摘要
采用铝热焊技术焊接在役输油管道时,铝粉焊剂量的选择多采用经验值,焊接过程中产生的温度与残余应力的不确定性给管道施工及其安全运行带来严重威胁。针对该问题,采用数值模拟软件ANSYS分析不同壁厚管道在不同焊剂用量下的铝热焊接过程,建立了铝热焊接有限元模型,仿真得到不同铝粉焊剂用量和不同壁厚管道之间的温度场及残余应力场变化规律,并进行试验验证。结果表明:对于相同壁厚管道,焊接区域的最高温度随焊剂用量的增加而升高;焊剂量相同时,焊接区域的最高温度随管道壁厚的增加而降低;随着管道壁厚的增加,焊缝处的残余应力最大可达150 MPa,小于材料屈服极限,铝热焊接过程不会出现烧穿、裂纹等现象,数值模拟结果与试验结果一致;当铝粉焊剂用量为10~20 g时,对壁厚6~8 mm管道进行在役铝热焊接是安全可靠的。数值模拟结果可为在役管道铝热焊接过程中的安全操作提供参考,有效降低在役施工风险。
During the thermite welding of in-service oil pipelines, empirical values are often used for the dosage of aluminum powder welding flux, and the uncertainty of temperature and residual stress generated during the welding poses a serious threat to the construction of pipeline and its safe operation. In response to this problem, the thermite welding process of pipelines in different wall thickness and with different dosages of welding flux was analyzed with the numerical simulation software ANSYS.Specifically, a finite element model of thermite welding was established, and thus the change law of the temperature field and residual stress field with different dosages of aluminum powder welding flux and different pipeline wall thicknesses was obtained,which was also verified by test. As indicated by the results, the maximum temperature in the welding area of pipelines with same wall thickness rises with the increasing dosage of welding flux. The maximum temperature in the welding area decreases with the increasing of pipeline wall thickness in the case that equivalent welding flux is used. Besides, with the increasing of pipeline wall thickness, the maximum residue stress at the weld is up to 150 MPa, lower than the yield limit of material, so that no burn-through and crack will occur during thermite welding, and the simulation results are consistent with the test results. Moreover, it is safe and reliable to conduct thermite welding in 6 mm to 8 mm pipeline in service with 10 g to 20 g of aluminum powder. Generally, the numerical simulation method could provide reference for the safe operation of thermite welding of in-service pipelines, thus reducing the construction risks of pipelines in service.
作者
赵宏涛
王永振
沈楠
王浩瑜
曾维国
ZHAO Hongtao;WANG Yongzhen;SHEN Nan;WANG Haoyu;ZENG Weiguo(PetroChina Changqing Oilfield Company;China Special Equipment Inspection and Research Institute)
出处
《油气储运》
CAS
北大核心
2022年第11期1305-1311,1318,共8页
Oil & Gas Storage and Transportation
关键词
管道
铝热焊接
数值模拟
温度场
残余应力场
pipelines
thermite welding
numerical simulation
temperature field
residual stress field
