ISO 898-1:2013

INTERNATIONAL ISO
STANDARD 898-1
Fifth edition
2013-01-15
Mechanical properties of fasteners made
of carbon steel and alloy steel
Part 1:
Bolts, screws and studs with specified
property classes — Coarse thread and
fine pitch thread
Caractéristiques mécaniques des éléments de fixation en acier au
carbone et en acier allié
Partie 1: Vis, goujons et tiges filetées de classes de qualité
spécifiées — Filetages à pas gros et filetages à pas fin

Reference number
©
ISO 2013
©  ISO 2013
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Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
1 Scope.1
2 Normative references.2
3 Terms and definitions .3
4 Symbols and abbreviated terms .4
5 Designation system for property classes.6
6 Materials.6
7 Mechanical and physical properties.8
8 Applicability of test methods .12
8.1 General.12
8.2 Loadability of fasteners .12
8.3 Manufacturer's test/inspection .13
8.4 Supplier's test/inspection.13
8.5 Purchaser's test/inspection.13
8.6 Feasible tests for groups of fasteners and machined test pieces .14
9 Test methods .21
9.1 Tensile test under wedge loading of finished bolts and screws (excluding studs).21
9.2 Tensile test for finished bolts, screws and studs for determination of tensile strength, R .25
m
9.3 Tensile test for full-size bolts, screws and studs for determination of elongation after
fracture, A , and stress at 0,0048d non-proportional elongation, R .27
f pf
9.4 Tensile test for bolts and screws with reduced loadability due to head design .31
9.5 Tensile test for fasteners with waisted shank.32
9.6 Proof load test for finished bolts, screws and studs.33
9.7 Tensile test for machined test pieces .35
9.8 Head soundness test .38
9.9 Hardness test.39
9.10 Decarburization test.41
9.11 Carburization test .44
9.12 Retempering test .46
9.13 Torsional test.46
9.14 Impact test for machined test pieces .47
9.15 Surface discontinuity inspection.48
10 Marking.48
10.1 General.48
10.2 Manufacturer's identification mark.49
10.3 Marking and identification of fasteners with full loadability.49
10.4 Marking and designation of fasteners with reduced loadability .53
10.5 Marking of packages .53
Annex A (informative) Relationship between tensile strength and elongation after fracture.54
Annex B (informative) Influence of elevated temperatures on mechanical properties of fasteners.55
Annex C (informative) Elongation after fracture for full-size fasteners, A .56
f
Bibliography.57

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 898-1 was prepared by Technical Committee ISO/TC 2, Fasteners, Subcommittee SC 11, Fasteners with
metric external thread.
This fifth edition cancels and replaces the fourth edition (ISO 898-1:2009), of which it constitutes a minor
revision.
ISO 898 consists of the following parts, under the general title Mechanical properties of fasteners made of
carbon steel and alloy steel:
⎯ Part 1: Bolts, screws and studs with specified property classes — Coarse thread and fine pitch thread
⎯ Part 2: Nuts with specified property classes — Coarse thread and fine pitch thread
⎯ Part 5: Set screws and similar threaded fasteners with specified hardness classes — Coarse thread and
fine pitch thread
)
⎯ Part 7: Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm

)
It is intended that, upon revision, the main element of the title of Part 7 will be aligned with the main element of the titles
of Parts 1 to 5.
iv © ISO 2013 – All rights reserved

INTERNATIONAL STANDARD ISO 898-1:2013(E)

