310S stainless steel pipe is a heat resistant pipe used in furnaces, kilns and hot gas lines. It is made to ASTM A312 TP310S and carries 0.08% carbon at most, which is why it is preferred for lines that are fabricated and welded on site. 310H pipe is the same material with carbon between 0.04 and 0.10%, and it is chosen when the line has to hold its strength at high temperature for years. At Metinox Overseas, we supply both grades as seamless pipe and as welded pipe, including ERW and EFW.
Table of content
- Stainless Steel 310H/310S Pipes Specification
- Types of 310S Stainless Steel Pipes: Seamless, Welded and EFW
- Chemical Composition of 310S/310H SS Pipes
- Mechanical Properties of Stainless steel 310S/310H Pipes
- Physical Properties of 310 Stainless Steel Pipe
- Equivalent Grades of 310S/310H SS Pipe
- Stainless Steel 310S & 310H Pipe Sizes: OD and Wall Thickness Chart
- SS 310S & 310H Pipe Weight Chart
- Applications of 310S/310H Stainless Steel Pipe
- Frequently Asked Questions
Stainless Steel 310H/310S Pipes Specification
| Specification | Details |
| Standard | ASTM A312 / ASME SA312, Grade TP310S and TP310H |
| UNS | S31008 (310S), S31009 (310H) |
| European Standard | EN 10216-5 (seamless), EN 10217-7 (welded), 1.4845 for 310S. 310H has a near match only |
| Type | Seamless, Welded, ERW, EFW |
| Seamless Pipe Size | 4 - 219 mm, wall thickness 0.5 - 20 mm |
| Welded (ERW) Pipe Size | 5.0 - 1219.2 mm |
| EFW Pipe Size | 5.0 - 1219.2 mm |
| Outside Diameter | ASME B36.19M and B36.10M sizes. |
| Schedules | Sch 5S, 10S, 40S, 80S, 160, XS, XXS |
| Length | Single random, double random or cut to length; 5.8 m and 11.8 m for 20 ft and 40 ft containers |
| End | Plain end, bevelled to ASME B16.25, threaded on small bore |
| Finish | Solution annealed and pickled, free of scale |
| Wall Tolerance | No more than 12.5% under nominal at any point |
| OD Tolerance | Per ASTM A999 for the size band |
| Marking | TP310S or TP310H, size, schedule, heat number and ASTM A312 on every length |
| Certificate | EN 10204 3.1 |
Square and rectangular 310 sections are ASTM A554 mechanical tubing, not pressure pipe. Tube for furnace coils and heat exchangers is a separate product: see 310S tubes and 310H tubes.
Types of 310S Stainless Steel Pipes: Seamless, Welded and EFW
We supply 310S and 310H pipe in three forms: seamless, welded (ERW) and EFW. The form decides how the pipe is made and how large it can go.
SS 310S & 310H Seamless Pipe
Seamless pipe has no seam along its length. It is made to ASTM A312 and is used on pressure lines and heavy wall jobs in furnaces and kilns. Schedules run from 5S to XXS.
SS 310S & 310H Welded Pipe
Welded pipe is rolled from strip and closed with an electric resistance weld (ERW), then annealed and pickled. It is used for hot air, flue gas and ducting lines in small and medium bores.
SS 310S & 310H EFW Pipe
EFW pipe is rolled from plate and fusion welded, and it follows ASTM A358. It is the form for large diameter lines, such as furnace and kiln gas ducts, where ERW sizes stop.
SS 310S & 310H Seamless, Welded and EFW Pipe Comparison
| Pipe Form | Seamless | Welded | EFW |
| Standard | ASTM A312 | ASTM A312 | ASTM A358 |
| Best for | Pressure and creep duty | Small to medium bore, hot gas | Large diameter lines |
| Size (OD) | 4 to 219 mm | 5.0 to 1219.2 mm | 5.0 to 1219.2 mm |
| Wall thickness | 0.5 to 20 mm | Sch 5S to XXS | Sch 5S to XXS |
Which one to order? If the line is pressure rated or runs for years at peak temperature, go seamless. For hot air and flue gas on smaller bores, ERW is usually enough. Once the bore is too big for ERW, EFW is the answer.
