Heat Treatment of Metals ›› 2021, Vol. 46 ›› Issue (11): 161-165.DOI: 10.13251/j.issn.0254-6051.2021.11.026

• PROCESS RESEARCH • Previous Articles     Next Articles

Effect of annealing temperature on microstructure and properties of large-diameter TA31 titanium alloy seamless tube

Deng Yajie1,2, Huang Haiguang3, Zhang Haoze3, Shi Yaming3, Zhang Yuqin1,2, Jiang Yehua1,2   

  1. 1. Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming Yunnan 650093, China;
    2. National-local Joint Engineering Laboratory of Metal Advanced Solidification Forming and Equipment Technology, Kunming Yunnan 650093, China;
    3. Engineering Technology Research Center of Titanium Products and Application of Yunnan Province, Chuxiong Yunnan 651209, China
  • Received:2021-05-04 Online:2021-11-25 Published:2021-12-08

Abstract: Ti-6Al-3Nb-2Zr-1Mo(TA31) titanium alloy round ingots were cast by using vacuum consumable electric arc furnace and electron beam cooling bed furnace, and a ø178 mm×12 mm large-diameter seamless tube was obtained by directly cross piercing, then the effect of annealing temperature (800, 850, 900, 950 ℃) on microstructure and properties of the seamless tubes was studied. The results show that the rolled seamless tube in deformed Widmanstätten structure is mainly composed of lamellar α-phase colonies and original β-phase grain boundaries. After annealing, the lamellar primary α-phase reduces and the original β-phase grain boundaries disappear, with the microstructure being gradually homogenized. But when the annealing temperature exceeds 900 ℃, the α-phase colonies are coarsened and transform into a basketweave structure. With the increase of annealing temperature, the tensile strength and yield strength of the tube first decrease slightly and then slowly increase, while the elongation first increases and then decreases, and the morphology of fracture changes from ductile + quasi-cleavage mixed fracture to ductile fracture and then to ductile + quasi-cleavage mixed fracture. The comprehensive analysis shows that the suitable annealing temperature for the TA31 titanium alloy large-diameter seamless tube prepared in a short process is about 900 ℃, at which the average values of tensile strength, yield strength and elongation are 873 MPa, 785 MPa and 12.8%, respectively.

Key words: TA31 titanium alloy, cast ingot cross piercing, large-diameter seamless tube, microstructure evolution, mechanical properties

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