低合金高强度结构钢Q345B特厚板的复合轧制工艺

Pilot Production of High Strength Low Alloy Steel Q345B Supper-Heavy Plate by Compound-Rolling Process

去除两块规格为（／mm）210×1630×2570的Q345B钢连铸坯待复合面上氧化铁皮，开环周坡口，叠放并焊接在一起得到（／mm）415×1630×2570的复合坯。对复合腔抽真空、密封、加热至1220—1260℃和在1150℃轧制成100mm特厚板，前3道次总压下率大于40％，终轧980℃。检验结果表明，Q345B钢复合板各项力学性能均达到GB6396-2008和GB1591-2008的要求，抗拉强度530—535MPa，屈服强度325MPa，伸长率27．5％～28．0％，厚度z方向抗拉强度为520～530MPa，断面收缩率30．0％～60．5％，界面组织结合率99％以上，拉伸试样断口为混合断裂和少量韧性断裂，冷弯性能良好。

The compound-slab （/mm） 415 ×1 630×2 570 for compound-rolling is got by removing the scale of awai- ting compound-rolling faces of double （/mm）210 × 1 630 × 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℃ the compound-slab is rolling at 1 150℃ to 100 mm supper heavy plate with total reduction more than 40% in preceding three passes, and finish- ing rolling at 980℃. 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.