Wojciech Jurczak

Effect of Frictional-Mechanical Treatment of the Low Alloy Steels on Some Exploitation Properties in Sea Water Simulated Solution

Abstract. Paper presents the results of the studies of the service properties of the 235JR and S355J2 low alloy steels subjected to the surface modification by friction-mechanical treatment, as tested in sea water simulated solution. The resistance of steels used in the marine vessels to the wear, cavitation erosion, general corrosion, corrosion cracking and hydrogen absorption has been examined. To evaluate the effect of the surface treatment, the comparative studies of the service properties of steels before and after treatment have been considered.

Damage and Corrosion Diagnostics of Welded Light Alloys Ship Constructions

Applying diagnostics consisting in evaluation of deformation based on corrosion potential measurements it is possible to extend lifetime of technical structures and make them safe for people and environment. Development of anticorrosion techniques and staff training is a fundamental requirement for safe exploitation of technical structures made of 7xxx aluminum alloys. Corrosive marine environment enforces engineers and technicians to implement advanced anticorrosion methods to make life on ship much safer. The paper presents selected problems connected with safety of exploitation of welded constructions made from 7020 and 7020M alloys in marine environment and a new method of corrosion diagnostics. Mechanical properties of the welded joints made from different kinds of binder have been determined. Corrosion resistance of these joints without anticorrosion protection has been investigated in seawater environment.

Dynamic properties of 7000 - series aluminum alloys at large strain rates

Dynamic properties of 7000 - series aluminum alloys at large strain rates This paper presents test results of mechanical properties of EN AW-AlZn5Mg1Zr and EN AW-AlZn5Mg1, 5CuZr aluminum alloys for various tensile strain rates. Static tests were conducted with the use of MTS 810.12 tension test machine, and dynamic tests - with RSO rotary impact test machine. The work was aimed at determination of effects of strain rate and notch geometry of specimens on their material mechanical properties and damage mechanisms.

Corrosion Influence on Safety of Hydraulic Pipelines Installed on Decks of Contemporary Product and Chemical Tankers

Abstract The corrosion influence on hydraulic pipelines safety mounted on product and chemical tankers has been presented in this paper. The issue of axial forces in pipelines mounted along ship open decks, resulting from ship hull deformations in waves, is highlighted. Corrosion degradation phenomena of hydraulic pipelines on open deck is described. The analysis of degradation effect on thickness of carbon steel material of pipes is given and influence of the effect on stress level increase in hydraulic pipelines during exploitation at sea is focused. The discussion about fighting against corrosion in hydraulic pipelines on open decks is performed. All the problems analyzed in the paper are based on examples of events observed on product and chemical tankers built in Szczecinska Shipyard, Szczecin, Poland.

Possibilities of Belzona Adhesive Joints Application for Austenitic Steel Used in Ship Constructions

This paper presents the results of research on adhesive joints durability properties of ship austenitic steel done with the use of the latest adhesives – glues: a composite one from Belzona company, described as 1111 and 1212 as well as a Hysol 9466 adhesive, produced by Hysol. The 1.4301 (304) and 1.3964 (2xx) steels used for shipbuilding were single-lap adhesive joint, with varying degree of edges’ chamfering and offsetting (with a deflection). This type of alternative connections will provide protection and temporary structure’s protection in case of emergency cracking (due to corrosion or an impact) of the examined steel or welded joints of the ship’s construction and hull’s sheathings. The adhesive joints of the tested steel were made in laboratory conditions (according to the technological card) as well as outside the laboratory, hereinafter called as the emergency ones with the use of Belzon 1212. Adhesive joints of 304 and 2xx steel using Hysol 9466 adhesive made in laboratory conditions showed better durability properties than the ones made with the use of Belzona 1111 composite. However, in case of emergency connections the bonding strength as well as the bonding time (hardening) are important factors. The use of the special Belzona 1212 (for wet surfaces) gives a relatively good durability of approx. 20MPa with a much shorter (up to 20 minutes) hardening time and does not require such an accurate surface preparation as the adhesive joints made with the use of Hysol 9466.

Design Methodology of Strength Verification of Platform During Load Out of the Arkutun Dagi SE-Topside 43.800 MT

Abstract This paper presents the methodology of strength verification during load out of the heavy cargo, in this case Arkutun Dagi SE-Topside platform. General methodology of making calculation models and load algorithms has been presented. Paper shows results of verification of global shear forces and bending moments using self-developed algorithms to modify centre of gravity, fill tanks and hydrostatically balance a 3D finite element model with commercial hydrostatic code. The NAPA and ANSYS codes were used to calculate hydrostatic pressures and to apply to 3D-FE models and to carry out strength calculation of barge construction.

