Inconel 625 Alloy

Gnee Alloy currently offers the Inconel 625 in various product forms and typical sizes

Product Form	Standard	Typical Size Range
Plate	ASTM B443	3mm–100mm thickness
Sheet	ASTM B443	0.3mm–3mm thickness
Bar (Round)	ASTM B446	6mm–300mm diameter
Seamless Tube	ASTM B444	OD 6.35mm–150mm
Seamless Pipe	ASTM B444	NPS 1/8 to 8

 

 

Inconel Alloy 625 Chemical Composition

Element	Content
	Nickel (Ni)	58% min
	Chromium (Cr)	20% to 23%
	Molybdenum (Mo)	8% to 10%
	Columbium + Tantalum (Nb + Ta)	3.15% to 4.15%
	Iron (Fe)	5.0% max
	Carbon (C)	0.10% max
	Manganese (Mn)	0.50% max
	Silicon (Si)	0.50% max
	Phosphorus (P)	0.015% max
	Sulfur (S)	0.015% max
	Aluminum (Al)	0.40% max
	Titanium (Ti)	0.40% max

 

Typical Inconel 625 Mechanical Properties

Material	Form and Condition	Tensile Strength MPa		Yield Strength (0.2% Offset) MPa		Elongation 4D(%)	Hardness HB
		Ksi	MPa	Ksi	MPa
Alloy 625 Bar	Annealed	120	827	60	414	30	≤ 287 HB
Alloy 625 Sheet	Annealed	120	827	60	414	30	145-240
Alloy 625 Tube Seamless and Welded	Annealed	120	827	60	414	35	-

 

Inconel 625 Physical Properties

Property	21°C	204 °C	316 °C	427 °C	538 °C	649 °C	760 °C	871 °C
Ultimate Tensile Strength /Mpa	992.9	923.9	910.1	910.1	896.3	820.5	537.8	275.8
0.2% Yield Strength /MPa	579.2	455.1	434.4	420.6	420.6	413.7	406.8	268.9
Elongation %	44	45	42.5	45	48	34	59	117
Coefficient of Thermal Expansion µm/m⁰C	-	13.1	13.3	13.7	14	14.8	15.3	15.8
Thermal Conductivity /kcal/(hr.m.°C)	8.5	10.7	12.2	13.5	15	16.4	17.9	19.6
Modulus of Elasticity MPa x 105	2.07	1.98	1.92	1.86	1.79	1.65	1.59	1.48

Click to download the Inconel 625 alloy PDF file now

 

 

Resistance to Pitting and Crevice Corrosion

The Pitting Equivalent Value (PREN) is a commonly used indicator for comparing chloride pitting resistance. For Inconel 625:

 

PREN = %Cr + 3.3 × %Mo + 16 × %N

A typical PREN value for Inconel 625: 21.5 + (3.3 × 9.0) + 0 ≈ 51.2

 

Inconel 625 corrosion resistance

Environment	Resistance Level	Notes
Oxidizing Acids (HNO₃)	Excellent	-
Reducing Acids (H₂SO₄, HCl)	Excellent	High Mo content provides excellent resistance
Chloride Pitting	Excellent	-
Crevice Corrosion	Excellent	-
Chloride Stress Corrosion Cracking	Excellent	-
Seawater	Excellent	-
High-Temperature Oxidation (to 980°C)	Excellent	-
Sour Gas (H₂S/CO₂)	Excellent	NACE MR0175 compliant

Corrosion Resistance Rating (1-5, 5 = best)

Environment	Inconel 625
Sulfuric Acid	5
Hydrochloric Acid	5
Seawater	5
Chloride SCC	5
High-Temp Oxidation (980°C)	5

 

 

625 Alloy Round Bar Products

Diameter (mm)	Length (mm)	Tolerance	Surface
6 – 25	2000 – 6000	h6 – h8	Ground / Bright
25 – 50	2000 – 6000	h6 – h8	Ground / Bright
50 – 100	2000 – 4000	h7 – h9	Black / Rough Turned
100 – 200	1000 – 3000	h8 – h10	Black / Rough Turned

