ISO/FDIS 1035

ISO/DISFDIS 1035:2025(en)
ISO /TC 17/SC3SC 3
Secretariat: AFNOR
Date:2025-09-29 2026-01-23
Hot-rolled steel bars — Dimensions, shape, masses and tolerances
Barres en acier laminées à chaud — Dimensions, formes, masses et tolérances
FDIS stage
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Published in Switzerland
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ISO/DISFDIS 1035:20252026(en)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Designation . 2
5 Cross-sectional form . 2
6 Dimensions, masses and tolerances . 4
7 Shape . 7
Annex A (informative) Dimensions, sectional areas and masses per unit length of hot-rolled
steel bars . 15
Bibliography . 8

1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Designation . 5
5 Cross-sectional form . 6
6 Dimensions, masses and tolerances . 7
6.1Dimensions and masses . 7
6.2 Tolerances on dimensions . 7
6.3 Tolerances on length . 9
7 Shape . 9
Annex A (informative) . 13
Bibliography . 20
iii
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
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
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represent the latest information, which may be obtained from the patent database available at
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www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 17, Steels, Subcommittee SC 3, Steels for
structural purposes.
This first edition of ISO 1035 cancels and replaces ISO 1035-1:1980, ISO 1035-2:1980, ISO 1035-3:1980 and
ISO 1035-4:1982, which have been technically revised.
The main changes are as follows:
— —figures illustrating forms of hot-rolled bars werehave been added. ;
— —the category of dimensions and second preference dimensions was canceled.has been cancelled;
— —upper limits of dimensions and dimensional tolerances for hot-rolled round, square and flat bars have
been revised.;
— —dimensions for hexagonal and octagonal bars werehave been added.;
— —requirement for maximum permissible value for hot-rolled flat bars was added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

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DRAFT International Standard ISO/DIS 1035:2025(en)

Hot-rolled steel bars — Dimensions, shape, masses and
tolerances
1 Scope
This document specifies dimensions, shape, mass and tolerances of metric series hot-rolled steel bars.
This document is applicable to:
a) a) hot-rolled round bars with diameter of 5,5 mm up to 400 mm;
b) b) hot-rolled square bars with side length of 5,5 mm up to 300 mm;
c) c) hot-rolled flat bars with thickness of 3 mm up to 60 mm and width of 10 mm up to
200 mm;
d) d) hot-rolled hexagonal bars with distance across opposite flats of 8 mm up to 70 mm;
e) e) hot-rolled octagonal bars with distance across opposite flats of 16 mm up to 40 mm.
NOTE  Wide flats maycan be covered under flat bars for practical reasons.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
ISO 6929, Steel products — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6929 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at
https://www.iso.org/obphttps://www.iso.org/obp
ISO/DIS 1035:2025(en)
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
4 Designation
The designation of hot-rolled steel bars shall comprise:
— — the term round bar, square bar, flat bar, hexagonal or octagonal bar;
— — the number of the standard, i.e. ISO 1035;
— — the nominal dimension(s) in mm and the tolerance classes;
— — the number of the quality standard and the steel name of the ordered steel.
EXAMPLE:
Round bar ISO 1035-50 N×6000L0
Steel ISO 630-2 S355D
5 Cross-sectional form
5.1 5.1 Cross-sectional forms of hot-rolled round bars and square bars are shown in
Figure 1.0.
a) b)
ISO/DIS 1035:2025(en)
Key
d diameter
a side length
Figure 1 — Cross-sectional forms of hot-rolled round bars and square bars
5.2 5.2 Cross-sectional form of hot-rolled flat bars is shown in Figure 2.0.

