GB/T 908-2019 PDF in English
GB/T 908-2019 (GB/T908-2019, GBT 908-2019, GBT908-2019)
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| GB/T 908-2019 | English | 145 |
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Forged bars for dimensions, shape, weight and tolerances
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| GB/T 908-2008 | English | 359 |
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Forged bars -- Dimensions, shape, weight and tolerances
| Obsolete |
| GB/T 908-1987 | English | 199 |
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Forged round and square steels dimension, shape, weight and tolerance
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Standards related to (historical): GB/T 908-2019
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GB/T 908-2019: PDF in English (GBT 908-2019) GB/T 908-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.60
H 44
Replacing GB/T 908-2008
Forged bars for dimensions, shape, weight and
tolerances
ISSUED ON: JUNE 04, 2019
IMPLEMENTED ON: MAY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Classification ... 5
3 Section shape ... 5
4 Section size, weight and allowable deviation ... 6
Annex A (normative) Size and theoretical weight of forged bars ... 13
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard replaces GB/T 908-2008 “Forged Bars - Dimensions, Shape,
Weight and Tolerances”. Compared with GB/T 908-2008, main changes are as
follows:
- maximum nominal diameter of round steel was increased from 400mm to
1000mm; maximum nominal side length of square steel was increased
from 400mm to 1000mm; correspondingly added stipulations on allowable
size deviation (see Table 1 of this Edition, Table 1 of Edition 2008);
- maximum nominal thickness of flat steel was increased from 160mm to
800mm; maximum nominal width was increased from 300mm to 1500mm;
correspondingly added stipulations on allowable size deviation (see Table
2 of this Edition, Table 2 of Edition 2008);
- added stipulations on size, shape and allowable deviation of polished round
steel (see Table 1 of this Edition);
- added stipulations on size, shape and allowable deviation of machined steel
bar (see Table 3 of this Edition);
- tightened stipulations on curvature of steel bar (see 4.4 of this Edition, 2.5
of Edition 2008);
- added requirements for steel bar delivery with both ends sawing and
stipulations on cutting slope (see Table 6 of this Edition);
- deleted marking examples (see Clause 4 of Edition 2008).
This Standard was proposed by China Iron and Steel Association.
This Standard shall be under the jurisdiction of National Technical Committee
on Steels of Standardization Administration of China (SAC/TC 183).
The drafting organizations of this Standard: Northeast Special Steel Group
Fushun Special Steel Co., Ltd., Xiwang Special Steel Company Limited,
Metallurgical Industry Information Standards Institute.
Main drafters of this Standard: Gu Qiang, Yu Zongyang, Wang Yujie, Zhang
Qingsheng, Chen Qingxin, Liu Baoshi, Li Wenshuang.
Versions of standard substituted by this Standard are:
- GB/T 908-1972, GB/T 908-1987, GB/T 908-2008;
Forged bars for dimensions, shape, weight and
tolerances
1 Scope
This Standard specifies section shape, section size, weight and allowable
deviation, length and allowable deviation, shape of forged bars (round steel,
square steel, flat steel).
This Standard is applicable to forged round steel of which diameter is
40mm~1000mm, forged square steel of which side length is 40mm~1000mm
and flat steel of which thickness is 20mm~800mm, width is 40mm~1500mm.
2 Classification
Forged bars, according to surface state of delivery, are classified into following
three categories:
a) hot-forged bars: known as black skin; bars that are delivered in original
surface (or through pickling, sandblasting);
b) polished steel bars: round bars of which surface is processed through
grinding, that are delivered in metal gloss surface;
c) machined steel bars: bars of which surface is processed through lathing,
milling and cutting, that are delivered in metal gloss surface.
3 Section shape
3.1 Section shapes of forged round steel and flat steel are shown as Figure 1.
according to allowable deviation of another nominal size.
Table 4 -- Size and allowable deviation of machined bars
mm
4.3 Length and allowable deviation
4.3.1 Generally, delivery length for forged bars shall not be less than 1500mm.
4.3.2 Short-foot forged bars of which length is not less than 1000mm are
allowed to deliver. But their weights must not exceed 10% of total weight of this
batch of delivery.
4.3.3 When delivered according to definite length, double length, its allowable
length deviation is mm.
4.4 Shape
4.4.1 Hot-forged bars
4.4.1.1 Hot-forged round steel
4.4.1.1.1 Curvature of hot-forged round steel shall not exceed 4mm per meter.
Total curvature shall not exceed 0.4% of total length.
4.4.1.1.2 Diameter difference of hot-forged round steel at one same section
shall not exceed 0.7 times nominal diameter tolerance.
4.4.1.2 Hot-forged square steel
4.4.1.2.1 Curvature of hot-forged square steel shall not exceed 4mm per meter.
Total curvature shall not exceed 0.4% of total length.
4.4.1.2.2 Diagonal difference of hot-forged square steel at one same section
shall not exceed 0.7 times nominal side length tolerance.
4.4.1.2.3 Hot-forged square steel allows for slightly-rounded corners. However,
distance between relative round corners (diagonal) shall not be less than 1.3
Allowable size deviation Section nominal size (diameter d, side length a or width t, thickness b)
times nominal side length.
4.4.1.2.4 Hot-forged square steel shall not have significant torsion.
4.4.1.3 Hot-forged flat steel
4.4.1.3.1 Plane curvature of hot-forged flat steel per meter shall not exceed
4mm. Total plane curvature shall not exceed 0.4% of total length.
4.4.1.3.2 Side curvature (sickle bend) per meter of hot-forged flat steel shall not
exceed 4mm. Total side curvature (sickle bend) shall not exceed 0.4% of total
length.
4.4.1.3.3 Hot-forged flat steel allows for slightly-rounded corners. However,
difference between lengths of two diagonals on one same section shall not
exceed tolerance of nominal width.
4.4.1.3.4 Hot-forged flat steel shall not have significant torsion.
4.4.2 Polished bars
4.4.2.1 Curvature of polished round steel per meter shall not exceed 4mm. Total
curvature shall not exceed 0.4% of total length.
4.4.2.2 Diameter difference of polished round steel at one same section shall
not exceed 0.7 times nominal diameter tolerance.
4.4.3 Machined bars
4.4.3.1 Curvature of round steel and square steel per meter shall not exceed
2.5mm. Total curvature shall not exceed 0.25% of total length.
4.4.3.2 Plane curvature and side curvature (sickle bend) of flat steel shall not
exceed 2.5mm per meter. Total curvature shall not exceed 0.25% of total length.
4.4.3.3 Fillet radius of square steel and flat steel shall not exceed 2.0mm.
4.4.3.4 Square steel and flat steel must not have significant torsion.
4.4.3.5 For square steel and flat steel, excluding both end faces, angular
tolerance of other adjacent planes shall not exceed 2°.
4.4.4 Cutting slope of end face
4.4.4.1 Both end faces of forged bars shall be delivered in sawing.
4.4.4.2 Cutting slope of end face of forged bars shall comply with Table 5.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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