鑄坯表面孔類缺陷軋制過程中演變規律

Evolution of surface porosity in round steel hot rolling

摘要: 對圓鋼軋制過程中鑄坯表面孔類缺陷演變規律進行了工業實驗研究.實驗中采用鉆孔法在鑄坯頭部鉆取一定直徑和深度的孔的方法來模擬鑄坯表面氣孔缺陷.鉆孔鑄坯經軋制后在圓鋼的對應位置發現了呈平行分布的表面直線型裂紋，裂紋處的金相組織發現裂紋四周有輕微的脫碳現象.裂紋測量結果表明，圓鋼表面直線型裂紋深度主要受鉆孔深度影響，當鉆孔深度大于4mm時，會導致深度明顯的裂紋.裂紋長度主要受鉆孔直徑影響，對于孔徑在1.0~2.5mm的孔，形成的裂紋長度大都分布在2~8cm之間.

Abstract: An industrial experiment was carried out to study the evolution of billet surface porosity in hot rolling of round steel.Holes were drilled at the head of a billet. Linear cracks were spot at the surface of rolled round steel in parallel. Slight decarburization appears around these cracks,which can be seen from the metallograph. Crack measurement results show that the crack depth is mainly influenced by the hole depth. When the hole depth exceeds 4 mm,serious cracks will be generated on the round steel. The crack length is mainly dependent on the hole diameter. When the hole diameter ranges from 1 to 2.5 mm,the crack length limits to 2 to 8 cm.