Mechanical properties of fasteners made of carbon steel and
alloy steel
Part 1:
Bolts, screws and studs with specified property classes —
Coarse thread and fine pitch thread
1 Scope
This part of ISO 898 specifies mechanical and physical properties of bolts, screws and studs made of carbon
steel and alloy steel when tested at an ambient temperature range of 10 °C to 35 °C. Fasteners (the term
used when bolts, screws and studs are considered all together) that conform to the requirements of this part of
ISO 898 are evaluated at that ambient temperature range. They might not retain the specified mechanical and
physical properties at elevated temperatures (see Annex B) and/or lower temperatures.
NOTE 1 Fasteners conforming to the requirements of this part of ISO 898 are used in applications ranging from −50 °C
to +150 °C. Users are advised to consult an experienced fastener metallurgist for temperatures outside the range of
−50 °C to +150 °C and up to a maximum temperature of +300 °C when determining appropriate choices for a given
application.
NOTE 2 Information for the selection and application of steels for use at lower and elevated temperatures is given, for
example, in EN 10269, ASTM F2281 and in ASTM A320/A320M.
Certain bolts and screws might not fulfil the tensile or torsional requirements of this part of ISO 898 because
the geometry of their heads reduces the shear area in the head compared to the stress area in the thread.
These include bolts and screws having a low or countersunk head (see 8.2).
This part of ISO 898 is applicable to bolts, screws and studs
⎯ made of carbon steel or alloy steel,
⎯ having triangular ISO metric screw thread in accordance with ISO 68-1,
⎯ 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.
It is not applicable to set screws and similar threaded fasteners not under tensile stress (see ISO 898-5).
It does not specify requirements for such properties as
⎯ weldability,
⎯ corrosion resistance,
⎯ resistance to shear stress,
⎯ torque/clamp force performance (for test method, see ISO 16047), or
⎯ fatigue resistance.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable to its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 68-1, ISO general purpose screw threads — Basic profile — Part 1: Metric screw threads
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 225, Fasteners — Bolts, screws, studs and nuts — Symbols and descriptions of dimensions
ISO 261, ISO general purpose metric screw threads — General plan
ISO 262, ISO general purpose metric screw threads — Selected sizes for screws, bolts and nuts
ISO 273, Fasteners — Clearance holes for bolts and screws
ISO 724, ISO general-purpose metric screw threads — Basic dimensions
ISO 898-2, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 2: Nuts with
specified property classes — Coarse thread and fine pitch thread
ISO 898-5, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 5: Set screws and
similar threaded fasteners with specified hardness classes — Coarse thread and fine pitch thread
ISO 898-7, Mechanical properties of fasteners — Part 7: Torsional test and minimum torques for bolts and
1)
screws with nominal diameters 1 mm to 10 mm
ISO 965-1, ISO general-purpose metric screw threads — Tolerances — Part 1: Principles and basic data
ISO 965-2, ISO general purpose metric screw threads — Tolerances — Part 2: Limits of sizes for general
purpose external and internal screw threads — Medium quality
ISO 965-4, ISO general purpose metric screw threads — Tolerances — Part 4: Limits of sizes for hot-dip
galvanized external screw threads to mate with internal screw threads tapped with tolerance position H or G
after galvanizing
ISO 4042, Fasteners — Electroplated coatings
ISO 6157-1, Fasteners — Surface discontinuities — Part 1: Bolts, screws and studs for general requirements
ISO 6157-3, Fasteners — Surface discontinuities — Part 3: Bolts, screws and studs for special requirements
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method (scales A, B, C, D, E, F, G, H,
K, N, T)
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Verification and calibration of the force-measuring system
2 © ISO 2013 – All rights reserved

ISO 10683, Fasteners — Non-electrolytically applied zinc flake coatings
ISO 10684:2004, Fasteners — Hot dip galvanized coatings
ISO 16426, Fasteners — Quality assurance system
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
finished fastener
fastener for which all manufacturing steps have been completed, with or without any surface coating and with
full or reduced loadability, and which has not been machined into a test piece
3.2
machined test piece
test piece machined from a fastener to evaluate material properties
3.3
full-size fastener
finished fastener with a shank diameter of d ≈ d or d > d, or screw threaded to the head, or fully threaded stud
s s
3.4
fastener with reduced shank
finished fastener with a shank diameter of d ≈ d
s 2
3.5
fastener with waisted shank
finished fastener with a shank diameter of d < d
s 2
3.6
base metal hardness
hardness closest to the surface (when traversing from core to outside diameter) just before an increase or
decrease occurs, denoting, respectively, carburization or decarburization
3.7
carburization
result of increasing surface carbon to a content above that of the base metal
3.8
decarburization
loss of carbon at the surface of a steel fastener
3.9
partial decarburization
decarburization with sufficient loss of carbon to cause a lighter shade of tempered martensite and a
significantly lower hardness than that of the adjacent base metal, without, however, showing ferrite grains
under metallographic examination
3.10
ferritic decarburization
decarburization with sufficient loss of carbon to cause a lighter shade of tempered martensite and a
significantly lower hardness than that of the adjacent base metal, with the presence of ferrite grains or grain
boundary network under metallographic examination
3.11
complete decarburization
decarburization with sufficient carbon loss to show only clearly defined ferrite grains under metallographic
examination
4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviated terms given in ISO 225 and ISO 965-1, and
the following apply.
A Percentage elongation after fracture (of machined test piece), %
A Elongation after fracture for full-size fastener
f
A Nominal stress area in thread, mm
s,nom
A Cross-sectional area of waisted shank, mm
ds
b Thread length, mm
b Thread length of stud metal end, mm
m
d Nominal thread diameter, mm
d Diameter of machined test piece, mm
d Basic minor diameter of external thread, mm
d Basic pitch diameter of external thread, mm
d Minor diameter of external thread, mm
d Transition diameter (internal diameter of the bearing face), mm
a
d Hole diameter of wedge or block, mm
h
d Diameter of unthreaded shank, mm
s
E Height of non-decarburized zone in thread, mm
F Ultimate tensile load, N
m
F Minimum ultimate tensile load, N
m,min
F Proof load, N
p
F Load at 0,0048d non-proportional elongation for full-size fastener, N
pf
G Depth of complete decarburization in thread, mm
H Height of fundamental triangle, mm
H Height of external thread in maximum material condition, mm
k Height of the head, mm
K Impact strength, J
v
4 © ISO 2013 – All rights reserved

