ASTM 309 Stainless Steel Plate Price 2025

In 2025 the ASTM 309 / 309S family remains a specialty high-temperature austenitic stainless plate where buyers should expect wide price dispersion driven by finish (hot vs. cold rolled), thickness, mill of origin, and regional supply dynamics — typical market offers in mid-2025 range roughly USD 1,900–6,500 per metric ton depending on those variables and order size. We recommend specifying exact grade (309, 309S, or 309H), thickness and finish when requesting quotes to avoid large price swings.

What is ASTM 309

We treat ASTM 309 as the family name used in commercial practice to identify the chromium-nickel, high-temperature austenitic stainless steels (commonly specified as 309, 309S, and 309H). These alloys are formulated for oxidation resistance and strength at elevated temperatures and are typically supplied to the chemistry and mechanical requirements appearing under ASTM/ASME plate standards.

Chemical composition and key mechanical differences

In plain terms, Alloy 309 contains more chromium and nickel than general-purpose grades (for example 304), granting better resistance to scaling and carburization at elevated temperature. Typical ranges used by mills are:

• Chromium ≈ 22–24%

• Nickel ≈ 12–15%

• Carbon: variable — 309 (up to ~0.20%), 309S (low-C ≤0.08%), 309H (high-C for creep resistance)

The low-carbon 309S improves weldability and reduces sensitization risk; the high-carbon 309H is chosen where creep strength at high temperatures is important. These composition bands come from mill datasheets and material suppliers.

Mechanically, tensile and yield strengths are typical of austenitic stainless plate (room temperature yield in the hundreds of MPa range, with good elongation). Design engineers usually consult the plate supplier’s certified mill test report (MTR) for exact guaranteed values for a given batch.

Applicable standards and spec references

The usual plate purchasing route is to reference the plate standard (for chemical, mechanical and permitted tests) and the product form. In practice the ASTM A240 / ASME SA240 family is commonly used for 309/309S flat products; vendors also reference UNS numbers such as UNS S30900 / S30908 / S30909. If you need pressure-vessel certification or piping weldments, mention the ASME/ASTM suites explicitly.

When you place an RFQ, require:

• Standard (e.g., “ASTM A240 / ASME SA240 plate, grade 309S”)

• Heat treatment condition and finish (e.g., “annealed, 2B” or “hot-rolled, BA”)

• Tests required (chemical report, tensile, hardness, PMI if required)

Typical industrial uses and allowable temperatures

We specify 309 variants when oxidation resistance is required in moderate to high temperatures — for example furnace components, burner liners, heating elements housings, boiler parts exposed to high oxygen partial pressures, and certain petrochemical process equipment. Suppliers note oxidation resistance up to roughly 1000–1050 °C in non-cyclic atmospheres (continuous service). Cyclic thermal excursions reduce life and oxidation resistance.

Plate types, finishes and how they affect price

Finish and plate processing have major cost implications:

• Hot-rolled plate: generally lowest cost per ton, typical for thicker plates and rougher surfaces.

• Cold-rolled / annealed / pickled (2B): higher cost — used when dimensional tolerance and surface finish matter.

• Bright annealed (BA): used for precise thickness or surface appearance — higher price.

• Thickness: thin sheets often are more expensive per unit weight because of processing and coil feedstock; thick plate can have higher absolute price but lower on a per-kg basis in some markets.

These choices alter producing steps (rolling, anneal, pickling, levelling) and therefore price. We always ask clients to choose finish first, then thickness. Supplier price quotes will differ for hot-rolled vs cold-rolled vs bright finishes.

Manufacturing tests & documentation to require

To avoid disputes we request the following on every order:

• MTR / Mill Test Report (chemical + mechanical) with heat number traceability

• Certificate of Conformance (C of C) to ASTM/ASME clause cited

• Non-destructive test reports if requested (UT for thick plates)

• Positive Material Identification (PMI) for critical orders or when local regulations require it

• Third-party inspection (when project critical — e.g., 3rd party witness of tests)

Insist on heat numbers marked on plates and a one-to-one correspondence to MTRs.

2025 market price drivers

Key inputs that shape 309 plate pricing in 2025:

• Nickel and chromium raw materials: stainless grades with higher Ni/Cr content are sensitive to nickel price swings.

• Scrap availability and stainless scrap premiums: scrap drives mill feedstock cost.

• Regional policies and tariffs: import duties or anti-dumping measures materially affect landed cost. Reuters coverage in 2025 indicates tariff and regional supply differences still shape stainless pricing.

