In the process of spinning, the composite steel plate has been pressed and flanged for many times, and the temperature stress and processing stress at the joint surface lead to the delamination trend of the composite plate head, which is much larger than that of the single material head, and any unbonded area will induce the falling off of the coating.Therefore, the requirements of composite plate head materials should be stricter than the general components.

　　The head material is Q345R+405 composite steel plate material, and on the basis of meeting NB/T47002.1-2009 Explosively Welded Composite Plates for Pressure Vessels, it shall also meet the following requirements.

　　The interface between the base and the cladding of the composite steel plate should be metallurgical, and the billet used for the production of the composite steel plate should be the whole plate, either the base or the cladding, that is, no stitching weld is allowed.

　　The chemical composition and mechanical properties of the composite steel base material should meet the requirements of GB/T713-2014 "Steel Plates for Boilers and Pressure Vessels", and be tested by 100% ultrasonic.

　　The chemical composition and mechanical properties of the composite steel plate cladding material under supply condition shall meet the requirements of ASME SA-240.

　　Requirements for the interface state of the composite steel plate:

　　The interface of the composite steel plate shall be inspected by ultrasonic, and the scanning method shall be 100%. The binding state shall meet the requirements of NB/T 47002.1-2009 Class B1.

　　The composite shear strength of the composite plate interface should not be less than 210MPa.

　　Scar, crack, inclusion, folding and other defects are not allowed on the surface of composite steel plate cladding.

　　The thickness of clad steel plate should be guaranteed to be positive deviation.