l Nominal length, mm
l Total length of fastener before loading, mm
l Total length of fastener after first unloading, mm
l Total length of fastener after second unloading, mm
l Length of unthreaded shank, mm
s
l Overall length of stud, mm
t
l Free threaded length of fastener in testing device, mm
th
L Length of straight portion (of machined test piece), mm
c
L Original gauge length (of machined test piece), mm
o
L Total length of machined test piece, mm
t
L Final gauge length (of machined test piece), mm
u
∆L Plastic elongation, mm
p
M Breaking torque, Nm
B
P Pitch of thread, mm
r Fillet radius, mm
R Lower yield strength for machined test piece, MPa
eL
R Tensile strength, MPa
m
R Stress at 0,2 % non-proportional elongation for machined test piece, MPa
p0,2
R Stress at 0,0048d non-proportional elongation for full-size fastener, MPa
pf
s Width across flats, mm
S Cross-sectional area of machined test piece before tensile test, mm
o
S Stress under proof load, MPa
p
S Cross-sectional area of machined test piece after fracture, mm
u
Z Percentage reduction of area after fracture for machined test piece, %
α Wedge angle for tensile test under wedge loading
β Angle of the solid block for head soundness test
max Subscript added to symbol to denote maximum value
min Subscript added to symbol to denote minimum value
nom Subscript added to symbol to denote nominal value

5 Designation system for property classes
The symbol for property classes of bolts, screws, and studs consists of two numbers, separated by a dot (see
Tables 1 to 3):
a) the number to the left of the dot consists of one or two digits and indicates 1/100 of the nominal tensile
strength, R , in megapascals (see Table 3, No. 1);
m,nom
b) the number to the right of the dot indicates 10 times the ratio between the nominal yield strength and the
nominal tensile strength, R , as specified in Table 1 (yield strength ratio). The nominal yield strength,
m,nom
as specified in Table 3 (Nos. 2 to 4), is:
⎯ lower yield strength R , or
eL,nom
⎯ nominal stress at 0,2 % non-proportional elongation R , or
p0,2 nom
⎯ nominal stress at 0,0048d non-proportional elongation R .
pf,nom
Table 1 — Ratio of nominal yield strength and nominal tensile strength
Number to the right of dot .6 .8 .9
R R R
eL,nom p0,2,nom pf,nom
or or
0,6 0,8 0,9
R R R
m,nom m,nom m,nom
c) an additional zero to the left of the property class designation indicates that fasteners have reduced
loadability (see 8.2 and 10.4).
EXAMPLE 1 A fastener of nominal tensile strength R = 800 MPa and with a yield strength ratio of 0,8 has the
m,nom
property class designation 8.8.
EXAMPLE 2 A fastener with material properties of property class 8.8 but with reduced loadability is designated by 08.8.
The multiplication of the nominal tensile strength and the yield strength ratio gives the nominal yield strength
in megapascals (MPa).
Marking and labelling of bolts, screws and studs with property classes shall be as specified in 10.3. For
fasteners with reduced loadability, specific marking symbols are specified in 10.4.
The designation system of this part of ISO 898 may be applied to sizes outside the scope of this part of
ISO 898 (e.g. d > 39 mm), provided all applicable requirements in accordance with Tables 2 and 3 are met.
Information on the relationship between the nominal tensile strength and elongation after fracture for each
property class is given in Annex A.
6 Materials
Table 2 specifies limits for the chemical composition of steels and minimum tempering temperatures for the
different property classes of bolts, screws and studs. The chemical composition shall be assessed in
accordance with the relevant International Standards.
NOTE National regulations for the restriction or prohibition of certain chemical elements might also have to be taken
into account in the countries or regions concerned.
For fasteners that are to be hot dip galvanized, the additional material requirements given in ISO 10684 apply.
6 © ISO 2013 – All rights reserved