Chemical Composition of 310S/310H SS Pipes
| Element | SS 310S | SS 310H |
| Carbon (C) | 0.08 max | 0.04 to 0.10 |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Silicon (Si) | 1.00 max | 0.75 max |
| Phosphorus (P) | 0.045 max | 0.045 max |
| Sulphur (S) | 0.030 max | 0.030 max |
| Chromium (Cr) | 24.0 to 26.0 | 24.0 to 26.0 |
| Nickel (Ni) | 19.0 to 22.0 | 19.0 to 22.0 |
| Molybdenum (Mo) | 0.75 max | - |
| Iron (Fe) | Balance | Balance |
Mechanical Properties of Stainless steel 310S/310H Pipes
| Property | SS 310S | SS 310H |
| Tensile strength, min | 515 MPa (75 ksi) | 515 MPa (75 ksi) |
| Yield strength (0.2% offset), min | 205 MPa (30 ksi) | 205 MPa (30 ksi) |
| Elongation in 50 mm, min | 35% longitudinal, 25% transverse | 35% longitudinal, 25% transverse |
| Grain size | Not required | ASTM No. 7 or coarser |
| Hardness | No limit for pipe; 217 HB / 95 HRB max is the ASTM A240 plate limit, for reference only | Same |
| Heat treatment | Solution annealed at 1040 °C (1900 °F) min, then quenched or rapidly cooled | Same |
For 310S: the same room temperature minimums as 310H, but lower allowable stress at temperature.
For 310H: the gain shows only in the code stress tables above about 540 °C.
Physical Properties of 310 Stainless Steel Pipe
| Property | Value |
| Density | 7.90 g/cm³ (0.285 lb/in³) |
| Melting range | 1400 to 1450 °C (2550 to 2640 °F) |
| Elastic modulus | 200 GPa (29.0 x 10⁶ psi) |
| Mean thermal expansion, 0 to 100 °C | 15.9 µm/m·°C |
| Mean thermal expansion, 0 to 538 °C | 17.0 µm/m·°C |
| Thermal conductivity at 100 °C | 14.2 W/m·K |
| Thermal conductivity at 500 °C | 18.7 W/m·K |
| Specific heat, 0 to 100 °C | 500 J/kg·K |
| Electrical resistivity | 0.78 µΩ·m, so a poor electrical conductor |
For 310S: it expands a little less than 304 and conducts heat poorly, so weld zones stay hot longer during welding.
For 310H: the same figures; plan supports for the full growth at operating temperature.
Equivalent Grades of 310S/310H SS Pipe
| Standard | 310S | 310H |
| ASTM / ASME | TP310S / SA312 TP310S | TP310H / SA312 TP310H |
| UNS | S31008 | S31009 |
| EN / Werkstoff No. | 1.4845 (X8CrNi25-21) | 1.4845 is the nearest match |
| JIS | SUS310S | SUS310S is the nearest; no H designation |
| BS | 310S16 | n/a |
| Swedish SS | 2361 | n/a |
| GOST | 20Kh23N18 | n/a |
For 310S: 1.4845 is the close European equivalent.
For 310H: order to ASTM A312 TP310H; there is no exact equivalent.
