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山西太钢不锈钢股份有限公司利用真空组坯复合轧制(真空电子束焊接+轧制复合)技术工业化试制了Q345R/304复合板。本文研究了常规轧制和控轧控冷工艺下轧制复合板的界面结合率、常规力学性能、界面结合强度和界面附近的显微硬度和显微组织变化。结果表明:界面结合不良来自于复合界面处形成的硅铝氧化物和铬锰氧化物,这可能是由于组坯时真空度不足、加热过程中形成的氧化产物。两种工艺下界面附近显微组织差异明显,沿远离界面方向,常规轧制的Q345R钢板组织沿厚度方向为均匀的块状铁素体和珠光体组织,304钢板组织已完全再结晶;控轧控冷工艺轧制的Q345R钢板组织沿厚度方向由多边形铁素体和珠光体组织向针状铁素体和贝氏体组织过渡,304钢板组织仍有变形特征。力学性能检测表明:常规热轧复合板的屈服强度和抗拉强度比控轧控冷复合板分别低115、71 MPa,强度裕量较小;纵向冲击功不小于130J,外弯、内弯、侧弯后无裂纹,复合板剪切强度在350 MPa以上,高于标准要求(不小于210 MPa),线扫描结果表明界面附近已存在由元素扩散形成的浓度梯度。
Shanxi TISCO Stainless Steel Co., Ltd. Vacuum Group Billet composite rolling (vacuum electron beam welding + rolling composite) technology industrial trial of the Q345R / 304 composite board. In this paper, the interfacial bonding ratio, conventional mechanical properties, interfacial bonding strength and the microhardness and microstructure of the rolled composite plate under conventional rolling and controlled rolling and controlled cooling process were studied. The results show that the interface bonding defects come from the silicon aluminum oxide and chromium manganese oxide formed at the composite interface, which may be due to the lack of vacuum during the blank formation and the oxidation products formed during the heating. The microstructures of the interface between the two processes are obviously different. Along the direction away from the interface, the conventional rolled Q345R steel plate has a uniform bulk ferrite and pearlite structure in the thickness direction and the steel plate of the 304 steel plate has completely recrystallized. Controlled cold rolling process Q345R steel plate along the thickness direction by the polygonal ferrite and pearlite microstructure transition to acicular ferrite and bainite, 304 steel plate is still the deformation characteristics. Mechanical properties tests show that the yield strength and tensile strength of the conventional hot-rolled composite sheet are respectively 115,71 MPa lower than that of the controlled rolling and cold-rolled composite sheet, the strength margin is small; the longitudinal impact energy is not less than 130J, There is no crack after bending. The shear strength of the composite plate is above 350 MPa, which is higher than the standard requirement (not less than 210 MPa). The line scanning results show that the concentration gradient formed by the element diffusion exists near the interface.