ASTM A234 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service

Grade: WP91

Chemical Composition, %：

C: 008-0.12

Mn: 0.30-0.60

P: ≤0.020

S: ≤0.010

Si: ≥0.20-0.50

Cr: 8.0-9.5

Mo: 0.85-1.05

Ni: ≤0.40

Cu: ≤0.40

V: 0.18-0.25

Nb: 0.06-0.10

N: 0.03-0.07

Al: ≤0.04

Ti: ≤0.01

Zr: ≤0.01

Tensile Requirements：

Tensile strength, MPa: 585 – 760

Yield strength, MPa: ≥415

Elongation Requirements:

Standard round specimen, or small proportional specimen, % in 4 D: ≥20

Hardness: ≤248 HB

Heat treatment：

Except when supplementary requirement S1 of ASTM A234 is specified by the purchaser, Grade WP91 shall be normalized at 1040 °C minimum, and 1080 °C maximum, and tempered in the temperature range of 730 °C to 800 °C as a final heat treatment.