Stainless Steel 310S & 310H Pipe Sizes: OD and Wall Thickness Chart
| NPS | DN | OD, mm (in) | Sch 5S | Sch 10S | Sch 40S | Sch 80S | Sch 160 | XXS |
| 1/8 | 6 | 10.3 (0.406) | – | 1.24 | 1.73 | 2.41 | – | – |
| 1/4 | 8 | 13.7 (0.539) | – | 1.65 | 2.24 | 3.02 | – | – |
| 3/8 | 10 | 17.1 (0.673) | – | 1.65 | 2.31 | 3.20 | – | – |
| 1/2 | 15 | 21.3 (0.839) | 1.65 | 2.11 | 2.77 | 3.73 | 4.78 | 7.47 |
| 3/4 | 20 | 26.7 (1.051) | 1.65 | 2.11 | 2.87 | 3.91 | 5.56 | 7.82 |
| 1 | 25 | 33.4 (1.315) | 1.65 | 2.77 | 3.38 | 4.55 | 6.35 | 9.09 |
| 1 1/4 | 32 | 42.2 (1.661) | 1.65 | 2.77 | 3.56 | 4.85 | 6.35 | – |
| 1 1/2 | 40 | 48.3 (1.902) | 1.65 | 2.77 | 3.68 | 5.08 | 7.14 | 10.15 |
| 2 | 50 | 60.3 (2.374) | 1.65 | 2.77 | 3.91 | 5.54 | 8.74 | 11.07 |
| 2 1/2 | 65 | 73.0 (2.874) | 2.11 | 3.05 | 5.16 | 7.01 | 9.53 | – |
| 3 | 80 | 88.9 (3.500) | 2.11 | 3.05 | 5.49 | 7.62 | 11.13 | 15.24 |
| 4 | 100 | 114.3 (4.500) | 2.11 | 3.05 | 6.02 | 8.56 | 13.49 | 17.12 |
| 5 | 125 | 141.3 (5.563) | 2.77 | 3.40 | 6.55 | 9.53 | 15.88 | – |
| 6 | 150 | 168.3 (6.626) | 2.77 | 3.40 | 7.11 | 10.97 | 18.26 | 21.95 |
| 8 | 200 | 219.1 (8.626) | 2.77 | 3.76 | 8.18 | 12.70 | 23.01 | 22.23 |
| 10 | 250 | 273.0 (10.748) | 3.40 | 4.19 | 9.27 | 12.70 | 28.58 | 25.40 |
| 12 | 300 | 323.8 (12.748) | 3.96 | 4.57 | 9.53 | 12.70 | 33.32 | 25.40 |
Note: The same OD and schedule table applies to seamless, welded and EFW pipe. The form changes the supply range, not the dimensions.
SS 310S & 310H Pipe Weight Chart
| NPS | OD, mm | Sch 10S | Sch 40S | Sch 80S | Sch 160 | XXS |
| 1/8 | 10.3 | 0.28 (0.19) | 0.37 (0.25) | 0.47 (0.32) | – | – |
| 1/4 | 13.7 | 0.49 (0.33) | 0.64 (0.43) | 0.80 (0.54) | – | – |
| 3/8 | 17.1 | 0.63 (0.43) | 0.85 (0.57) | 1.10 (0.74) | – | – |
| 1/2 | 21.3 | 1.00 (0.68) | 1.27 (0.86) | 1.63 (1.09) | 1.96 (1.32) | 2.56 (1.72) |
| 3/4 | 26.7 | 1.29 (0.87) | 1.70 (1.14) | 2.21 (1.49) | 2.92 (1.96) | 3.66 (2.46) |
| 1 | 33.4 | 2.11 (1.42) | 2.52 (1.69) | 3.26 (2.19) | 4.26 (2.86) | 5.48 (3.69) |
| 1 1/4 | 42.2 | 2.71 (1.82) | 3.41 (2.29) | 4.50 (3.02) | – | – |
| 1 1/2 | 48.3 | 3.13 (2.10) | 4.08 (2.74) | 5.45 (3.66) | 7.29 (4.90) | 9.61 (6.46) |
| 2 | 60.3 | 3.96 (2.66) | 5.47 (3.68) | 7.53 (5.06) | 11.18 (7.52) | 13.53 (9.09) |
| 2 1/2 | 73.0 | 5.29 (3.56) | 8.69 (5.84) | 11.48 (7.72) | – | – |
| 3 | 88.9 | 6.50 (4.37) | 11.36 (7.64) | 15.37 (10.33) | 21.48 (14.44) | 27.86 (18.72) |
| 4 | 114.3 | 8.42 (5.66) | 16.18 (10.87) | 22.46 (15.10) | 33.75 (22.68) | 41.29 (27.75) |
| 5 | 141.3 | 11.64 (7.82) | 21.91 (14.72) | 31.17 (20.94) | – | – |
| 6 | 168.3 | 13.91 (9.35) | 28.44 (19.11) | 42.83 (28.78) | 68.00 (45.69) | 79.73 (53.58) |
| 8 | 219.1 | 20.10 (13.50) | 42.82 (28.78) | 65.06 (43.72) | 111.98 (75.25) | 108.62 (72.99) |
| 10 | 273.0 | 27.95 (18.78) | 60.68 (40.77) | 82.05 (55.13) | 173.37 (116.51) | 156.09 (104.89) |
| 12 | 323.8 | 36.21 (24.33) | 74.33 (49.95) | 98.06 (65.89) | 240.21 (161.42) | 188.11 (126.41) |
| 14 | 355.6 | 41.62 (27.97) | 81.85 (55.01) | 108.08 (72.63) | – | – |
| 16 | 406.4 | 47.65 (32.02) | 93.87 (63.08) | 124.09 (83.39) | – | – |
| 18 | 457.0 | 53.65 (36.05) | 105.84 (71.12) | 140.04 (94.11) | – | – |
| 20 | 508.0 | 69.09 (46.43) | 117.90 (79.23) | 156.12 (104.91) | – | – |
| 24 | 610.0 | 95.13 (63.93) | 142.02 (95.44) | 188.27 (126.52) | – | – |
