ASTM B575 Inconel 686 UNS N06686 Plate and Sheet
INCONEL alloy 686 plate and sheet, designated UNS N06686 / W.Nr. 2.4606, is a nickel-chromium-molybdenum-tungsten alloy selected for severe corrosive environments. The combination of high molybdenum, chromium and tungsten supports resistance to reducing acids, oxidizing media, pitting and crevice corrosion.
SASA ALLOY supplies Alloy 686 plate and sheet to ASTM B575 / ASME SB-575 and project requirements. For quotation, send the thickness, width, length, quantity, surface condition, dimensional tolerance, testing and certificate requirements.
Product Identification and Supply Range
| Product | INCONEL alloy 686 plate, sheet and cut-to-size pieces |
|---|---|
| Material designation | Alloy 686 / UNS N06686 / W.Nr. 2.4606 / NiCr21Mo16W |
| Primary standard | ASTM B575 / ASME SB-575 |
| Thickness range | 0.5–50 mm |
| Width and length | Width 50–2000 mm; length 100–6000 mm |
| Condition | Hot or cold rolled, solution annealed and descaled; bright finish when ordered and technically applicable |
| Processing | Shearing, sawing, waterjet or plasma cutting, machining and formed parts according to drawing review |
These dimensions describe a practical market supply range, not current stock. Availability, minimum quantity and production route are confirmed for each inquiry.
Why Alloy 686 Is Selected
Alloy 686 is used when corrosion exposure is too aggressive for general-purpose nickel alloys. Its chemistry is balanced to provide resistance across several corrosion mechanisms rather than a single environment.
Nickel and molybdenum support resistance in reducing conditions while chromium contributes resistance to oxidizing media.
Molybdenum and tungsten improve resistance to pitting and crevice corrosion in chloride-bearing environments.
Low carbon helps limit grain-boundary precipitation and supports corrosion resistance in qualified welded constructions.
Chemical Composition
| Ni | Cr | Mo | W | Fe | C | Ti |
|---|---|---|---|---|---|---|
| Balance | 19.0–23.0 | 15.0–17.0 | 3.0–4.4 | 2.0 max | 0.01 max | 0.02–0.25 |
Composition is shown in weight percent. Purchase requirements and acceptance must follow the ordered ASTM B575 edition and the material test certificate.
ASTM B575 Mechanical Requirements
| Property | N06686 requirement | Purchasing note |
|---|---|---|
| Tensile strength | 690 MPa minimum | Confirm product form and ordered edition |
| 0.2% yield strength | 310 MPa minimum | Verify against the MTC for the supplied heat |
| Elongation | 45% minimum | Applicable specimen and thickness rules follow the standard |
| Hardness | 100 HRB maximum, informative | Not an acceptance basis unless the order states otherwise |
Surface, Cutting and Fabrication
Plate can be supplied solution annealed and descaled, with pickled, ground or project-specified surface preparation. Sheet may be hot or cold rolled and supplied with a descaled or bright finish according to the ordered route. State any surface cleanliness, flatness or protective-film requirement in the inquiry.
- Cut-to-size: rectangular blanks, discs and profile-cut pieces can be reviewed from drawings.
- Machining: Alloy 686 work-hardens, so stable tooling, suitable cutting parameters and adequate coolant are important.
- Forming: bend radius, rolling direction and final heat-treatment requirements should be confirmed before production.
- Welding: use a qualified welding procedure and select compatible filler metal for the service environment.
Inspection, Testing and Documentation
- Material test certificate with heat number, chemical analysis and mechanical-property traceability.
- Dimensional and visual inspection covering thickness, width, length, flatness and surface condition.
- PMI, ultrasonic testing, third-party inspection or additional corrosion testing when stated in the purchase order.
- EN 10204 3.1 documentation or another agreed certificate format when requested.
Additional tests require an applicable test method, sampling plan and acceptance criterion. No test result shown for one heat or lot should be treated as a blanket value for all Alloy 686 material.
Typical Applications and Selection Questions
Alloy 686 plate and sheet are considered for chemical-process vessels and internals, heat exchangers, scrubbers, ducts, dampers, stack liners, flue-gas desulfurization equipment, pulp and paper systems, marine components and industrial or municipal waste-treatment equipment.
Final alloy selection should consider acid type and concentration, chloride content, temperature, pressure, aeration, contaminants, crevice geometry, fabrication condition and cleaning procedure. Send the service conditions when the project requires material-selection review.
Ordering Checklist
- Material: Alloy 686 / UNS N06686 / W.Nr. 2.4606
- Standard and required edition: ASTM B575 or ASME SB-575
- Product form: plate, sheet or cut-to-size piece
- Thickness × width × length and quantity
- Condition, surface finish, flatness and dimensional tolerances
- Cutting, forming or machining allowance
- Required certificate, inspection, testing and third-party witnessing
- Package marking, destination and project documentation requirements
Frequently Asked Questions
What standard covers Inconel 686 plate and sheet?
ASTM B575 covers UNS N06686 plate, sheet and strip for general corrosive service. ASME SB-575 is referenced for applicable pressure-equipment procurement.
What is the difference between Alloy 686 and Alloy 625 plate?
Both are nickel-chromium-molybdenum alloys, but Alloy 686 contains substantially more molybdenum together with tungsten and is selected for more severe mixed-acid and localized-corrosion exposure. Selection still depends on the actual service conditions.
Can Alloy 686 plate be supplied as cut parts?
Yes. Rectangular blanks, discs and profile-cut pieces can be reviewed. Send a drawing with dimensions, tolerances, edge condition, quantity and inspection requirements.
Do product photographs prove the N06686 grade?
No. Photographs illustrate the plate or sheet form. Grade identity is established by heat-number traceability, the material test certificate and ordered inspection.
Request an Alloy 686 Plate Quotation
Send the ASTM B575 / UNS N06686 requirement with size, quantity, condition, surface, tolerance, testing and certificate details. We will review the specification and production route before quotation.
