Nickel Alloy 625 – Properties, Composition, Corrosion Data and Specifications

Nickel Alloy 625 is used both for its high strength and outstanding aqueous corrosion resistance. The strength of Nickel Alloy 625 is primarily a solid solution effect from molybdenum and columbium. Nickel Alloy 625 has excellent weldability. The matching filler metals are often used for dissimilar metal joining and to weld the aqueous corrosion alloy AL-6XN®.

Features of Nickel Alloy 625

The key features of Nickel Alloy 625 include:

  • Outstanding resistance to chloride pitting and crevice corrosion cracking
  • Immune to chloride ion stress corrosion cracking
  • Resistant to caustics
  • Resistant to seawater, in both flowing and stagnant • conditions, and under fouling

Applications of Nickel Alloy 625

Typical Applications for the Nickel Alloy 625 include:

  • Chemical process equipment handling mixed acids both oxidizing and reducing
  • Flue gas desulfurization scrubbers
  • Evaporators for wet-process phosphoric acid containing H2SO4, HF and ferric salts
  • Weld Overlay

Composition of Nickel Alloy 625

The composition range for Nickel Alloy 625 is provided in table 1.

Table 1. Composition of nickel alloy 625.

Chemistry, %

AMS 4967

Min

Max

Chromium

20.00

23.0

Nickel

58.00

Balance

Molybdenum

8.00

10.00

Cobalt

-

1.00

Columbium + Tantalum

3.15

4.15

Aluminum

-

0.40

Titanium

-

0.40

Carbon

-

0.10

Iron

-

5.00

Manganese

-

0.50

Silicon

-

0.50

Phosphorus

-

0.015

Sulfur

-

0.015

Specifications

The various forms of nickel alloy 625 are covered by the following standards:

  • UNS/W. Nr N06625/2.4856
  • Rod and bar ASTM B 446 and ASME SB-446 Gr 1

Physical Properties of Nickel Alloy 625

Density:

0.305 lb/inch3

Melting Range:

2350-2460°F

Thermal Properties of Nickel Alloy 625

The thermal properties of Nickel Alloy 625 are summarised in table 2.

Table 2. Thermal properties of Nickel Alloy 625.

Temp

Coefficient of Thermal Exp.

Thermal Conductivity

Modulus of Elasticity Dynamic

°F

in/in °F x 10-6

Btu. ft/ft2.hr°F

psi x 106

70

-

5.7

29.8

400

7.3

7.2

28.4

600

7.4

8.2

27.5

800

7.6

9.1

26.6

1000

7.8

10.1

25.6

1200

8.2

11.0

24.4

1400

8.5

12.0

23.1

1600

8.8

13.2

-

Typical Mechanical Properties of Nickel Alloy 625

The minimum mechanical properties of nickel alloy 625 are provided in table 3.

Table 3. Minimum Specified Tensile Properties, Room Temperature ASTM B 446 Bar, Grade 1

Property

Value

Ultimate Tensile Strength

120 ksi

0.2% Yield

60 ksi

Elongation (2”)

30%

Corrosion Resistance of Nickel Alloy 625

Table 4. Corrosion by quiet & flowing seawater, Wrightsbille Beach, NC.

Alloy

Quiet

Flowing, 2 ft/sec

Weight Loss, g

Range of Pit Depth, mils

Weight Loss, g

Range of Pit Depth, mils

Panel

Crevice Area

Panel

Crevice Area

625

Nil

Nil

Nil

0.25

Nil

Nil

C-276

Nil

Nil

Nil

0.10

Nil

Nil

René 41

0.80

Nil

Nil

0.30

Nil

Nil

X

0.10

Nil

Nil

0.60

Nil

Nil

825

0.25

0-1

0-9

0.20

3-6

1-26

718

2.70

Nil

37-165P

5.15

Nil

40-165P

Test duration two years. P=perforated by local attack

Table 5. Crevice corrosion temperature (CCT).

Alloy

UNS No.

Molybdenum Content

°C

°F

Pitting Resistance Equivalent, (PRE)N

316L

S31603

2.1

-3

27

23

825

N08825

2.7

-3

27

30

2205

S31803

3.1

20

68

38

317L

S31703

3.2

2

35

29

AL-6XN®

N08367

6.2

43

110

48

625

N06625

9.0

45

113

51

C-276

N10276

15.4

55

130

66

10% FeCl3.6H2O, per ASTM G 48 Practice B

(PRE) N=Cr + 3.3Mo + 16N

This information has been sourced, reviewed and adapted from materials provided by NeoNickel.

For more information on this source, please visit NeoNickel.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    NeoNickel. (2019, May 01). Nickel Alloy 625 – Properties, Composition, Corrosion Data and Specifications. AZoM. Retrieved on September 18, 2019 from https://www.azom.com/article.aspx?ArticleID=4189.

  • MLA

    NeoNickel. "Nickel Alloy 625 – Properties, Composition, Corrosion Data and Specifications". AZoM. 18 September 2019. <https://www.azom.com/article.aspx?ArticleID=4189>.

  • Chicago

    NeoNickel. "Nickel Alloy 625 – Properties, Composition, Corrosion Data and Specifications". AZoM. https://www.azom.com/article.aspx?ArticleID=4189. (accessed September 18, 2019).

  • Harvard

    NeoNickel. 2019. Nickel Alloy 625 – Properties, Composition, Corrosion Data and Specifications. AZoM, viewed 18 September 2019, https://www.azom.com/article.aspx?ArticleID=4189.

Comments

  1. lavanya Ravichandran lavanya Ravichandran India says:

    THIS IS STAIN LESS STEEL

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of AZoM.com.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit