High-Carbon Molybdenum Austenitic Stainless for Creep Service
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UNS NUMBER
S31609
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ALLOY FAMILY
Austenitic (Mo-bearing)
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STRUCTURE
100% Austenite
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UTS (MIN)
≥515 MPa
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MAX TEMP
~815°C
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DENSITY
8.00 g/cm³
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Stainless Steel 316H (UNS S31609) is the high-carbon version of 316, with carbon held at 0.04–0.10% to deliver certified creep and stress-rupture strength above ~525°C. It keeps 316's 2–3% molybdenum, so it carries both creep rating and chloride corrosion margin that plain 304H lacks. EN equivalent is 1.4919.
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Cr
16–18%
Oxidation resistance
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Ni
10–14%
Austenite stabilizer
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Mo
2–3%
Pitting / crevice + creep margin
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C
0.04–0.10%
Controlled high carbon for creep
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UTS
≥515 MPa
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YS 0.2%
≥205 MPa
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Elong.
≥30%
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Service
525–815°C
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What is Stainless Steel 316H?
316H takes the molybdenum-bearing 18/10 base and tightens carbon to a 0.04–0.10% band (with a minimum grain size), giving it ASME code-listed allowable stresses in the creep range up to roughly 815°C for pressure duty. Below that range, standard or L-grade 316 is the economical choice.
The molybdenum is what separates 316H from 304H: it keeps a chloride corrosion margin that plain high-carbon 304 cannot offer. The cost is the same sensitization risk as 316/304, so 316H is for high-temperature pressure systems, not general welded tanks. Where the welded joint must also avoid sensitization during shutdowns, the stabilized 321H and 347H are the engineered substitutes.
Chemical Composition (Weight %)
| Element |
Min (%) |
Max (%) |
Role in Alloy |
| Chromium (Cr) |
16.0 |
18.0 |
Oxidation resistance |
| Nickel (Ni) |
10.0 |
14.0 |
Austenite stabilizer |
| Molybdenum (Mo) |
2.0 |
3.0 |
Pitting + creep corrosion margin |
| Carbon (C) |
0.04 |
0.10 |
Defining range for creep strength |
| Manganese (Mn) |
— |
2.00 |
Deoxidizer |
| Silicon (Si) |
— |
0.75 |
Deoxidizer |
| Phosphorus (P) |
— |
0.045 |
Impurity |
| Sulfur (S) |
— |
0.030 |
Impurity |
| Nitrogen (N) |
— |
0.10 |
Minor |
| Iron (Fe) |
Balance |
— |
Matrix former |
★ Carbon 0.04–0.10% with a minimum grain size (ASTM No. 7 or coarser) underwrites the creep strength. Molybdenum 2–3% keeps a chloride corrosion margin that plain 304H lacks.
Mechanical Properties
Values are for the solution-annealed condition per ASTM A240, A182 (F316H), and A312 (TP316H). The real advantage is in ASME time-dependent allowable stresses above 525°C.
| Condition / Form |
UTS (MPa) |
YS 0.2% (MPa) |
Elong. % (min) |
Hardness (max) |
| Minimum (ASTM A240 / A182 F316H) |
≥515 |
≥205 |
30 |
217 HBW (95 HRB) |
| Typical mill-annealed |
515–690 |
205–340 |
35–45 |
160–210 HBW |
Modulus of Elasticity 200 GPa. 316H carries code-listed creep/rupture allowable stresses from about 525°C to ~815°C. It also requires a minimum grain size per ASTM.
Physical Properties
| Property |
Value |
Note |
| Density |
8.00 g/cm³ |
Slightly above 316L |
| Melting Range |
1375–1400°C |
Solidus ~1375°C |
| Thermal Conductivity (100°C) |
16.3 W/m·K |
Comparable to austenitics |
| Thermal Expansion (20–100°C) |
16.0 ×10⁻⁶ /K |
Higher than carbon steel |
| Specific Heat |
500 J/kg·K |
At 21°C |
| Electrical Resistivity |
0.74 µΩ·m |
At 21°C |
| Magnetic Property |
Non-magnetic* |
*Slight after cold work |
| PREN (Pitting Resistance) |
~26 |
PREN = %Cr + 3.3×%Mo + 16×%N |
Corrosion Resistance
High-Temperature Strength
The controlled carbon and coarse grain give 316H certified creep and stress-rupture strength from about 525°C to ~815°C, carrying ASME allowable stresses where plain 316 drops out.
