What Inconel 625 Plate Is
Inconel 625 is a nickel-base alloy from the nickel-chromium-molybdenum family. The high nickel and chromium content delivers oxidation resistance at elevated temperature, while molybdenum and niobium give strength and resistance to pitting, crevice attack, and chloride stress-corrosion cracking. That combination is why 625 plate is specified where austenitic stainless and even super-austenitic grades run out of margin.
In plate form the alloy is used for vessel shells, tube sheets, liners, reactor internals, and fabricated components that must hold up in hot, chloride-bearing, or acidic environments. Our 625 plate is supplied solution-annealed and ready for cutting, forming, and welding, with full traceability back to the heat.
For the wider alloy context, see our overview of nickel alloys and where each family fits.
Grade, Standard, and Designation
Inconel 625 plate conforms to ASTM B443, the plate, sheet, and strip specification for the grade. The UNS number is N06625. Read the full scope of the plate standard on our ASTM B443 reference page, and cross-check international equivalents on the UNS, Werkstoff, and JIS cross-reference.
| Attribute | Detail |
|---|---|
| Grade | Inconel 625 |
| UNS number | N06625 |
| Alloy family | Nickel-chromium-molybdenum alloy |
| Plate standard | ASTM B443 |
| Related bar standard | ASTM B446 |
| Product form | Plate (also available as sheet) |
| Condition | Solution annealed |
| Certification | EN 10204 3.1 or 3.2 mill test certificate |
Why Specifiers Choose Inconel 625
Buyers reach for 625 plate when a single material has to survive more than one attack mode at once. The alloy resists pitting and crevice corrosion in chlorides, resists chloride stress-corrosion cracking that limits austenitic stainless, and holds strength and oxidation resistance at high temperature. For an explanation of how pitting resistance is ranked, see our guide to PREN and pitting-resistance equivalent.
Where the duty is sour, acidic, or hot and chloride-laden, 625 often sits one step beyond 904L or Incoloy 825 on the selection ladder. If your service is closer to combined reducing and oxidizing acids or sour gas, compare the two directly in our Incoloy 825 vs Inconel 625 comparison, and review the Incoloy 825 grade page before you finalize the purchase order.
Typical Applications
Inconel 625 plate is specified across industries where temperature, pressure, and corrosion overlap:
- Oil and gas, including sour and high-chloride service
- Petrochemical process equipment
- Chemical and acid processing vessels and internals
- Pollution control and FGD scrubber components
- Marine and seawater-exposed structures
Corrosion and Service Behavior
The value of 625 is its breadth of resistance. Molybdenum and niobium raise resistance to localized pitting corrosion, while the nickel-rich matrix is largely immune to the chloride stress-corrosion cracking that affects austenitic stainless. For sour duty, specify the acceptance criteria clearly and reference NACE MR0175 / ISO 15156 on the order so the heat is supplied in the qualified condition.
As with any welded nickel-alloy fabrication, keep heat input controlled to protect the heat-affected zone. Background on filler choice and procedure is in our note on welding stainless and nickel alloys, and the general risk of intergranular corrosion is worth reviewing before you set the weld procedure.
Sizes, Thickness, and Cutting
We stock 625 plate across a range of thicknesses and can cut to your plan. To estimate shipping or fabrication weight, use the plate weight calculator or follow the method in how to calculate steel plate weight. If you are still fixing the section, our guide on how to choose plate thickness and the explainer on sheet vs plate vs coil will help you land the right form. Thin-gauge requirements are covered on the Inconel 625 sheet page.
Matching Forms and Fittings
For a complete 625 system, we also supply matching product forms:
| Form | Catalog |
|---|---|
| Pipe | Inconel pipe |
| Pipe fittings | Inconel pipe fittings |
| Forged fittings | Inconel forged fittings |
| Flanges | Inconel flanges |
| Round bar | Inconel round bar |
| Fasteners | Inconel fasteners |
Quality, Traceability, and Certification
Nandini Steel has supplied corrosion-resistant and high-temperature steel since 2003 and is ISO 9001:2015 certified. Every order ships with an EN 10204 3.1 or 3.2 mill test certificate, so the chemistry and mechanical properties are traceable to the heat. Learn how to read one in our guide to the mill test certificate and the EN 10204 standard reference, and see our quality assurance and certifications pages for the full picture.
Frequently Asked Questions
What standard does Inconel 625 plate conform to?
What is the UNS number for Inconel 625?
Is Inconel 625 suitable for high-temperature service?
How does Inconel 625 compare with Incoloy 825?
Do you provide a mill test certificate with Inconel 625 plate?
Is Inconel 625 plate available ex-stock?
Request a Quote
Tell us your thickness, dimensions, and quantity and we will confirm stock and live pricing. Reach the Nandini Steel team on +91 99202 09184 (WhatsApp), email reachus@nandinisteel.com, or use our contact page to send an RFQ.
Part of our steel plate range.