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ISO 898-5 Specification

Set Screws

Related Specifications of ISO 898-5 Bolting

ISO 898-1 ISO 898-2 ISO 898-3

ISO 898-5 Steel specifications

Hardness class Material Heat treatment a Chemical composition limit (cast analysis, %) b
C P max. S max.
max. min.
14H Carbon steel c - 0.5 - 0.11 0.15
22H Carbon steel d Quenched and tempered 0.5 0.19 0.05 0.05
33H Carbon steel d Quenched and tempered 0.5 0.19 0.05 0.05
45H Carbon steel de Quenched and tempered 0.5 0.45 0.05 0.05
Carbon steel with additives d (e.g. Boron or Mn or Cr) Quenched and tempered 0.5 0.28 0.05 0.05
Alloy steel df Quenched and tempered 0.5 0.3 0.05 0.05
  • a Case hardening is not allowed.
  • b In case of dispute, the product analysis applies.
  • c Free-cutting steel may be used, with maximum lead content 0,35 %, maximum phosphorus content 0,11 % and maximum sulfur content 0,34 %.
  • d Steel with a maximum lead content of 0,35 % may be used.
  • e For d ≤ M16 only.
  • f 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 lower alloy contents than those given above in this footnote, the limit value to be applied for steel class determination is 70 % of the sum of the individual limit values shown above in this footnote for the two, three or four elements concerned.

ISO 898-5 Mechanical Properties

Mechanical and physical properties Hardness class
14H 22H 33H 45H
Performance hardness
1.1 Vickers hardness, HV 10 min. 140 220 330 450
max. 290 300 440 560
1.2 Brinell hardness HBW, F = 30 D 2 min. 133 209 314 428
max. 276 285 418 532
1.3 Rockwell hardness HRB min. 75 95 - -
max. 105 a - -
HRC min. - a 33 45
max. - 30 44 53
Torque strength - - - see Table 5
Height of non-decarburized thread zone, E , mm min. - 1/2 H1 2/3 H1 3/4 H1
Depth of complete decarburization, G , mm max. - 0.015 0.015 b
Surface hardness HV 0,3 max. - 320 450 580
Non-carburization, HV 0,3 max. c c c
Surface integrity in accordance with ISO 6157-1
  • a For hardness class 22H: if hardness is tested in Rockwell, it is necessary to test the minimum value in HRB and the maximum value in HRC.
  • b No complete decarburization permitted in hardness class 45H.
  • c Surface hardness shall not be more than 30 Vickers points above the measured base metal hardness of the fastener when determination of both the surface hardness and base metal hardness are carried out with HV 0,3

Proof Torque requirements

Nominal thread diameter (coarse and fine pitch) Minimum length of hexagonal socket set screw for test a mm Proof torque Nm
Flat point Cone point Dog point Cup point
3 4 5 6 5 0.9
4 5 6 8 6 2.5
5 6 8 8 6 5
6 8 8 10 8 8.5
8 10 10 12 10 20
10 12 12 16 12 40
12 16 16 20 16 65
16 20 20 25 20 160
20 25 25 30 25 310
24 30 30 35 30 520
30 36 36 45 36 860
  • a For hexalobular socket set screws, there is no requirement for minimum length (as tmin of the socket is the same for all lengths).

ISO 898-5 Bolting Surface Treatment Specifications

ISO 898-5 Bolting Components Marking

Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

ISO 898-5 Bolting Certifications

  • EN 10204 3.1
  • EN 10204 3.2
  • PED 2014/68/EC
  • MERKBLATT AD 2000 W2/W7/W10
  • API 20 E BSL 1/ BSL 2
  • NACE MR 0175
  • NACE MR 0103