One of the methods to reduce the production costs to increase competitiveness is to minimize waste products as well as the cost of testing products, and numerical simulation is a useful tool to solve that task. In this study, the authors use SYSWELD software to compute in advance the suitable heat input range to weld specific layers in heat-resistant stainless steel butt welded joints in chemical plants, oil and gas, and energy. The simulation results show that with the butt-welded joint made by SUS316L steel in 8 mm thick and weld by the MIG welding process, the appropriate heat input of the root pass is 506 J/mm ≤ qđl ≤ 650 J/mm and the heat input suitable for cap pass is 754 J/mm ≤ qđl ≤ 1066 J/mm.
