Stainless Steel
pipe fittings & flanges
TeCarve stainless steel pipe fittings and flanges cover butt-weld elbows, tees and reducers to ASME B16.9, forged socket-weld and threaded fittings to ASME B16.11, cast threaded fittings, sanitary tri-clamp fittings, compression tube fittings, expansion joints, tube sheets and forged flanges to ASME B16.5. Sourced from qualified specialist makers, inspected and exported by TeCarve. They ship with TeCarve pipe and tube, so one order covers the line.
Wrought austenitic fittings are ordered to ASTM A403 by grade and class: WP-S seamless, or WP-W, WP-WX and WP-WU welded with radiographic or ultrasonic examination as ASTM A403 Table 1 sets out.
Stock sizes of butt-weld fittings ship from 5–10 pieces in about 7–10 days; forged 3000# fittings from 10–20 pieces in about 5–7 days; Class 150/300 flanges from 1–5 pieces in about 7–10 days. Non-standard and large-bore items take about 15–35 days.
The flange and fitting maker holds a material manufacturer certificate under the Pressure Equipment Directive 2014/68/EU, Annex I paragraph 4.3 (flanges DN 10–3500, fittings DN 10–1000, valid to September 2027), and an ISO 9001 quality system certificate. The sanitary fitting maker holds 3-A authorization to 3-A Sanitary Standard 63-04 for sanitary fittings in 304, 304L, 316 and 316L, valid through 31 December 2026.
Specifications
| Module | Standard and Scope |
|---|---|
| Butt-weld fittings | Elbows, tees, reducers, caps and stub ends to ASME B16.9 (NPS ½–48), EN 10253-4 Type A or B, DIN 2605. Seamless NPS ½–24; welded NPS 26 and up. SCH 5S to XXS, wall 1.0–60 mm |
| Forged socket-weld and threaded | ASME B16.11, NPS ⅛–4 (DN 6–100): threaded Class 2000, 3000 and 6000; socket-weld Class 3000, 6000 and 9000. ASTM A182 F304/304L, F316/316L, F321, F310S, F347, F51, F53, F55 |
| Branch outlets | MSS SP-97 integrally reinforced forged branch outlets, 90° and 45°, socket-weld, threaded and butt-weld ends |
| Cast threaded fittings | MSS SP-114 Class 150 and ISO 4144, CF8/CF8M to ASTM A351; NPT (ASME B1.20.1) or BSPT (ISO 7-1) threads |
| Sanitary fittings | Tri-clamp ferrules and clamps, DIN 11851 and SMS unions, DIN 11864-2 aseptic flanges, elbows, tees and reducers: OD ½–6 in (12.7–152.4 mm), DN 10–150, 304/304L/316/316L; ID polish Ra ≤ 0.8 or 0.4 µm, electropolish Ra ≤ 0.25 µm |
| Expansion joints | Metallic bellows expansion joints, flanged and tied, designed with EJMA calculations; calculation sheet on request |
| Flanges | Weld neck, slip-on, blind, lap joint and threaded. ASME B16.5 NPS ½–24, Class 150–2500 (Class 2500 to NPS 12); ASME B16.47 Series A/B NPS 26–60, Class 75–900; EN 1092-1 PN 6–PN 100. Sealing face Ra 3.2–6.3 µm (125–250 AARH) |
| Instrument tube fittings | Twin-ferrule compression fittings OD 3–25 mm and ⅛–1 in, in 316/316L, 2507, Alloy 400 and C-276; working pressure set by the tube wall, up to 10,000 psi (68 MPa) on heavy-wall tube |
| Tube sheets and baffles | Machined to drawing for shell-and-tube exchangers: OD 150–2500 mm, thickness 15–200 mm, F304L/F316L forgings or carbon steel + 316L explosion-clad plate; deep-hole CNC drilling |
| Testing and documents | 100% PMI; RT, UT or PT of welds by class; thread gauging on threaded fittings; EN 10204 3.1 certificate from the producing maker, 3.2 with SGS or TÜV witness on request |
Get Your Pipe Fittings & Flanges Quote
Send the fitting or flange type, size, schedule or class, material grade and quantity. Fittings and flanges are sourced from qualified specialist makers, inspected by TeCarve and shipped with your pipe and tube.
