CAJ | 학술논문

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。
통과Gleeble-1500열모의시험궤，분별대취자동일괴Q345B강판배적횡향、종향、수향화중심사개방위적시양화AH32강판배표면급기후도1/4처적륙조불동부위적종향시양진행료고온연소성적연구。채용료금상현미경화소묘전경방법대단구화부근적조직진행료관찰。연구결과발현：Q345B강판배사개방위적시양저온구역(950℃이하)고온연소성곡선변화교소，이고온구역(950℃이상)적연소성곡선변화상대교대。 AH32강판배표면적삼조종향시양적고온연소성곡선변화규률상동，단면수축솔몰유출현특별대적파동；이후도1/4처적삼조시양적고온연소성곡선여표면적삼조시양차이교대，단면수축솔발생료흔대파동，기원인주요시시양위우발체적주상정구，교표면적등축정구경용역출현미렬문、원소적편석、주배조직소송등결함。
The high temperature ductility of samples, taking from a Q345B continuous casting slab in the transverse direction, drawing direction, vertical direction and at the central part, as well as an AH32 continuous casting slab at the surface and 1/4 thick-ness position, was investigated by using a Gleeble-1500 testing machine. The fractographs and microstructures of high-temperature tensile samples were observed by optical microscopy and scanning electron microscopy. Experimental results show that the high temper-ature ductility below 950℃ changes little between 4 groups of different samples from the Q345B slab, but the variation tendencies of high temperature ductility above 950℃ are greatly different. The changes of high temperature ductility of 3 groups of samples from the AH32 slab at the surface are the same, and the reduction of area has little fluctuation. Whereas the high temperature ductility of 3 groups of samples at the 1/4 thickness differs entirely from that at the surface, and the reduction of area appears fluctuant greatly. The reason is that microcracks, composition segregation, porosity and looseness occur more easily in the columnar crystal zone of sampling than in the equiaxed crystal zone of the surface.