Differences between Inconel 600 and 625 sheets
Differences between Inconel 600 and 625 sheets
Both Inconel 600 and 625 plates are nickel-chromium alloys, but Inconel 625 plates, due to the addition of a large amount of molybdenum and a higher chromium content, have superior corrosion resistance and strength, making them more suitable for harsh marine/chemical environments. Inconel 600 plates, with a higher nickel content, have better resistance to high chlorides (though overall not as good as 625 plates) and perform slightly better in some ultra-high temperature furnace applications. 600 plates are a more basic alloy, while 625 plates are a more advanced, stronger alloy with better weldability.
What are the advantages of Inconel 625?
Inconel 625 alloy is an ideal choice for seawater applications because it possesses the following characteristics: it is not prone to localized corrosion (pitting and crevice corrosion), has high corrosion fatigue strength, high tensile strength, and is resistant to chloride stress corrosion cracking.
Chemical Composition of Inconel 600 and Inconel 625 Alloy Plates
| Element | Inconel 600 (ASTM B168 Plate) | Inconel 625 (ASTM B443 Plate) |
|---|---|---|
| Nickel (Ni) | ≥ 72.0 % | ≥ 58.0 % |
| Chromium (Cr) | 14.0 - 17.0 % | 20.0 - 23.0 % |
| Iron (Fe) | 6.0 - 10.0 % | ≤ 5.0 % |
| Molybdenum (Mo) | - | 8.0 - 10.0 % |
| Niobium (Nb) + Tantalum (Ta) | - | 3.15 - 4.15 % |
| Manganese (Mn) | ≤ 1.0 % | ≤ 0.50 % |
| Carbon (C) | ≤ 0.15 % | ≤ 0.10 % |
| Silicon (Si) | ≤ 0.50 % | ≤ 0.50 % |
| Sulfur (S) | ≤ 0.015 % | ≤ 0.015 % |
| Copper (Cu) | ≤ 0.50 % | ≤ 0.070 % |
| Phosphorus (P) | ≤ 0.015 % | ≤ 0.015 % |
| Aluminum (Al) | - | ≤ 0.40 % |
| Titanium (Ti) | - | ≤ 0.40 % |
| Cobalt (Co) | - | ≤ 1.0 % |
Inconel 600 Alloy Plate: High nickel content (approximately 76%), approximately 15% chromium, contains iron, and very low levels of other elements.
Inconel 625 Plate: Low nickel content (approximately 58%), high chromium content (20-23%), high molybdenum content (8-10%), contains niobium and iron.
Corrosion Resistance of Inconel 600 and Inconel 625 Plates
| Environment / Corrosion Type | Inconel 600 Plate | Inconel 625 Plate |
|---|---|---|
| General Principle | Good resistance in high-temperature, non-chloride oxidizing environments. | Excellent, broad-spectrum resistance in both oxidizing and reducing environments, particularly against localized corrosion. |
| Oxidizing Environments | Excellent. Maintains resistance due to a stable chromium oxide (Cr₂O₃) surface film. Performs well in air, steam, and combustion atmospheres up to ~1175°C. | Excellent. Also forms a stable Cr₂O₃ film. Effective in hot oxidizing media like nitric acid (HNO₃) and mixed acids. |
| Chloride-Induced Stress Corrosion Cracking (Cl-SCC) | Poor to Moderate. Susceptible in hot, concentrated chloride solutions (e.g., >42% MgCl₂). | Excellent. One of its key advantages. The high Mo and Nb content provides superior resistance in hot chloride-bearing water and brines. |
| Pitting & Crevice Corrosion | Poor to Moderate. Lacks molybdenum, making it vulnerable in halide-containing solutions. | Outstanding. High molybdenum (Mo) content provides exceptional resistance, especially in seawater and chemical process streams. |
| Reducing / Non-Oxidizing Acids | Poor. Limited resistance to acids like sulfuric (H₂SO₄) and hydrochloric (HCl) without oxidizing agents. | Very Good to Excellent. The Ni-Cr-Mo-Nb composition offers good resistance to a wide range of non-oxidizing acids. |
| Caustic Environments | Excellent. Highly resistant to hot alkaline solutions and molten hydroxides. | Excellent. Also highly resistant to caustic attack. |
| High-Temperature Oxidation | Primary Strength. Excellent resistance to scaling and oxidation in air up to 1175°C. | Excellent. Also offers very good oxidation resistance, though often used for its strength and other corrosion properties at high temps. |
| Organic Acids | Good resistance to many organic acids (e.g., acetic) under mild conditions. | Excellent resistance to a broader range of organic acids, including more aggressive conditions. |
| Marine / Seawater | Limited use; susceptible to pitting and stress corrosion cracking. | Preferred Material. Excellent resistance to pitting, crevice corrosion, and erosion-corrosion in seawater. |
Inconel 600 Plate: Good high-temperature resistance, but susceptible to chloride stress corrosion cracking.
Inconel 625 Plate: Excellent overall corrosion resistance; due to the presence of molybdenum, it is less susceptible to chloride stress corrosion cracking and pitting corrosion.