We confirm the dimensional standard, grade and class (for example WP316L-WX) before quoting.
Stock butt-weld fittings from 5–10 pieces and flanges from 1–5 pieces.
PMI, dimensions and marking checked before shipment.
Test reports from the producing maker ship with every order.
| Standard | What It Covers |
|---|---|
| ASME B16.9-2024 | Overall dimensions, tolerances, ratings, testing and marking for factory-made wrought butt-welding fittings, NPS ½–48. Fabricated laterals and fittings with circumferential or intersection welds are outside its scope (clause 1.3). |
| ASTM A403/A403M-26 | Wrought austenitic stainless piping fittings. WP grades follow ASME B16.9 and B16.11; CR grades follow MSS SP-43. It does not cover cast fittings (clause 1.6). |
| ASME B16.11-2021 | Forged socket-welding and threaded fittings. Threaded: Class 2000, 3000, 6000. Socket-weld: Class 3000, 6000, 9000 (clause 2.1). |
| ASME B16.5-2025 | Pipe flanges and flanged fittings, NPS ½–24. Limited to flanges from cast or forged material; blind and certain reducing flanges may also be made from plate (clause 1.1). |
| EN 10253-4:2025 | Seamless and welded butt-welding elbows, reducers, tees and caps in austenitic and duplex stainless steel. Type A has a reduced pressure factor; Type B is for full service pressure. |
| MSS SP-97-2025 | 90° and 45° integrally reinforced forged branch outlets with butt-weld, socket-weld and threaded ends. |
| ISO 4144:2003 | Stainless fittings threaded to ISO 7-1, for steam, air, gas, water and oil. Non-shock rating 20 bar from −20 to 40 °C, falling to 13.5 bar at 220 °C (Table 2). |
| EN 1092-1:2018 | Circular steel flanges PN 2.5 to PN 400, DN 10 to DN 4000, including lapped ends and collars. |
| DIN 11864-2:2024 | Aseptic flange connections with O-ring for tube to DIN 11866: 2.5 MPa for OD 12.7–41.0 mm, 1.6 MPa for OD 42.4–104.0 mm, 1.0 MPa for OD 114.3–154.0 mm, from −10 to 140 °C with suitable seals. |
| ASME B16.47-2025 | Large-diameter steel flanges NPS 26–60, Series A and B, Class 75, 150, 300, 400, 600 and 900; cast or forged, blind flanges also from plate (clause 1.1). |
| ASTM B366/B366M-25 | Factory-made wrought nickel and nickel alloy fittings to ASME B16.9, B16.11, MSS SP-43, SP-95 and SP-97; WP and CR grades such as WPNICMC, WPNCMC and WPHC276. |
| ASTM A351 | Austenitic castings for pressure-containing parts, the material route for cast stainless fittings |
Standards
Features
• Butt-weld, forged, cast, sanitary and flanged connections on one order with the pipe they join
• Each fitting tied to its dimensional standard and ASTM grade, marked as ASTM A403 Section 15 requires
• Welded fittings ordered by class: W, WX (full radiography) or WU (full ultrasonic)
• Fittings supplied free of scale and passivated (ASTM A403 clause 10.7)
• Matching welded and seamless stainless pipe from the same export channel
• Chemical and petrochemical process piping
• Food, dairy and pharmaceutical lines with tri-clamp and DIN 11851 sanitary connections
• Power and energy plant piping with forged high-pressure fittings
• Water treatment and utility lines with flanged joints and expansion joints
Applications
Quality Control
• Visual examination: surface discontinuities deeper than 5% of nominal wall removed; surface checks deeper than 0.5 mm and mechanical marks deeper than 1.5 mm removed (ASTM A403 clauses 10.3–10.5)
• Radiographic or ultrasonic examination of welds by fitting class (ASTM A403 Table 1)
• Positive material identification by handheld XRF before shipment
• Test reports with chemistry, tensile results, heat treatment and NDE results (ASTM A403 Section 14)
Stainless Steel Pipe Fittings and Flanges: Classes, Standards and Photos
ASTM A403 Fitting Classes for WP Grades
| Class | Construction | Nondestructive Examination |
|---|---|---|
| S | Seamless | None |
| W | Welded | Radiography or ultrasonic |
| WX | Welded | Radiography of all welds |
| WU | Welded | Ultrasonic of all welds |
ASTM A403/A403M-26 Table 1. CR grades have no classes and follow MSS SP-43 without nondestructive examination (clause 5.9). Duplex 2205 fittings are not an A403 grade and are ordered to ASTM A815.
