M Rajabpour - Young Researchers and Elite Club, Shahmirzad Branch, Islamic Azad University, Shahmirzad, Iran.
H Babaei - Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
M.R Eslami - Department of Mechanical Engineering, Amirkabir University of Technology, Tehran

This paper presents a three dimensional numerical analysis of heat transfer and thermal stresses in the submerged arc welding (SAW) of pipes used in the oil and gas pipelines network. A finite element analysis is performed using the ANSYS Parametric Design Language (APDL) provided by ANSYS commercial FE code. In this analysis, preheating of pipes is modeled. Also, the effect of preheating condition, which consist of thermal stresses, are considered in the analysis. The model provides a full description of the temperature distribution on pipe with preheating pipe and without preheating, as well as calculation of different thermal stresses. It is found that the quality of the submerged arc welding is affected by the preheating. Results show that with utilized preheating in pipes, thermal stressesdecrease. For oil and gas pipeline networks, it is suggested to use pipe with preheating to increase the strength.

preheating, pipe, finite element method, thermal stresses, submerged arc welding