延迟焦化1Cr5Mo炉管使用状况分析

为掌握延迟焦化炉管的使用状况,确保加热炉的安全运行,对使用中的延迟焦化加热炉1Cr5Mo炉管经现场取样,检测,通过壁厚测试、显微组织检验,氧化层与结焦层分析,讨论了炉管运行过程中对炉管造成损伤的影响因素.结果表明,因外壁氧化,炉管减薄已出现,内壁增碳和外壁脱碳现象出现,珠光体球化导致炉管组织损伤.珠光体球化,不符合GB9948-88中的供货热处理工艺规定的退火状态和金相组织为铁素体+珠光体要求.结合珠光体球化形态说明短时超温现象的存在,外壁表面出现高温蠕变特征,壁厚减薄虽不严重,但炉管继续使用存在安全隐患的问题.

Analysis of 1Cr5Mo Tube Used Status for Delayed Coking Furnace

For insuring the safety running of delayed coking furnace, status of tube of delayed coking furnace must be in control. Take samples from 1Cr5Mo furnace tube in service and had them examined. Through testing tube wall thickness, inspecting microstructure and analyzing oxidizing layer and coking layer, influencing factors which may damage furnace tube were discussed. Results show that tube wall thickness decreases, acieration on inner wall and decarburization on outside wall occur because of oxidation on outer wall surface and pearlite globular carbide results in then microstructure damage. Emergence of pearlite globular carbide does not accord with standard GB9948-88 in which heat treatment requires annealing and microstructure is ferrite and pearlite. Combining configuration of globular carbide and appearance of high temperature creep characteristics on outer wall surface, though wall thickness decreasing is not serious, it indicates that if it is overheated for a short period of time and used continuously, there exists potential safety trouble.