engleski

Challenges of application of high-strength steel in welded constructions

Application of high-strength steel enables reduction of welded constructions’weight. This is especially important in mobile and portable welded structures (e.g. pressure vessels, road and rail vehicles, cranes, bridges, etc.), where a smaller mass of exploited welded construction facilitates the reduction of energy consumption. Thanks to the greater strength of these steels, it is possible to realize larger bridges and long arms and levers at large cranes with a smaller construction mass. In addition to giving examples of practical applications of high-strength steels, this paper also discusses the welding problems of these steels. The results of welding the modern high-strength steels (S690QL, S960QL and S1100QL) and practical examples of welding technology are presented in the paper. The welding tests were carried out after the weld thermal cycle simulation on the Smitweld 1406 simulator and on real-welded samples. The obtained results of mechanical properties (hardness, strength, toughness...) and metallographic tests showed that welding of these high-strength steels was succes sful, however, it was extremely important to strictly monitor the prescribed welding technology, as even the smallest deviations could cause the weakening of at least one zone in the welded joint. There is a lack of experimental results referring to the weldability and practical experience in the application of these steels. Any contribution to the experience of using these high-strength steels shall be also a valuable contribution to the reliability of constructions made of these steels, as well as to the wider application of these steels in mechanical engineering constructions.

high-strength steels ; welded, thermal cycle simulation

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