Titanium and titanium alloys are mainly used in submarines, deep submersibles, and other ships to cope with the occasion of high requirements for yield strength, density, and corrosion resistance.
At present, we have a series of marine titanium alloys with strength levels of 490MPa, 585MPa, 686MPa, and 785MPa, and the commonly used ones are titanium alloy for hull пт-1 The composition and mechanical properties of the titanium alloys are as follows: пт-1 м, пт-7м, пт-3B, 5B, etc., which are commonly used for ship hulls, but due to the high manufacturing costs and processing difficulties of titanium alloy materials. The shell material is selected from more advanced special materials, and its demagnetization effect and pressure-bearing capacity are close to titanium alloy, but the price is only a fraction of titanium alloy, and the processing difficulty is also much smaller.
In addition to Ti-6Al-4V, there is also Ti-6Al-2Nb-1Ta-0.8Mo of the near-alpha type used in Seacliff manned deep submersible which can dive 6100m deep. "Deepsea 6500" class deep-sea research vessel's pressure-resistant hull uses a low clearance Ti6Al4VELI alloy containing few interstitial elements.
The new Ti80 alloy is used in the manufacture of deep submersible and submarine pressure shells, the alloy has high strength, high toughness, corrosion resistance, weldability, and other excellent properties, in the tensile strength of 880 ~ 925 MPa, yield strength of 785 ~ 885 MPa, fracture toughness, and stress corrosion resistance is significantly better than the Ti6Al4VELI alloy. 1990s design Ti91 titanium alloy. Ti80 and Ti91 alloys were designed in the following years, and after 2000, they were mass-produced and put into use one after another.
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