... Q390,Q420,Q640GB/T1591—19944Structural steels for bridgesQ235q, Q345q,Q370q,Q420qGB/T714—20005Hot-rolled steel plates for plasticMouldsSM3Cr2Mo,SM3Cr3NiMoYB/T107—19976Hull structural ... of classificationsociety7Steel plates for boilersH 6~120W 1500~3600L 6000~1800020g,16MngGB713—19978Steel plates for pressure vessels20R,16MnR,15MnNbR,16MnDRGB6654—1996GB3531—19969Steel plates for building structuralH ...