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通过Gleeble--1500热模拟试验机,分别对取自同一块Q345B钢板坯的横向、纵向、竖向和中心四个方位的试样和AH32钢板坯表面及其厚度1/4处的六组不同部位的纵向试样进行了高温延塑性的研究.采用了金相显微镜和扫描电镜方法对断口和附近的组织进行了观察.研究结果发现:Q345B钢板坯四个方位的试样低温区域(950℃以下)高温延塑性曲线变化较小,而高温区域(950℃以上)的延塑性曲线变化相对较大.AH32钢板坯表面的三组纵向试样的高温延塑性曲线变化规律相同,断面收缩率没有出现特别大的波动;而厚度1/4处的三组试样的高温延塑性曲线与表面的三组试样差异较大,断面收缩率发生了很大波动,其原因主要是试样位于发达的柱状晶区,较表面的等轴晶区更容易出现微裂纹、元素的偏析、铸坯组织疏松等缺陷.
By Gleeble - 1500 thermal simulation testing machine, respectively, from the same piece of Q345B steel slab transverse, longitudinal, vertical and central four azimuths of the sample and the AH32 slab surface and the thickness of 1/4 at six different And the microstructure of the fracture near the fracture was observed by the metallographic microscope and scanning electron microscope.The results showed that the microstructure of the Q345B steel slab in the four directions of low temperature (950 ℃ The ductility curve of high temperature ductility curve is relatively small, while the ductility curve of high temperature ductility (950 ℃ and above) is relatively large.The three groups of longitudinal ductility of AH32 steel slab surface have the same rule of high temperature ductility curve, There is a special large fluctuations; and the thickness of 1/4 of the three samples at high temperature ductility curve and the surface of the three groups of samples differ greatly, the section shrinkage rate has undergone great fluctuations, the main reason is that the sample is located in the developed Of the columnar zone, the surface of the equiaxed zone is more prone to micro-cracks, elemental segregation, slab porosity and other defects.