Abstract
Numerical weldability analysis is a new powerful research and development tool which is useful for metallurgistics technologist and design engineers. Saying strictly the numerical analysis of weldability comprises thermodynamic, thermomechanical and microstructural modelling of the welding process. The fracture resistance of welded joints is mainly characterised by normalised parameters: SU1 = KIth / KIC for cold cracking or in the exploitation condition by or SU2 = Δ/ΔC or J/JC, SU1 ≠ SU2. Conclusions from the theoretical analysis form a basis to an assessment measure of the stress state parameter Sp as a physical measure of the deformation and effort of the mismatched weld joints. There also was made characteristic of the effect on the inclination of the layer (W) on the form of fracture. Finally, some aspects of estimation of the KC and KIC values for the layer (W) with the SINTAP programme overview are presented.