Questions regarding the minimum wall thickness of fittings in GB/T12459S standard
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In the GB/T12459-2017 standard, the tolerance table specifies only that the wall thickness at the ends must be not less than 87.5% of the nominal wall thickness. What are the requirements for the minimum wall thickness in other parts of the pipe fitting body? Appendix B specifies that the minimum wall thickness shall be no less than the nominal wall thickness, but Appendix B is not usually followed in orders. In such cases, how is the allowable minimum wall thickness determined?
In the GB/T12459-2017 standard, for parts of the pipe fitting other than its ends, if no specific requirement regarding the minimum wall thickness is specified, and Appendix B is not applied in the order contract, then the allowable minimum wall thickness of the pipe fitting can be determined in accordance with general engineering practices and relevant design specifications. Generally, it is recommended to consult the manufacturer to confirm the specific wall thickness requirements for these areas, to ensure that the fittings meet safety and functional requirements in actual use. .
Can the wall thickness of the main body be checked by referring to the requirements for the wall thickness at the ends? So it’s also accepted at 87.5%?
This is essentially a bug, as the wall thickness at the thinnest point varies due to differences in the manufacturing processes of the pipe fittings; this is especially true for elbows, where methods such as extrusion, hot bending, and cold bending result in different thicknesses at the thinnest points. It is hoped that these issues can be addressed in future versions.
According to the GB/T 12459-2017 standard, the requirement for the end wall thickness is specifically that it must be no less than 87.5% of the nominal wall thickness. For other parts of the pipe fitting body, since the standards do not specify identical requirements, it is not appropriate to inspect the wall thickness of the body solely based on the standard for the end wall thickness. If not specified in the standards and order contract, it is recommended to negotiate with the manufacturer to determine this, or to use the specific design specifications and safety requirements of the project as a reference to establish the acceptance criteria for the minimum wall thickness of the body. In practice, it is still necessary to jointly determine an acceptable standard based on the specific application scenario and security requirements. .