4.2 Metallic Tank Body
Ⅰ Primary and Secondary Liquid Container
4.2.1 The delivery states of steel plates used for low temperature steel storage tanks for petrochemical services shall be in accordance with Table 4.2.1.
Table 4.2.1 Delivery states of steel plates used for low temperature steel storage tanks
Table 4.2.1（continued）
Notes：1 The compression ratio shall not be less than 3 for the steel plates made by continuous casting-direct rolling process.
2 See the List of Reference Codes/Standards for the standard names of the steel plates shown in the table above.
4.2.2 For 9Ni590A and 9Ni590B steel plates，tensile test and Charpy V-notch impact test shall be carried out per heat treatment of the material.Tensile test and impact test shall be carried out for each completed plate from which liquid containing tank plates are cut.
4.2.3 Where Q245R and Q345R steel plates of thickness greater than 25mm are used to construct the shell and bottom of the primary container or the secondary container，they shall be in normalized condition.
4.2.4 Where the following steel plates are used to construct the shell and bottom of the primary container and the secondary container，each piece of steel plate shall be ultrasonically examined，and the examination method and quality grade shall be in accordance with the current applicable national standard Nondestructive testing of pressure equipment-part 3：ultrasonic testing JB/T 4730.3：
1 For Q245R and Q345R steel plates of thickness greater than 30mm，their acceptance quality criterion shall not be lower than LevelⅡ；
2 For 16MnDR，15MnNiDR and 09MnNiDR steel plates of thickness greater than 20mm，their acceptance quality criterion shall not be lower than LevelⅡ；
3 For Q370R steel plate of thickness greater than 25mm，its acceptance quality criterion shall not be lower than LevelⅡ；
4 For the steel plates supplied in quenched and tempered state and of thickness greater than 16mm，their acceptance quality criterion shall not be lower than LevelⅠ.
4.2.5 If no corresponding standards are available for the steel structures used to construct the low temperature steel storage tanks in petrochemical services，the steel plates having the same performance may be used for substitution after prefabrication.
4.2.6 Where aluminum is used to construct the suspended roof，the selected aluminum plates and aluminum profiles shall be in accordance with the current applicable national standard Wrought aluminum and aluminum alloy plates，sheets and strips for general engineering GB/T 3880.1～GB/T 3880.3 and Wrought aluminum and aluminum alloy extruded profiles for general engineering GB/T 6892.
4.2.7 The delivery states of steel pipes used for low temperature steel storage tanks shall be in accordance with specifications in Table 4.2.7.
Table 4.2.7 Delivery states of steel pipes used for low temperature steel storage tanks
Note：See the List of Reference Codes/Standards for the standard names of the steel pipes shown in the table above.
4.2.8 The materials of forgings used for tank nozzles shall comply with the current national standard Low-alloy steel forgings for low temperature pressure equipments NB/T 47009 and Stainless and heatresisting steel forgings for pressure equipments NB/T 47010.
4.2.9 The materials of bolts，studs and nuts used for tank nozzle flanges shall comply with the current national standard Pressure vessels-part 2：Materials GB 150.2.
Ⅱ Vapotur Container
4.2.10 The delivery states of steel plates used for vapour container shall be in accordance with the specifications in Table 4.2.10.
Table 4.2.10 Delivery states of steel plates used for vapour container
Note：See the List of Reference Codes/Standards for the standard names of the steel plates shown in the table above.
Ⅲ Welding Consumables
4.2.11 Welding consumables shall be determined based on the chemical compositions，mechanical performances and welding performances of the parent metals as well as the construction characteristics，service conditions and welding procedures of the storage tanks，and they shall be determined by testing if necessary.
4.2.12 Welding consumables shall be provided with quality certificates.
4.2.13 Welding materials used to weld carbon steel and low alloy steel of different strength classes shall ensure the anti-cracking performance and mechanical performance of the welded joints，and the tensile strength shall not be higher than the upper limit of the parent metal in higher strength and shall not be lower than the lower limit of the parent metal in lower strength.
4.2.14 Welding consumables used for joints between high alloy steel and carbon steel or low alloy steel shall ensure the crack resistant performance and mechanical performance of the weld joints，and the welding consumables with Ni-Cr content higher than that of the high alloy steel should be used.
4.2.15 Welding materials used for primary liquid container shall be re-tested.