Stainless Steel 310H Seamless Pipe and SS 310 / 310S / 310H Seamless Pipes

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Stainless steel 310H seamless pipe stencilled ASTM A312 TP310H SMLS with heat number, bundled with end caps

Stainless Steel 310H Seamless Pipe and SS 310 / 310S / 310H Seamless Pipes

The seamless pipes SS 310/310S/310H are heat resistant pipes containing approximately 25% of chromium and 20% of nickel, allowing them to withstand high temperatures of up to 1100 degrees Celsius without suffering from scaling. As these pipes come from a solid piece of material, they do not have weld seams that make them more vulnerable in terms of high heat and pressure. Maximum of 0.25% of carbon is allowed in 310 grade pipes, while grade 310S pipes can only contain 0.08% or less of carbon, making welds resistant to corrosion. Finally, stainless steel 310H pipes can include from 0.04 to 0.10% of carbon to ensure strength in high temperature environment.   Metinox Overseas supplies both from Mumbai.

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SS 310 / 310S / 310H Seamless Pipe - Grade Comparison

Point310 (S31000)310S (S31008)310H (S31009)
Carbon0.25% max0.08% max0.04 to 0.10%
Chromium / nickel24 to 26% / 19 to 22%24 to 26% / 19 to 22%24 to 26% / 19 to 22%
Grain size ruleNoneNoneASTM No. 7 or coarser
In ASTM A312 as pipeNoYes, TP310SYes, TP310H
Weld zone after hot cyclingCan lose corrosion resistanceStays corrosion resistantStrong; less suited to wet corrosive service
Strength under load when hotModerateLowest of the threeHighest of the three
Typical seamless useRarely ordered as pipeWelded hot air and flue gas lines, furnace partsPressure lines and heater parts designed on creep strength

SS 310S / 310H Seamless Pipe - ASTM A312 Standard Requirements

ASTM A312 covers seamless and welded austenitic pipe for high temperature and general corrosive service. It lists TP310S and TP310H. Plain TP310 is not a listed A312 grade; a request for TP310 seamless pipe will be filled as TP310S or TP310H. Confirm which one before ordering.

RequirementASTM A312 / ASME SA312, seamless
GradesTP310S (S31008), TP310H (S31009)
ManufactureSeamless, hot finished or cold finished
Heat treatmentSolution annealed at 1040 °C (1900 °F) min, then quenched or rapidly cooled 
Grain sizeTP310H: ASTM No. 7 or coarser, reported
Tension and flattening testsOn each lot
Hydrostatic or electric testEvery length
MarkingManufacturer, ASTM A312, grade, size, schedule, heat number and “SMLS”
General requirementsASTM A999

SS 310S / 310H Seamless Pipe Specifications

ItemRange
StandardASTM A312 / ASME SA312, TP310S, TP310H
European standardEN 10216-5 (seamless), 1.4845
Size rangeNPS 1/8 to 12 (10.3 to 323.8 mm OD) in stock sizes; larger hot finished sizes on request 
SchedulesSch 10S, 40S, 80S, 160, XS, XXS
DimensionsASME B36.19M; Sch 160 and XXS per ASME B36.10M
Finish routeHot finished or cold finished
LengthSingle random (about 5 to 7 m), double random (about 10 to 12 m) or cut to length
EndsPlain or bevelled to ASME B16.25
SurfaceAnnealed and pickled
CertificatesEN 10204 3.1; 3.2 through an independent inspector on request 

Welded 310S pipe is a separate product: see 310S welded pipes. For large diameter lines, see 310H EFW pipe.

Chemical Composition of 310 & 310H Seamless Pipe 

High chromium and nickel content gives 310 its scaling resistance -  carbon is the only element that differs meaningfully between the three grades.

