Chemical composition and mechanical properties of Q245R, a Chinese grade of  pressure vessel steel.
Q245R Approximate Grade Lookup Table

Table 1  Chemical Composition

Grade Chemical Composition(Quality Fraction)/%
C Si Mn Cu Ni Cr Mo Nb V Ti Altb P S Others
Q245R ≤0.20 ≤0.35 0.50-1.10 ≤0.30 ≤0.30 ≤0.30 ≤0.08 ≤0.050 ≤0.050 ≤0.030 　 ≤0.025 ≤0.010 Cu+Ni
+Cr+Mo
≤0.7c

7.1.3   Trace amounts of niobium, vanadium, and titanium may be added to Q245R steel. The content of these elements should be specified in the quality certificate. The total content of these three elements should not exceed 0.050%, 0.120%, and 0.150%, respectively.
7.1.6 The content of residual elements chromium, nickel, and copper should not exceed 0.30% each, and molybdenum should not exceed 0.080%, with the total content of these elements not exceeding 0.70%. Analysis is not required if the supplier can guarantee this.
7.1.7 According to the buyer's requirements, the carbon equivalent of the Q245R grade can be specified, and the value shall be determined through negotiation between the supplier and the buyer.
7.1.8  The permissible deviation of the chemical composition of finished steel products shall comply with the provisions of CB/T 713.1.
7.1.9  For a comparison of similar grades with relevant international standards, please refer to Appendix A.

Table 2  Mechanical properties and processing properties

Grade Delivery status Thickness mm Tensile test Impact test 180°Bending test b=2a
Tensile strength Rm/MPa Lower yield strength ReL/MPa Elongation after fractureA/% Temperature/℃ Impact absorption energy KV2/J
≥ 　 ≥
Q245R Hot rolled,Normalized rolling or normalized 3～16 400～520 245 25 0 34 D=1.5a
>16～36 235
>36～60 225
>60～100 390～510 205 24 D=2a
>100～150 380～500 185
>150～250 370～490 175

Note: D is the diameter of the bending indenter; b is the width of the specimen; a is the thickness of the specimen. When the yielding phenomenon is not obvious, the specified plastic elongation strength Rp0.2 can be used instead.

Table 3  High temperature mechanical properties/p>

Grade Thickness/mm Test temperature/℃
100 150 200 250 300 350 400 450 500
ReLᵃ  ( or Rp0.2)/MPa,≥
Q245R >20～36 210 200 186 167 153 139 129 121 　
>36～60 200 191 178 161 147 133 123 116 -—
>60～100 184 176 164 147 135 123 113 106 　
>100～150 168 160 150 135 120 110 105 95 　
>150～250 160 150 145 130 115 105 100 90 —

ᵃ When the yielding phenomenon is not obvious, the specified plastic elongation strength Rp0.2 can be used instead.