Inconel 625 Tube Products

OD (mm)	Wall Thickness (mm)	Tolerance	Surface
6 – 30	0.5 – 3.0	±0.05 – ±0.10 mm	BA / AP
30 – 50	1.0 – 5.0	±0.10 – ±0.15 mm	BA / AP
50 – 100	2.0 – 8.0	±0.15 – ±0.30 mm	BA / AP

Uns N06625 Alloy Plate Products

Thickness (mm)	Width (mm)	Length (mm)	Tolerance
0.5 – 4.0	500 – 1200	1000 – 3000	±5% – ±10%
4.0 – 10.0	500 – 1500	1000 – 4000	±5% – ±10%
10.0 – 25.0	500 – 1500	1000 – 4000	±5% – ±10%

Contact us to customize Inconel 625 products to fit your project dimensions

 

 

 

Industry	Applications	Key Reasons / Details
Oil & Gas	- Subsea umbilicals - Wellhead components - Riser systems - Chemical injection lines	- Excellent seawater corrosion resistance and sulfide stress cracking (SSC) resistance - NACE MR0175 compliant for H₂S-containing fluids - Used in flexible risers (armor & pressure sheaths) for FPSOs - Small-bore tubing for corrosion inhibitors, methanol, scale inhibitors
Aerospace & Defense	- Jet engine exhaust systems - Rocket engine thrust chambers - Aircraft skin components (supersonic) - Helicopter rotor hubs & seals	- Oxidation resistance above 800°C (combustion liners, afterburners) - Used in nozzle extensions (NASA & commercial launches) - Withstands aerodynamic heating where Al or Ti are unsuitable - Fatigue resistance and toughness
Chemical Processing	- Heat exchangers (phosphoric, sulfuric, HCl) - Reaction vessels (corrosive organic acids) - Scrubber systems (mixed acid vapors & chlorides) - Distillation columns (pharma & fine chemicals) - Mixers & tanks (mechanical wear + chemical attack)	- Resists a wide range of strong acids and mixed corrosive streams - Suitable for high-temperature and high-purity processes
Marine & Naval	- Propeller shafts & propellers (high-performance ships) - Seawater piping systems (naval & research vessels) - Submarine pressure hull penetrations - Sonar domes & transducer housings (non-magnetic)	- Extreme resistance to chloride corrosion, biofouling, and mechanical loads - Non-magnetic property required for certain sonar applications
Nuclear Power	- Steam generator tubing (PWRs) - Reactor pressure vessel internals - Fuel assemblies (dimensional stability at high temp)	- Certified for light water reactors (LWRs) - Withstands high neutron fluence and coolant chemistry - Maintains dimensional stability under high temperature

 

 

Test Method	Requirement	Standard	Acceptance Criteria
Ultrasonic Testing (UT)	As specified (100% for aviation)	ASTM E2375	No defects exceeding 0.8mm
Eddy Current Testing (ET)	As specified (100% for tubes)	ASTM E426	No relevant indications
Hydrostatic Test	100% (tubes/pressure parts)	ASTM B444	No leakage
Liquid Penetrant Inspection (LPI)	As specified	ASTM E1417	No relevant indications
Visual Inspection	100%	-	No surface defects

 

 

A Comparison Guide to INCONEL 625 and Other Nickel Alloys

 

Inconel 625 vs Inconel 718

Property	Inconel 625	Inconel 718
UNS	N06625	N07718
Strengthening Mechanism	Solid solution	Precipitation hardening
Max UTS (aged)	~1100 MPa	~1380 MPa
Max Service Temperature	~1000°C	~700°C
Weldability	Excellent	Good (requires post-weld heat treatment)
Corrosion Resistance	Superior	Moderate
Cost	Lower	Higher
Primary Use	Corrosion-critical environments	High-strength aerospace components

Inconel 718 delivers higher strength in its aged condition but requires a two-stage aging heat treatment and is more susceptible to stress corrosion cracking in certain environments. For applications where corrosion resistance is the primary driver, Inconel 625 is usually the correct selection.

