Stainless Steel (SS) Pipes are essential in industries requiring corrosion resistance, hygiene, and durability—such as chemical processing, food and beverage, pharmaceuticals, and oil and gas. Selecting the correct pipe size, schedule, and weight is critical for system performance, safety, and cost control.
Shengtian Group provides a complete reference for stainless steel pipe dimensions, covering seamless and welded pipe types, in both metric (mm) and imperial (inch) units. All dimensional data follows ASME/ANSI B36.19, the standard for stainless steel pipe dimensions.
To select the right stainless steel pipe:
1. Determine Size: Choose the required Nominal Pipe Size (NPS) or DN based on your flow and system design.
2. Select Schedule: Based on your design pressure, select the wall thickness (Schedule). Always specify the "S" series (e.g., Sch 40S) for stainless steel.
3. Verify Standards: Confirm the material meets ASTM A312 requirements and that the tolerances are acceptable for your application.
Stainless Steel Pipe Dimensions – Metric (mm) with Weight (Kg/m)
This table provides the Nominal Bore (mm/inch), Outside Diameter (OD), wall thickness, and weight per meter for common schedules (Sch 5S to XXS) as per ANSI B36.19.
| Nominal Bore (NB) | Outside Diameter (mm) |
Sch-5S | Sch-10S | Sch-40S | Sch-80S | Sch-160S | Sch-XXS | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| mm | inch | WT (mm) | Weight (Kg/m) |
WT (mm) |
Weight (Kg/m) |
WT (mm) |
Weight (Kg/m) |
WT (mm) |
Weight (Kg/m) |
WT (mm) |
Weight (Kg/m) |
WT (mm) |
Weight (Kg/m) |
|
| 3 | 1/8 | 10.3 | 1.24 | 0.276 | 1.24 | 0.28 | 1.73 | 0.37 | 2.41 | 0.47 | - | - | - | - |
| 6 | 1/4 | 13.7 | 1.24 | 0.390 | 1.65 | 0.49 | 2.24 | 0.631 | 3.02 | 0.80 | - | - | - | - |
| 10 | 3/8 | 17.1 | 1.24 | 0.490 | 1.65 | 0.63 | 2.31 | 0.845 | 3.20 | 1.10 | - | - | - | - |
| 15 | 1/2 | 21.3 | 1.65 | 0.800 | 2.11 | 1.00 | 2.77 | 1.27 | 3.75 | 1.62 | 4.75 | 1.94 | 7.47 | 2.55 |
| 20 | 3/4 | 26.7 | 1.65 | 1.03 | 2.11 | 1.28 | 2.87 | 1.68 | 3.91 | 2.20 | 5.54 | 2.89 | 7.82 | 3.63 |
| 25 | 1 | 33.4 | 1.65 | 1.30 | 2.77 | 2.09 | 3.38 | 2.50 | 4.55 | 3.24 | 6.35 | 4.24 | 9.09 | 5.45 |
| 32 | 1 1/4 | 42.2 | 1.65 | 1.65 | 2.77 | 2.70 | 3.56 | 3.38 | 4.85 | 4.47 | 6.35 | 5.61 | 9.70 | 7.77 |
| 40 | 1 1/2 | 48.3 | 1.65 | 1.91 | 2.77 | 3.11 | 3.68 | 4.05 | 5.08 | 5.41 | 7.14 | 7.25 | 10.16 | 9.54 |
| 50 | 2 | 60.3 | 1.65 | 2.40 | 2.77 | 3.93 | 3.91 | 5.44 | 5.54 | 7.48 | 8.74 | 11.1 | 11.07 | 13.44 |
| 65 | 2 1/2 | 73.0 | 2.11 | 3.69 | 3.05 | 5.26 | 5.16 | 8.63 | 7.01 | 11.4 | 9.53 | 14.9 | 14.2 | 20.39 |
| 80 | 3 | 88.9 | 2.11 | 4.51 | 3.05 | 6.45 | 5.49 | 11.30 | 7.62 | 15.2 | 11.1 | 21.3 | 15.24 | 27.65 |
| 100 | 4 | 114.3 | 2.11 | 5.84 | 3.05 | 8.36 | 6.02 | 16.07 | 8.56 | 22.3 | 13.49 | 33.54 | 17.12 | 41.03 |
| 125 | 5 | 141.3 | 2.77 | 9.47 | 3.40 | 11.57 | 6.55 | 21.8 | 9.53 | 31.97 | 15.88 | 49.11 | 19.05 | 57.43 |
| 150 | 6 | 168.3 | 2.77 | 11.32 | 3.40 | 13.84 | 7.11 | 28.3 | 10.97 | 42.7 | 18.2 | 67.56 | 21.95 | 79.22 |
| 200 | 8 | 219.1 | 2.77 | 14.79 | 3.76 | 19.96 | 8.18 | 42.6 | 12.7 | 64.6 | 23.0 | 111.2 | 22.23 | 107.8 |
