Titanium alloy product having high strength and excellent cold rolling property

Abstract

A titanium alloy product according to the present invention: has a strength level higher than that of an existing titanium alloy product; can be successfully cold rolled (coil rolled); and is also provided with workability. In the titanium alloy product according to the invention, expensive alloy elements are not essentially required, and hence cost can be suppressed. The titanium alloy product according to the invention includes Al equivalent represented by (Al+100 (oxygen)): 3.5 to 7.2% (% by mass, the same hereinafter), Al: more than 1.0% and 4.5% or less, O: 0.60% or less, Fe equivalent represented by (Fe+0.5Cr+0.5Ni+0.67Co+0.67Mn): 0.8% or more and less than 2.0%, and one or more elements selected from the group consisting of Cu: 0.4 to 3.0% and Sn: 0.4 to 10%, in which the balance is Ti and unavoidable impurities.

Description

technical field [0001] The present invention relates to a titanium alloy material having high strength and excellent cold rollability. Background technique [0002] Titanium alloys are used in a wide range of fields such as aerospace equipment components, chemical plant components, and automobile components because of their high specific strength and excellent corrosion resistance. A representative titanium alloy is Ti-6Al-4V alloy. This Ti-6Al-4V alloy has excellent strength characteristics such as a 0.2% yield strength of 828 MPa or more standardized in ASTM Gr.5, but contains a large amount of Al as an additive element, so its cold rollability is poor. Therefore, it is difficult to manufacture a thin plate by coil rolling, and it is generally processed into a thin plate by a method called stack rolling (puck rolling). This so-called laminate rolling is a method of laminating titanium plates obtained by hot rolling, wrapping them with a mild steel cover, and rolling whil...

AI Technical Summary

Problems solved by technology

Even if cold rolling (coil rolling) is possible, but the cold rolling property is significantly low, it is necessary to repeat cold rolling-annealing many times, resulting in cost increase

In addition, when the workability of the titanium alloy material is low, even if cold rolling is possible, it may be difficult to perform processing (such as bending, etc.) at the current product level.

[0008] The titanium alloy disclosed in the above-mentioned Japanese Patent No. 3297027 and Japanese Patent Application No. Hei 01-111835, and the above-mentioned Ti-4Al-2.5V-1.5Fe-0.25O alloy, as mentioned above, although possess high strength and cold rollability Titanium alloys, but as β-phase strengthening elements, they must be rare metals, which are high-priced alloying elements (Mo, V, Nb, etc.), costing

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