ASTM B983 is the ASTM standard specification governing precipitation-hardenable Incoloy 925 (UNS N09925) and the related UNS N09945 alloy in flat-product forms: hot-rolled and cold-rolled plate, sheet and strip. It is the companion specification to ASTM B805 (bar / forgings), chemistry envelope and mechanical-property minimums are identical, but the test methods, thickness tolerances and surface finish requirements are tailored for flat product. ASTM B983 is the primary specification cited on MTCs for Incoloy 925 pressure-vessel plate, cladding sheet, exchanger tube sheet and strip used to manufacture seam-welded pipe and tube. TorqBolt manufactures Incoloy 925 plate and sheet to ASTM B983 with EN 10204 3.1 (or 3.2 with TPI witness) MTC documenting heat chemistry, mechanical results and heat-treatment cycle.
Need ASTM B983 Incoloy 925 plate / sheet? Email info@torqbolt.com with thickness, dimensions, quantity and any companion-spec requirements (NACE MR0175 stamp, NORSOK MDS, ASME Section II / VIII code stamping). WhatsApp +91-22-66157017.
Scope of ASTM B983
ASTM B983 covers wrought UNS N09925 (and UNS N09945) in:
- Plate, hot-rolled, thickness 5 mm and above; up to 100 mm available with limited mill capacity
- Sheet, cold-rolled, thickness 0.1 mm to 5 mm
- Strip, cold-rolled, thickness 0.1 mm to 5 mm; supplied in coil for further fabrication
Companion ASTM specifications: ASTM B805 covers bar and forgings; ASTM B829 covers wrought-pipe general requirements; ASTM B829 / B751 cover seam-welded pipe and tube made from ASTM B983 strip.
Chemical Composition Requirements (UNS N09925)
Identical to ASTM B805 / Special Metals SMC HA 46. See the full chemical composition page for element-by-element commentary.
| Element | Min % | Max % | Element | Min % | Max % |
|---|---|---|---|---|---|
| Ni | 42.0 | 46.0 | Mn | 1.0 | |
| Cr | 19.5 | 22.5 | Si | 0.5 | |
| Fe | 22 min | balance | Nb | 0.5 | |
| Mo | 2.5 | 3.5 | C | 0.03 | |
| Cu | 1.5 | 3.0 | S | 0.03 | |
| Ti | 1.9 | 2.4 | P | 0.03 | |
| Al | 0.1 | 0.5 |
Mechanical Property Requirements
| Condition | UTS, ksi (MPa) min | 0.2% YS, ksi (MPa) min | Elongation, % min | Hardness, HRC max |
|---|---|---|---|---|
| Solution Annealed only | 110 (760) | 45 (310) | 30 | 32 |
| Solution Annealed + Aged | 165 (1140) | 110 (760) | 18 | 35 |
Test methods per ASTM E8 / E8M (tensile) and ASTM E18 (Rockwell hardness). For sheet thinner than 5 mm, sub-size tensile specimens per ASTM E8 Annex A1 are permitted. Charpy V-notch impact testing is not mandatory under ASTM B983 but is required by companion specifications, see the full mechanical properties page.
Mandatory Heat-Treatment Condition
ASTM B983 requires solution-annealing in all cases. Ageing is optional and depends on end use:
- Class 1, Solution Annealed only: 1900±25°F (1040±14°C), 1 h per 1" of section, water quench. Used when the customer plans final ageing in their own furnace, or when the application requires high formability (cladding, transition pieces).
- Class 2, Solution Annealed + Aged: Anneal cycle as Class 1, then 1365°F × 8h with slow furnace cool to 1150°F, hold 8h, air cool. This is the standard condition for pressure-vessel plate and high-strength applications.
Furnace pyrometry per AMS 2750 mandatory. Chart-recorder traces and charge-thermocouple data retained 5 years. See the full heat-treatment page for cycle rationale.
