Threaded Flange
Product Description
Screws directly onto threaded pipe without welding. Ideal for high-pressure systems where welding could cause distortion, or for field assembly in hazardous areas.
Every flange is supplied with a mill test certificate (EN 10204 3.1), material traceability, and optional third-party inspection (BV / SGS / TUV). Available in Raised Face, Flat Face, and Ring Type Joint configurations per ASME B16.5.
Applications
Threaded (screwed) flanges eliminate field welding, making them indispensable in explosive atmospheres and areas where hot work permits are impractical. They are standard on instrument air lines, hydraulic control manifolds, fire water branch connections, and galvanized piping networks in refineries, chemical plants, and offshore platforms where Class 150 through Class 2500 ratings apply.
Typical use cases include small-bore chemical injection lines, gas regulator station piping, electrical conduit grounding flanges, and boiler blowdown connections. The NPT bore threads engage directly with threaded pipe, providing a mechanical seal that, when combined with thread sealant, handles pressures up to 102 bar at ambient (Class 600) and temperatures from -29°C to 425°C with A105.
They are also preferred in remote field installations, rooftop HVAC connections, and food-grade CIP systems where welding would introduce heat-affected zones that compromise corrosion resistance. Stainless F304/F316 threaded flanges serve corrosive media in pharmaceutical and brewing process piping.
Quality Assurance & Certification
Threaded flanges are manufactured to ASME B16.5 dimensional tolerances with NPT threads gauged using ring and plug gauges per ASME B1.20.1. Each unit ships with an EN 10204 3.1 material certificate covering chemistry, mechanical properties, and thread inspection records. Heat number marking ensures traceability from raw forging to finished product.
Surface crack detection via magnetic particle (carbon steel) or liquid penetrant (stainless) is available on request. Hydrostatic proof testing can be performed at 1.5 times the pressure rating per ASME B16.5 Section 8. Third-party witness by SGS, BV, or TUV is arranged for export orders requiring independent verification.
Each flange is protected with thread plugs to prevent bore damage during transit, coated with rust inhibitor for carbon steel, and packed in export-strength wooden crates. Packages are labeled with size, class, thread specification, material grade, and heat number for straightforward customs clearance.
ASME Standard Data
Dimensional, pressure–temperature and material data transcribed from the ASME B16.5-2025 standard (NPS 1/2–24, Metric/Inch). Ratings shown for carbon steel Group 1.1 (ASTM A105) and stainless Groups 2.1–2.3 (A182 F304/F316 family).
1. Pressure–Temperature Ratings — Group 1.1 Materials (A105) — SI Units (bar)
Source: ASME B16.5-2025, Table 2-1.1 (SI Units). Notes: (1) Prolonged use above 427°C permissible but not recommended; (2) only killed steel above 455°C; (3) not over 260°C; (4) not over 371°C; (5) not over 343°C; (6) see para. 2.5.3 for minimum temperatures.
2. Pressure–Temperature Ratings — Group 1.1 Materials (A105) — U.S. Customary Units (psig)
Source: ASME B16.5-2025, Table 2-1.1C (U.S. Customary Units). SI and US tables are independently rounded per ASME practice.
3. Material Group Correspondence (ASME B16.5, Table 1.1-1)
Source: ASME B16.5-2025, Table 1.1-1 (Material Groups). “…” denotes not applicable in the standard.
4. Minimum Use Temperatures (ASME B16.5, Appendix G, Table G-1)
Source: ASME B16.5-2025, Nonmandatory Appendix G, Table G-1 (Example Minimum Use Temperatures). Impact testing requirements per applicable code.
5. Threaded (Screwed) Flange Dimensions — Class 150, SI Units (mm, ASME B16.5 Table 9)
Source: ASME B16.5-2025, Table 9 (Class 150, SI). Class 300/400/600/900/1500/2500 dimensions also per Table 9. Full column set (incl. hub X and A_h) per standard.
