Alloy 718

UNS N07718

Alloy 718 material

nickel alloybar / forging

⚡

Key Engineering Metrics

Instant specifications summary for Alloy 718

Yield Strength💪

1030.0MPa

Min specified

Tensile Strength🏋️

1240.0MPa

Ultimate min

Carbon Eq. (CE)🧪

N/A

IIW Formula

P-No. / Group⚙️

ASME Sec. IX

Flange Group🛡️

N/A

ASME B16.5

MDMT Curve❄️

Refer to

ASME B31.3

General Specifications & Standard Data

Alloy 718

Standard Specification

Alloy 718

Grade / Designation

Alloy 718

UNS Designation

N07718

ASME P-No. / Group No.

Unassigned

ASME B31.3 MDMT Curve

Refer to ASME B31.3 Fig 323.2.2A

Minimum Design Metal Temperature rules for impact testing exemption under ASME B31.3 paragraph 323.2.2.

Mechanical Properties

Room Temp (20°C / 68°F)

Yield-to-Tensile Ratio83%

Yield Strength (1030.0 MPa)Tensile Strength (1240.0 MPa)

Density

8190kg/m³

Min Yield

1030.0MPa

Min Tensile

1240.0MPa

Elastic Modulus

200GPa

Elongation (min)

25%

Thermal Expansion

13.5µm/m·K

Thermal Cond.

12W/m·K

Poisson’s Ratio

0.3

Allowable Stress Data (ASME B31.3 Table A-1)

asme-b31-3

Allowable Stress vs Temperature

ASME B31.3 / BPVC Section II Part D Reference Curve

Max: 137.9 MPaRange: 38° - 500°

Temperature (°C)	Allowable Stress (MPa)	% of Room Temp Rating
38	137.9	100%
100	137.9	100%
150	137.9	100%
200	131.0	95%
250	122.0	88%
300	115.0	83%
350	112.0	81%
400	108.0	78%
450	105.0	76%
500	102.0	74%

Chemical Composition (% Weight)

Heat & Product Analysis

50–55%

17–21%

4.75–5.5%

2.8–3.3%

🛡️ Service Compatibility

Severe Acid & Corrosiveexcellent

Exceptional resistance to hydrofluoric, hydrochloric, and hot sulfuric acids.

High Temp Oxidation / Carburizationexcellent

Maintains mechanical strength and oxidation resistance up to 1000°C.

🔥 Welding & Heat Treatment

Weldabilityeasy

Preheat Requirements

10°C min; preheat required for heavy wall thickness per ASME B31.3.

PWHT Requirements

Required if nominal wall thickness t > 19mm (0.75 in) per ASME B31.3 Table 331.1.1.

Charpy Impact Test (CVN)

Exempt down to -29°C (-20°F) per B31.3 Fig 323.2.2A. Impact test required if MDMT is lower.

⚠️ Engineering Verification Notice

Material property data provided is for preliminary engineering reference. Always verify properties against the latest ASME BPVC Section II, ASTM material specification, and Material Test Report (MTR/MTC).