Plate / Sheet / Strip Specific Requirements
| Requirement | Plate | Sheet | Strip |
|---|---|---|---|
| Surface Finish | HR pickled / annealed (matt) | 2B (cold-rolled, annealed, mildly polished) | 2D (matt) or BA (bright annealed) |
| Thickness Tolerance | per ASTM A480 Table 7 | per ASTM A480 Table 6 | per ASTM A480 Table 6 |
| Flatness | per ASTM A480 Table A1 | per ASTM A480 Table A2 | (supplied in coil) |
| Edge condition | mill / sheared / sawn | mill / slit / sheared | slit edge |
Required Testing
| Test | Method | Frequency |
|---|---|---|
| Heat chemistry | ASTM E1473 | Each heat |
| Tensile | ASTM E8 / E8M | One test per heat per heat-treatment lot per thickness |
| Hardness | ASTM E18 (HRC) / E384 (microhardness for sheet) | Each piece (plate); each coil end (sheet/strip) |
| Grain size (if specified) | ASTM E112 | One test per heat, ASTM 5 or finer |
| Bend test (sheet/strip) | ASTM E290 | One test per coil, 180° bend over 1t mandrel |
| Liquid penetrant (S5 surface) | ASTM E165 | If purchaser-required; both surfaces of plate |
| Ultrasonic (S6 volume) | ASTM A578 | If purchaser-required; 100% scan, plate >10 mm |
Marking & Certification
Per ASTM B983 Section 16, plate must be marked (one face) with: specification number (B983), UNS designation (N09925), heat number, manufacturer ID, condition (Class 1 or Class 2), thickness and width × length. Sheet and strip are tagged at the coil end. The MTC must reference all of the above plus full chemistry, mechanical-test data and heat-treatment cycle. EN 10204 3.1 default; 3.2 with third-party witness on request; NACE-stamped variant for sour service.
Companion-Specification Compliance
- NACE MR0175 / ISO 15156-3: 35 HRC max in CW+aged; sour-service stamping; optional NACE TM0177 / TM0316 test data on production-coupon basis
- NORSOK M-630 MDS A30: Norwegian certification body acceptance
- ASME Section II Part B + ASME Section VIII Div 1: Code-acceptance for pressure vessels, ASME III nuclear code via Code Case 2727 (UNS N09925)
- EN 10028: European pressure-vessel-plate equivalent, harmonised with ASTM B983
- EN 10204: Inspection certification 3.1 / 3.2
Available Product Forms (TorqBolt)
| Form | Thickness Range | Application |
|---|---|---|
| Plate | 5 mm to 50 mm | Pressure-vessel shells, cladding, tube sheets |
| Sheet | 0.5 mm to 5 mm | Cladding, transition pieces, formed components |
| Strip (in coil) | 0.1 mm to 5 mm | Seam-welded pipe / tube, springs |
Frequently Asked Questions
What is the difference between ASTM B983 Class 1 and Class 2? Class 1 is solution-annealed only (~110 ksi UTS / 45 ksi YS); Class 2 is solution-annealed + aged (165 ksi UTS / 110 ksi YS minimum). Class 1 is the form-and-supply condition for cladding, transition pieces and components that will receive a further field-installed weld + age cycle. Class 2 is the as-supplied condition for finished pressure-vessel plate and structural plate.
Can ASTM B983 plate be used for ASME pressure-vessel construction? Yes. UNS N09925 is covered under ASME Section II Part B (specification SB-983) and ASME Section VIII Division 1 / 2 / 3 with maximum allowable stress values published in ASME Section II Part D Table 1B. For nuclear use, UNS N09925 is permitted via ASME III Code Case 2727 with TorqBolt as ASME-certified manufacturer.
Why is the yield strength minimum lower for Class 1 (45 ksi) than for ASTM B805 annealed (50 ksi)? Both standards quote nominally the same alloy in the same condition; the minor difference reflects sample-geometry differences between bar (round tensile specimen) and sheet (flat tensile specimen with sub-size geometry). In practice, both tested materials yield at 50–55 ksi.
Is ASTM B983 plate available with NACE MR0175 stamp? Yes. TorqBolt supplies ASTM B983 plate and sheet with NACE MR0175 sour-service certification on request, the MTC carries the NACE stamp and the hardness is verified at 100% within the 35 HRC sour-service cap. Specify "NACE MR0175 stamped" at RFQ stage.
Request a Quote
For ASTM B983 Incoloy 925 plate, sheet or strip with full MTC:
- Email: info@torqbolt.com
- WhatsApp: +91-22-66157017
- Datasheet PDF + sample MTC available on request
Specify thickness, width × length (or coil ID/OD for strip), quantity (kg or pieces), condition (Class 1 annealed or Class 2 aged), surface finish, companion-specification requirements (NACE MR0175 stamp, NORSOK MDS, ASME code stamping), required NDE (PT, UT, RT) and MTC type (3.1 or 3.2 with TPI witness).
References: ASTM B983 Standard Specification for Precipitation Hardened UNS N09925 Plate, Sheet, and Strip (latest edition). ASTM B805 companion bar/forging specification. Special Metals Corporation: INCOLOY® alloy 925 Technical Bulletin. ASTM E8 / E18 / E112 / E165 / E290 / A480 / A578 referenced test methods. ASME Section II Part B (SB-983); ASME Section VIII Div 1; ASME III Code Case 2727. AMS 2750 Pyrometry. EN 10204 / EN 10028. INCOLOY® is a registered trademark of Special Metals Corporation.
