The compound-slab (/mm) 415 x 1 630 x2 570 for compound-rolling is got by removing the scale of awaiting compound-rolling faces of double (/mm)210 x 1 630 x 2 570 Q345B steel casting slabs

cutting circle welding V and welding together. By vacuum-pumping compound-slab cave

packing and heating to 1 220 ~ 1 260 °C the compound-slab is rolling at 1 150 °C to 100 mm supper heavy plate with total reduction more than40% in preceding three passes

and finishing rolling at 980 T. Examination results show that all mechanical properties of Q345 steel compound plate meet the requirements of GB6396-2008 and GB1591-2008

that is its tensile strength 530 -535 MPa

yield strength 325 MPa

elongation 27. 5% ~28.0%

thickness Z direction tensile strength 520 ~530 MPa and reduction of area 30.0% ~ 60. 5%. The ratio of bonding interface of compound-plate is more than 99%

and the tensile specimen fracture is mixing fracture and a small amount of toughness fracture with nice cold-bending performance.