engleski

Mechanical characteristics of the shipbuilding stainless steel at sub-zero temperatures

Ships for liquefied natural gas are of increasing interest for extensive research of the classification societies, scientific institutes and shipyards. Since the liquefied gas is transferred in the cargo tanks at -165°C, the mechanical characteristics of the materials for ship building are faced with high-level demands on low temperatures. Therefore this paper brings forward the results of mechanical testing of shipbuilding steel on low temperatures. The paper at the beginning shortly resumes the problems of ships for liquefied gas transport, their structural characteristics and materials for building of the hull and of the cargo tanks. Furthermore, requirements of the Croatian Register of Shipping for mechanical testing of the material are summarized. Mechanical characteristics of material are examined in the Laboratory for experimental mechanics at the Faculty of Mechanical Engineering and Naval Architecture of the University of Zagreb by static tensile test. Material specimens were provided by Shipbuilding Industry in Split, Croatia. The equipment, specimens and testing procedure are described in details and the results of testing are carefully investigated. The specimens are tested in cooled chambers on 4 different temperatures from 22°C to -165°C. Values of the tensile strength, deformation, total uniform elongation, breaking elongation and modulus of elasticity are measured during each test. The results are presented by tables and graphs and they are compared for different temperatures also. The conclusion contains remarks about mechanical characteristics of the stainless steel at sub-zero temperatures. The plans for future research include low temperature fatigue and toughness testing.

liquefied gas transport; mechanical characteristics; stainless steel and sub zero temperatures; tensile test

nije evidentirano