Table 2 — Steels
Chemical composition limit
Tempering
a
temperature
(cast analysis, %)
Property
Material and heat treatment
b
class
C P S B °C
min. max. max. max. max. min.
c d
4.6
— 0,55 0,050 0,060
d
4.8
c
Carbon steel or carbon steel with additives —
0,13 0,55 0,050 0,060
5.6
d
5.8 — 0,55 0,050 0,060
d
6.8 0,15 0,55 0,050 0,060
Carbon steel with additives (e.g. Boron or Mn
e
0,15 0,40 0,025 0,025
or Cr) quenched and tempered
or
f 0,25 0,55 0,025 0,025
8.8 0,003 425
Carbon steel quenched and tempered
or
0,20 0,55 0,025 0,025
g
Alloy steel quenched and tempered
Carbon steel with additives (e.g. Boron or Mn
e
0,40 0,025 0,025
0,15
or Cr) quenched and tempered
or
f 0,25 0,55 0,025 0,025
9.8 0,003 425
Carbon steel quenched and tempered
or
0,20 0,55 0,025 0,025
g
Alloy steel quenched and tempered
Carbon steel with additives (e.g. Boron or Mn
e
0,20 0,55 0,025 0,025
or Cr) quenched and tempered
or
f 0,25 0,55 0,025 0,025
10.9 0,003 425
Carbon steel quenched and tempered
or
0,20 0,55 0,025 0,025
g
Alloy steel quenched and tempered
f h i g
12.9 Alloy steel quenched and tempered 0,30 0,50 0,025 0,025 0,003 425
Carbon steel with additives (e.g. Boron or Mn
f h i
0,28 0,50 0,025 0,025 0,003 380
12.9
or Cr or Molybdenum) quenched and tempered
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.
Not specified
7 Mechanical and physical properties

2)
The bolts, screws and studs of the specified property classes shall, at ambient temperature , meet all the
applicable mechanical and physical properties in accordance with Tables 3 to 7, regardless of which tests are
performed during manufacturing or final inspection.
Clause 8 sets forth the applicability of test methods for verifying that fasteners of different types and
dimensions fulfil the properties in accordance with Table 3 and Tables 4 to 7.
NOTE 1 Even if the steel properties of the fasteners meet all relevant requirements specified in Tables 2 and 3, some
types of fasteners have reduced loadability due to dimensional reasons (see 8.2, 9.4 and 9.5).
NOTE 2 Although a great number of property classes are specified in this part of ISO 898, this does not mean that all
classes are appropriate for all fasteners. Further guidance for application of the specific property classes is given in the
relevant product standards. For non-standard fasteners, it is advisable to follow as closely as possible the choice already
made for similar standard fasteners.
Table 3 — Mechanical and physical properties of bolts, screws and studs
Property class
12.9/
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9
No. Mechanical or physical property 12.9
d ≤ d > d ≤
a b
16 mm
16 mm 16 mm
c
400 500 600 800 900 1 000 1 200
nom.
1 Tensile strength, R , MPa
m
min. 400 420 500 520 600 800 830 900 1 040 1 220
c
240 — 300 — — — — — — —
nom.
d
2 Lower yield strength, R , MPa
eL
min. 240 — 300 — — — — — — —
c
— — — — — 640 640 720 900 1 080
nom.
Stress at 0,2 % non-proportional
elongation, R , MPa
p0,2
min. — — — — — 640 660 720 940 1 100
c
Stress at 0,0048d non-proportional
— 320 — 400 480 — — — — —
nom.
4 elongation for full-size fasteners, R ,
pf
e e e
min. — — — — — — —
MPa 340 420 480
f
nom. 225 310 280 380 440 580 600 650 830 970
Stress under proof load, S , MPa
p
5 S /R or
p,nom eL,min
Proof strength ratio S /R or 0,94 0,91 0,93 0,90 0,92 0,91 0,91 0,90 0,88 0,88
p,nom p0,2 min
S /R
p,nom pf,min
Percentage elongation after fracture for
6 min. 22 — 20 — — 12 12 10 9 8
machined test pieces, A, %
Percentage reduction of area after
7 min. — 52 48 48 44
fracture for machined test pieces, Z, %
Elongation after fracture for full-size
8 fasteners, A min. — 0,24 — 0,22 0,20 — — — — —
f
(see also Annex C)
9 Head soundness No fracture
2) Impact strength is tested at a temperature of −20 °C (see 9.14).
8 © ISO 2013 – All rights reserved

