GB/T 4697-1991 Hot-rolled U-Profiles for Mine Roadway Support
This Chinese technical standard specifies the requirements, appearance examination, tensile properties, bendability and hardness tests of hot-rolled U-profiles for mine roadway support. The technical standard applies to hot-rolled profiles used for supporting mine roadways.
The standard has specified the requirements for cold formable U-profiles with a nominal profile height of up to 40 mm and with a nominal profile width of up to 28 mm. The profiles should have a different shape and thickness of their flanges and webs according to the intended application scope. The standard shall be exercised with reference to GB/T 706-1994 “Hot Rolled Sections”, GB/T 702-1991 “Test Methods for Dimension and Shape of Hot Rolled Steel Diameters and Sections” and other related regulations.
Section 1 of the standard outlines the product classification and scope of application. The scope of application includes the requirements, appearance inspection and technical requirements of hot-rolled U-profiles for mine roadway support. Section 2 outlines the technical requirements, including the requirements and tests relating to the dimensional tolerances, the flatness and the straightness of the profiles. Technical requirements on working performance, including fatigue strength and corrosion resistance are specified in Section 3 of the standard. Section 4 outlines the appearance examination requirements, including the burrs, cut edges, stretching marks, pit marks and other requirements. In Section 5 of the standard, requirements and examination methods on the tensile properties of steels are specified. Section 6 and Section 7 of the standard set out rules for bending tests, and hardenability tests, respectively. Section 8 of the standard specifies the marking, packaging and inspection certificates for products. The standard also contains a requirement, stating that the inspection of products shall be done in accordance with GB/T 14443-1993 “Acceptance Inspection Specification for Steel Products”.
The standard supersedes and replaces GB/T 4697-1967 “Hot Rolled U-Profiles for Mine Roadway Support”, and came into effect on May 15th 1991. This standard has been in use since its publication date.
