制氢转化炉炉管开裂原因分析

Analysis on Cracking of Furnace Tube of Hydrogen Production Reformer

对某石化制氢转化炉开裂炉管进行取样,通过化学成分、断口形貌、金相及扫描电镜等分析。发现开裂炉管成分合格,未见减薄,但材料拉伸性能和冲击性能下降明显;裂纹断口形貌呈不连续开裂,金相观察可见裂纹由许多孔洞连接而成,扫描电镜下孔洞表面呈液相凝固时形成的结晶面和録固收缩形貌。结果表明,炉管铸造时形成的微观缺陷,在高温环境长期服役过程中形成蠕变孔洞,逐浙形成裂纹,最终导致开裂。

The cracked tube of a petrochemical hydrogen refonner was sampled and analyzed by chemical composition,fracture morphology,metallography and scanning electron microscopy.lt was found that the cracked furnace tube composition was qualified and no thinning was found,but the tensile and impact properties of the material decreased obviously.The fracture morphology of the crack was discontinuous,and metallographic observation showed that the crack was connected by many holes.Under the scanning electron microscope,the surface of the hole was formed when the liquid phase solidified,and the crystallization surface and solidification shrinkage morphology were formed.The results show that the micro-defects formed during the casting of the furnace tube form creep holes during the long・term service in the high temperature environment.Crack is gradually formed,and finally lead to cracking.