ASTM A182 – Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service

Grade: F91 （Low Alloy Steels）

UNS number: K90901

Category: Low Alloy Steels

Chemical Requirements, %

C: 0.08-0.12

Mn: 0.30-0.60

P: ≤0.020

S: ≤0.010

Si: 0.20-0.50

Ni: ≤0.40

Cr: 8.0-9.5

Mo: 0.85-1.05

Nb: 0.06-0.10

N: 0.03-0.07

Al: ≤0.02

V: 0.18-0.25

Ti: ≤0.01

Zr: ≤0.01

Heat treatment

Normalize(1040-1080 °C)+temper(730-800 °C)

Tensile Requirements

Tensile Strength: ≥585MPa

Yield Strength: ≥415MPa

Elongation: ≥20

Reduction of Area: ≥40

Hardness(HB): ≤248