| 250 | 10 | 273.1 | 3.40 | 22.63 | 4.19 | 27.78 | 9.27 | 60.5 | 12.7 | 96.0 | 28.6 | 172.4 | 25.40 | 155.15 |
| 300 | 12 | 323.9 | 3.96 | 31.25 | 4.57 | 36.00 | 9.52 | 73.88 | 12.7 | 132.0 | 33.32 | 238.76 | 25.40 | 186.97 |
| 350 | 14 | 355.6 | 3.96 | 34.36 | 4.78 | 41.3 | 11.13 | 94.59 | 19.05 | 158.08 | 35.71 | 281.70 | - | - |
| 400 | 16 | 406.4 | 4.19 | 41.56 | 4.78 | 47.29 | 12.7 | 123.30 | 21.41 | 203.33 | 40.46 | 365.11 | - | - |
| 450 | 18 | 457.2 | 4.19 | 46.80 | 4.78 | 53.42 | 14.27 | 155.80 | 23.8 | 254.36 | 45.71 | 466.40 | - | - |
| 500 | 20 | 508.0 | 4.78 | 59.25 | 5.54 | 68.71 | 15.09 | 183.42 | 26.19 | 311.2 | 49.99 | 564.68 | - | - |
| 600 | 24 | 609.6 | 5.54 | 82.47 | 6.35 | 94.45 | 17.48 | 255.41 | 30.96 | 442.08 |
||||
ASME B36.10 vs ASME B36.19 – Core Difference
It is essential to understand that ASME B36.10 covers carbon and alloy steel pipe, while ASME B36.19 covers stainless steel pipe.
For smaller NPS (up to about NPS 8), Sch 40S equals Sch 40 (carbon steel) in wall thickness. However, for NPS 10 and above, Sch 40S is thinner than carbon steel Sch 40.
| NPS | Sch 40S Stainless Steel (mm) | Sch 40 Carbon Steel (mm) | Difference |
| 10 | 9.27 | 12.70 | –27% |
| 12 | 9.53 | 12.70 | –25% |
| 14 | 9.53 | 12.70 | –25% |
This is why you must specify the correct standard when ordering stainless steel pipe.
Common Stainless Steel Pipe Materials (Grades per ASTM A312)
ASTM A312/A312M is the primary material specification for austenitic stainless steel pipe (Grades 304, 304L, 316, 316L, 321, 347, etc.) for high-temperature and corrosive service. It references ASME B36.19 for dimensions and also specifies tolerances.
| Grade | Type | Key Characteristics |
|---|---|---|
| TP304 / 304L | Austenitic | Most common; general corrosive service |
| TP304H | High-Temp | Modified TP304 for creep resistance |
| TP316 / 316L | Austenitic | Molybdenum added; better chloride resistance |
| TP316H | High-Temp | Modified TP316 for creep resistance |
| TP321 / 321H | Stabilized | Titanium-stabilized; good for welding |
| TP347 / 347H | Stabilized | Niobium-stabilized; high-temperature strength |
| TP309H / TP310H | High-Temp | Higher chromium/nickel; extreme heat resistance |
Dimension Tolerances per ASTM A312
ASTM A312 covers seamless, welded, and heavily cold worked austenitic stainless steel pipe. The “H” grades (e.g., TP304H, TP316H, TP321H, TP347H) are modified for high-temperature service where creep and stress rupture properties are important.
| Dimension | Tolerance | Notes |
|---|---|---|
| Outside Diameter (OD) | Varies by size; typically ±0.031″ for 1-1/2″ to 4″ NPS | Tighter tolerances apply for smaller sizes under ASTM A269/A213 |
| Wall Thickness | Seamless: -12.5% under nominal wall thickness | Per ASME SA999 |
| Length | Random lengths normally ordered | Specific tolerances apply per ASTM A530 |
| Out-of-Roundness | Not to exceed specified limits | Varies by NPS |
ASTM Specification & Tolerances for Tubing & Piping
This table summarizes allowable outside diameter and wall thickness variations, length tolerances, and required tests for key ASTM standards (A213, A249, A269, A270, A312, A358).
