Difference between Inconel 600 flange and 625 alloy flange

Inconel 600 flanges are made of nickel-chromium-iron alloy and are renowned for their excellent high-temperature resistance and oxidation resistance; while Inconel 625 flanges are made of nickel-chromium-molybdenum alloy, offering higher strength and superior corrosion resistance, making them particularly suitable for environments with high chloride content. Adding molybdenum to the 625 alloy improves its corrosion resistance and strength, but also increases cost and processing difficulty.

Are Nickel Alloy 600 and Inconel 600 the same alloy?

Nickel Alloy 600, also sold under the brand name Inconel 600, is a unique nickel-chromium alloy known for its oxidation resistance at high temperatures. It has a wide range of applications, suitable for high-temperature applications from low temperatures up to 2000°F (1093°C).

The Inconel 600 flange is a pipe fitting made of a high-performance nickel-chromium alloy (Inconel 600) designed for extreme operating conditions. Its high nickel content allows it to maintain strength at high temperatures (up to approximately 1150°C) and provides excellent resistance to oxidation, chloride stress corrosion, and various acid and alkali media. Therefore, it is primarily used in applications where cost is not a primary concern but reliability and safety are paramount, such as nuclear reactors, high-temperature chemical plants, aero-engines, and highly corrosive fluid handling systems. Its core value lies in providing a robust and durable sealing solution for harsh environments where stainless steel or carbon steel cannot meet the requirements, but at a significantly higher cost in terms of material purchase and processing.

The Inconel 625 flange is a key fitting made of a high-performance nickel-chromium alloy (Inconel 625). Building upon the Inconel 600, it achieves even more comprehensive and robust performance through the addition of molybdenum and niobium. It not only inherits excellent high-temperature oxidation and chloride ion corrosion resistance, but also significantly enhances its resistance to pitting corrosion, crevice corrosion, and reducing acid media due to the reinforcement of molybdenum. Meanwhile, the addition of niobium gives it excellent creep resistance and endurance strength at high temperatures. Therefore, it is a top-tier solution for dealing with extremely complex corrosive environments (such as offshore platforms, hydrometallurgy, and harsh chemical processes) and high-temperature, high-pressure scenarios (such as aerospace hot-end components), representing broader and more robust corrosion resistance than Inconel 600, but at a correspondingly higher cost.

Standard Specification For Inconel 600 / 625 Flanges

Specifications : ASTM B564 / ASME SB564

Dimensions : ANSI/ASME B16.5, B 16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, etc.

Standard : ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, etc.

Size : 1/2" (15 NB) to 48" (1200NB)

Class/Pressure : 150#, 300#, 600#, 900#, 1500#, 2500#, PN6, PN10, PN16, PN25, PN40, PN64 etc.

Flange Face Type : Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ)

Type : Slip on flanges, Socket weld flanges, Forged flanges, Blind flanges, Welding neck flange, Ring type joint flange, Spectacle blind flange, Reducing flange, Threaded / Screwed flange, Tongue and Groove flange, Long weld neck flange, Flat flange, Industrial flanges, Plate flange, ASME B16.5 flanges.

600 / 625 Inconel Flanges Equivalent Grades

STANDARD	WERKSTOFF NR.	UNS	JIS	BS	GOST	AFNOR	EN
Inconel 600	2.4816	N06600	NCF 600	NA 13	МНЖМц 28-2,5-1,5	NC15FE11M	NiCr15Fe
Inconel 625	2.4856	N06625	NCF 625	NA 21	ХН75МБТЮ	NC22DNB4M	NiCr22Mo9Nb

Differnt Types of Inconel Alloy 600 / 625 Flanges

Inconel 600 Alloy SWRF Flange

ASTM B564 718 Grade Threaded Flange

600 Inconel Threaded Flange

Inconel 600 Alloy Weld Neck Flange

UNS N06600 Industrial Flange

Inconel 601 Threaded Flange

601 Inconel Sliding Flange

Inconel 601 RTJ Flange Distributor

Inconel 600 Orifice Plate Flange Supplier

Inconel 718 Alloy Forged Flange

Inconel 718 Raised Face Flange

Inconel 625 Alloy WNRF Flange

Inconel 600 Flat Face Flange

Alloy 601 Blind Flange Manufacturer

ASME 16.5 Inconel 600 SORF Flange

Inconel 718 Socket Welding Flange

Alloy 625 Lap Flange

625 Inconel WNRF Flange Manufacturer

Chemical Composition of Inconel 600 / 625 Flanges

Grade	C	Mn	Si	S	Cu	Fe	Ni	Cr	Al	Ti
Inconel 600	0.10 max	1.50 max	1.00 max	0.015 max	0.75 max	39.50 min	30 – 35	19 – 23	0.15 – 0.60	0.15 – 0.60
Inconel 625	0.06 – 0.10	1.50 max	1.00 max	0.015 max	0.75 max	39.50 min	30 – 35	19 – 23	0.15 – 0.60	0.15 – 0.60

Mechanical Properties of Inconel 600 / 625 Flange

Grade	Density	Melting Point	Tensile Strength	Yield Strength (0.2%Offset)	Elongation
Inconel 600	8.47 g/cm3	1413 °C (2580 °F)	Psi – 95,000 , MPa – 655	Psi – 45,000 , MPa – 310	40 %
Inconel 625	8.4 g/cm3	1350 °C (2460 °F)	Psi – 1,35,000 , MPa – 930	Psi – 75,000 , MPa – 517	42.5 %

Feature	Inconel 600 Flange	Inconel 625 Flange
Composition	Nickel-Chromium-Iron alloy	Nickel-Chromium-Molybdenum alloy
Corrosion Resistance	Good resistance in high-temperature and non-chloride environments	Excellent resistance to a wide range of corrosive environments, including high-chloride, pitting, and stress-corrosion cracking
Strength	High strength, but lower than 625	Higher tensile and yield strength
High-Temperature Performance	Excellent	Excellent, with superior oxidation resistance at extreme temperatures
Cost	More cost-effective	More expensive due to complex composition and processing
Machinability	Generally easier to machine	More difficult to machine due to its toughness
Common Applications	Chemical processing, heat treating, and aerospace	Petrochemical, aerospace, marine engineering, and high-pressure/temperature systems