肉眼观察时,连铸坯缺陷可分为内部缺陷、外表面缺陷和形状缺陷。一、内部缺陷一部分内部缺陷与连铸时的凝固条件有关,因此首先说明连铸坯的组织。一般情况下,连铸坯的凝固组织由三个区域组成:外层等轴晶区、柱状晶区和芯部等轴晶区。外层细晶粒区是由于钢液与水冷的结晶器接触时有强烈的散热而形成的。当钢液存在局部较大的过冷度时,形成无数的晶核,由此而形成细小的多边形晶粒。继续凝固时,沿温度梯度大的方向上的晶粒比其 Visual observation, continuous casting defects can be divided into internal defects, outer surface defects and shape defects. First, the internal defects Part of the internal defects and solidification conditions when casting, so the first description of the slab organization. Under normal circumstances, the slab solidification organization consists of three areas: the outer equiaxed zone, columnar zone and core equiaxed zone. The outer fine grain area is formed by the intense heat dissipation when the molten steel is in contact with the water-cooled crystallizer. When the molten steel has a large local undercooling, the formation of numerous nuclei, thus forming small polygonal grains. When the solidification continues, the grains in the direction of the larger temperature gradient than it does