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 developed in accordance with the rules given in GB/T 1.1-2009.
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.
Hot-rolled steel channels with parallel flanges
1 Scope
This standard specifies the order information, dimension, shape, weight and permissible deviation, technical requirements, test methods, inspection rules, and packaging, marking and quality certificate of hot-rolled steel channels with parallel flanges.
This standard is applicable to hot-rolled steel channels with parallel flanges (hereinafter referred to as "steel channels").
2 Normative references
The following referenced documents are indispensable for the application 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.
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 232 Metallic materials - Bend test
GB/T 700 Carbon structural steels
GB/T 1591 High strength low alloy structural steels
GB/T 2101 General requirement of acceptance, packaging, marking, and certification for section steel
GB/T 2975 Steel and steel products - Location and preparation of samples and test pieces for mechanical testing
GB/T 34560.1 Structural steels - Part 1: General technical delivery condition for hot-rolled products
YB/T 081 Rule for rounding off of numberical values and judgment of testing values for technical standards of metallurgy
YB/T 4427 General requirements for surface condition of hot-rolled sections
3 Order information
The order contract concluded according to this standard shall contain the following technical content:
a) product name;
b) standard No.;
c) designation;
d) model and specification;
e) delivery length;
f) weight and quantity;
g) other special requirements proposed by the purchaser, such as special specification requirements and special surface quality requirements.
4 Dimension, shape, weight and permissible deviation
4.1 Dimension and representation
4.1.1 The sectional sketch for steel channels and the marked symbols in the sketch are given in Figure 1.
4.1.2 The sectional dimensions, sectional area, theoretical weight and sectional characteristic parameters of steel channels shall meet those specified in Annex A, Table A.1.
Key
h——height;
b——flange width;
d——waist thickness;
t——flange thickness;
r——inner arc radius;
Z0——centroidal distance.
Figure 1 Schematic diagram for steel channel with parallel flanges
4.2 Dimension, shape and permissible deviation
4.2.1 The dimension, shape and permissible deviation of steel channels shall meet those specified in Table 1. According to the requirements of the purchaser, the dimension, shape and permissible deviation of steel channels may also be stipulated in the agreement between the supplier and the purchaser.
4.2.2 The passivation of the shoulder and flange ends of steel channel shall not allow a round bar with a diameter of 0.18t to pass through.
4.2.3 The outer edge slope and bending deflection of steel channels shall be checked at a distance of not less than 750mm from the end.
4.2.4 The steel channels shall be free from significant twist.
4.2.5 The delivery length of steel channels shall be specified in the contract, and the permissible deviation of their length shall be as specified in Table 1.
Table 1 Permissible deviations for dimension and shape of steel channels In: mm
Item Permissible deviation Illustration
Height
(h) h≤65 ±1.5
65400 ±4.0
Flange width
(b) b≤50 ±1.5
5015 ±1.5
Flange thickness
(t) t≤10 ±0.5
1015 ±1.5
Outer edge slope
(T1+T2) b≤100 T1+T2≤2.0
b>100 T1+T2≤2.5%b
Bending deflection
(W) h≤100 ±0.5
100200 ±1.5
Curvature Suitable for large bends up and down & left and right All specifications Curvature per meter ≤ 3mm;
Total curvature ≤ 0.30% of the total length
Length
(l) ≤8,000 +50
0
>8,000 +80
0
Note: The measuring positions of dimension and shape are shown in the illustrations.
4.3 Weight and permissible deviation
4.3.1 The steel channels shall be delivered according to their theoretical weight (density: 7.85g/cm3). By mutual agreement between the supplier and the purchaser and specified in the contract, they may also be delivered by actual weight.
4.3.2 The permissible deviation (%) of delivery weight of steel channels shall be in accordance with those specified in Table 2. It is calculated by using Formula (1):
Weight deviation =( (Actual weight - Theoretical weight))/(Theoretical weight) × 100 (1)
Table 2 Permissible deviation of delivery weight of steel channels
Specification/mm Permissible deviation of delivery weight
h≤125 Permissible deviation of delivery weight of each steel channel ±6%
h>125 Permissible deviation of delivery weight of each steel channel ±4%
Notes: h is the height of a steel channel.
4.3.3 Specification representation
The specification is represented by PC followed by height × flange width × waist thickness × flange thickness.
Example: PC200×75×9×11 (PC20b for short).
5 Technical requirements
5.1 Designation and chemical composition of steels
The designation and chemical composition (heat analysis) of steel channels shall be in accordance with those specified in GB/T 700 or GB/T 1591. Upon agreement between the supplier and the purchaser and indicated in the contract, the steel channels of other designations or chemical compositions may be supplied.
5.2 Mechanical properties
The mechanical properties of steel channels shall meet the relevant requirements of GB/T 700 or GB/T 1591. Upon agreement between the supplier and the purchaser and indicated in the contract, steel channels of other mechanical properties may be supplied.
5.3 Final delivery condition
The steel channels shall be delivered in hot rolled condition.
5.4 Surface quality
5.4.1 The surfaces of steel channels shall free of crack, fold, scar, delamination and inclusion.
5.4.2 The surfaces of steel channels may have local hairline, pits, pitting, scratches, pressed scale or other similar defects, but these defects shall not exceed the permissible dimensional deviations of the steel channels.
5.4.3 The defects on surfaces of steel channels may be removed but not in a coursewise way; the part on which defects are removed shall be made smooth and edge-free. The defect removing width shall not less than 5 times the removing depth; the dimensions of the product after defect removing shall be within the permissible dimensional deviations.
5.4.4 There shall be no burr larger than 5mm on ends of the steel channels.
5.4.5 The surface quality of steel channels may meet the requirements of YB/T 4427 upon negotiation between the supplier and the purchaser.
Foreword II
1 Scope
2 Normative references
3 Order information
4 Dimension, shape, weight and permissible deviation
5 Technical requirements
6 Test methods
7 Inspection rules
8 Packaging, marking and quality certificate
Annex A (Normative) Sectional dimensions, sectional area, theoretical weight and sectional characteristics of steel channels
