碳结圆钢表面缺陷对冷顶锻性能影响分析

Effect Analysis of Surface Defect of Carbon Structure Round Steel on Cold Heading Property

对Φ22 mm Q235-B圆钢进行了塔形试验、冷顶锻试验和轧制过程坯料低倍金相检验。结果表明:圆钢冷顶锻H/3级别的性能保证能力较差,但无缺陷碳结圆钢H/2级别的冷顶锻完好率有保证,有缺陷的碳结圆钢性能保证能力较差;轧制过程中各道次的不均匀变形和挤压褶皱造成了圆钢表面的长条形缺陷,而表面和近表面缺陷是造成冷顶锻开裂的主要原因。

To make tower test, cold heading test on Ф22 mm Q235 - B and low times microstructure inspection on rolling steel. The results show that property guarantee capability of round steel is worse as H/3 level cold heading, but finish rate of non-defect carbon structure round steel is guaranteed and property guarantee capability of defect carbon structure round steel is worse as 11/2 level cold heading. Uneven deformation and extrusion drape in the different pass when rolling cause long strip defect on the surface. Defects on the surface and near surface are the main cause for cold heading to craze.