Ultra-high-strength steels are sensitive to heat input during welding, which can lead to softening in the heat-affected zone. This softening can also reduce the limit load capacity in non-load-carrying welds. One challenge is how to address this phenomenon in the design phase. To solve this problem, a method to determine material parameters for design and failure criteria is required. In this paper, a procedure using notched specimens to determine material parameters and failure criteria is presented. The results are compared with component-scale tests. The results show that the developed method results agree with results from the component tests. This procedure is a practical method to estimate the ultimate capacity of ultra-high-strength steels.