• Global demand for high-temp alloys: specialty stainless markets are smaller and therefore more price-sensitive to order size.

• Mill capacity & lead times: when mills prioritize high-volume commodity grades, niche alloys can have longer lead times and higher prices.

We always factor these into our quotes and advise buyers to lock in medium-sized releases when raw material markets are volatile.

2025 global price snapshot

Market quotations for 309 class plate in 2025 vary widely because of grade variant, finish, thickness and region. The following table is a practical snapshot compiled from supplier price lists and market reports in mid-2025; treat all numbers as indicative and request firm quotes for firm delivery dates.

Notes on the table:

• The range is wide by design: commodity steel prices (general HRC) are much lower; specialty stainless plate with higher Ni/Cr carries a premium. Mill brands (Outokumpu, Acerinox, Jindal, TISCO, etc.) and certified mills typically price at the upper end of the ranges. Suppliers that publish sample ton prices for hot-rolled vs cold-rolled 309 plates show the higher cost for cold-rolled/finished plate.

Why ranges are broad: small orders, cut-to-size processing, and export packing push per-kg pricing upward; large tonnage contracts and direct deliveries from a mill to a domestic buyer reduce unit cost.

How Luokaiwei (us) prepares a commercial quote

When we quote 309 plate we ask for the following minimum information:

1. Grade required: 309 / 309S / 309H (state UNS if available).

2. Standard: ASTM A240 / ASME SA240 (or equivalently list MTR requirement).

3. Thickness range and plate size (L×W) and quantity (tons or pieces).

4. Finish required: hot-rolled, 2B, BA, pickled, etc.

5. Surface condition tolerance and flatness requirements.

6. Delivery terms, incoterm & destination port.

7. Any third-party inspection requirements.

8. Desired lead time and acceptance windows.

We price and show separately: material cost, processing (cutting/conditioning), packaging & export, and shipping/insurance. For small orders we typically add a handling supplement.

Cost-saving and specification strategies

If budget is tight, consider:

• Switching to 309S for welding-heavy projects (may lower downstream rework).

• Using hot-rolled plate when surface finish is not critical.

• Buying larger lots or joining group buys to reach mill MOQ discounts.

• Considering alternate grades (e.g., 310 or duplex stainless for certain thermal regimes) — but only after engineering review because composition, creep strength and oxidation behaviour differ.

• Ordering coil or sheet and having a local service center cut plates can be cheaper for thin thicknesses.

We never recommend substitution without engineering sign-off.

Risks, weldability and thermal cycling

Weldability: 309S is intended to reduce carbon-induced sensitization during welding — so for fabrication it often reduces post-weld heat treatment needs. 309 is still weldable with standard austenitic welding consumables, but filler selection matters if the application demands high creep/temperature performance.

Thermal cycling: repeated heating and cooling accelerates oxidation and can cause scale spallation — in those cases surface protection or higher alloyed grades should be considered.

Corrosion: 309 family is not a “super-austenitic” corrosion alloy; for aggressive chloride environments austenitic 316-class or duplex/316L with appropriate design is more suitable.

FAQs

Q1 — Is 309 the same as 309S?
Short answer: Not exactly. 309S is the low-carbon variant of 309 and is preferred where weldability and avoidance of carbide precipitation are concerns. If welding and post-weld corrosion are expected, specify 309S in the PO.

Q2 — Which finish should I choose for furnace parts?
For components exposed to high temperatures where surface finish doesn’t affect performance, hot-rolled annealed plates are cost-effective. If dimensional accuracy or smoother interfacing surfaces are required, choose 2B or BA finishes.

Q3 — How much premium does 309 cost versus 304 in 2025?
The premium depends heavily on nickel & chromium content and market dynamics. In mid-2025 the premium for 309 versus commodity 304 can be several hundred to a few thousand USD per metric ton depending on finish and region; check current quotes because nickel price moves change the premium rapidly.

Q4 — Can I use 309H instead of 309 for creep applications?
Yes: 309H has higher carbon to improve high-temperature creep resistance. However, the higher carbon may require additional fabrication controls to avoid sensitization. Use 309H only with engineering approval.

Q5 — How long is a typical lead time for 309 plate?
Lead times vary from stock availability (days to weeks from a large service center) to 6–12 weeks or more for mill production and export. Specialty thicknesses or finishes add time. Always obtain a firm lead time in the quotation.