When Inconel 625 (UNS N06625 / W.Nr. 2.4856) lining plates are used in chemical reactors, they must conform to ASTM B443 or ASME SB-443 standards (product forms: plate/sheet/strip, manufacturing specifications include AMS 5599). The chemical composition requirements are: nickel ≥58%, chromium 20–23%, molybdenum 8–10%, niobium + tantalum 3.15–4.15%, and excellent tensile strength and fatigue resistance maintained from low temperatures to 1093°C (2000°F).
Due to the extremely high cost of solid Inconel 625, two main supply methods are used in engineering: weld overlay (forming a protective layer directly on the surface of carbon steel or low alloy steel substrate by welding) and rolled composite plates (metallurgically bonding a thin layer of Inconel 625 to a thicker carbon steel structural backing plate using a hot rolling process).
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Challenges of Inconel 625 Sheet Metal in Chemical Reactor Linings
Chemical reactor linings operate under some of the most demanding conditions in process equipment. Based on 18 years of experience supplying nickel-based alloy reactors, the most common causes of failure include:
Highly corrosive media: Strong inorganic acids, organic chlorides, high-salinity process fluids, and mixed redox environments rapidly corrode standard stainless steel.
High temperature and pressure: Operating temperatures typically range from 180°C to 650°C, with internal pressures between 10 and 150+ bar, which accelerates corrosion and deterioration of mechanical properties.
Weld heat-affected zone (HAZ) vulnerability: We have observed over 80% of lining failures occurring at welds, where sensitization and intergranular corrosion are prone to occur.
Thermal cycling fatigue: Intermittent heating/cooling cycles generate repetitive thermal stress, which over time can lead to cracking and spalling of the lining.
Gnee Alloy Inconel 625 Reactor Liner Material Specifications
All Inconel 625 liners used in your project and all reactor projects are manufactured and tested to stringent international standards.
| Inconel 625 Liner Applicable Standards | Specification / Details |
|---|---|
| Plate Specification | ASTM B443 / ASME SB-443 |
| UNS Number | UNS N06625 |
| Pressure Vessel Code Approval | ASME BPVC Section VIII, Division 1 & Division 2 |
| Optional Compliance | NACE MR0175 / ISO 15156 for sour service (H₂S-containing) reactor applications |
Chemical Composition of UNS N06625 Alloy Cladding Plate (Weight Percent, Wt%)
| Element | Standard Range | Role in Reactor Lining Performance | |
|---|---|---|---|
|
|
Nickel (Ni) | ≥ 58.0 (balance) | Austenitic matrix stability; chloride SCC resistance |
| Chromium (Cr) | 20.0 – 23.0 | General & high-temperature oxidation resistance | |
| Molybdenum (Mo) | 8.0 – 10.0 | Pitting & crevice corrosion resistance in chlorides | |
| Niobium + Tantalum (Nb+Ta) | 3.15 – 4.15 | HAZ stabilization; intergranular corrosion prevention | |
| Iron (Fe) | ≤ 5.0 | - | |
| Carbon (C) | ≤ 0.10 | Controlled for weldability and corrosion stability | |
| Phosphorus / Sulfur | ≤ 0.015 each | Minimized for optimum corrosion and toughness |
Gnee Alloy Nickel-Based Alloy PMI Testing
UNS N06625 Alloy Cladding Plate Mechanical Properties (Solution Annealed)
| Plate Thickness | Tensile Strength (Min) | 0.2% Yield Strength (Min) | Elongation (Min) |
|---|---|---|---|
| Thin lining (≤ 4.76 mm) | 690 MPa | 275 MPa | 30% |
| Heavy lining / clad overlay (> 4.76 mm) | 690 MPa | 414 MPa | 30% |
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Differences in room temperature mechanical properties between Inconel 625 liner grades
Grade 1: Annealed Condition (Standard Lining Choice - ≤ 593°C Service)
| Product Form | Thickness (mm) | UTS (MPa) | YS 0.2% (MPa) | Elongation (%) | Hardness (HB) |
|---|---|---|---|---|---|
| Plate | > 4.76 | ≥ 830 | ≥ 414 | ≥ 30 | ≤ 220 |
| Sheet / Strip | ≤ 4.76 | ≥ 827 | ≥ 275 | ≥ 30 | ≤ 220 |
Source: ASTM B443 / ASME SB-443
Grade 2: Solution Annealed Condition (High-Temperature Lining Choice - > 593°C Service)
| Product Form | Thickness (mm) | UTS (MPa) | YS 0.2% (MPa) | Elongation (%) | Application |
|---|---|---|---|---|---|
| Plate / Sheet | All thicknesses | ≥ 690 | ≥ 276 | ≥ 30 | High-temperature (>600°C) creep-sensitive service |
Strength Difference Explanation: Plate (> 4.76 mm) exhibits higher yield strength (414 MPa) compared to sheet (275 MPa) due to grain refinement and dislocation density differences from hot rolling. This is critical for lining design - the actual purchased thickness must be used for design calculations; values cannot be interchanged.