Table 3 (continued)
Property class
12.9/
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9
No. Mechanical or physical property 12.9
d ≤ d > d ≤
a b
16 mm
16 mm 16 mm
min. 120 130 155 160 190 250 255 290 320 385
Vickers hardness, HV
F ≥ 98 N
g
max. 250 320 335 360 380 435
min. 114 124 147 152 181 245 250 286 316 380
Brinell hardness, HBW
11 2
F = 30 D
g
max. 238 316 331 355 375 429
min. 67 71 79 82 89 —
Rockwell hardness, HRB
g
max. 95,0 99,5 —
min. — 22 23 28 32 39
Rockwell hardness, HRC
max. — 32 34 37 39 44
13 Surface hardness, HV 0,3 max. — — 390 435
h h h
14 Non-carburization, HV 0,3 max. —

Height of non-decarburized thread zone,
1 2 3
min. — / H / H / H
2 3 4
1 1 1
E, mm
Depth of complete decarburization in the
max. — 0,015
thread, G, mm
Reduction of hardness after
16 max. — 20
retempering, HV
17 Breaking torque, M , Nm min. — in accordance with ISO 898-7
B
i j
k
18 min. — 27 — 27 27 27 27
Impact strength, K , J
V
ISO
l
19 Surface integrity in accordance with ISO 6157-1
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, R , cannot be determined, it is permissible to measure the stress at 0,2 % non-
eL
proportional elongation R .
p0,2
e
For the property classes 4.8, 5.8 and 6.8, the values for R are under investigation. The values at the time of publication of this
pf,min
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 K is under investigation.
V
l
Instead of ISO 6157-1, ISO 6157-3 may apply by agreement between the manufacturer and the purchaser.

Table 4 — Minimum ultimate tensile loads — ISO metric coarse pitch thread
Nominal Property class
a
stress area
Thread
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9

b
d
A
s,nom
mm
Minimum ultimate tensile load, F (A × R ), N
m,min s,nom m,min
M3 5,03 2 010 2 110 2 510 2 620 3 020 4 020 4 530 5 230 6 140
M3,5 6,78 2 710 2 850 3 390 3 530 4 070 5 420 6 100 7 050 8 270
M4 8,78 3 510 3 690 4 390 4 570 5 270 7 020 7 900 9 130 10 700
M5 14,2 5 680 5 960 7 100 7 380 8 520 11 350 12 800 14 800 17 300
M6 20,1 8 040 8 440 10 000 10 400 12 100 16 100 18 100 20 900 24 500
M7 28,9 11 600 12 100 14 400 15 000 17 300 23 100 26 000 30 100 35 300
c c c c
M8 36,6 14 600 15 400 18 300 19 000 22 000 29 200 32 900 38 100 44 600
c c c c
M10 58 23 200 24 400 29 000 30 200 34 800 46 400 52 200 60 300 70 800
d
M12 84,3 33 700 35 400 42 200 43 800 50 600 67 400 75 900 87 700 103 000

