Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 702-2008 Hot-rolled Steel Bars - Dimensions, Shape, Weight and Tolerances; the following changes have been made with respect to GB/T 702-2008:
——The ranges of hot-rolled round steel and square steel are adjusted;
——The tolerances of hot-rolled round steel and square steel are adjusted;
——The requirements for the normal length of hot-rolled steel bars with fair average quality are deleted;
——The requirements for the shearing slant on both ends of hot-rolled round and square steels are adjusted;
——The requirements for the corner radius of hot-rolled flat steel are added;
——The requirements for the curvature of hot-rolled hexagonal steel and octagonal steel are adjusted;
——The requirements for the shearing slant of hot-rolled hexagonal steel and octagonal steel are adjusted;
——The marking examples are deleted.
This standard was proposed by China Iron and Steel Association.
This standard is under the jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous editions of the standard replaced by this standard are as follows:
——GB/T 702-1965, GB/T 702-1972, GB/T 702-1986, GB/T 702-2004 and GB/T 702-2008;
——GB/T 704-1983, GB/T 704-1989;
——GB/T 705-1983, GB/T 705-1990;
——GB/T 911-1966, GB/T 911-2004.
Hot-rolled Steel Bars - Dimensions, Shape, Weight and Tolerances
1 Scope
This standard specifies section shape, sectional dimension, weight and tolerances, length and tolerances, shape, etc. of hot-rolled steel bars (round steel, square steel, flat steel, hexagonal steel and octagonal steel).
This standard is applicable to hot-rolled round steel with the diameter of 5.5mm~380mm, hot-rolled square steel with side length of 5.5mm~300mm, hot-rolled flat steel for general purpose with thickness of 3mm~60mm and width of 10mm~200mm, hot-rolled flat tool steel (the hot-rolled flat steel for general purpose and flat tool steel are hereinafter referred to as hot-rolled flat steel) with the thickness of 4mm~100mm and the width of 10mm~310mm, hot-rolled hexagonal steel with the opposite side distance of 8mm~70mm and hot-rolled octagonal steel with the opposite side distance of 16mm~40mm.
2 Section Shape
2.1 See Figure 1 for the section shape of hot-rolled round and square steels.
Figure 1 Sectional Drawing for Hot-rolled Round and Square Steels
2.2 See Figure 2 for the section shape of hot-rolled flat steel.
Figure 2 Sectional Drawing for Hot-rolled Flat Steel
2.3 See Figure 3 for the section shape of hot-rolled hexagonal steel and octagonal steel.
Figure 3 Sectional Drawing for Hot-rolled Hexagonal Steel and Octagonal Steel
3 Sectional Dimension, Weight and Tolerances
3.1 Dimension and weight
3.1.1 The dimension and theoretical weight of hot-rolled round and square steels shall comply with those specified in Table A.1 of Annex A.
3.1.2 The dimension and theoretical weight of hot-rolled flat steel for general purpose shall comply with those specified in Table A.2.
3.1.3 The dimension and theoretical weight of hot-rolled flat tool steel shall comply with those specified in Table A.3.
3.1.4 The dimension and theoretical weight of hot-rolled hexagonal steel and octagonal steel shall comply with those specified in Table A.4.
3.1.5 As agreed by both the Supplier and the Demander and indicated in the contract, steel bars with dimensions other than those specified in the tables of Annex A may also be adopted.
3.1.6 Hot-rolled steel bars are generally delivered at actual weight. As agreed by the Supplier and the Demander and indicated in the contract, they may be supplied according to theoretical weight.
3.2 Dimension and tolerance
3.2.1 The dimension tolerances of hot-rolled round and square steels shall comply with those specified in Table 1. The dimension tolerance group shall be indicated in corresponding product standard or order contract, otherwise, the tolerance of Group 3 shall apply.
Table 1 Dimension Tolerances of Hot-rolled Round and Square Steels In: mm
Section nominal dimension
(diameter of round steel or side length of square steel) Dimension tolerances
Group 1 Group 2 Group 3
>5.5~20 ± 0.25 ± 0.35 ± 0.40
>20~30 ± 0.30 ± 0.40 ± 0.50
>30~50 ± 0.40 ± 0.50 ± 0.60
>50~80 ± 0.60 ±0.70 ±0.80
>80~110 ±0.90 ± 1.00 ± 1.10
>110~150 ± 1.20 ± 1.30 ± 1.40
>150~200 ± 1.60 ± 1.80 ± 2.00
>200~280 ± 2.00 ±2.50 ±3.00
>280~310 ±2.50 ± 3.00 ±4.00
>310~380 ± 3.00 ± 4.00 ±5.00
3.2.2 The dimension tolerance of hot-rolled flat steel for general purpose shall comply with those specified in Table 2. The dimension tolerance group shall be indicated in corresponding product standard or order contract, otherwise, the tolerance of Group 2 shall apply.
