Alloy 20

UNS N08020

Alloy 20 material

nickel alloypipe / fitting / flangeP-No. 45

⚡

Key Engineering Metrics

Instant specifications summary for Alloy 20

Yield Strength💪

240.0MPa

Min specified

Tensile Strength🏋️

550.0MPa

Ultimate min

Carbon Eq. (CE)🧪

N/A

IIW Formula

P-No. / Group⚙️

P45

ASME Sec. IX

Flange Group🛡️

N/A

ASME B16.5

MDMT Curve❄️

Refer to

ASME B31.3

General Specifications & Standard Data

Alloy 20

Standard Specification

Alloy 20

Grade / Designation

Alloy 20

UNS Designation

N08020

ASME P-No. / Group No.

P-No. 45

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 Ratio44%

Yield Strength (240.0 MPa)Tensile Strength (550.0 MPa)

Density

8050kg/m³

Min Yield

240.0MPa

Min Tensile

550.0MPa

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

32–38%

19–21%

3–4%

2–3%

🛡️ 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).