| Specification | Nominal Diameter (mm) |
Allowable OD Variation (mm) | Allowable Wall Thickness Variation |
Exact Length Tolerance (mm) | Testing Requirements |
|||
|---|---|---|---|---|---|---|---|---|
| Over | Under | %Over | %Under | Over | Under | |||
| ASTM-A213 (Seamless Boiler, Superheater, Heat Exchanger Tubes) |
Under 25.4 | 0.1016 | 0.1016 | +20 | 0 | 3.175 | 0 | Tension, Flare, Hardness, 100% Hydrostatic |
| 25.4-38.1 incl | 0.1524 | 0.1524 | +22 | 0 | 3.175 | 0 | ||
| 38.1-50.8 excl | 0.2032 | 0.2032 | +22 | 0 | 3.176 | 0 | ||
| 50.8-63.5 excl | 0.254 | 0.254 | +22 | 0 | 4.46 | 0 | ||
| 76.2-101.6 incl | 0.381 | 0.381 | +22 | 0 | 4.76 | 0 | ||
| ASTM-A249 (Welded Boiler, Superheater, Heat Exchanger, Condenser Tubes) |
Under 25.4 | 0.1016 | 0.1016 | +10 | -10 | 3.175 | 0 | Tension, Flattening, Flange, Reverse Bend, Hardness, 100% Hydrostatic |
| 25.4-38.1 incl | 0.1524 | 0.1524 | +10 | -10 | 3.175 | 0 | ||
| 38.1-50.8 Excl | 0.2032 | 0.2032 | +10 | -10 | 3.175 | 0 | ||
| 50.0-63.5 excl | 0.254 | 0.254 | +10 | -10 | 4.762 | 0 | ||
| 76.2-101.6 incl | 0.381 | 0.381 | +10 | -10 | 4.762 | 0 | ||
| ASTM-A269 (Seamless & Welded Tubing for General Service) |
Untp 12.7 | 0.13 | 0.13 | +15 | -15 | 3.2 | 0 | Flare (Seamless), Flange (Welded), Hardness, Reverse Flattening (Welded), 100% Hydrostatic |
| 12.7-38.1 excl | 0.13 | 0.13 | +10 | -10 | 3.2 | 0 | ||
| 38.1-88.9 excl | 0.25 | 0.25 | +10 | -10 | 4.8 | 0 | ||
| 88.9-139.7 excl | 0.38 | 0.38 | +10 | -10 | 4.8 | 0 | ||
| 139.7-203.2 excl | 0.76 | 0.76 | +10 | -10 | 4.8 | 0 | ||
| ASTM-A270 (Seamless & Welded Sanitary Tubing) |
25.4 | 0.05 | 0.20 | +10.0 | -10.0 | 3.2 | 0 | Reverse Flattening, 100% Hydrostatic, External Polish |
| 50.8 | 0.05 | 0.28 | +10.0 | -10.0 | 3.2 | 0 | ||
| 76.2 | 0.08 | 0.30 | +10.0 | -10.0 | 3.2 | 0 | ||
| 101.6 | 0.08 | 0.38 | +10.0 | -10.0 | 4.8 | 0 | ||
| ASTM-A312 (Seamless & Welded Pipe) |
3.175-38.1 incl | 0.4 | 0.79 | Minimum Wall: 12.5% under | 6.4 | 0 | Tension, Flattening, 100% Hydrostatic | |
| 38.1-101.6 incl | 0.79 | 0.79 | 12.5% under nominal | 6.4 | 0 | |||
| 101.6-203.2 incl | 1.59 | 0.79 | 12.5% under nominal | 6.4 | 0 | |||
| ASTM A-358 (Welded pipe) |
219.08-750mm | +0.5% | -0.3% | - | 6.0 | 0 | Refer to ASTM A-530 | |
Weight & Thickness of Stainless Steel Gauge Pipes
This table provides the weight per meter for common imperial OD sizes based on standard gauge (SWG) wall thicknesses.
| Size (inch) | OD (mm) | Weight per Meter (Kg/m) by Gauge (SWG) | |||||
|---|---|---|---|---|---|---|---|
| 10 SWG (3.2 mm) | 12 SWG (2.6 mm) | 14 SWG (2.1 mm) | 16 SWG (1.65 mm) | 18 SWG (1.2 mm) | 19 SWG (1.0 mm) | ||
| 1/2" | 12.7 | 0.754 | 0.651 | 0.552 | 0.452 | 0.342 | 0.290 |
| 5/8" | 15.875 | 1.006 | 0.856 | 0.718 | 0.582 | 0.437 | 0.369 |
| 3/4" | 19.05 | 1.258 | 1.061 | 0.883 | 0.712 | 0.531 | 0.448 |
| 1" | 25.4 | 1.762 | 1.470 | 1.214 | 0.972 | 0.720 | 0.605 |
| 1 1/4" | 31.75 | 2.266 | 1.880 | 1.544 | 1.232 | 0.909 | 0.763 |
| 1 1/2" | 38.1 | 2.770 | 2.289 | 1.875 | 1.492 | 1.098 | 0.920 |
| 2" | 50.8 | 3.778 | 3.108 | 2.537 | 2.012 | 1.476 | 1.235 |
| 2 1/2" | 63.5 | 4.786 | 3.928 | 3.198 | 2.531 | 1.854 | 1.550 |
| 3" | 76.2 | 5.794 | 4.747 | 3.860 | 3.051 | 2.232 | 1.865 |
| 3 1/2" | 88.9 | 6.802 | 5.566 | 4.521 | 3.571 | 2.610 | 2.180 |
| 4" | 101.6 | 7.810 | 6.385 | 5.183 | 4.091 | 2.988 | 2.495 |
For special specifications, complex applications, or if you need a quote for custom sizes, please contact our technical support team Email : pipe@stpipefitting.cn
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