ASTM A234 WP12

UNS K12062

ASTM A234 WP12 material

alloy steelfittingP-No. 4 / Gr. 1

⚡

Key Engineering Metrics

Instant specifications summary for ASTM A234 WP12

Yield Strength💪

205.0MPa

Min specified

Tensile Strength🏋️

415.0MPa

Ultimate min

Carbon Eq. (CE)🧪

0.680

High Cracking Risk

P-No. / Group⚙️

P4 / Gr1

ASME Sec. IX

Flange Group🛡️

Grp 1.1

ASME B16.5

MDMT Curve❄️

Refer to

ASME B31.3

General Specifications & Standard Data

ASTM A234

Standard Specification

ASTM A234

Grade / Designation

WP12

UNS Designation

K12062

ASME P-No. / Group No.

P-No. 4 / Group 1

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 Ratio49%

Yield Strength (205.0 MPa)Tensile Strength (415.0 MPa)

Density

7850kg/m³

Min Yield

205.0MPa

Min Tensile

415.0MPa

Elastic Modulus

205GPa

Elongation (min)

25%

Thermal Expansion

12.5µm/m·K

Thermal Cond.

35W/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%

🛡️ ASME B16.5 Flange P-T Ratings & Calculator

Material Group 1.1 (Carbon and low-alloy steel materials)

bar / °C

Rating Class: Class 150

Max Allowable Pressure19.6 bar

Design Temp (°C):

Code Limit: -29° to 538°

Temp (°C)	Class 150	Class 300	Class 400	Class 600	Class 900	Class 1500	Class 2500
-29 to 38	19.6	51.1	68.1	102.1	153.2	255.3	425.5
50	19.2	50.1	66.8	100.2	150.4	250.6	417.7
100	17.7	46.6	62.1	93.2	139.8	233	388.3
150	15.8	45.1	60.1	90.2	135.2	225.4	375.6
200	13.8	43.8	58.4	87.6	131.4	219	365
250	12.1	41.9	55.9	83.9	125.8	209.7	349.5
300	10.2	39.8	53.1	79.6	119.5	199.1	331.8
325	9.3	38.7	51.6	77.4	116.1	193.6	322.6
350	8.4	37.6	50.1	75.1	112.7	187.8	313
375	7.4	36.4	48.5	72.7	109.1	181.8	303.1
400	6.5	34.7	46.3	69.4	104.2	173.6	289.3
425	5.5	28.8	38.4	57.5	86.3	143.8	239.7
450	4.6	23	30.7	46	69	115	191.7
475	3.7	17.4	23.2	34.9	52.3	87.2	145.3
500	2.8	11.8	15.7	23.5	35.3	58.8	97.9
538	1.4	5.9	7.9	11.8	17.7	29.5	49.2

Working pressures are in gauge (bar). Values interpolated linearly for intermediate temperatures per ASME B16.5 para. 2.3.

Chemical Composition (% Weight)

Heat & Product Analysis

Carbon Equivalent (CE - IIW Formula)

CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

Preheat and strict PWHT required

0.680

High Cracking Risk

≤ 0.15%

≤ 0.6%

1–1.5%

0.45–0.65%

🛡️ Service Compatibility

High Temp Superheated Steamexcellent

Industry standard for main steam & reheat piping up to 593°C (1100°F) for P91.

High Temp Hydrogen (HTHA)excellent

Resistant to High Temperature Hydrogen Attack per API RP 941 (Nelson Curves).

Hydrocarbon Crackinggood

High creep-rupture strength in refinery vacuum furnaces and hydrocrackers.

Wet H2S / Sour Servicenot-recommended

High weld heat-affected zone hardness; requires strict PWHT to prevent SSC.

Cryogenic / Low Tempnot-recommended

High ductile-to-brittle transition temp; strictly high-temperature service.

🔥 Welding & Heat Treatment

Weldabilityspecial control required

Preheat Requirements

Mandatory preheat: 150°C–200°C for P11/P22; 200°C–250°C for P91/C12A. Maintain preheat until PWHT or post-bake.

PWHT Requirements

Mandatory post-weld heat treatment for all thicknesses: P11/P22 (650°C–700°C), P91 (730°C–760°C) per ASME B31.3 Table 331.1.1.

Charpy Impact Test (CVN)

Impact testing required for low-temperature applications or code thickness thresholds.

⚠️ 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).