Inconel 600 and Inconel 625 Sheets: Strength and Temperature
| Property | Inconel 600 Plate | Inconel 625 Plate |
|---|---|---|
| Room Temperature Mechanical Strength | ||
| Typical Yield Strength (0.2% Offset) | 240 - 415 MPa (35 - 60 ksi) | 415 - 550 MPa (60 - 80 ksi) |
| Typical Ultimate Tensile Strength | 550 - 655 MPa (80 - 95 ksi) | 830 - 950 MPa (120 - 138 ksi) |
| Elevated Temperature Strength | ||
| Key Characteristic | Maintains useful strength, but primarily valued for oxidation resistance at very high temperatures. | Maintains significantly higher strength than Inconel 600 at all elevated temperatures due to solid-solution strengthening (Mo, Nb). |
| Maximum Recommended Service Temperature | ||
| Continuous Service (Oxidizing) | Up to ~1175°C (2150°F) for oxidation resistance. | Up to ~980°C (1800°F) for corrosion/strength applications. Up to ~1095°C (2000°F) for oxidation resistance. |
| High-Temperature Capability Focus | ||
| Primary Advantage | Exceptional oxidation and carburization resistance at extreme temperatures. Its strength at these highs is secondary. | Excellent combination of high strength, fatigue resistance, and oxidation/corrosion resistance at intermediate to high temperatures. |
| Creep Strength | Moderate creep rupture strength. | Superior creep and creep rupture strength compared to Inconel 600, especially in the 650°C - 980°C (1200°F - 1800°F) range. |
Inconel 600 Sheets: Suitable for high-temperature environments, but strength decreases significantly at extreme temperatures.
Inconel 625 Sheets: High strength at high temperatures, better oxidation resistance, suitable for aerospace/chemical industries.
Main Applications of Inconel 600 and Inconel 625 Sheets
| Industry / Application Area | Inconel 600 Plate | Inconel 625 Plate |
|---|---|---|
| Core Application Philosophy | Selected for high-temperature oxidation resistance and stability in non-chloride atmospheres, where extreme heat is the primary concern. | Selected for exceptional corrosion resistance (especially to chlorides) combined with high strength in aggressive chemical and marine environments. |
| Thermal Processing & Heat Treating | Primary Use. Furnace muffles, retorts, radiant tubes, baskets, and structural components for continuous service up to 1175°C. | Used for fixtures, trays, and fans where both heat and corrosive atmospheres (e.g., salt, sulfur) are present. |
| Chemical & Petrochemical Processing | Used in non-chloride environments: Caustic soda (NaOH) handling, phenol condensers, and equipment for fatty acid processing. | Primary Use. Reactors, columns, heat exchangers, and piping for handling sulfuric, phosphoric, and hydrochloric acids, chloride-containing streams, and aggressive organic chemicals. |
| Power Generation | Steam superheater tubes, nuclear reactor control rod cladding, and core components in non-aggressive high-temperature steam. | Flue Gas Desulfurization (FGD) systems (dampers, scrubbers), wet scrubber internals, and critical components in advanced supercritical plants. |
| Aerospace & Gas Turbines | Combustion cans, thermocouple tubes, and engine nacelles in older designs. Primarily for heat resistance. | Extensively Used. Jet engine ducting, fire seals, thrust reverser systems, and casings. Valued for high strength-to-weight ratio and corrosion resistance. |
| Marine & Offshore | Limited use, primarily for non-structural high-temperature parts. | Critical Material. Seawater piping, propeller blades, subsea components, and fasteners due to superb resistance to pitting and stress corrosion cracking. |
| Pollution Control & Waste Processing | Incinerator internals and heat recovery sections. | Scrubbers, fans, and ducting in harsh, wet corrosive exhaust environments. |
| Nuclear Industry | Steam generator tubing and core components in certain water-cooled reactor designs. | Used for more specialized, high-strength, corrosion-resistant components and spent fuel handling. |
| Oil & Gas | Downhole instrumentation housings in high-temperature, sweet (non-sour) wells. | Downhole tool components, wellhead parts, and components for sour service (H₂S-containing) and deep, high-pressure, high-temperature (HPHT) wells. |
Inconel 600 Sheets: Heat exchangers, chemical processing, furnace components.
Inconel 625 Sheets: Marine engineering, petrochemicals, aerospace, highly corrosive environments.
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅ Over 18 years of export experience, products sold to more than 80 countries
✅ Certified by ISO, SGS, and BV
✅ Global inventory of Inconel, Hastelloy, Incoloy, and Monel alloy tubing, plates, and bars
✅ Custom processing services available – including cutting, polishing, CNC machining, and packaging
✅ Fast delivery within 7-15 days, supported by global logistics partners
📦 Packaging and Shipping
All stainless steel products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel also supplies custom Inconel 600 products in various sizes and specifications. Please send us your drawings for a quote!
Gnee Steel is a supplier of Inconel 600 alloy, offering a wide range of products including: seamless pipe (sizes: 4-219 mm; thickness: 0.5-20 mm); welded pipe (sizes: 5.0-1219.2 mm; thickness: 0.5-20 mm); plates (thickness: 0.1 to 100 mm; width: 10-2500 mm); strips; alloy round bars (diameter: 3-800 mm); flat bars (thickness: 2-100 mm; width: 10-500 mm); hexagonal bars (size: 2-100 mm); wire rods; and extruded profiles. We collaborate with steel mills to provide our customers with Inconel 600 alloy products that meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells Inconel 600, pipes, plates, strips, round bars, flat bars, forged billets, hexagonal steel, wire rods, and extruded profiles. Please feel free to contact us at ss@gneesteel.com for a quote.
