Chemical Composition and Mechanical Properties of Q345R Pressure Vessel Steel

Q345R is a Chinese pressure vessel steel grade specified in GB/T 713, widely used for boilers and pressure vessels. This page provides the chemical composition, mechanical properties, and high-temperature performance of Q345R steel plates.

Q345R Approximate Grade Lookup Table

Q345R Chemical Composition

Chemical Composition of Q345R Steel (Mass Fraction %)
Grade Chemical Composition (%)
C Si Mn Cu Ni Cr Mo Nb V Ti Alt P S Others
Q345R ≤0.20 ≤0.55 1.20–1.70 ≤0.30 ≤0.30 ≤0.30 ≤0.08 ≤0.050 ≤0.050 ≤0.030 - ≤0.025 ≤0.010 Cu+Ni+Cr+Mo ≤0.70

Notes:
a) The lower limit of carbon content may be waived by agreement between supplier and buyer.
b) Aluminum content is not required unless otherwise specified.

Q345R Mechanical Properties

Mechanical Properties of Q345R Steel Plates
Thickness (mm) Tensile Strength (MPa) Yield Strength (MPa) Elongation (%) Impact Test (0°C, J) Bending Test
3–16 510–640 345 21 41 D = 2a
>16–36 500–630 325 21 41 D = 3a
>36–60 490–620 315 21 41 D = 3a

D = bending indenter diameter; a = specimen thickness. When yield point is not obvious, Rp0.2 may be used instead.

Q345R High-Temperature Mechanical Properties

Yield Strength of Q345R at Elevated Temperatures (MPa)
Thickness (mm) 100°C 200°C 300°C 400°C 500°C
20–36 295 255 215 190 180
60–100 275 225 185 165 155