High-Temperature Mechanical Properties of Inconel 625 Lining
| Temperature (°C) | UTS (MPa) | YS 0.2% (MPa) | Elongation (%) | Creep Rupture (1000h, MPa) | Engineering Significance |
|---|---|---|---|---|---|
| 20 (RT) | ≥ 830 | ≥ 414 | ≥ 30 | - | Baseline |
| 200 | ~ 780 | ~ 370 | ~ 32 | - | Typical reactor operating temperature |
| 400 | ~ 720 | ~ 340 | ~ 35 | - | High-temperature reactor |
| 600 | ~ 650 | ~ 320 | ~ 38 | - | Creep becomes significant |
| 650 | - | - | - | ~ 360 | Grade 2 recommended starting temperature |
| 760 | ~ 450 | ~ 300 | ~ 40 | ~ 160 | High-temperature process |
| 870 | ~ 350 | ~ 280 | ~ 42 | ~ 50 | High-temperature process |
| 980 | ~ 200 | - | - | ~ 18 | Maximum short-term service temperature |
Critical Selection Conclusion:
Service temperature ≤ 593°C: Select Grade 1 (Annealed) - higher yield strength
Service temperature > 593°C: Select Grade 2 (Solution Annealed) - superior creep resistance
inconel 625 Alloy Clad Plate Melting & Manufacturing Requirements
| Parameter | ASTM B443 / ASME SB-443 Requirement | Lining Engineering Practice |
|---|---|---|
| Melting Process | VIM + ESR (typical); VIM + VAR (when specified) | High cleanliness requirement - affects lining fatigue life |
| Product Form | Hot-rolled plate (> 4.76 mm); cold-rolled sheet/strip (≤ 4.76 mm) | Selected based on vessel size and thickness design requirements |
| Supply Condition | Grade 1: Annealed (≥ 871°C); Grade 2: Solution Annealed (≥ 1093°C) | Grade 1 is standard; Grade 2 for service > 600°C |
| Surface Finish | Pickled, blasted, bright annealed, or as-rolled | Linings require pickled or blasted surface for clad bond quality |
| Edge Condition | Sheared, slit, or rolled edges | Machined bevel required for butt weld joints |
| Dimensional Tolerances | ASTM B906 | Tighter flatness (≤ 3 mm/m) required for lining adhesion |
Gnee Alloy Inconel 625 Reactor Liner Supply Range
| Thickness | 2.0 mm – 25.0 mm (Standard lining thicknesses: 3 mm, 4 mm, 5 mm, 6 mm, 8 mm) |
| Standard Sheet Sizes | 1219 x 2438 mm, 1500 x 3000 mm; Custom sizes available |
| Surface Finish | Solution Annealed and Pickled (standard); Bright Annealed for high-purity applications |
| Value-Added Processing | Precision cutting, Edge preparation (chamfering), Surface polishing, Assembly marking |
Gnee Alloy Tip: We can pre-cut the liners to your vessel shell design dimensions and pre-process the weld edges so your team can install them directly, minimizing on-site cutting work, thus reducing waste and shortening manufacturing time.
