Abstract: Oil tank is welded with steel plates, of which the weld joint is the weakest part of the tank. With the increase of steel plate thickness, welding crack sensitivity is enhanced. 20×10⁴ m³ tank foundation ring wallboard is made of 44 mm thick steel plates, of which welding performance is not verified by engineering examples. Therefore, experimental research is carried out for welding crack sensitivity to determine reasonable welding parameters. Oblique Y groove cracking test results show that the metallographic structures of base metal and overheated zone are granular bainite and weld joint structure is "proeutectoid ferrite + bainite + acicular ferrite" without abnormal conditions. JFE-HITEN610E steel plates use the LB-62UL electrode for welding and the weld joints have better crack resistance at room temperature 14 ℃ and under warm-up conditions of 50 ℃ and 100 ℃. Butt joint rigidity restraint welding crack test results show that metallographic structures of base metal and overheated zone are granular bainite, and metallographic structure of weld joint is bainite without abnormal conditions. JFEHITEN610E steel plates use supporting US49/US62A (diameter of 3.2 mm) welding wire + MF33H flux, of which weld joints have the better crack resistance at room temperature 14 ℃ and under warm-up conditions of 50 ℃.