某连续退火炉辐射管开裂原因

Cracking Cause of Radiant Tube in a Continuous Annealing Furnace

某连续退火炉辐射管在服役过程中开裂,通过断口宏观与微观形貌观察、化学成分分析、力学性能测试与受力分析等方法分析了辐射管开裂的原因。结果表明:高温蠕变和高温氧化腐蚀的共同作用导致连续退火炉辐射管的失效。在低应力和高温作用下,因晶界滑动形成的孔洞长大并连接而形成裂纹,同时氧化膜破裂形成的孔隙加速了裂纹的合并及生长,在蠕变应力作用下裂纹加速扩展并最终导致辐射管失效;在高温环境中长期服役后,辐射管内壁因氧化腐蚀而减薄严重,辐射管的强度明显低于标准值,承载能力降低,从而在高温集中区的应力集中处萌生裂纹,并导致辐射管的开裂。

The radiant tube in a continuous annealing furnace cracked during service.The cracking causes of the radiant tube were analyzed by fracture macromorphology and micromorphology observation,chemical composition analysis,mechanical property test and force analysis.The results show that the combined action of high temperature creep and high temperature oxidation corrosion led to the failure of radiation tube in the continuous annealing furnace.Under low stresses and high temperatures,holes formed by grain boundary sliding grew and connected to form cracks;the pores formed by the rupture of the oxide film accelerated the combination and growth of cracks,and the cracks propagated fast under the creep stresses,finally leading to the failure of the radiant pipe.After long-term service in a high temperature environment,the inner wall of the radiant tube was seriously thinned by oxidation corrosion;the strength of the radiant tube was obviously lower than the standard value,and the bearing capacity decreased,which resulted in the initiation of cracks in the stress concentration area of the high temperature concentration area and the final failure of the radiant tube.