d
104 000
M14 115 46 000 48 300 57 500 59 800 69 000 92 000 120 000 140 000

d 141 000
M16 157 62 800 65 900 78 500 81 600 94 000 125 000 163 000 192 000
M18 192 76 800 80 600 96 000 99 800 115 000 159 000 200 000 234 000
—
M20 245 98 000 103 000 122 000 127 000 147 000 203 000 — 255 000 299 000
M22 303 121 000 127 000 152 000 158 000 182 000 252 000 — 315 000 370 000
M24 353 141 000 148 000 176 000 184 000 212 000 293 000 — 367 000 431 000
M27 459 184 000 193 000 230 000 239 000 275 000 381 000 — 477 000 560 000
M30 561 224 000 236 000 280 000 292 000 337 000 466 000 — 583 000 684 000
M33 694 278 000 292 000 347 000 361 000 416 000 576 000 — 722 000 847 000
M36 817 327 000 343 000 408 000 425 000 490 000 678 000 — 850 000 997 000
M39 976 390 000 410 000 488 000 508 000 586 000 810 000 — 1 020 000 1 200 000
a
Where no thread pitch is indicated in a thread designation, coarse pitch is specified.
b
To calculate A , see 9.1.6.1.
s,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).

10 © ISO 2013 – All rights reserved

Table 5 — Proof loads — ISO metric coarse pitch thread
Nominal Property class
a
stress area
Thread
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
b
d A
s,nom
mm
Proof load, F (A × S ), N
p s,nom p,nom
M3 5,03 1 130 1 560 1 410 1 910 2 210 2 920 3 270 4 180 4 880
M3,5 6,78 1 530 2 100 1 900 2 580 2 980 3 940 4 410 5 630 6 580
M4 8,78 1 980 2 720 2 460 3 340 3 860 5 100 5 710 7 290 8 520
M5 14,2 3 200 4 400 3 980 5 400 6 250 8 230 9 230 11 800 13 800
M6 20,1 4 520 6 230 5 630 7 640 8 840 11 600 13 100 16 700 19 500
M7 28,9 6 500 8 960 8 090 11 000 12 700 16 800 18 800 24 000 28 000
c c c c
M8 36,6 8 240 11 400 10 200 13 900 16 100 21 200 23 800 30 400 35 500
c c c c
M10 58 13 000 18 000 16 200 22 000 25 500 33 700 37 700 48 100 56 300
d
M12 84,3 19 000 26 100 23 600 32 000 37 100 48 900 54 800 70 000 81 800
d 74 800
M14 115 25 900 35 600 32 200 43 700 50 600 66 700 95 500 112 000
d
102 000
M16 157 35 300 48 700 44 000 59 700 69 100 91 000 130 000 152 000
M18 192 43 200 59 500 53 800 73 000 84 500 115 000 159 000 186 000
—
M20 245 55 100 76 000 68 600 93 100 108 000 147 000 — 203 000 238 000
M22 303 68 200 93 900 84 800 115 000 133 000 182 000 — 252 000 294 000
M24 353 79 400 109 000 98 800 134 000 155 000 212 000 — 293 000 342 000
M27 459 103 000 142 000 128 000 174 000 202 000 275 000 — 381 000 445 000
M30 561 126 000 174 000 157 000 213 000 247 000 337 000 — 466 000 544 000
M33 694 156 000 215 000 194 000 264 000 305 000 416 000 — 576 000 673 000
M36 817 184 000 253 000 229 000 310 000 359 000 490 000 — 678 000 792 000
M39 976 220 000 303 000 273 000 371 000 429 000 586 000 — 810 000 947 000
a
Where no thread pitch is indicated in a thread designation, coarse pitch is specified.
b
To calculate A , see 9.1.6.1.
s,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).
Table 6 — Minimum ultimate tensile loads — ISO metric fine pitch thread
Nominal Property class
Thread stress area
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
a
d × P
A
s,nom
mm
Minimum ultimate tensile load, F (A × R ), N
m,min s,nom m,min
M8×1 39,2 15 700 16 500 19 600 20 400 23 500 31 360 35 300 40 800 47 800
M10×1,25 61,2 24 500 25 700 30 600 31 800 36 700 49 000 55 100 63 600 74 700
M10×1 64,5 25 800 27 100 32 300 33 500 38 700 51 600 58 100 67 100 78 700
M12×1,5 88,1 35 200 37 000 44 100 45 800 52 900 70 500 79 300 91 600 107 000
M12×1,25 92,1 36 800 38 700 46 100 47 900 55 300 73 700 82 900 95 800 112 000
M14×1,5 125 50 000 52 500 62 500 65 000 75 000 100 000 112 000 130 000 152 000
150 000
M16×1,5 167 66 800 70 100 83 500 86 800 100 000 134 000 174 000 204 000
M18×1,5 216 86 400 90 700 108 000 112 000 130 000 179 000 225 000 264 000