Element, %310 (S31000)TP310S (S31008)TP310H (S31009)
Carbon (C)0.25 max0.08 max0.04 to 0.10
Manganese (Mn)2.00 max2.00 max2.00 max
Silicon (Si)1.50 max1.00 max0.75 max
Phosphorus (P)0.045 max0.045 max0.045 max
Sulphur (S)0.030 max0.030 max0.030 max
Chromium (Cr)24.0 to 26.024.0 to 26.024.0 to 26.0
Nickel (Ni)19.0 to 22.019.0 to 22.019.0 to 22.0
Molybdenum (Mo)n/a0.75 maxn/a
Iron (Fe)BalanceBalanceBalance

Silicon limit for 310H is lower than 310S - higher silicon can reduce creep strength at elevated temperatures.

Mechanical Properties of SS 310S / 310H Seamless Pipe 

At room temperature both grades meet identical minimums. The 310H advantage only shows up in ASME code stress tables above about 540 °C - which is where creep strength starts to matter.

PropertyTP310STP310H
Tensile strength, min515 MPa (75 ksi)515 MPa (75 ksi)
Yield strength (0.2% offset), min205 MPa (30 ksi)205 MPa (30 ksi)
Elongation in 50 mm, min35% longitudinal, 25% transverse35% longitudinal, 25% transverse
Grain sizeNot requiredASTM No. 7 or coarser
HardnessNo limit set for pipeNo limit set for pipe

Physical Properties of SS 310 / 310S / 310H Seamless Pipe

PropertyValue
Density7.90 g/cm³ (0.285 lb/in³)
Melting range1400 to 1450 °C (2550 to 2640 °F)
Elastic modulus200 GPa (29.0 x 10⁶ psi)
Mean thermal expansion, 0 to 100 °C15.9 µm/m·°C
Mean thermal expansion, 0 to 538 °C17.0 µm/m·°C
Thermal conductivity at 100 °C14.2 W/m·K
Thermal conductivity at 500 °C18.7 W/m·K
Specific heat, 0 to 100 °C500 J/kg·K
Electrical resistivity0.78 µΩ·m

Typical data for all three grades. A 10 m run heated from 20 to 900 °C grows by roughly 150 mm, so hot lines need loops, bellows or sliding supports.

Equivalent Grades for 310, 310S and Stainless Steel 310H Seamless Pipe

Standard310310S310H
UNSS31000S31008S31009
EN / Werkstoff No.No exact match 1.4845 (X8CrNi25-21)1.4845 is the nearest 
JISSUH310 SUS310SNo H designation
BS310S24 310S16 n/a
GOST20Kh25N20S2 20Kh23N18 n/a

EN 1.4841 is often listed as the 310 equivalent. It is X15CrNiSi25-21 with about 1.5 to 2.5% silicon, closer to grade 314, so treat it as a different alloy.

Ask for: where a drawing names a European or Japanese grade, order to that standard and check the carbon line on the certificate.

SS 310S / 310H Seamless Pipe Size and Weight Chart - ASME B36.19M

Each cell shows wall thickness in mm, then weight in kg/m at 7.90 g/cm³. ODs and S schedule walls per ASME B36.19M; Sch 160 and XXS per ASME B36.10M. Weight (kg/m) = (OD − wall) × wall × 0.02482. Sch 5S is a welded pipe wall and is rarely made seamless.

