4.2　Plates

4.2.1　Modulus of elasticity of the materials at various temperatures shall meet the requirements in Table 4.2.1.

4.2.2　Standards，service limitations and allowable stresses of steel plates shall meet the requirements in Table 4.2.2.

4.2.3　Q245R and Q345R steel plates used for the walls of tanks with thickness greater than 30mm but not exceeding 36mm shall be ultrasonic tested on each piece using the methods specified in JB/T 4730，and their quality class shall not be lower than ClassⅢ.

4.2.4　For Q345R plates with thickness greater than 20mm，when operating temperature is less than-10℃but not less than-20℃，the charpy（V-notch）impact test（at low temperature）shall be conducted on one piece per lot.The test temperature shall be identical with the application temperature of steel plate，i.e.the minimum design temperature of corresponding pressure parts or with that as prescribed on drawing.

Sampled position and the direction taken for of Charpy（V-notch）impact test specimens shall meet the appropriate requirements of GB 713.Three standard specimens per group are used in the impact test，and average impact energy of three specimens，KV2，shall not be less than 41 J.It is allowed that impact energy of one specimen is less than 41 J but not less than 29 J.