Alloy 718 | 2.4668 | API 6A

UNS N07718 | ASTM B637 | ASTM B670 | NACE MR0175

Alloy 718 is a precipitation hardened nickel-chromium alloy with additions of niobium, molybdenum, aluminium and
titanium for improved corrosion resistance combined with extremely high strength and excellent weldability.

Though originally developed for aerospace applications the unique combination of strength and corrosion resistance
of Alloy 718 made it candidate for applications in the oil and gas sector. As well environments became more severe
stress corrosion and hydrogen embrittlement became a challenge the chemistry and microstructure of Alloy 718 was
optimised to offer the greatest resistance and distinguishes today’s oil field grade (API 6A) from aerospace grades.

 

For oil and gas applications Alloy 718 is produced to meet API 6A and NACE MR0175 requirements. The specification
API 6A has tighter controls on chemistry and is heat treated following a different solution annealing and precipitation
hardening procedure as compared to the AMS specifications.

 

With different specification and heat treatment procedures resulting in optimised properties for the industry sector
it is important to understand which specification is required.

 

Please see our datasheet Alloy 718 | AMS 5662 | AMS 5663 for more information on Alloy 718 for aerospace applications.

 

Areas of application for ALLOY 718 | 2.4668 | API 6A

down hole tools, pump shafts and impellers, pressure vessels and tanks, valves

Contact us if you have any questions.

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Available from stock in the following dimensions

  • 12,70 mm Ø
  • 19,05 mm Ø
  • 25,40 mm Ø
  • 34,925 mm Ø
  • 41,20 mm Ø
  • 50,80 mm Ø
  • 63,50 mm Ø
  • 76,20 mm Ø
  • 88,90 mm Ø
  • 101,60 mm Ø
  • 114,30 mm Ø
  • 127,00 mm Ø
  • 152,40 mm Ø

Details at a glance

Chemical composition - limits in % according API 6A

Ni
50,00 - 55,00
Cr
17,00 - 21,00
Nb
4,87 - 5,20
Mo
2,80 - 3,30
Co
max. 1,00
Ti
0,80 - 1,15
Al
0,40 - 0,60
Mn
max. 0,35
Si
max. 0,35
Cu
max. 0,23
C
max. 0,045
P
max. 0,010
B
max. 0,006
Pb
max. 0,001
Se
max. 0,0005
Bi
max. 0,00005
Fe
Rest

Physical constants and thermal properties

Density
8,19 g/cm³
Melting point
1260 - 1336 °C
Thermal conductivity at 20°C
9,5 W/m · °C
Coefficient of expansion at 21 - 93°C
13,1 μm/m · °C

Mechanical properties - room temperature according API 6A

Yield strength
min. 827 MPa
Tensile strength
min. 1034 MPa
Elongation
min. 20%
Hardness
32-40 HRC
NACE MR0175
requires hardness 40 HRC max. only

Downloads

Downloads

Datasheets_Alloy 718.pdfDatasheets_Alloy 718.pdf