NPS (DN)OD, mmSch 10S wall / kg/mSch 40S wall / kg/mSch 80S wall / kg/mSch 160 wall / kg/mXXS wall / kg/m
1/8 (6)10.31.24 / 0.281.73 / 0.372.41 / 0.47n/an/a
1/4 (8)13.71.65 / 0.492.24 / 0.643.02 / 0.80n/an/a
3/8 (10)17.11.65 / 0.632.31 / 0.853.20 / 1.10n/an/a
1/2 (15)21.32.11 / 1.002.77 / 1.273.73 / 1.634.78 / 1.967.47 / 2.56
3/4 (20)26.72.11 / 1.292.87 / 1.703.91 / 2.215.56 / 2.927.82 / 3.66
1 (25)33.42.77 / 2.113.38 / 2.524.55 / 3.266.35 / 4.269.09 / 5.48
1 1/4 (32)42.22.77 / 2.713.56 / 3.414.85 / 4.506.35 / 5.659.70 / 7.82
1 1/2 (40)48.32.77 / 3.133.68 / 4.085.08 / 5.457.14 / 7.2910.15 / 9.61
2 (50)60.32.77 / 3.963.91 / 5.475.54 / 7.538.74 / 11.1811.07 / 13.53
2 1/2 (65)73.03.05 / 5.295.16 / 8.697.01 / 11.489.53 / 15.0114.02 / 20.52
3 (80)88.93.05 / 6.505.49 / 11.367.62 / 15.3711.13 / 21.4815.24 / 27.86
4 (100)114.33.05 / 8.426.02 / 16.188.56 / 22.4613.49 / 33.7517.12 / 41.29
5 (125)141.33.40 / 11.646.55 / 21.919.53 / 31.1715.88 / 49.4319.05 / 57.80
6 (150)168.33.40 / 13.917.11 / 28.4410.97 / 42.8318.26 / 68.0021.95 / 79.73
8 (200)219.13.76 / 20.108.18 / 42.8212.70 / 65.0623.01 / 111.9822.23 / 108.62
10 (250)273.04.19 / 27.959.27 / 60.6812.70 / 82.0528.58 / 173.3725.40 / 156.09
12 (300)323.84.57 / 36.219.53 / 74.3312.70 / 98.0633.32 / 240.2125.40 / 188.11

Example: 2 inch SS 310S seamless pipe, Sch 40S (60.3 × 3.91 mm) weighs 5.47 kg/m -  a standard 6 m length is approximately 33 kg. Seamless wall can run above nominal, so delivered weight is often a few percent higher. More sizes are in the SS pipe weight chart.

Request bundle weights on the packing list - this lets you verify freight costs and lifting requirements against this chart before the shipment arrives.

Have a 310 seamless size list ready? Send it with grade, schedule, length and quantity through our quotation form and we will reply with a firm offer.

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Applications of Stainless Steel 310H Seamless Pipes by Industry

IndustryTypical seamless linesUsual grade
Heat treatment and furnacesRadiant tubes, muffle and retort lines, burner parts310S
Petrochemical and refiningHeater parts, catalyst regeneration air, thermal oxidisers310H, 310S
Power and boilersHot gas, soot blower and combustion air lines310H
Cement and mineralsKiln and calciner parts in hot oxidising gas310S
Chemical processingIncinerator and hot gas lines310S
Food processingOvens and roasting equipment running hot and dry310S

SS 310 / 310S / 310H Seamless Pipes FAQs

Carbon. 310 allows up to 0.25%, 310S up to 0.08% and 310H requires 0.04 to 0.10% with a coarse grain size. Pipe to ASTM A312 is made as TP310S or TP310H.

ASTM A312 lists TP310S and TP310H rather than plain TP310, so an order for TP310 seamless pipe should name which of the two is wanted.

Choose 310H when the line carries pressure or load at high temperature and its design is governed by creep strength. Choose 310S for welded hot air and flue gas lines, or where condensate may form.

In air, 310S resists scaling up to about 1100 °C in continuous service and about 1035 °C where it heats and cools often. Pressure lines must still be designed from the allowable stress at the design temperature.

About 5.47 kg per metre for the nominal 60.3 x 3.91 mm size at 7.90 g/cm³.

For pressure, yes: seamless pipe takes a joint factor of 1.0 in ASME B31.3 against 0.85 for welded pipe without full radiography. For low pressure hot air ducting, welded pipe is often better value.

EN 1.4845 (X8CrNi25-21). EN 1.4841 is a high silicon grade and should not be treated as an equivalent.

Send the grade, SMLS, OD and wall or NPS and schedule, length, quantity, ends, operating temperature, certification, inspection and destination port.

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