Difference Between Inconel 625 and 718

INCONEL 625 (ALLOY 625 UNS N06625)

Common Trade Names :
Inconel 625®, Chronin® 625, Altemp® 625, Haynes® 625, Nickelvac® 625, Nicrofer® 6020

Inconel ® 625 is a nonmagnetic, corrosion and oxidation resistant, nickel-base alloy. Alloy 625 has high strength and toughness in the temperature range cryogenic to 2000°F (1093°C) which is derived largely from the solid solution effects of the refractory metals, columbium and molybdenum, in a nickel-chromium matrix. Alloy 625 has excellent fatigue strength and stress - corrosion cracking resistance to chloride ions.

INCONEL® 625 LCF is a variant of INCONEL® 625. LCF stands for Low Cycle Fatigue. This means that the alloy has improved cycle fatigue properties and better thermal fatigue resistance. In other aspects such as chemical composition and other mechanical properties the alloy is similar to INCONEL® 625. The alloy is e.g. used for bellows, aircraft exhausts and expansion joints.

Chemical Analysis of ALLOY 625 (UNS N06625)
Common Names : Inconel 625®, Chronin® 625, Altemp® 625, Haynes® 625, Nickelvac® 625, Nicrofer® 6020

ASTM Specifications

Pipe Smls	Pipe Welded	Tube Smls	Tube Welded	Sheet/Plate	Bar	Forging	Fitting	Wire
B444	B705	B444	B704	B443	B446	-	-	-

Mechanical Properties
Representative Tensile Properties, bar, 1800° F anneal

Temp° F	Tensile (psi)	.2% Yield (psi)	Elongation in 2 “ (%)
70	144,000	84,000	44
400	134,000	66,000	45
600	132,000	63,000	42.5
800	131,500	61,000	45
1000	130,000	60,500	48
1200	119,000	60,000	34
1400	78,000	58,500	59
1600	40,000	39,000	117

Inconel 625 Melting Point

Melting Point

1290 - 1350 °C

2350 - 2460 °F

Inconel 625 Equivalent

STANDARD	WERKSTOFF NR.	UNS	JIS	BS	GOST	AFNOR	EN
Inconel 625	2.4856	N06625	NCF 625	NA 21	ХН75МБТЮ	NC22DNB4MNiCr22Mo9Nb	NiCr23Fe

INCONEL 718 （UNS N07718）

Inconel Alloy 718 is austenitic nickel-based superalloy. Inconel 718 is designated as UNS N07718 and Werkstoff Number 2.4668. Inconel 718 is also known as Nicrofer 5219, Superimphy 718, Haynes 718, Pyromet 718, Supermet 718. and Udimet 718. Inconel 718 Chemistry is Nickel 52%, Chromium 19%, Iron, 18%, Columbium 5%, Molybdenum 3%, Titanium 1%. Alloy 718 is mainly used in Gas turbine engines ducts, cryogenic tanks, springs and fasteners and motor components. For most applications, Alloy 718 / Inconel 718 is specified as: solution annealed and precipitation hardened. Inconel Alloy 718 is hardened by the precipitation of secondary phases.

Inconel 718 Chemical Composition, %

Ni	Fe	Cr	Cu	Mo	Nb	C	Mn
50.00-55.00	Remainder	17.00-21.00	.30 max	2.80-3.30	4.75-5.50	.08 max	.35 max

P	S	Si	Ti	Al	Co	B
.015 max	.015 max	.35 max	.65-1.15	.20-.80	1.00 max	.006 max

Inconel 718 ASTM Specifications

Sheet/Plate	Bar	Wire
B670	B637	-

Inconel 718 Mechanical Properties
Typical room temperature properties, 1800°F annealed condition

Ultimate Tensile Strength, psi	.2% Yield Strength psi	Elongation %	Hardness Rockwell B
135,000	70,000	45	100

Inconel 718 Melting Point

	Solution Treated	Solution Treated and Aged
Density	0.296 lb/in3 (8.192 g/cm3)	0.297 lb/in3 (8.22 g/cm3)
Specific Gravity	8.19	8.22
Melting Range	2500-2600°F	1370-1430°C

Inconel 718 Equivalent

STANDARD	WERKSTOFF NR.	UNS	JIS	BS	GOST	AFNOR	EN
Inconel 718	2.4668	N07718	NCF 718	–	–	–	–

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