T91热轧管坯表面裂纹浅析

Analysis of Surface Cracking of T91 Hot Rolled Tube Blank

经过对产生表面裂纹的T91圆钢进行取样、检验和分析,发现裂纹内残存物含有与浇注用保护渣相同的特征元素,结合工艺过程,初步探明钢锭表面质量是该圆钢产生表面纵裂的主要原因。而改善钢锭表面质量除优化浇注工艺参数外,选择粘度小、熔点低、熔速快等合适理化性能指标的保护渣至关重要。

By sampling, examining and analyzing of T91 bars with surface cracks, it was found that the residue remains in the cracks have the same elements as that of the mould powder. Combining with the study of technical process, it can be concluded that the longitudinal cracking on the bar surface is caused by the imperfections on ingot surface. For improvement of surface quality on ingot, it is crucial to select the proper mould powder with proper physical chemical properties including little viscosity, low melting point and high smelting rate, except optimizing the pouring process parameters.