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Haosheng Fasteners supplies HG/T 20634-2009 fully threaded studs for Class series steel pipe flange connections, threaded along the full shank and secured with nuts at both ends to deliver the clamping force flanges and gaskets require. Available in 35CrMo, 42CrMo, 25Cr2MoV, stainless and ASTM special grades across M14-M90, with bluing treatment and traceable heat-number records. Length, marking, companion nuts and inspection items follow your flange assembly drawing, so each set matches the design pressure, temperature and medium. Send your standard, thread, length, material and nut requirements for a quote.
Haosheng Fasteners supplies HG/T 20634-2009 fully threaded studs for Class series steel pipe flange connections. Machined with external threads along the full shank and secured with nuts at both ends, these studs deliver the clamping force required by the flanges and gaskets. They are the preferred bolting for detachable joints in petrochemical plants, process piping, pumps, valves and equipment interfaces, where the connection must be opened and reassembled during maintenance.
Material options cover 35CrMo, 42CrMo and 25Cr2MoV alloy steel, 0Cr18Ni9 and 0Cr17Ni12Mo2 stainless steel, and ASTM A193 B8 Class 2, B8M Class 2, A320 L7 and A453 660 special grades. Alloy steel fasteners receive bluing (black oxide) treatment, while other anti-corrosion finishes, thread fit and inspection rules can be defined in the technical agreement. Selection follows design pressure, design temperature, service medium, flange type and gasket type; length, end chamfer, marking, companion nuts and quality documents are then confirmed from the flange assembly drawing for distributors, EPC contractors and industrial procurement teams.
| Executive Standard | HG/T 20634-2009 | Standard Title | Fasteners for Steel Pipe Flanges (Class Series) |
|---|---|---|---|
| Product Form | Fully Threaded Stud | Thread Requirements | GB/T 901 (dimensions, tolerances, end chamfers) |
| Thread Range | M14-M90 | Pitch Series | Coarse P2-P3.5 / Fine P3 |
| Material Groups | Alloy Steel / Stainless Steel / ASTM Special Grades | Surface Treatment | Bluing (Black Oxide) / Project-Specified |
| Stud Length | Per Flange Assembly Drawing | Samples | Available upon request |
Technical note: The HG/T 20634 thread series runs M14, M16, M20, M24, M27, M30, M33 in coarse pitches of 2 to 3.5 mm, then M36×3 through M90×3 in a 3 mm fine pitch. Length is not read from a fixed table; it is calculated from the actual flange thickness, gasket, nuts and installation allowance, and checked again when washers, insulating components or other accessories are added. Mechanical properties of these special-grade studs are accepted by material grade, heat treatment condition and size class, with tensile strength, yield strength, elongation and hardness stated in the order; low-temperature impact requirements follow the material and design temperature. Companion nuts, flanges and gaskets must jointly satisfy the connection design, and installation preload is defined by the design and construction documents.
Threads run the entire shank, so nuts can be positioned at both ends to suit different flange thicknesses and gasket build-ups.
Nuts at both ends generate the clamping force that holds the flange faces and gasket together under design pressure.
Alloy, stainless and ASTM special grades are chosen against design pressure, temperature and service medium rather than by stock availability.
High-temperature lines and low-temperature systems are handled by the specified heat treatment, inspection and impact test requirements.
Quality documents correspond to the material heat number, production batch and inspection results of the actually delivered studs.
Thread, length, chamfer, marking, finish, companion nuts, inspection items and packaging are all agreed from the assembly drawing.
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Design pressure, temperature, medium, flange type and gasket type are checked first to set stud material, specification and length.
Grade, standard edition, chemical composition, heat treatment condition and finished-product performance are verified before machining.
Thread diameter, pitch, tolerance, end chamfers and thread quality follow the requirements of GB/T 901 referenced by the standard.
Acceptance considers material grade, heat treatment condition and size class, with low-temperature impact tests set by design temperature.
Bluing is applied to alloy steel; agreed coatings also define thickness, thread fit, friction conditions and installation torque.
Marking, batch records and inspection documents are matched to the delivered lot for single-piece or stud-and-nut set supply.
| Comparison Feature | Generic All-Thread Rod | Haosheng HG/T 20634 Studs |
|---|---|---|
| Governing Standard | General threaded rod practice | HG/T 20634-2009 Class series |
| Material Definition | Common carbon steel stock | Named alloy, stainless and ASTM grades |
| Property Acceptance | Mill certificate only | By grade, heat treatment and size class |
| Companion Nuts | Standard hex nuts | Pipe flange nuts per standard or project |
| Traceability | Batch level at best | Heat number, batch and inspection results |
Selection note: Choose the stud material, specification, length and companion nuts from the design pressure, design temperature, service medium, flange type and gasket type, then confirm them against the flange nominal size, Class rating and sealing face type. When working from standard length tables, verify whether the assembly adds washers, insulating components or other accessories. For inquiries, use the format "executive standard + thread specification + length + material + companion requirements", for example HG/T 20634-2009, M24×120, 35CrMo, fully threaded stud, with two pipe-flange nuts.
HG/T 20634 covers Class series steel pipe flanges; HG/T 20613 covers the PN series. State the flange series first, then the thread specification, length and material, since the two standards use different size ranges.
Base the choice on design temperature and medium. 35CrMo, 42CrMo, 25Cr2MoV, stainless and the ASTM special grades are listed in the standard; heat treatment and low-temperature impact tests follow the design documents.
Use the actual flange thickness plus the gasket, both nuts and the installation allowance. Recheck the calculation if washers, insulating components or other accessories are added to the assembly.
No. Special-grade studs are accepted by material grade, heat treatment condition and size class. Tensile strength, yield strength, elongation, hardness and any impact test requirements are stated in the order.
Yes. Companion nuts are selected to the standard or project requirements, and both single-piece and set supply are available. The stud, nuts, flanges and gaskets must satisfy the connection design together.
ISO 9001, ISO 14001 and ISO 45001 certified production, with quality documents linked to the material heat number, production batch and inspection results. Samples are available on request.
Please include the executive standard, thread specification, length, material grade and companion nut requirements. Example: HG/T 20634-2009, M24×120, 35CrMo, fully threaded stud, with two pipe-flange nuts.
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