Contact us to customize Inconel 625 products to fit your project dimensions
Inconel 625 Liner Non-Destructive Testing (NDT) Requirements
| Test Item | ASTM B443 (Standard) | Reactor Lining Supplement |
|---|---|---|
| Ultrasonic Testing (UT) | As specified (typically required) | 100% mandatory - per ASTM B564, typically Level II acceptance |
| Liquid Penetrant Testing (PT) | As specified | 100% mandatory - lining side surface and welds |
| Visual Inspection | 100% | 100% - stricter acceptance criteria |
| Hardness Testing | Per lot | Per plate - documented in MTR |
| Intergranular Corrosion Test | As specified (ASTM G28) | Mandatory - verifies sensitization resistance for lining material |
Inconel 625 liner Quality Certifications (MTR Requirements)
| Document Item | ASTM B443 (Standard) | ASME SB-443 (Pressure Vessel) |
|---|---|---|
| Heat Number | Full traceability | Full traceability |
| Melting Process | VIM + ESR or VAR noted | VIM + VAR certification (if specified) |
| Chemical Composition | Full analysis | Full analysis + trace elements (by agreement) |
| Mechanical Properties | UTS, YS, Elongation | UTS, YS, Elongation, Hardness |
| Intergranular Corrosion Test | As specified (ASTM G28) | Mandatory for lining material |
| UT Report | As specified | 100% UT report + defect location map |
| Dimensional Inspection | Standard requirement | Standard + flatness record |
| Certification Type | EN 10204 Type 3.1 or 3.2 | EN 10204 Type 3.2 + ASME Data Report + "SA" marking |
Inconel 625 Chemical Reactor Liner Alloy Comparison
Based on 18 years of actual reactor performance data, the following is a comparison of Inconel 625 with other lining materials:
| Parameter | Inconel 625 | 316L Stainless Steel | Super Duplex 2507 | Hastelloy C276 |
|---|---|---|---|---|
| UNS Number | N06625 | S31603 | S32750 | N10276 |
| Material Type | Ni-Cr-Mo-Nb Solid-Solution Strengthened Alloy | Austenitic Stainless Steel (Cr-Ni-Mo) | Super Duplex Stainless Steel (Austenitic-Ferritic) | Ni-Cr-Mo-W Solid-Solution Strengthened Alloy |
| Product Form | Plate, sheet, strip | Plate, sheet, strip | Plate, sheet, strip | Plate, sheet, strip |
| Typical Lining Applications | Chloride organic reactors, acetic acid/acetic anhydride reactors, FGD absorbers | Fresh water / low-corrosion environments, non-critical equipment | High-chloride environments, high-strength structural linings | Strong oxidizing acids, wet chlorine, mixed acid reactors |
| Strengthening Mechanism | Solid-Solution Strengthening (Mo + Nb) | Cold Work Hardening | Cold Work + Ferrite Phase | Solid-Solution Strengthening (Mo + W) |
| Maximum Service Temperature | ~ 980°C | ~ 425°C | ~ 280°C | ~ 870°C |
| PREN (Pitting Resistance Equivalent) | ≥ 45 | ~ 25 – 27 | ~ 40 – 45 | ≥ 60 |
| NACE MR0175 Sour Service | ✅ Yes (Annealed) | ❌ No | ⚠️ Limited (Hardness Sensitive) | ✅ Yes (Annealed) |
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Why Choose Gnee Alloy as Your Reactor Liner Supplier
Gnee Alloy, a supplier specializing in nickel-based alloys, boasts over 18 years of experience exporting professional nickel alloy products. We offer more than just sheet metal; we provide end-to-end project assurance.
✅️Reactor-Specific Inventory
We maintain a year-round stock of ASTM B443 / ASME SB-443 Inconel 625 sheet metal in various standard thicknesses. Most standard orders can be shipped within 48 hours.
✅️In-House Precision Machining
Our machining center offers cutting, chamfering, surface finishing, and marking services, providing ready-to-use liner assemblies that reduce your machining workload and scrap loss.
✅️Fully Compliant and Traceable
Each shipment includes a complete, traceable factory test report with full chemical and mechanical data. ASME stamp, EN 10204 3.1B certificate, and third-party inspection are standard options.
✅️On-Demand Technical Support
Our in-house engineering team provides comprehensive support to your team, from material selection and thickness calculations to welding process guidance and corrosion testing advice, all free of charge.
✅️Global Export and Project Logistics
We regularly supply materials for reactor projects in over 30 countries, handling all export documentation, customs clearance, and on-site delivery. We understand the documentation requirements for pressure vessel projects in major markets.
Gnee Alloy inconel 625 Lining Plates certificate
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Gnee Alloy 625 Lining Plates Packaging
All stainless steel products are:
✅️Packed in wooden pallets or crates
✅️Covered with moisture-proof wrapping
✅️Labeled with heat number, standard, and size
✅️Shipped worldwide via sea, air, or express
Gnee Alloy 625 Alloy Packaging
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Gnee Alloy Production Equipment and Product Testing
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FAQ
Q1: Is Inconel 625 interchangeable with Hastelloy C276 for linings?
A: It depends on the acid. Inconel 625 is superior for oxidizing acids and thermal fatigue. However, for reducing acids like hot Hydrochloric (HCl), Hastelloy C276 is the mandatory upgrade. We provide technical audits to ensure you choose the most Cost-effective Solution.
Q2: Can I weld Inconel 625 lining plates directly to a carbon steel shell?
A: Yes, via cladding or "loose lining" methods. We recommend matching Alloy 625 (ERNiCrMo-3) filler metal to handle the dilution from the base steel while maintaining a corrosion-resistant seal.
Q3: What is the lead time for custom-cut reactor head "petals"?
A: We maintain a massive Wholesale Inventory of master sheets. Custom precision blanking typically takes only 5-7 business days for global dispatch.
Q4: Do you offer bulk discounts for petrochemical refinery overhauls?
A: Absolutely. As a direct manufacturer, we support long-term MRO (Maintenance, Repair, and Overhaul) contracts with attractive tiered pricing and priority inventory reserves.