ASTM A335 P11 Lap Joint FlangeASTM A182 · ASME B16.5 · Manufacturer, stockist & exporter, India
SA-335 P11 · 1¼Cr-½Mo alloy pipe · LJ
An ASTM A335 P11 lap joint flange is a loose flange that sits behind a stub end welded to the pipe, for use with ASTM A335 P11 pipe. ASTM A335 P11 itself is a pipe or plate specification, so the matching lap joint flange is made to ASTM A182 F11 — which is what we supply for P11 lines. A lap joint flange rotates freely, making bolt alignment easy on lines that are dismantled often. In corrosive service the flange never touches the fluid, so it can be carbon steel while the stub end is the alloy — a big saving.
- ASTM A182
- ASME B16.5
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an ASTM A335 P11 Lap Joint Flange?
- What it is
- A loose flange that sits behind a stub end welded to the pipe
- Material
- ASTM A182 F11
- Dimensions
- ASME B16.5
- Grade
- ASTM A335 P11
- Best at
- Steam and hot-oil piping up to about 550 °C
ASTM A335 P11 Lap Joint Flange Specification
| Product | ASTM A335 P11 Lap Joint Flange |
|---|---|
| Material standard | ASTM A182 F11 |
| Dimensional standard | ASME B16.5 |
| Sizes | ½" – 24" (ASME B16.5) · 26" – 60" (ASME B16.47) |
| Pressure class | Class 150, 300, 400, 600, 900, 1500, 2500 · PN 6 – PN 100 |
| Facing | RF · FF · RTJ · tongue & groove |
| Bore | To match pipe schedule (state on order) |
| Testing | Chemical & mechanical per heat · NDT · impact where specified |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Lap Joint Flange
A lap joint flange rotates freely, making bolt alignment easy on lines that are dismantled often. In corrosive service the flange never touches the fluid, so it can be carbon steel while the stub end is the alloy — a big saving.
- Used with a stub end (MSS SP-43 or ASME B16.9)
- Flange can be a cheaper material than the stub end
- Lower pressure rating than a weld neck
ASTM A335 P11 Lap Joint Flange Chemical Composition
| Element | Weight % |
|---|---|
| Chromium | 1.00 – 1.50 |
| Molybdenum | 0.44 – 0.65 |
| Carbon | 0.05 – 0.15 |
| Manganese | 0.30 – 0.60 |
| Silicon | 0.50 – 1.00 |
| Phosphorus | 0.025 max |
| Sulphur | 0.025 max |
ASTM A335 P11 Lap Joint Flange Mechanical Properties
| Minimum values | Value |
|---|---|
| Tensile strength | 415 MPa · 60 ksi |
| Yield strength 0.2% | 205 MPa · 30 ksi |
| Elongation | 30% |
Full chemistry, properties and equivalents are on the ASTM A335 P11 grade page.
Other ASTM A335 P11 flanges
ASTM A335 P11 Lap Joint Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiASTM A335 P11 Lap Joint Flange dimensions — ASME B16.5 Class 150 & 300
Outside diameter, thickness and bolting are set by size and class. Values in mm; thickness excludes the 1.6 mm raised face.
| NPS | Cl 150 OD | Cl 150 thickness | Cl 150 bolt circle | Cl 150 bolts | Cl 300 OD | Cl 300 thickness | Cl 300 bolt circle | Cl 300 bolts |
|---|---|---|---|---|---|---|---|---|
| ½" | 90 | 9.6 | 60.3 | 4 × ½" | 95 | 12.7 | 66.7 | 4 × ½" |
| 1" | 110 | 12.7 | 79.4 | 4 × ½" | 125 | 15.9 | 88.9 | 4 × ⅝" |
| 1½" | 125 | 15.9 | 98.4 | 4 × ½" | 155 | 19.1 | 114.3 | 4 × ¾" |
| 2" | 150 | 17.5 | 120.7 | 4 × ⅝" | 165 | 20.7 | 127.0 | 8 × ⅝" |
| 3" | 190 | 22.3 | 152.4 | 4 × ⅝" | 210 | 27.0 | 168.3 | 8 × ¾" |
| 4" | 230 | 22.3 | 190.5 | 8 × ⅝" | 255 | 30.2 | 200.0 | 8 × ¾" |
| 6" | 280 | 23.9 | 241.3 | 8 × ¾" | 320 | 35.0 | 269.9 | 12 × ¾" |
| 8" | 345 | 27.0 | 298.5 | 8 × ¾" | 380 | 39.7 | 330.2 | 12 × ⅞" |
| 10" | 405 | 28.6 | 362.0 | 12 × ⅞" | 445 | 46.1 | 387.4 | 16 × 1" |
| 12" | 485 | 30.2 | 431.8 | 12 × ⅞" | 520 | 49.3 | 450.8 | 16 × 1⅛" |
Full chart: ASME B16.5 flange dimensions.
ASTM A335 P11 Lap Joint Flange — questions buyers ask
Does a lap joint flange have to be the same alloy as the pipe?
No. Only the stub end touches the fluid, so the backing flange is often carbon steel, saving the cost of an alloy forging.
Which standard covers ASTM A335 P11 lap joint flanges?
The material is ASTM A182 F11; dimensions follow ASME B16.5. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a ASTM A335 P11 lap joint flange?
The steel price, the size and pressure class, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026