269 - - 25CD4 NF E29-043 24CrMo5 DIN 17240 - - ET
Bolt 25CrMo4 EN 10269 - - 25CD4 NF E29-043 26CrMo5 DIN 17280 - - LT
Bolt 42CrMo4 EN 10269 630 BS 1506 42CD4 NF E29-043 - - B7 ASTM A193 ET
Bolt 42CrMo4 EN 10269 630 BS 1506 42CD4 NF E29-043 - - L7 ASTM A320 LT
Nut 42CrMo4 EN 10269 253 BS 1506 42CD4 NF E29-043 - - 7 ASTM A194 LT
Bolt 42CrMo5-6 EN 10269 - - - - - - - - -
Bolt 30CrNiMo8 EN 10269 - - 40NCD7-03 NF E29-043 - - L43 ASTM A320 -
Bolt 40CrMoV4-6 EN 10269 670-860 BS 1506 42CDV4 NF E29-043 40CrMoV4 7 DIN 17240 B16 ASTM A193 -
Bolt and Nut 21CrMoV5-7 EN 10269 - 20CDV5-07 NF E29-043 21CrMoV5 7 DIN 17240 - -
Bolt and Nut 20CrMoVTiB 4-10 EN 10269 681-820 BS 1506 - - - -
Bolt and Nut X6NiCrTiMoVB 25-15-2 EN 10269 286 BS 1506 Z6NCTDV25-15 NF E29-043 X5NiCrTi26 15 VdTueV 435/3 Gr.660 ASTM A 453 -
Bolt and Nut X7CrNiMoBNb 16-16 EN 10269 - - - - X8CrNiMoBNb 16 16 DIN 17240 - - -
Bolt and Nut A4-50 EN ISO 3506-2 A4-50 BS EN ISO 3506 : Part 2: 1998 A4-50 NF EN ISO 3506-2 A4-50 DIN EN ISO 3506-2 - - 2)
Bolt and Nut A4-70 EN ISO 3506-2 A4-70 BS EN ISO 3506 : Part 2: 1998 A4-70 NF EN ISO 3506-2 A4-70 DIN EN ISO 3506-2 - - 2)
Bolt and Nut A2-50 EN ISO 3506-2 A2-50 BS EN ISO 3506 : Part 2: 1998 A2-50 NF EN ISO 3506-2 A2-50 DIN EN ISO 3506-2 - - 2)
Bolt and Nut A2-70 EN ISO 3506-2 A2-70 BS EN ISO 3506 : Part 2: 1998 A2-70 NF EN ISO 3506-2 A2-70 DIN EN ISO 3506-2 - - 2)
Bolt X5CrNiMo 17-12-2 EN 10269 B8M 316S31 BS 4882 Z7CND17-11-02 NF E29-043 X6CrNiMoTi 17 12 2 DIN 17440 B8M CL.1 ASTM A193 ASTM A320 -
Bolt X5CrNiMo 17-12-2 AT+C EN 10269 B8MX 316S31 BS 4882 Z7CND17-11-02 Ecroui NF E29-043 - - B8M CL.2 ASTM A193 ASTM A320 -
Nut X5CrNiMo 17-12-2 EN 10269 8M 316S31 BS 4882 Z7CND17-11-02 NF E29-043 X6CrNiMoTi 17 12 2 DIN 17440 8M ASTM A194 -
Bolt X5CrNi 18-10 EN 10269 B8 304S31 BS 4882 Z6CN18-09 NF E29-043 X5CrNi18 10 DIN 17440 B8 CL.1 ASTM A193 ASTM A320 -
Bolt X5CrNi 18-10 AT+C EN 10269 B8X 304S31 BS 4882 Z6CN18-09 Ecroui NF E29-043 - - B8 CL.2 ASTM A193 ASTM A320 -
Nut X5CrNi 18-10 EN 10269 8 304S31 BS 4882 Z6CN18-09 NF E29-043 X5CrNi18 10 DIN 17440 8 ASTM A194 -
  • 1) ET = service at elevated temperatures, LT = service at low temperatures.
  • 2) BS 3692, BS 4190, NF E29-043, NF E25-100 and NF E25-400 may also be used.

Bolting Types

  1. Material Grades