—
M20×1,5 272 109 000 114 000 136 000 141 000 163 000 226 000 — 283 000 332 000
M22×1,5 333 133 000 140 000 166 000 173 000 200 000 276 000 — 346 000 406 000
M24×2 384 154 000 161 000 192 000 200 000 230 000 319 000 — 399 000 469 000
M27×2 496 198 000 208 000 248 000 258 000 298 000 412 000 — 516 000 605 000
M30×2 621 248 000 261 000 310 000 323 000 373 000 515 000 — 646 000 758 000
M33×2 761 304 000 320 000 380 000 396 000 457 000 632 000 — 791 000 928 000
M36×3 865 346 000 363 000 432 000 450 000 519 000 718 000 — 900 000 1 055 000
M39×3 1 030 412 000 433 000 515 000 536 000 618 000 855 000 — 1 070 000 1 260 000
a
To calculate A , see 9.1.6.1.
s,nom
Table 7 — Proof loads — ISO metric fine pitch thread
Nominal Property class
stress area
Thread
4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9/12.9
a
d × P
A
s,nom
mm
Proof load, F (A × S ), N
p s,nom p,nom
M8×1 39,2 8 820 12 200 11 000 14 900 17 200 22 700 25 500 32 500 38 000
M10×1,25 61,2 13 800 19 000 17 100 23 300 26 900 35 500 39 800 50 800 59 400
M10×1 64,5 14 500 20 000 18 100 24 500 28 400 37 400 41 900 53 500 62 700
M12×1,5 88,1 19 800 27 300 24 700 33 500 38 800 51 100 57 300 73 100 85 500
M12×1,25 92,1 20 700 28 600 25 800 35 000 40 500 53 400 59 900 76 400 89 300
M14×1,5 125 28 100 38 800 35 000 47 500 55 000 72 500 81 200 104 000 121 000
109 000
M16×1,5 167 37 600 51 800 46 800 63 500 73 500 96 900 139 000 162 000
M18×1,5 216 48 600 67 000 60 500 82 100 95 000 130 000 179 000 210 000
—
M20×1,5 272 61 200 84 300 76 200 103 000 120 000 163 000 — 226 000 264 000
M22×1,5 333 74 900 103 000 93 200 126 000 146 000 200 000 — 276 000 323 000
M24×2 384 86 400 119 000 108 000 146 000 169 000 230 000 — 319 000 372 000
M27×2 496 112 000 154 000 139 000 188 000 218 000 298 000 — 412 000 481 000
M30×2 621 140 000 192 000 174 000 236 000 273 000 373 000 — 515 000 602 000
M33×2 761 171 000 236 000 213 000 289 000 335 000 457 000 — 632 000 738 000
M36×3 865 195 000 268 000 242 000 329 000 381 000 519 000 — 718 000 839 000
M39×3 1 030 232 000 319 000 288 000 391 000 453 000 618 000 — 855 000 999 000
a
To calculate A , see 9.1.6.1.
s,nom
8 Applicability of test methods
8.1 General
Two main groups of test series are established for testing the mechanical and physical properties of fasteners
specified in Table 3, FF and MP. Whereas group FF is used for testing finished fasteners, group MP is used
for testing material properties of the fasteners. The two groups are divided into test series FF1, FF2, FF3 and
FF4, and MP1 and MP2, respectively, for different types of fasteners. However, not all mechanical and
physical properties specified in Table 3 can be tested on all types or sizes of fasteners due primarily to
dimensional and/or loadability reasons.
8.2 Loadability of fasteners
8.2.1 Fasteners with full loadability
A fastener with full loadability is a finished fastener, standardized or non-standardized, which, when tensile
tested in accordance with the test series FF1, FF2 or MP2,
a) breaks
⎯ in the free threaded length for fasteners with d > d , or
s 2
⎯ in the free threaded length or in the unthreaded shank for fasteners with d ≈ d , and
s 2
b) meets the minimum ultimate tensile load, F , in accordance with Tables 4 or 6.
m,min
8.2.2 Fasteners which, due to their geometry, have reduced loadability
A fastener with reduced loadability is a finished fastener, standardized or non-standardized, with material
properties in accordance with property classes as specified in this part of ISO 898 which, due to its geometry,
does not fulfil the test requirements for loadability when tested in accordance with test series FF1, FF2 or MP2.
12 © ISO 2013 – All rights reserved