Chloride Corrosion Margin
The 2–3% molybdenum keeps PREN ~26, so 316H resists pitting/crevice corrosion better than 304H in chloride-containing hot process streams. This is its key edge over plain high-carbon 304.
Sensitization Risk
Carbon 0.04–0.10% means weldments can sensitize in the 425–815°C range during shutdowns, risking intergranular/polythionic-acid attack in refinery service. Stabilized 321H/347H avoid this.
Pitting in Seawater
PREN ~26 is not enough for warm seawater. For aggressive chloride at temperature, use 317L, 904L, or 254SMO.
Stainless Steel 316H vs Similar Grades — Selection Guide
| If you need... |
Choose... |
Why |
| High-temp pressure, also chlorides |
316H |
Creep + Mo corrosion margin |
| Boiler / steam line >525°C |
316H |
Code-listed allowable stresses |
| Welded high-temp, avoid sensitization |
321H / 347H |
Stabilized carbides |
| High-temp, no chloride load |
304H |
Lower cost |
| Furnace 1000°C+ |
310S / 253MA |
Better oxidation |
Applicable Standards
| Standard |
Product Form |
| ASTM A240 |
Plate, sheet, strip |
| ASTM A182 F316H |
Forged flanges & fittings |
| ASTM A312 TP316H |
Seamless & welded pipe |
| ASTM A403 WP316H |
Butt-weld fittings |
| ASTM A213 |
Boiler & superheater tube |
| EN 1.4919 / X6CrNiMo17-13 |
European equiv. |
HT PIPE Supply — Stainless Steel 316H Product Forms
| Product Form |
Specifications |
HT PIPE Supply |
| Seamless Pipe |
ASTM A312 TP316H |
✅ Available |
| Forged Flanges |
ASTM A182 F316H, ASME B16.5 |
✅ In stock |
| Butt-Weld Fittings |
ASTM A403 WP316H |
✅ Available |
| Plate / Sheet |
ASTM A240 |
✅ Available |
| Bar / Rod |
ASTM A276 / A479 |
✅ Available |
| Boiler Tube |
ASTM A213 |
✅ Available |
HT PIPE supplies 316H with controlled carbon, coarse-grain practice (EN 1.4919 equivalent), and MTRs showing high-temperature properties for creep design.
Project Experience — Stainless Steel 316H
HT PIPE supplies 316H for high-temperature pressure piping and boiler/steam service where creep strength and chloride margin both matter.
| Project |
Product |
Specification |
| Power Plant Steam Line (Asia) |
316H Pipe + Flanges |
A312, A182 F316H |
| Refinery High-Temp Header (Middle East) |
316H Forgings + Fittings |
A182, A403 |
| Chemical Reactor Outlet (China) |
316H Pipe + Forgings |
A312, A182 |
We verify grain size and provide ASME high-temperature allowable-stress data for 316H creep design.
| FREQUENTLY ASKED QUESTIONS |
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FAQ — Stainless Steel 316H
| What makes 316H different from 316? |
| Carbon is held at 0.04–0.10% (with a minimum grain size) instead of ≤0.08%, giving certified creep and stress-rupture strength in the 525–815°C range where plain 316 has no code-listed allowable stresses. |
| How is 316H better than 304H? |
| Both are high-carbon creep grades, but 316H keeps 2–3% molybdenum, so it also resists chloride pitting/crevice corrosion — a margin 304H does not have. Use 316H when the hot stream also contains chlorides. |
| What temperature is 316H good for? |
| It carries code-listed allowable stresses from about 525°C up to roughly 815°C for pressure duty. Below the creep range, standard or L-grade 316 is cheaper. |
| What filler is used for 316H? |
| ER316H / E316H to keep the weld metal creep-resistant. Substituting 316L filler quietly removes the creep strength the H grade was specified for. |
| When use 321H or 347H instead? |
| When the welded joint must stay in the sensitizing range and resist polythionic-acid stress corrosion during refinery shutdowns. The stabilized grades avoid the intergranular attack 316H can suffer. |
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Need Stainless Steel 316H for High-Temperature Service?
HT PIPE supplies 316H (UNS S31609) pipe, flanges, fittings, and plate with controlled carbon, coarse-grain practice, and high-temperature MTRs. Contact our technical team for creep-design support.
Request a Quote |
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