An Analysis of Impact Testing of High Strength Low-Alloy Steels Used in Ship Construction

Abstract

Brittle damages have been examined widely since welding became common practice when it comes to carrying out robust structures. Welded structure of the ship hull has to be continuous. Brittle damages that occur on hull structures have always been examined thoroughly. Cracks are most commonly initiated at locations where stress concentrators exist. These concentrators can originate due to flaws that occur during the design phase or due to mistakes that occur during the assembly of the structure. When it comes to failures and damages that occur at ship structures, it has been noticed that damages due to brittleness practically always happen at low temperatures. Impact test analysis is significant due to the fact that it replicates the ductile to brittle transition of steel in practically identical range of temperatures for all ship structures. Impact of ductile-brittle transition temperature is an important factor especially because there have been many ship failures and damages in history. In ship structures made of welded joints of high strength low-alloy (HSLA) steels with their segments (parent metal, weld metal and heat-affected-zone), the toughness test determines the tendency of steel to brittle fracture, respectively the tendency to increase brittleness during exploitation. Parameters obtained by testing the properties of plasticity are the fundamental for the composition of ship structures with the aim of realize strengths under tested load. The test results of high strength low-alloy steel toughness assessment at different test temperatures show that temperature significantly affects the impact toughness of steels and their alloys.

Experimental Determination of the Critical Value of the J-Integral that Refers to the HSLA Steel Welded Joint

“…Steel NN-70 is the Yugoslav version of American steel HY-100. It was designed for the production of ship structures [13], underwater vessels, pressure vessels etc. by welding due to the fact that it provides adequate ductility, depending on accumulated strain that ultimately transforms into plastic strain.…”

Enhancement of Marine Corrosion and Tribocorrosion Resistance of Offshore Mooring Chain Steel by Aluminizing Process

“…Since the onset of wear and corrosion corresponds to materials' surface properties, improving only the surface properties rather than the entire material is often a more costeffective method for resistance to tribocorrosion [44]. Due to the chemical composition, a very satisfactory level of plasticity and toughness can be achieved by hardening and tempering after appropriate heat treatment for HSLA steel [45]. Surface hardening processes are among the most straightforward and cost-effective ways to enhance iron-based materials' mechanical properties and corrosion resistance [46].…”