中文摘要：

为研究钢结构厚板的z向性能，针对Q345B结构用钢，在不同板厚，不同尺寸十字形对接焊缝下，进行不同取样位置、方向的取样，在常温和低温下进行简单拉伸试验．分析了不同板厚、焊缝尺寸、取样位置、方向及温度下的屈服强度、极限强度及断面收缩率的变化规律．试验结果表明：随钢板厚度增大，屈服强度fy，极限强度fu。和断面收缩率妒皆降低；Z向取样的fy，fu和ψ皆低于X向取样，焊缝热影响的母材Z向数值比未受焊缝影响的母材Z向的更低；随着温度的降低，fy和fu升高，但是ψ皆降低，结构表现出明显的低温冷脆现象．试验积累了大量Z向拉伸性能的数据，为今后更精确的Z向指标衡量及设计提供了实验依据．

英文摘要：

To study the Z-direction properties of thick plate steel, samples were extracted by different locations and directions from plate steel of different thickness and different sizes of crossing butt weld. Then the samples were supplied to simple tensile test at temperatures from -60 ℃ to 20 ℃. The princi-ples that Z-direction property and ψ change with the thickness of the plate, the size of the weld, the differ-ence of sampling and the difference of temperatures were analyzed. It is indicated that： fy, fu and ψ de-crease with the increase of the plate thickness; fy, fu and ψ of the samples of Z-direction affected by weld are much lower than that of non-affected Z-direction, which are lower than X direction;fy and fu increase, but ψ decreases with the decrease of temperature; and the brittleness with cooling is manifested. The data of Z-direction tensile is accumulated, which can be applied in much more accurate measurement of Z-direc-tion properties and much more rational design.