Influence of Friction Stir Welding (FSW) on Mechanical and Corrosion Properties of AW-7020M and Aw-7020 Alloys

Abstract Friction welding associated with mixing the weld material (FSW - Friction Stir Welding ) is an alternative to MIG and TIG welding techniques for Al-alloys. This paper presents experimental results obtained from static tension tests on specimens made of AW-7020M and AW-7020 alloys and their joints welded by using FSW method carried out on flat specimens, according to Polish standards : PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Results of corrosion resistance tests are also presented. The tests were performed by using the electrochemical impedance spectroscopy (EIS). EIS measurement was conducted with the use of three-electrode system in a substitute sea water environment (3,5% NaCl - water solution). The impedance tests were carried out under corrosion potential. Voltage signal amplitude was equal to 10mV, and its frequency range - 100 kHz ÷ 0,1 Hz. Atlas 0531 EU&IA potentiostat was used for the tests. For the tested object an equivalent model was selected in the form of a substitute electric circuit. Results of the impedance spectroscopy tests are presented in the form of parameters which characterize corrosion process, as well as on Nyquist’s graphs together with the best-fit theoretical curve. Analysis of the test results showed that the value of charge transfer resistance through double layer , Rct , for the FSW-welded specimen , was lower than that for the basic material, and that much greater difference was found in the case of AW-7020M alloy. The impedance spectroscopy tests showed that both the FSW-welded joints and basic material of AW-7020M and AW-7020 alloys were characterized by a good resistance against electrochemical corrosion in sea water environment , and that FSW-welded joints revealed a greater corrosion rate.. The performed tests and subject-matter literature research indicate that application of FSW method to joining Al-alloys in shipbuilding is rational.

Possibility of corrosion monitoring resistance of austenitic steel for ship construction

The article presents the investigation results on possibility of electrochemical corrosion monitoring of the 1.3964 steel used for ship construction according of the patent Pl 216723. The patent’s assumption describes the method of on-line registration of electrochemical potential specifying the protective effectiveness of a thin oxide layer formed spontaneously on the steel surface. Essentials drop of the potential’s value with respect to the stationary one indicates layer cracking and initiation of pitting corrosion. Such a corrosion can be initiated by salinity and temperature of seawater and/or by a mechanical factor (strain). The carried out measurements of the potential and mechanicalelectrochemical teats made it possible to determine the stress level causing the crack of oxide layer and initiation of corrosion processes in the steel. Thereby, the mechanical properties (Rm and A5) thin passive oxide layers investigated steel. Application of Electrochemical Impedance Spectroscopy (EIS) in the laboratory allows monitoring of weakness (stratification) of the film as a stage preceding to fracture [1, 2]. Stress cracking of the protective oxide layer on the 1.3964 steel takes place beyond the exploitation zone (above the tensile strength) and there is no indication to monitor the corrosion resistance on ship construction made of this stainless steel. However, in specific cases when temperature of the steel exceeds 40oC, application of the monitoring may be justified.

Exploitation Load Impact on Electrochemical Properties of Shipbuilding 7xxx Series Aluminum Alloy Joints Prepared with TIG and FSW Methods

The paper presents the results of investigations on mechanical properties and electrochemical potential distribution within arc welded (TIG) and friction stir welded (FSW) joints subjected to slow strain rate tests. The materials investigated were high-strength 7xxx series (7020 and its modification 7020M) aluminum alloys intended for shipbuilding. The objectives were joint quality assessment and comparison of the advantages of new FSW method with the traditional TIG methods commonly utilized in shipbuilding industry. Joint quality was evaluated based on mechanical investigations, hardness distribution tests and simultaneous electrochemical corrosion potential measurements at various locations within the welded joints.Initiation of corrosion processes on TIG and FSW joints was identified as a radical decrease in corrosion potential related to load followed by oxide layer cracking. Arc welded (TIG) joints of 7xxx series alloys undergo corrosion at lower values of tensile load applied as compared to the FSW joints. Superior mechanical properties and higher corrosion resistance of the FSW joints make this technology well-suited for joining high-strength 7xxx series alloys.

Impact and Ballistic Resistance of a New Aluminium Alloy for Ship Construction Elements

Abstract The article presents results of examination of the new alloy 7020M intended to be used in shipbuilding. The examination concerned impact properties, verified on a numerical model, and the resistance to perforation (ballistic resistance). Impact and ballistic resistance tests aimed at increasing the operational safety of marine construc-tions to be made of this alloy under the threat of gunfire or explosion. Dynamic loading of the alloy 7020M leads to the increase of its strength, as compared to the static load, with the range of this increase depending on the strain rate. Splitting of the structure made of the alloy 7020M increases its impact resistance by three times when preserving the same thickness (g = 12 mm <=> g = 2x6 mm). The alloy examined in the structurally homogenous form revealed low resistance to perforation, while the use of 6 mm thick ballistic ceramic (Al2O3) fully protected this material against damage done by ŁPS 7,62 mm shells having the energy of 3 kJ. The split structure of the alloy ensured better protection against explosive pieces formed during 1,4 kg TNT explosion than the homogeneous structure having the same thickness.