Stainless Steel S30435
UNS S30435
S30435 is a copper- and niobium-bearing 304-type austenitic stainless developed for higher creep strength in superheater and reheater boiler tubing, where fine Cu-rich and NbC precipitates strengthen the matrix.
Reference datasheet — S30435 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ST condition
S30435 tempers and conditions
S30435 is supplied in 2 conditions, soft to hard. ST is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STDefault Solution annealed | Standard supply condition for A213/A249 superheater and reheater tubing — Cu and Nb in solution, ready for in-service precipitation strengthening. | 300 | 655 | 45 | 180 HB | 2.3 % IACS |
Cold drawn | Intermediate mill condition or special order where higher room-temperature strength and tight tolerance matter more than ductility; not the code condition for creep service. | 620 | 830 | 20 | 25 HRC | 2.3 % IACS |
Supply forms, finishes and certifications
Ways S30435 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
BA | Bright annealed | Surface finish |
ST+SB | Solution annealed with shot-blasted inner surface | Surface finish |
What is S30435?
S30435 is a copper- and niobium-bearing 304-type austenitic stainless developed for higher creep strength in superheater and reheater boiler tubing, where fine Cu-rich and NbC precipitates strengthen the matrix. Engineers specify it as an upgrade to 304H in tube and pipe form; it is supplied solution treated, bright annealed, solution treated plus shot-blasted, and cold drawn. Solution-treated properties are 300 MPa yield, 655 MPa tensile and 45 % elongation, with a listed maximum service temperature of 700 °C. Machinability is low (score 38) and it is essentially a tubing product, so bar and plate availability is limited; 347H or 321H are the common alternatives. S30435 has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F). S30435 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 197 GPa (28.6 Msi).
What is S30435 used for?
- boiler superheater tubes
- reheater tubing
- high-temperature pressure parts
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
S30435 properties
Typical room-temperature values for S30435-ST; bars are the position among stainless steel grades.
Physical3
S30435 has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
S30435 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
S30435 is rated for continuous service to 700°C (1,292 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 16.8 µm/m·K (9.33 µin/in·°F).
Electrical3
S30435 conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of S30435 takes about 55 MJ of energy and emits 4.6 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
S30435's machinability is fair (38/100, better than 63% of stainless steel grades); weldability good (68/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. S30435 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S30435
Is S30435 easy to machine?
Gummy, strongly work-hardening austenitic: rigid setup, positive-rake sharp carbide, 60–100 m/min, heavy feed and flood coolant, avoid dwelling to prevent glazing.
Can S30435 be welded?
GTAW/GMAW with low heat input, interpass < 150 °C, no post-weld heat treatment normally; use matching Cu-Nb 304H filler or ERNiCr-3/EPRI P87 for dissimilar joints — watch hot-cracking and creep-strength mismatch at the HAZ.
Can S30435 be formed, bent or molded?
Cold bends and expansions are readily made in the solution-annealed state; cold work above ~20% should be re-solution annealed, and hot working is done at 1100–1200 °C followed by rapid cooling.
S30435 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CH-grade carbon level for creep strength | 0.07 – 0.13 | 0.1 |
| Si | ≤ 0.3 | 0.2 |
| Mn | ≤ 1 | 0.8 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.01 | 0 |
| Cr | 17 – 19 | 18 |
| Ni | 7.5 – 10.5 | 9 |
| Cuforms fine Cu-rich precipitates during service — main creep strengthener | 2.5 – 3.5 | 3 |
| NbMX carbonitride strengthening | 0.3 – 0.6 | 0.45 |
| N | 0.05 – 0.12 | 0.1 |
| Bgrain-boundary strengthening (when specified) | 0 – 0.01 | 0 |
| Alrestricted to keep Nb effective | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on S30435?
Pickle and passivate per ASTM A380 after welding or hot work; ID shot-blasting is the usual order option to improve steam-side oxidation resistance; not anodizable.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
How much does S30435 cost?
S30435 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S30435 — frequently asked
What is S30435 used for?
S30435 is typically used for boiler superheater tubes, reheater tubing and high-temperature pressure parts. In short: creep-strengthened 304H upgrade; cu-Nb precipitation hardening; mainly boiler tube product.
What is the yield strength of S30435?
S30435 has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is S30435 easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Gummy, strongly work-hardening austenitic: rigid setup, positive-rake sharp carbide, 60–100 m/min, heavy feed and flood coolant, avoid dwelling to prevent glazing.
Can S30435 be welded?
Yes — weldability is rated good (68/100). GTAW/GMAW with low heat input, interpass < 150 °C, no post-weld heat treatment normally; use matching Cu-Nb 304H filler or ERNiCr-3/EPRI P87 for dissimilar joints — watch hot-cracking and creep-strength mismatch at the HAZ.
What surface finishes work on S30435?
Pickle and passivate per ASTM A380 after welding or hot work; ID shot-blasting is the usual order option to improve steam-side oxidation resistance; not anodizable.
Can S30435 be formed, bent or molded?
Cold bends and expansions are readily made in the solution-annealed state; cold work above ~20% should be re-solution annealed, and hot working is done at 1100–1200 °C followed by rapid cooling.
What is the maximum service temperature of S30435?
S30435 is rated for continuous use to about 700°C (1,292 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S30435-ST and S30435-CD?
ST is the default condition — standard supply condition for A213/A249 superheater and reheater tubing — Cu and Nb in solution, ready for in-service precipitation strengthening. CD: intermediate mill condition or special order where higher room-temperature strength and tight tolerance matter more than ductility; not the code condition for creep service. Yield strength is 300 MPa in ST versus 620 MPa in CD.
How much does S30435 cost?
S30435 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A213/A213M — Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes — ASTM International (2022)
- ASTM A249/A249M — Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes — ASTM International (2022)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- Super304H (18Cr-9Ni-3Cu-Nb-N) boiler tube data — Nippon Steel (Sumitomo Metals) (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.