A fastener with reduced loadability does not normally break in the free threaded length when tensile tested in
accordance with test series FF3 or FF4.
Basically, there are two geometrical reasons for reduced loadability of fasteners compared with the ultimate
tensile load of the thread:
a) a head design which applies to bolts and screws with:
⎯ low head with or without external driving feature,
⎯ low round head or low cylindrical head with internal driving feature, or
⎯ countersunk head with internal driving feature;
b) a shank design which applies to fasteners which are especially designed for applications where the
loadability in accordance with this part of ISO 898 is not required or even not desired, e.g. screws with
waisted shank.
Test series FF3 (see Table 10) is used for the fasteners mentioned in a), above, while FF4 (see Table 11) is
used for those fasteners mentioned in b).
8.3 Manufacturer's test/inspection
Fasteners produced in accordance with this part of ISO 898 shall be capable of conforming to all applicable
requirements of Tables 3 to 7 when using the “feasible” tests specified in Tables 8 to 11.
This part of ISO 898 does not mandate which of the tests the manufacturer shall perform on each
manufacturing lot. It is the responsibility of the manufacturer to apply suitable methods of his (or her) choice,
such as in-process test or inspection, to ensure that the manufactured lot does conform to all of the applicable
requirements.
In case of dispute, the test methods in accordance with Clause 9 shall apply.
8.4 Supplier's test/inspection
Suppliers may test the fasteners they provide using the methods of their choice, provided the mechanical and
physical properties specified in Tables 3 to 7 are met.
In case of dispute, the test methods in accordance with Clause 9 shall apply.
8.5 Purchaser's test/inspection
The purchaser may test the delivered fasteners by the test methods given in Clause 9 using tests selected
from the relevant test series given in 8.6.
In case of dispute, the test methods in accordance with Clause 9 shall apply.
8.6 Feasible tests for groups of fasteners and machined test pieces
8.6.1 General
The applicability of test series FF1 to FF4 and MP1 to MP2, using the test methods described in Clause 9, is
specified in Tables 8 to 13.
Test series FF1 to FF4 in accordance with Tables 8, 9, 10 and 11 are provided for the testing of finished
fasteners:
⎯ FF1: these are tests for the determination of the properties of finished bolts and screws with full head
strength and full or reduced shank (full loadability), d > d or d ≈ d (see Table 8);
s 2 s 2
⎯ FF2: these are tests for the determination of the properties of finished studs with full or reduced shank
(full loadability), d > d or d ≈ d (see Table 9);
s 2 s 2
⎯ FF3: these are tests for the determination of the properties of finished bolts and screws with d > d or
s 2
d ≈ d and reduced loadability due to
s 2
1) low head with or without external driving feature,
2) low round head or low cylindrical head with internal driving feature, or
3) countersunk head with internal driving feature
(see Table 10);
⎯ FF4: these are tests for the determination of the properties of finished bolts, screws and studs especially
designed for applications where the full loadability in accordance with this part of ISO 898 is not required
or not desired, e.g. fasteners with waisted shank (reduced loadability), d < d (see Table 11).
s 2
Test series MP1 and MP2 in accordance with Tables 12 and 13 are provided for testing the material
properties of fasteners and/or for process development. Test series FF1 to FF4 may also be used for that
purpose.
⎯ MP1: these are tests for the determination of the material properties of fasteners and/or for process
development using machined test pieces (see Table 12).
⎯ MP2: these are tests for the determination of material properties of fasteners with full loadability, d ≈ d or
s 2
d > d , and/or for process development (see Table 13).
s 2
8.6.2 Applicability
The relevance of the test methods to the group of fasteners shall be in accordance with Tables 8 to 13.
8.6.3 Delivery of test results
When, for a specific order, the purchaser requires a report including test results, they shall be established
using the test methods specified in Clause 9 and selected from Tables 8 to 13. Any specific test specified by
the purchaser shall be agreed upon at the time of order.
14 © ISO 2013 – All rights reserved

Table 8 — Test series FF1 — Finished bo
...