Note: A dash means the size is not listed here. For NPS 8 and above, XXS can be thinner than Sch 160 under ASME B36.10M.
Need a price on this size range? Send your line list with grade, size, schedule and quantity through our quotation form and we will reply with a firm offer.
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Applications of 310S/310H Stainless Steel Pipe
| Industry | SS 310S | SS 310H |
| Heat treatment and furnaces | Furnace piping, radiant and muffle sections, retort and burner lines | Hot air lines and radiant sections under load |
| Kilns and minerals | Cement, lime and ceramic kiln parts in hot oxidising gas | Kiln and calciner components |
| Power generation and boilers | Hot gas, combustion air and soot blower lines | High temperature lines and hot flue gas handling |
| Petrochemical and chemical processing | Thermal oxidisers, incinerators and hot gas ducting | Hot process gas lines and catalyst regeneration air |
| Food processing | Ovens and roasting equipment running hot and dry | n/a |
Frequently Asked Questions
Both are 25Cr 20Ni austenitic grades. 310S limits carbon to 0.08% max for easier welding and fabrication, while 310H requires 0.04 to 0.10% carbon and a coarser grain size, which gives better creep strength in long term high temperature service.
Welded (ERW) pipe is formed from strip and closed with an electric resistance weld, so it is used in small and medium bores. EFW pipe is rolled from plate and made to ASTM A358, which is how larger diameters are produced.
Seamless is the usual choice for pressure lines and for long service at high temperature. Welded pipe is enough for lighter duty such as hot air and flue gas lines. For 310H, the grain size should be reported on the certificate whichever form you pick.
Seamless and welded 310H pipe is made to ASTM A312 / ASME SA312 grade TP310H, UNS S31009. Dimensions follow ASME B36.19M and B36.10M.
In air, 310S resists scaling up to about 1100 °C in continuous service and about 1035 °C where it heats and cools often. Pressure bearing lines must still be designed from the allowable stresses in the governing code.
Weight depends on size: for example, NPS 2 schedule 40S weighs about 5.47 kg/m and NPS 4 about 16.18 kg/m at 7.90 g/cm³. Calculate any size as (OD - wall) x wall x 0.02482 kg/m, with OD and wall in mm.
Schedule 10S suits low pressure hot air and flue gas lines. Schedule 40S is the safer starting point for pressure lines and for long service at very high temperature, because the extra wall leaves margin as the surface scales.
It should show the heat number, full chemistry with carbon between 0.04 and 0.10%, tensile and yield results, the hydrostatic or nondestructive test result, and the grain size. If grain size is missing, ask for it before accepting the pipe.
Yes. It is welded with matching 25Cr 20Ni filler, and its low carbon limits carbide formation beside the weld. Thick or highly restrained joints need a qualified procedure because fully austenitic weld metal can be prone to hot cracking.
Send the grade, standard, OD, wall, length, quantity, end finish, certification, inspection, destination port and required date. Add the operating temperature and your material specification if you have them.
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