Flange Dimensions — ASME B16.5-2025 Table 9 (SI Units, mm)
Complete flange dimensional data extracted from ASME B16.5-2025 (Pipe Flanges and Flanged Fittings), Table 9, for all pressure classes 150–2500. All values in millimeters (SI). Data verified against the ASME B16.5-2025 source corpus; the standard’s footnote numbering is preserved exactly.
Class 150 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 21 rows. Values in millimeters (SI).
Class 300 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 21 rows. Values in millimeters (SI).
Class 400 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 21 rows. Values in millimeters (SI). Rows marked * use the dimensions of Class 600 per Note (5).
Class 600 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 21 rows. Values in millimeters (SI).
Class 900 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 19 rows. Values in millimeters (SI). Rows marked * use the dimensions of Class 1500 per Note (5).
Class 1500 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 19 rows. Values in millimeters (SI).
Class 2500 Flanges — ASME B16.5-2025 Table 9 (SI Units, mm)
Flange dimensions, NPS 1/2–24, 20 rows. Values in millimeters (SI). NPS 14–24 are not included in the extracted corpus — see ASME B16.5-2025 Table 22.
Notes — ASME B16.5-2025 Table 9
- Note (5) — Class 400: Use Class 600 dimensions in this size. Values in rows marked * are taken from Class 600.
- Note (5) — Class 900: Use Class 1500 dimensions in this size. Values in rows marked * are taken from Class 1500.
- Note (6) — Class 900 / Note (8) — Class 300 / Note (9) — Class 150 (B column, NPS 14 and larger): To be specified by the purchaser.
- Note (5) — Class 600, 1500, 2500 (B column): To be specified by the purchaser.
- Classes 900, 1500 and 2500 do not list NPS 3 1/2 and NPS 22 in ASME B16.5-2025 Table 9.
- Class 2500 Table 9 covers NPS 1/2–12 in this dataset; NPS 14–24 refer to ASME B16.5-2025 Table 22.
- “—” = value not fully rendered in the extraction corpus (PDF text-layer conversion); refer to the standard original. Where a footnote text was truncated during extraction, the standard’s note numbering is preserved as-is.
- Blind (blank) flanges: hub and bore columns (X, Ah, Y, T, B2/B1/B, r, Q, D) do not apply; the O and tf columns remain valid.
- Socket-welding flanges cover NPS 1/2–4 per ASME B16.5-2025; rows above NPS 4 apply to the other flange types (WN / Threaded / SO / Lapped / Blind).
Stainless Steel (Group 2.1) Pressure–Temperature Ratings — ASME B16.5-2025
Pressure–Temperature Ratings, Group 2.1 Materials (18Cr-8Ni / 18Cr-8Ni-Mo) — ASME B16.5-2025 Table 2-2.1 (SI Units, bar)
Material designations in Group 2.1 — austenitic stainless steels (F304, F304H, F316 and related forgings, castings and plates). Working pressures in bar by class; values for temperatures in °C.
Notes — ASME B16.5-2025 Table 2-2.1 (Group 2.1)
- Group 2.1 covers 18Cr-8Ni (e.g. A182 F304, A351 CF3/CF8, A240 304) and 18Cr-8Ni-Mo (e.g. A182 F316, A351 CF3M/CF8M, A240 316) austenitic stainless steels.
- Working pressures shown in bar (SI units). Class 150 rating at room temperature is 19.1 bar, Class 2500 is 414.3 bar, per Table 2-2.1.
- The Group 1.1 (carbon steel A105 / WCB) ratings are provided in the earlier section of this page.
- “—” = value not fully rendered in the extraction corpus; refer to the standard original.
- Data extracted and verified against the ASME B16.5-2025 source corpus; footnote numbering preserved as-is.
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Frequently Asked Questions
Classes 150, 300, 600, 900, 1500, and 2500 per ASME B16.5 §2 Pressure-Temperature Tables. Ratings vary by material group and temperature.
Carbon steel ASTM A105, stainless A182 F304/F316/F321, and low-temperature A350 LF2. Alloy steels (A182 F5/F9/F11) available on request.
Yes — EN 10204 3.1 MTC, full material traceability, and third-party inspection (BV / SGS / TUV) upon request.