 

Inconel 625 vs Incoloy 825

Property	Inconel 625	Incoloy 825
UNS	N06625	N08825
Nickel Content	~62%	~42%
Chromium Content	~21.5%	~21.5%
Molybdenum Content	~9%	~3%
Pitting Resistance (PREN)	~51	~32
Tensile Strength	827 MPa	586 MPa
Cost	Higher	Lower
Application Fit	Severe corrosion environments	Moderately aggressive environments

Incoloy 825 is significantly less expensive and is adequate for many oil and gas applications in sweet service. However, when chloride concentrations increase or temperatures rise, Inconel 625's higher molybdenum content makes it the more reliable choice.

 

Inconel 625 vs Hastelloy C-276

Property	Inconel 625	Hastelloy C-276
UNS	N06625	N10276
Molybdenum (%)	8–10	15–17
Chromium (%)	20–23	14.5–16.5
Pitting Resistance	~51 PREN	~60 PREN
High-Temp Oxidation	Superior	Moderate
Welding Heat Sensitivity	Lower	Higher
Cost	Lower	Higher
Application Fit	Balanced corrosion/temperature	Extreme corrosion, lower temperatures

Hastelloy C-276 has higher molybdenum and thus better resistance to reducing acids and pitting in the most aggressive chloride conditions. However, at high temperatures, C-276 is more prone to sigma phase precipitation, which can embrittle the alloy. Inconel 625 handles thermal cycling and elevated-temperature service more reliably.

 

 

Pricing is one of the first practical questions the purchasing team asks, and it's impossible to give a single figure because the cost of Inconel 625 is influenced by a variety of market and specification factors.

 

Key cost drivers for Inconel 625 alloy:

Nickel spot price: As nickel accounts for over 58% of the alloy, fluctuations in the London Metal Exchange (LME) nickel price directly impact raw material costs. Historically, nickel prices have traded between $10,000 and $50,000 per ton.

Molybdenum and niobium prices: Both are specialty metals with limited supply, which can lead to significant price volatility.

Product form: Finished products such as seamless tubes are more expensive than plates or bars.

Specification requirements: AMS certification, NACE compliance, or customer-specific testing can increase costs.

Quantity and delivery time: The cost per kilogram for spot purchases from distributor inventory is higher than the delivery time for factory orders.

 

General approximate price range (for reference only, prices are subject to market fluctuations):

Plates and sheets: $25-55/kg

Bar stock (annealed): $28-60/kg.

Seamless tube: $40-100/kg.

 

We recommend contacting Gnee Alloy directly for the latest pricing based on your specific grade, shape, certification requirements, and quantity.

 

For details, please refer to: Inconel 625 Price per lb (2026)

 

 Gnee Alloy Inconel 625 certificate

 

Q：Is Inconel 625 stainless steel?

A：Inconel refers to a series of registered trademarks of high-strength austenitic nickel-chromium-iron alloys with excellent corrosion resistance and heat resistance. These alloys have a high nickel content and can be considered super stainless steel.

 

Q：What is the material grade 625?

A：Alloy 625 is a nickel-chromium-molybdenum alloy widely used due to its high strength, high toughness, and excellent corrosion resistance. The strength of alloy 625 comes from the reinforcing effect of molybdenum and niobium on the nickel-chromium matrix.

 

Q：What are the uses of Inconel 625?

A：Inconel 625 is a high-performance nickel-chromium superalloy favored for its outstanding strength, excellent corrosion resistance, and ability to withstand extreme temperatures from low temperatures to 2000°F (1093°C).

 

Q：Will Inconel 625 rust?

A：Nickel-based alloys, such as Inconel 625 and Inconel 718, are known for their high-temperature resistance, corrosion resistance, and oxidation resistance.

 

Q：How hard is Inconel 625?

A：Inconel 625 is very tough and difficult to machine, but it is actually one of the softer and easier-to-machine alloys in the Inconel series of high-temperature alloys. Its typical hardness in the annealed state is approximately 29 HRC (compared to approximately 22 HRC for ordinary commercial steel), and its minimum tensile strength is 120,000 PSI.

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