Key
w width
t thickness
Figure 2 — Cross-sectional form of hot-rolled flat bars
5.3 5.3 Cross-sectional forms of hot-rolled hexagonal and octagonal bars are shown in
Figure 3.0.
ISO/DIS 1035:2025(en)
a) b)
Key
S distance across flats
Figure 3 — Cross-sectional forms of hot-rolled hexagonal and octagonal bars
6 Dimensions, masses and tolerances
6.1 Dimensions and masses
6.1.1 6.1.1 The preferred dimensions and masses per unit length of hot-rolled round bars are
given in Table A.1.0.
6.1.2 6.1.2 The preferred dimensions and masses per unit length of hot-rolled square bars are
given in Table A.2.0.
6.1.3 6.1.3 The preferred dimensions and masses per unit length of hot-rolled flat bars are given
in Table A.3.0.
ISO/DIS 1035:2025(en)
6.1.4 6.1.4 The preferred dimensions, sectional areas and masses per unit length of hot-rolled
hexagonal and octagonal bars are given in Table A.4.0.
6.1.5 6.1.5 Upon agreement between the supplier and purchaser, steel bars may be delivered in
other dimensions unlisted in Annex A,Annex A, and it shall be indicated in the contract.
6.2 Tolerances on dimensions
6.2.1 6.2.1 The tolerances on diameter for round bars and side length for square bars shall be as
specified in Table 1.0. The class of dimensional tolerance shall be indicated in the contract. If no
tolerance class is requested, the tolerance class is N.
Table 1 — Tolerances on diameter for round bars and side length for square bars
Tolerance on diameters or side lengths for classes
Nominal diameters or side
lengths mm
mm
N F S
5,5-15 ±0,40 ±0,30 ±0,20
>15-25 ±0,50 ±0,40 ±0,25
>25-35 ±0,60 ±0,50 ±0,30
>35-50 ±0,80 ±0,60 ±0,40
>50-80 ±1,00 ±0,80 ±0,50
>80-100 ±1,30 ±1,00 ±0,90
>100-120 ±1,60 ±1,30 ±1,20
>120-160 ±2,00 ±1,60 ±1,40
>160-200 ±2,50 ±2,00 ±1,60
>200-280 ±3,00 ±2,50 ±2,00
>280-310 ±4,00 ±3,00 ±2,50
>310-380 ±5,00 ±4,00 ±3,00
>380-400 ±6.,00 ±5.,00 ±4.,00
Note: N=normal, F=fine, S=superfine.
6.2.2 6.2.2 The tolerances on width and thickness of hot-rolled steel flat bars shall be as specified
in Table 20 and Table 3.0.
6.2.3 6.2.3 Tolerances of thickness and width shall not apply for the part of out-of-squareness.
Table 2 — Tolerances on width for hot-rolled flat bars
Nominal widths Tolerances on width
mm mm
10-50 ±0,80
>50-75 ±1,20
>75-100 ±1,50
ISO/DIS 1035:2025(en)
Nominal widths Tolerances on width
mm mm
>100-125 ±2,00
>125-150 ±2,50
>150-200 To be agreed between the supplier and purchaser
Table 3 — Tolerances on thickness for hot-rolled flat bars
Tolerances on thicknesses for nominal widths (w)
Nominal
mm
thicknesses
mm
w≤50 50 3-20 ±0,40 ±0,50
To be agreed between the supplier
>20-40 ±0,80 ±1,00
and purchaser
>40-60 — ±1,50
6.2.4 6.2.4 The distance across flats and tolerances of hot-rolled hexagonal and octagonal bars
shall be in accordance with Table 4.0. The class of tolerances shall be indicated in the contract.
Table 4 — Distance across flats and tolerances for hot-rolled hexagonal and octagonal bars
Tolerance for classes
Distance across flats
mm
mm
N F
8-15 ±0,40 ±0,30
>15-25 ±0,50 ±0,40
>25-35 ±0,60 ±0,50
>35-50 ±0,80 ±0,60
>50-70 ±1,00 ±0,80
6.2.5 6.2.5 The tolerances on length shall be as specified in Table 5.0. If no tolerance class is
requested, the tolerance class is L1.
Table 5 — Tolerances on length
Tolerances on length for class
mm
Nominal lengths
L0 L1 L2 L3 L4
0 0 0
a c
All ±200
b b b
+100 +50 +25
a The length of the bar is left to the choice of the manufacturer, it shall be not less than 3 000 mm. If agreed between the
purchaser and the manufacturer, other dimensions and tolerances may be used.
ISO/DIS 1035:2025(en)
Tolerances on length for class
mm
Nominal lengths
L0 L1 L2 L3 L4
b When agreed at the time of ordering, the bars can be supplied with symmetrical “±” tolerances. In this case, the total
tolerance range shall be the same as specified for the relevant “+” tolerances (for example ±25 mm instead of 0 +50 mm.
Possible short-length may appear, their percentage and minimum length has to be agreed on during the order.
c Tighter tolerances in cases where cold cutting is possible might be agreed at the time of enquiry and order.
6.2.6 6.2.6 Upon agreement between the supplier and purchaser, other dimensional tolerances of
steel bars may be used and it shall be indicated in the contract.
7 Shape
7.1 7.1 The permissible ovality for all diameters of round bars, measured as the difference
between the maximum and minimum diameters of the same cross-section, shall not exceed 75 % of
the total tolerance specified on the diameter according to Table 1.0. If agreed between the purchaser
and the manufacturer, other ovality may be used.
7.2 7.2 The permissible out-of-squareness for all side lengths of square bars, measured as the
difference of the distance between parallel faces of the same cross-section, shall not exceed 75 % of
the total tolerance specified on the nominal width of side in Table 1.0. If agreed between the
purchaser and the manufacturer, other out-of-square may be used. The out-of-squareness of square
bars are shown in Figure 40 a), b), c) and d).
ISO/DIS 1035:2025(en)
a) b)
ISO/DIS 1035:2025(en)
c) d)
Figure 4 — Out-of-squareness of hot-rolled square bars

7.3 7.3 The permissible out-of-section for all distances across flats of hexagonal and octagonal
bars, measured as the maximum difference in the distance across
...