718 NACE / NACE MRO175

718 NACE / NACE MRO175

NACE 718 is a precipitation hardened nickel-chromium alloy. It combines high strength in the aged condition with good corrosion resistance and weldability. NACE 718 indicates material stocked in the heat treated condition and provides high strength while meeting the maximum hardness requirements of the NACE MR0175, MR0103 and ISO 15156-3 specifications for use in oil tools used for sour service.

NACE 718 is annealed between 1875-1925°F and water quenched. Subsequently it is aged in the range of 1425-1475°F for 6-8 hours and air cooled or faster to room temperature.

Chemistry

 NiCrMoMnCuSiCSPCoCb+TaPbSeBMgTiAlFe
MIN 50 17 2.8 - - - - - - - 4.87 - - - - 0.8 0.4 -
MAX 55 21 3.3 0.35 0.23 0.35 0.045 0.01 0.01 1.0 5.2 1000
ppm
0.0005
ppm
50
ppm
0.0006
ppm
1.15 0.6 Balance

Specifications

API 6A, API 6A718
EN 2.4668
ISO 15156-3
NACE MR0103, NACE MR0175
UNS N07718
Werkstoff 2.4668

Inventory

718 NACE Round Bar

Common Trade Names

Inconel® 718, Nickel Alloy 718, NACE MRO175, MRO175

Features

  • Highly resistant to chloride and sulfide stress corrosion cracking
  • High strength
  • Good corrosion resistance

Applications

  • Valves
  • Wellhead completion equipment
  • Fasteners
  • Blowout preventers (BOPs)
  • Tubing hangers
  • Mandrels

Physical Properties

Density: 0.297 lb/inch3
Melting Point: 2160 - 2440°F

Temperature, °F 70 200 400 600 1000 1200
Coefficient* of Thermal Expansion, in/in°F x 10-6 - 7.3 7.5 7.7 8.1 8.4
Thermal Conductivity
Btu • ft/ft2 • hr • °F
6.4 7.2 8.2 9.3 11.3 12.3
Modulus of Elasticity, Dynamic psi x 106 29.0 28.4 27.6 26.7 24.8 23.7

* 70°F to indicated temperature.

Mechanical Properties

Minimum Specified Properties, API 6A 718 bar Solution Annealed And Aged Condition

  Minimum Maximum
Ultimate tensile strength, ksi 150 -
0.2% yield strength, ksi 125 145
Elongation, % 20% -
Reduction of area, % 35% -
Impact Strength*Min average/
min single, ft-lbs
40/35 -
Hardness, Rockwell C 32 40