Chemical composition and mechanical properties of Q370R, a Chinese grade of low-temperature pressure vessel steel.
Q370R Approx. Grade Lookup Table

Table 1  Chemical Composition

7.1.2    For Q370R steel plates with a thickness greater than 60 mm, the upper limit of carbon content can be increased to 0.22% and 0.20% respectively; for Q370R steel plates with a thickness greater than 60 mm, the upper limit of manganese content can be increased to 1.20%.                                                            
7.1.3   Trace amounts of niobium, vanadium, and titanium may be added to Q370R 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 Q370R 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

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

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