Table 2 Dimension Tolerance of Hot-rolled Flat Steel for General Purpose In: mm
Width (b) Thickness (t)
Nominal dimension Tolerance Nominal dimension Tolerance
Group 1 Group 2 Group 1 Group 2
10~50 +0.3
-0.9 +0.5
-1.0 3~16 +0.2
-0.4 +0.3
-0.5
>50~75 +0.4
-1.2 +0.6
-1.3
>75~100 +0.7
-1.7 +0.9
-1.8 >16~60 +1.0%t
-2.5%t +1.5%t
-3.0%t
>100~150 +0.8%b
-1.8%b +1.0%b
-2.0%b
>150~200 Upon the agreement of the Supplier and the Demander
The thickness difference between two points randomly measured on the same section shall not be greater than 50% of the thickness tolerance.
3.2.3 The dimension tolerance of hot-rolled flat tool steel shall comply with those specified in Table 3.
Table 3 Dimension Tolerances of Hot-rolled Flat Tool Steel In: mm
Width and tolerance Thickness and tolerance
Nominal width Tolerance Nominal thickness Tolerance
10 0~+0.70 ≥4~6 0~+0.40
>10~18 0~+0.80 >6~10 0~+0.50
>18~30 0~+1.20 >10~14 0~+0.60
>30~50 0~+1.60 >14~25 0~+0.80
>50~80 0~+2.30 >25~30 0~+ 1.20
>80~160 0~+2.50 >30~60 0~+1.40
>160~200 0~+2.80 >60~100 0~+1.60
>200~250 0~+3.00 - -
>250~310 0~+3.20 - -
3.2.4 The dimension tolerances of hot-rolled hexagonal steel and octagonal steel shall compy with those specified in Table 4. The dimension tolerance group shall be indicated in corresponding product standard or order contract, otherwise, the tolerance in Group 3 shall apply. As agreed by both the Supplier and the Demander and indicated in the contract, overgauge rolling may be adopted, in which case, the dimension tolerances of hot-rolled hexagonal steel and octagonal steel shall be the tolerance of the hexagonal steel and octagonal steel of the same dimension specified in Table 4.
Table 4 Dimension Tolerance of Hot-rolled Hexagonal Steel and Octagonal Steel In: mm
Opposite side distance S Tolerance
Group 1 Group 2 Group 3
≥8~17 ±0.25 ±0.35 ±0.40
>17~20 ±0.25 ±0.35 ±0.40
>21~30 ±0.30 ±0.40 ±0.50
>30~50 ±0.40 ±0.50 ±0.60
>50~70 ±0.60 ±0.70 ±0.80
3.2.5 The dimension tolerance of steel bar may be in accordance with the special requirements other than those specified in Tables 1, 2, 3 and 4 if agreed by both the Supplier and the Demander and indicated in the contract.
4 Length and Tolerance
4.1 The normal length and short length of hot-rolled round and square steels shall comply with those specified in Table 5. The tolerance of specified length or multiple length shall be mm.
Table 5 Normal Length and Short Length of Hot-rolled Round and Square Steels In: mm
Normal length Short length
Section nominal dimension Length of steel bar
All specifications 2,000~12,000 ≥1,500
Carbon and alloy tool steel ≤75 2,000~12,000 ≥1,000
>75 1,000~8,000 ≥500a
a Including high-speed tool steels of all specifications.
4.2 The tolerance of the normal length, short length and specified length or multiple length of hot-rolled flat steel for general purpose shall meet those specified in Table 6.
Table 6 Length of Hot-rolled Flat Steel for General Purpose In: mm
Normal length Tolerance of specified length or multiple length Short length
2,000~12,000 ≤4,000 +30 ≥1,500
>4,000~6,000 +50
>6,000 +70
4.3 The normal length and short length of hot-rolled flat tool steels shall comply with the those specified in Table 7. The length tolerance of hot-rolled flat tool steel delivered at specified length or multiple length shall be mm.
Table 7 Normal Length and Short Length of Hot-rolled Flat Tool Steel In: mm
Nominal width Normal length Short length
≤50 ≥2,000 ≥1,500
>50~70 ≥2,000 ≥750
>70 ≥1,000 -
4.4 The normal length and short length of hot-rolled hexagonal steel and octagonal steel shall comply with those specified in Table 8. The tolerance of specified length or multiple length is mm.
Table 8 Normal Length and Short Length of Hot-rolled Hexagonal Steel and Octagonal Steel In: mm
Normal length Short length
2,000~6,000 ≥1,500
4.5 As for steel bars, the length requirements other than those specified in Tables 5, 6, 7 and 8 may be implemented if it is agreed by the Supplier and the Demander and indicated in the contract.
4.6 The delivery of short length steel bars shall not exceed 10% of the total weight of this batch of steel bars.
5 Shape
5.1 Hot-rolled round steel and square steel
5.1.1 The hot-rolled round steel and square steel shall be delivered in vertical bars, they may also delivered in coils if agreed by the Supplier and the Demander.
5.1.2 The ovality of round steel and diagonal length of square steel shall comply with those specified in Table 9. The ovality of round steel refers to the difference between maximum and minimum diameter of the same cross section.
Foreword i
1 Scope
2 Section Shape
3 Sectional Dimension, Weight and Tolerances
4 Length and Tolerance
5 Shape
Annex A (Normative) Dimension and Theoretical Weight of Hot-rolled Steel Bars
