中低碳锰钢管外表面麻面缺陷分析

Analysis on Outer Surface Pit Defect of Low and Medium Carbon-manganese Steel Tube

为查明中低碳锰钢管外表面麻面缺陷的产生原因,分析了钢管及轧辊的化学成分、硬度、微观形貌。结果表明,轧辊表面硬度偏低,且在轧制过程中发生石墨及碳化物破碎导致轧辊掉块,少部分掉落的轧辊块在轧制过程中重新黏附于轧辊表面,高温轧制时钢管被轧辊上的黏结物损伤而产生麻面。建议定期修磨轧辊表面,剔除凸出黏结物;适当降低钢管轧制温度;更换轧辊材质;优化轧辊的铸造工艺,使轧辊基体组织中石墨小型化、碳化物球化和小型化,避免轧辊在使用中破碎掉块。

In order to find out the causes for the outer surface pit defect of the low and medium carbon-manganese steel tube,the chemical composition,hardness and micromorphology of the steel pipe and the roll are analyzed.The analysis result shows that the said pit defective outer surface of the pipe is caused due to the facts as follows.First the hardness of the roll is rather low;and second,during the rolling process the graphite and carbide on the roll surface are broken,resulting in chipping of the roll,then during the rolling process a small part of the chips adhere to the roll surface again,and thus during high-temperature rolling,the steel pipe surface is damaged by the adhesive on the roll,and inevitably causes the pitting.It is suggested to take actions,including grinding the roll surface,and picking up and throwing the adhesive away,properly lowering the pipe rolling temperature,changing the roll material,optimizing the roll casting process to get the graphite in the roll matrix structure miniaturized,and the carbide sphericized and miniaturized so as to avoid the said in-process chipping of the roll.