Forming method for improving structure uniformity of titanium alloy bar by combining free forging and pulse current auxiliary extrusion

A technology of pulse current and uniform structure, applied in the direction of metal processing equipment, etc., can solve the problems of aerospace, poor micro-uniformity, and reduced mechanical properties, etc., to compensate for uneven distribution of temperature field, large temperature window, and mechanical performance indicators Improved effect

Active Publication Date: 2021-10-12
TIANJIN UNIV OF TECH & EDUCATION TEACHER DEV CENT OF CHINA VOCATIONAL TRAINING & GUIDANCE
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main reason is that the micro-uniformity of grain size, phase volume fraction and texture of titanium alloy billets prepared by traditional forging, rolling or extrusion methods is poor (such as figure 1 As shown in Vacuum, 2019, 160:81-88), the mechanical properties are seriously reduced, making the quality not up to standard and unable to meet aerospace standards
This problem has become a major bottleneck restricting the quality improvement of domestic titanium alloy fasteners. How to solve this technical problem poses a severe challenge to domestic research institutions and manufacturing enterprises.

Method used

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  • Forming method for improving structure uniformity of titanium alloy bar by combining free forging and pulse current auxiliary extrusion
  • Forming method for improving structure uniformity of titanium alloy bar by combining free forging and pulse current auxiliary extrusion
  • Forming method for improving structure uniformity of titanium alloy bar by combining free forging and pulse current auxiliary extrusion

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Experimental program
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Effect test

Embodiment 1

[0041] Embodiment 1: Ti6554 rod preparation

[0042] The chemical composition of Ti6554 titanium alloy is (%, mass fraction): chromium 5.7, molybdenum 4.7, vanadium 4.8, aluminum 3.9, iron 0.08, silicon 0.028, carbon 0.025, and the rest of titanium. Phase transition temperature T of Ti6554 β =820°C, which belongs to high-strength and tough near-β titanium alloy with high content of alloying elements, so a 70kg ingot (diameter 170mm×length 200mm) was obtained by smelting three times in a vacuum consumable electric arc furnace. The specific smelting parameters are shown in Table 1.

[0043] Heat the 70kg ingot to 1150°C for 2 hours, quickly move it to a 3-ton hammer forging machine, implement A and B upsetting and drawing deformation treatments to complete the free forging billet opening process, and obtain a forged bar with a diameter of 100mm. Perform A and B extrusion deformation treatments to complete the pulse current assisted extrusion process of forged bars (see Table 2 ...

Embodiment 2

[0044] Embodiment 2: Ti55531 rod preparation

[0045] The chemical composition of the Ti55531 titanium alloy is (%, mass fraction): aluminum 5.3, molybdenum 5.2, vanadium 5.2, chromium 2.65, zirconium 1.02, and the rest of titanium. Phase transition temperature T of Ti55531 β =850°C, which belongs to high-strength and tough near-β titanium alloy with high content of alloying elements, so a 70kg ingot (diameter 170mm×length 200mm) was obtained by smelting three times in a vacuum consumable electric arc furnace. The melting parameters are shown in Table 1.

[0046] Heat the 70kg ingot to 1100°C for 2 hours, quickly move it to a 3-ton hammer forging machine, perform A and B upsetting and drawing to complete the free forging billet opening process, and obtain a forged bar with a diameter of 100mm. Extrusion A and B were performed to complete the pulse current assisted extrusion process for the forged bar (see Table 3 for specific process parameters), and a bar with a diameter of ...

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Abstract

The invention relates to a forming method for improving the structure uniformity of a titanium alloy bar by combining free forging and pulse current auxiliary extrusion, which comprises the following steps of: heating a titanium alloy ingot to temperature T1, performing upsetting and drawing deformation treatment A, and air-cooling the titanium alloy ingot to room temperature after the upsetting and drawing deformation treatment A is finished; and then heating the titanium alloy ingot to the temperature T3 for upsetting and drawing deformation treatment B, obtaining a titanium alloy forged bar after the upsetting and drawing deformation treatment B is finished, rapidly blowing and cooling the titanium alloy forged bar to the room temperature, conducting extrusion deformation treatment A, extrusion deformation treatment B and extrusion deformation treatment C on the obtained titanium alloy forged bar in sequence on pulse current auxiliary extrusion equipment, and air-cooling the obtained titanium alloy forged bar to room temperature after extrusion deformation treatment C to obtain the titanium alloy bar. The homogeneous high-strength titanium alloy bar is prepared by combining free forging and pulse current auxiliary extrusion, the microstructure uniform distribution and the mechanical property of the bar are improved, and the requirement for the performance of aerospace fasteners is met.

Description

technical field [0001] The invention relates to the field of preparation of titanium alloy materials, in particular to a forming method for improving the microstructure uniformity of titanium alloy rods by combining free forging and pulse current assisted extrusion. Background technique [0002] As high-end parts, titanium alloy fasteners play an irreplaceable role in the thermal control systems and structural systems of aircraft, satellites, rockets and other aircraft. At present, my country's titanium alloy fastener billets mainly rely on imports. The main reason is that the micro-uniformity of grain size, phase volume fraction and texture of titanium alloy billets prepared by traditional forging, rolling or extrusion methods is poor (such as figure 1 As shown, Vacuum, 2019, 160:81-88), the mechanical properties are seriously reduced, so that the quality is not up to standard, and it cannot meet the aerospace standards. This problem has become a major bottleneck restrict...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22F3/00B21J5/00C22C14/00
CPCC22F3/00B21J5/002C22C14/00
Inventor 武川
Owner TIANJIN UNIV OF TECH & EDUCATION TEACHER DEV CENT OF CHINA VOCATIONAL TRAINING & GUIDANCE
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