Preparation method of TC17 titanium alloy flat square section bar

Abstract

The invention provides a preparation method of a TC17 titanium alloy flat square section bar. The preparation method comprises the following steps that (1) a riser and an ingot bottom of a TC17 titanium alloy cast ingot are cut off, and surface defects are removed; (2) billet forging is performed on the TC17 titanium alloy cast ingot, and primary forging stocks are obtained; (3) first middle forging is performed on the primary forging stocks, and first middle forging stocks are obtained; (4) second middle forging is performed on the first middle forging stocks, and second middle forging stocks are obtained; (5) sawing is performed on the second middle forging stocks, then forming forging is performed, and a semi-finished flat square section bar is obtained; and (6) heat treatment is performed on the semi-finished flat square section bar, and the TC17 titanium alloy flat square section bar with the length of 850 mm to 1600 mm, the width of 132 mm and the thickness of 65 mm to 100 mm is obtained. The preparation method has the advantages of integral technical scheme, strong process controllability, uniformity in product texture and shape, excellent overall performance, high batch stability and high yield and is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of titanium alloy material preparation, in particular to a preparation method of a TC17 titanium alloy flat square profile. Background technique [0002] TCl7 titanium alloy is a new type of aero-engine material, and its nominal composition is Ti-5AL-2Sn-2Zr-4Mo-4Cr. TCl7 titanium alloy has the advantages of high strength, good fracture toughness and high hardenability, and can meet the needs of damage tolerance design and high reliability. It is widely used in the manufacture of aerospace components. With the development of aviation and aerospace industry technology , the increasing demand for TCl7 alloy titanium alloy profiles, due to the low transformation point of the alloy (T β 880 ℃ ~ 890 ℃), the conventional preparation method: after heating and forging in the temperature range above the transformation point, the method of rolling the finished product in the temperature range of 30 ℃ ~ 50 ℃ below the...

AI Technical Summary

Problems solved by technology

TCl7 titanium alloy has the advantages of high strength, good fracture toughness, high hardenability, etc., and can meet the needs of damage tolerance design and high reliability requirements. It is widely used to manufacture aviation components. With the development of aviation and aerospace industry technology , The demand for TCl7 alloy titanium alloy profiles is increasing, due to the low phase transition point of the alloy (T β 880°C to 890°C), the conventional preparation method: after heating and forging in the temperature range above the phase transition point, the method of rolling the finished product in the temperature range of 30°C to 50°C below the phase transition point has a large deformation resistance, and the billet There are many problems such as easy cracking, uneven structure, difficulty in flaw detection clutter, easy distortion of rolled profiles and difficult straightening, etc., which are not suitable for mass production of TCl7 titanium alloy flat square profiles; in addition, because TC17 titanium alloy is a typical rich β-type two-phase titanium alloy, the β-stable elements Mo and Cr content in TC17 titanium alloy are relatively high, and Cr is a eutectoid β-stable element, which is easy to form segregation in the head area of ​​the ingot, resulting in the enrichment of Cr in some areas. The Cr element content in the normal area is higher than that of the normal area, so that the phase transition point of these areas is lowered. When the TC17 titanium alloy rectangular profile is in the process of thermal processing, the actual temperature of the area may exceed the temperature of the phase transition point due to the thermal effect of deformation, resulting in β spots.