The article presents the development of a method enabling the calculation of force necessary to bend a chain link during butt welding, taking into consideration a plastic strain in the shunting zone. The study also discusses technological peculiarities concerned with the welding of single-contact chain links characterised by high bending rigidity and describes principles of the elastic-plastic strain of chain link shunting zone during bending. The work also contains the theoretical justification of the possibility of calculating the value of bending force based on the ultimate limit state and presents an analytical  formula identifying the mathematical correlation between ultimate force, geometrical parameters and physico-chemical properties of the welded chain link material. Using an anchor chain as an example, the above-named analytical formula and the Finite Element Method were used to calculate the value of bending force, thereby confirming the reliability of the proposed method. It was ascertained that taking plastic strains into consideration significantly affected calculations results concerning the value of bending force during the butt welding of products having a closed shape and characterised by significant bending rigidity. The value of bending force calculated on the basis of the ideal elasticity of the anchor chain link material was higher (by more than an order of magnitude) than the value of the above-named force calculated taking into consideration plastic strains in the chain shunting zone.

doi: 10.17729/ebis.2018.2/7