Download the ASTM A403/A403M-26 specification matrix (PDF)
Butt-Weld Fittings: Elbows, Tees, Reducers and Caps
Elbows, tees, reducers, caps and stub ends to ASME B16.9 in ASTM A403 grades WP304/304L, WP316/316L, WP321, WP310S and WP347H; duplex to ASTM A815 (S31803, S32205, S32750); nickel alloy fittings to ASTM B366 grades WPNICMC (N08825), WPNCMC (N06625) and WPHC276 (N10276). Seamless fittings run NPS ½–24 (DN 15–600) and welded fittings NPS 26 and up; B16.9 covers up to NPS 48, so larger sizes are made to the order drawing. Lap joint stub ends may also be fabricated where they meet the ASTM material specification (ASME B16.9 clause 1.3).
For European projects, EN 10253-4:2025 covers seamless and welded elbows, reducers, tees and caps in austenitic and duplex stainless steel: Type A with a reduced pressure factor, Type B for full service pressure. DIN 2605-1 elbows and bends also have a reduced pressure factor.
Forged Socket-Weld, Threaded and Branch Fittings
ASME B16.11 elbows, tees, couplings and unions: threaded ends in Class 2000, 3000 and 6000; socket-weld ends in Class 3000, 6000 and 9000. Fittings combining both end types take the lower rating (clause 2.1.2). Branch outlets follow MSS SP-97-2025: 90° and 45° integrally reinforced fittings, conventionally STD × STD, XS × XS, SCH 160 × SCH 160, XXS × XXS, XS × 3000, SCH 160 × 6000 and XXS × 9000 (clause 1.1.1).
Forged fittings run NPS ⅛–4 (DN 6–100) in ASTM A182 F304/304L, F316/316L, F321, F310S and F347, duplex F51, F53 and F55, and Alloy 625 or Alloy 400. Each threaded fitting is checked with go/no-go gauges and each socket for depth and concentricity.
Threaded Fittings, Sanitary Tri-Clamp Fittings and Expansion Joints
Cast threaded elbows, tees, crosses, sockets, bushes, nipples, caps, plugs and unions to ISO 4144, threaded to ISO 7-1, rated 20 bar non-shock up to 40 °C. Aseptic flange connections to DIN 11864-2 are rated 2.5, 1.6 or 1.0 MPa by tube OD. Tri-clamp and DIN 11851 sanitary fittings and metallic bellows expansion joints complete the range.
Sanitary fittings run OD ½–6 in (12.7–152.4 mm) and DN 10–150 in 304, 304L, 316 and 316L, polished inside to Ra ≤ 0.8 µm or Ra ≤ 0.4 µm, or electropolished to Ra ≤ 0.25 µm, with a measured roughness report. Standard clamp joints are rated 10–16 bar; heavy-duty double-pin clamps reach 25 bar.
