Specializing in the R&D, manufacturing, and sales of pressure piping components since 1975.
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中文Introduction to Professional Fasteners for Butt-Weld Flanges
Mechanical property specimens should be taken from the as-rolled stock after heat treatment, following the rolling direction. The sampling location is determined as follows: If the stock diameter is no more than 40 mm, the sample should be taken from the center; if the stock diameter exceeds 40 mm, the sample should be collected from a point located at one-quarter of the diameter from the center.
2023-03-30
Welding flanges come in a wide variety of bolt materials and grades—some are designed to withstand high temperatures, while others are made from specialized materials.
Welding-neck flanges have a large outer diameter and are used in critical applications, so extra care is especially important.
Mechanical property specimens should be taken from the as-rolled billet along the rolling direction after heat treatment. The sampling locations are as follows: If the billet diameter is no more than 40 mm, a sample should be taken from the center; if the billet diameter exceeds 40 mm, the sample should be collected from a point located at one-quarter of the diameter from the center.
Equal-length double-end studs and fully threaded studs shall be subjected to batch-wise performance tests. Nuts shall undergo hardness tests on a batch basis; and the raw materials used for specialized fasteners must be accompanied by material certificates issued by the manufacturer.
Dedicated fasteners shall be sampled for inspection in batches after heat treatment. The inspection results must comply with relevant regulations, and the mechanical properties of the finished products must not fall below those of the samples taken before treatment.
Pipe flanges with a nominal pressure PN of at least 10.0 MPa shall have their full studs individually subjected to magnetic particle inspection according to JB 4730-1994 *Nondestructive Testing of Pressure Vessels*. Once the inspection is completed and no defects are found, the product meets the requirements and should comply with the standards for Class II forged-welded flanges.
Specializing in the R&D, manufacturing, and sales of pressure piping components since 1975.
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