This standard specifies the terminologies and definitions, classification and marking, materials, requirements, test methods, inspection rules, ordering details, marking and packaging as well as quality certificate of cold-formed thin-wall steel sections for building structures.
This standard is applicable to the cold-formed thin-wall open sectional steel for industrial and civil buildings and structures.
2 Normative References
The following documents for the application of this document are essential. For dated references, only the edition cited applies. For undated references, the latest editions (including all the amendments) are applicable.
GB/T 228 Metallic Materials-Tensile Testing at Ambient Temperature
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 2518 Continuous Hot-dip Zinc-coated Steel Sheets and Strips
GB/T 2975 Steel and Steel Products - Location and Preparation of Test Pieces for Mechanical Testing
GB/T 4171 Atmospheric Corrosion Resisting Structural Steel
GB/T 6723 Cold Forming Sectional Steel - Open Sectional Steel for General Structure - Dimensions Shape Weight and Permissible Tolerances
GB/T 6725 Cold Forming Steel Sections
GB/T 14978 Continuously Hot-dip Aluminum-zinc Alloy Coated Steel Sheet and Strip
CB/T 17505 Steel and Steel Products - General Technical Delivery Requirements
3 Terminologies and Definitions
For the purpose of this document, the following terminologies and definitions apply.
3.1
Cold-formed thin-wall open sectional steel
Thin-wall steel sections with groove-shaped or angular openings, which are made through cold forming by processing the cold-rolled or hot-rolled steel strip with thickness no larger than 6 mm on the continuous roller type cold forming units.
3.2
Concavo-convex
The dimensions of the parts sinking or raising along the direction perpendicular to the same surface of the cold-formed thin-wall steel section.
3.3
Curving
The maximum vector height of the cold-formed thin-wall steel section curved along the length direction.
3.4
Twisting
The maximum clearance height formed between the horizontal plane and the lower edge of one end of the cold-formed thin-wall steel section due to the twisting when the steel section surface along the length direction is placed on the horizontal plane with the lower edge of the other end appressed to the horizontal plane.
4 Classification and Marking
4.1 Classification
As shown in Figure A.1, the section shape of the cold-formed thin-wall open sectional steel in this standard are classified into 6 kinds, the codes of which are as follows:
a) Cold-formed equal angle steel, code-named JL-JD;
b) Cold-formed unequal angle steel, code-named JL-JB;
c) Cold-formed equilateral flanging angle steel, code-named JL-JJ;