Class 150 cast threaded fittings are also supplied to MSS SP-114 in ASTM A351 CF8 (304) and CF8M (316), threaded NPT to ASME B1.20.1 or BSPT to ISO 7-1. Metallic bellows expansion joints are designed with EJMA stress and fatigue-life calculations, and an EJMA-based design calculation sheet can be supplied with project orders.
Stainless Steel Flanges: Weld Neck, Slip-On, Blind and Lap Joint
Weld neck, slip-on, blind and lap joint flanges to ASME B16.5, and PN flanges to EN 1092-1 (PN 2.5 to PN 400, DN 10 to DN 4000, lapped ends and collars included). Plate slip-on flanges are supplied as EN 1092-1 Type 01, which EN 1092-1 Table 1 permits to be made from plate; ASME B16.5 limits plate material to blind and certain reducing flanges, and EN 1092-1 does not allow plate for Type 11 weld neck flanges.
Large-diameter flanges NPS 26–60 are supplied to ASME B16.47 Series A or B, which covers Class 75 to 900; above Class 900 the flange is made to the order drawing. Every flange is checked for sealing-face finish (Ra 3.2–6.3 µm, 125–250 AARH), full dimensions and material by PMI.
Compression Tube Fittings, Tube Sheets and Baffles
Twin-ferrule compression tube fittings OD 3–25 mm and ⅛–1 in, in 316/316L, super duplex 2507, Alloy 400 and C-276, ship from 20–50 pieces with 100% gas leak testing. Their working pressure is set by the tube they join, typically 3,000–6,000 psi and up to 10,000 psi on heavy-wall tube.
Tube sheets and baffle plates for shell-and-tube heat exchangers are machined to the exchanger drawing: OD 150–2500 mm, thickness 15–200 mm, in F304L or F316L forgings or carbon steel with explosion-clad 316L. Lead time is about 25–35 days including CNC deep-hole drilling and ultrasonic checks of ligament thickness.
Product Photos
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& End Caps
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Seaworthy Wooden Cases & Pallets
Tailored Solutions, Timely Fulfillment
CUSTOMIZATION
& DELIVERY
One Order, One Line
Fittings, flanges and joints ship together with TeCarve pipe and tube.
Graded and Classed
Each fitting ordered by ASTM A403 grade and class, with the class stated on the marking.
Inspected Before Export
TeCarve checks dimensions, marking and material before each shipment.
Export Packing
Ends capped, fittings boxed or crated for container transit.
Frequently Asked Questions
Are the flanges and fittings covered for the EU Pressure Equipment Directive?
The flange and fitting maker holds a PED 2014/68/EU material manufacturer certificate under Annex I paragraph 4.3, covering flanges DN 10 to 3500 and fittings DN 10 to 1000, and ships EN 10204 3.1 certificates with the products.
Which standard covers stainless butt-weld fittings?
ASME B16.9 covers dimensions, tolerances, ratings, testing and marking for factory-made wrought butt-welding fittings from NPS 1/2 to NPS 48. The stainless material and class are ordered to ASTM A403, for example WP316L-S for a seamless fitting.
What do the A403 classes S, W, WX and WU mean?
S is seamless with no NDE required. W is welded with radiography or ultrasonic examination, WX is welded with all welds radiographed, and WU is welded with all welds ultrasonically examined (ASTM A403 Table 1).
Which pressure classes does ASME B16.11 cover?
Threaded fittings are Class 2000, 3000 and 6000. Socket-weld fittings are Class 3000, 6000 and 9000. A fitting with both end types takes the lower rating.
Can ASME B16.5 flanges be machined from plate?
Only blind flanges and certain reducing flanges. Other B16.5 flanges are limited to cast or forged material (clause 1.1).
Who makes the fittings and flanges?
They are sourced from qualified specialist makers, then inspected and exported by TeCarve, and they ship with the maker’s test report.