“Ocean metal” – titanium alloy on the ship!.(HY-industry technical centre)
The ship is the most important equipment of the navy. It is a platform for maritime transportation and combat. The materials used to build the ship should be resistant to seawater and marine atmosphere corrosion, with high specific strength, good plastic toughness and good processingmanship.
Due to the complex structure of the ship, the amount of materials used is large, and there are many varieties and specifications. The selection of high-performance materials to make warships is the basis for ensuring the integrity and advancement of naval equipment.
The ship is the most important equipment of the navy. It is a platform for maritime transportation and combat. The materials used to build the ship should be resistant to seawater and marine atmosphere corrosion, with high specific strength, good plastic toughness and good processingmanship.
Due to the complex structure of the ship, the amount of materials used is large, and there are many varieties and specifications. The selection of high-performance materials to make warships is the basis for ensuring the integrity and advancement of naval equipment.
Let’s take a look at the use of titanium and titanium alloys in the marine sector in the following countries:
Russia
Russia is the earliest country in the world to develop and use marine titanium alloys, and it is also the country with the widest range and the largest number of marine titanium alloys. It mainly includes PT-7M, PT-1M, PT-3V, 37, 5V titanium alloy and its corresponding welding wire, and forms marine titanium alloy products of different strength grades such as 490, 585, 686 and 785 MPa. Titanium alloy has been successfully applied to the following components and equipment on ships: deep water risers, supply pipes, pumps, filters, sea pipes, drinking water pipes, drilling pipes and groundwater pipes, heat exchangers, diesel engines. Fire pump and fire extinguishing system, deep water equipment shell, outer well system flexible pipe, pressure vessel, high-strength flexible tensile parts of platform fastening joints, process solution piping and containers, etc., and successively in the former Soviet series nuclear power icebreaker ” The Lenin, the “Arctic”, the “Russian”, the “Soviet” and other types of ships are used. The titanium steam generator on the former Soviet series of nuclear-powered icebreakers has been safely used for 20 to 40 years. Any serious damage has occurred.
United States
The titanium alloy for marine use in the United States is mainly based on aerospace titanium alloy, and has a corrosion resistance, weldability and stress corrosion resistance in a seawater corrosive environment, including pure titanium, Ti-0. 3Mo-0. 8Ni , Ti-3Al-2. 5V, Ti-6Al-4V, Ti-6Al-4V ELI, Ti-3Al-8V-6Cr-4Mo-4Zr. In addition, for the characteristics of marine titanium alloy, Ti-5Al-1Zr-1Sn-1V-0. 8Mo-0. 1Si, Ti-6Al-2Nb-1Ta-0. 8Mo and other marine titanium alloys have also been developed. The use of high-performance titanium alloys on ships has a significant effect on improving the mobility, stability, effectiveness, and hull quality of ships. The US Navy has certified the following ships in the 1990s, including: Nuclear Powered Carrier (CVN), Missile Cruiser (CG-47), Missile Frigate (FFG-7), Exploration Vessel (MCM), amphibious landing craft (LSD41CV), landing ship, hovercraft (LVCA), amphibious assault landing ship (LHD), fast combat munitions supply ship (AOE-6), double-shell monitoring ship (SWATH T-AGOS19), coastal survey ship (MHC-51), guided missile destroyer (DDG-51). High-performance titanium alloys have been or will be used in seawater cooling systems, seawater systems and fire suppression systems, structural components, propulsion, sewage treatment systems, electrical components, fasteners, etc. of these ships.
Japan
Japan’s marine titanium alloys are mainly pure titanium, Ti-6Al-4V, Ti-6Al-4V ELI, which are mainly used in pressure-resistant shells of deep submersibles and various civilian cruise ships and fishing boats.
China
The research and application of Chinese marine titanium alloy began in the 1960s. After decades of development, a relatively complete marine titanium alloy system has been formed, which can meet the requirements of different strength levels of ships, submarines and deep submersibles. Applications include hull structures, propulsion systems, power systems, electronic information systems, auxiliary systems, and special equipment.
According to the yield strength grade, the yield strength is below 490 MPa for low-strength titanium alloy, which has excellent plasticity; 490-790 MPa is medium-strength titanium alloy, higher than 790 MPa is high-strength titanium alloy, mainly used in ship power engineering. Heat resistant and corrosion resistant parts and marine special machinery.
For material research, Chinese marine titanium alloys also need to carry out research on the performance of titanium alloys in the marine environment, including:
-
Working environment (temperature, pH value, solution composition), stress mode (free state, reverse bending, torsion), alternating load on corrosion fatigue of titanium alloy in air and seawater, fatigue crack growth rate, stress corrosion Research on the influence of fracture toughness;
-
The influence of the processing technology on the texture type (radial texture, axial texture) and texture type of the titanium alloy pipe on the performance of the pipe processing technology (flare, flattening, blasting);
-
Pd, Ru trace elements on the corrosion resistance mechanism of titanium alloy in H2S, Cl- environment;
-
Tensile and fatigue performance evaluation of titanium alloy under irradiation environment;
-
Welding deformation control and correction research of different welding forms of corrosion resistant titanium alloy.