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CN-122007296-A - Segregation-free high-strength Ti6Al6V2Sn titanium alloy forging and preparation method thereof

CN122007296ACN 122007296 ACN122007296 ACN 122007296ACN-122007296-A

Abstract

The invention belongs to the technical field of titanium alloy material processing, and relates to a non-segregation high-strength large-specification Ti6Al6V2Sn titanium alloy forging and a preparation method thereof. The titanium alloy forging piece is 350-420 mm in thickness, 420-470 mm in width and 3200-4400 mm in length, and concretely comprises the steps of firstly placing raw materials of the titanium alloy forging piece into a vacuum self-consumption smelting furnace, smelting for a plurality of times to obtain a Ti6Al6V2Sn cast ingot, then sequentially performing cogging forging, intermediate forging and finished product forging on the pretreated cast ingot to obtain a finished product forging stock, finally performing solid solution aging heat treatment on the finished product forging stock, and sequentially performing straightening and machining to obtain the Ti6Al6V2Sn titanium alloy forging piece, wherein the titanium alloy forging piece has good strength and plasticity comprehensive performance, and can be applied to the fields of high-end equipment manufacturing and key industry.

Inventors

  • QIAO ENLI
  • MA XU
  • GU ZHONGMING
  • YANG NA
  • WANG SHUANGLI
  • TONG XIAOLE
  • Duan Haixing
  • Nan Diaofei
  • SHI YANPENG

Assignees

  • 新疆湘润新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. A Ti6Al6V2Sn titanium alloy forging with no segregation and high and strong specification is characterized in that the thickness of the Ti6Al6V2Sn titanium alloy forging is 350-420 mm, the width is 420-470 mm, the length is 3200-4400 mm, the room temperature tensile strength is more than or equal to 1035MPa, the specified plastic elongation strength is more than or equal to 965MPa, and the elongation is more than or equal to 12%.
  2. 2. The preparation method of the non-segregation high-strength Ti6Al6V2Sn titanium alloy forging based on claim 1 is characterized by comprising the following steps: S1, pressing titanium sponge, titanium copper alloy, aluminum vanadium alloy, titanium iron alloy, ti0 2 , titanium tin alloy and aluminum material into a consumable electrode, carrying out vacuum consumable arc melting on the consumable electrode, and then carrying out trimming treatment and machining in sequence to obtain a Ti6Al6V2Sn cast ingot; S2, coating a coating on the surface of the Ti6Al6V2Sn cast ingot to obtain a pretreated cast ingot, and carrying out cogging forging, intermediate forging and finished product forging on the pretreated cast ingot in sequence to obtain a finished product forging stock; s3, carrying out solid solution aging heat treatment on the finished forging stock, and then sequentially straightening and machining to finally obtain a titanium alloy forging finished product.
  3. 3. The method for preparing the high-strength Ti6Al6V2Sn titanium alloy forging without segregation according to claim 2, wherein in S2, the cogging forging comprises 1-fire upsetting forging, wherein the upsetting forging comprises the steps of heating a pre-treated cast ingot to 800-850 ℃ and preserving heat for 60-150 min, heating the pre-treated cast ingot to (T β +150）℃~（T β +250) DEG C in 120-240 min, preserving heat for 120-550 min, forging for the first time, and cooling and polishing to obtain a primary forging blank after the forging is completed.
  4. 4. The method for preparing a titanium alloy forging piece with no segregation and high and strong specification Ti6Al6V2Sn according to claim 3, wherein in S2, the initial forging temperature of the first forging is more than or equal to 900 ℃ and the final forging temperature is more than or equal to 850 ℃.
  5. 5. The method for producing a segregation-free, high-strength Ti6Al6V2Sn titanium alloy forging according to claim 2, wherein in S2, the intermediate forging includes 1 fire intermediate high Wen Duiba forging, 4-6 fire intermediate low temperature upsetting forging, and post-forging treatment, wherein: The intermediate high-temperature upsetting forging comprises the steps of heating the primary forging stock to 800-850 ℃ and preserving heat for 60-120 min, then heating the primary forging stock to (T β +50）℃~（T β +200) DEG C in 90-210 min, preserving heat for 180-700 min, and then sequentially carrying out secondary forging, air cooling and polishing to obtain a second forging stock; The 4-6-fire middle low-temperature upsetting forging comprises a heating stage and a forging stage, wherein the heating stage comprises the steps of heating a forging stock prepared in the previous step to 800-850 ℃ and preserving heat for 60-150 min, then heating the previous-fire forging stock to (T β -30）℃~（T β -80) DEG C and preserving heat for 240-920 min within 60-210 min, the forging stage comprises a plurality of reversing upsetting operations, and the forging stock is subjected to squaring in the middle low-temperature forging process of the last 1 fire; The step of post-forging treatment comprises the steps of sequentially carrying out air cooling and polishing on the third forging stock to obtain an intermediate forging stock.
  6. 6. The preparation method of the non-segregation high-strength Ti6Al6V2Sn titanium alloy forging piece is characterized in that the initial forging temperature of the intermediate high-temperature upsetting forging is more than or equal to 800 ℃, the final forging temperature is more than or equal to 750 ℃, and the initial forging temperature of each firing of the intermediate low-temperature upsetting forging is more than or equal to 750 ℃ and the final forging temperature is more than or equal to 700 ℃.
  7. 7. The method for preparing the non-segregation high-strength Ti6Al6V2Sn titanium alloy forging piece, which is characterized by comprising the steps of heating the intermediate forging stock to 800-850 ℃ and preserving heat for 60-120 min, heating the intermediate forging stock to (T β -30）℃~（T β -80) DEG C in 60-180 min, preserving heat for 210-570 min, and then sequentially performing drawing forging, straightening and air cooling to obtain the finished forging stock.
  8. 8. The preparation method of the non-segregation high-strength Ti6Al6V2Sn titanium alloy forging piece is characterized in that the total deformation amount in the cogging forging process is 80% -90%, the total deformation amount in the middle high-temperature upsetting forging process is 80% -90%, the total deformation amount of each fire of the middle low-temperature upsetting forging process is 70% -80%, and the total deformation amount in the finished product forging process is 30% -50%.
  9. 9. The method for preparing the titanium alloy forging with no segregation and high and strong specification Ti6Al6V2Sn according to claim 7, wherein the initial forging temperature of the final 1-firing-time drawing forging is more than or equal to 750 ℃ and the final forging temperature is more than or equal to 700 ℃.
  10. 10. The method for preparing the non-segregation high-strength Ti6Al6V2Sn titanium alloy forging piece according to claim 2, wherein in S3, the temperature of the solution heat treatment is 850-900 ℃, the heat preservation time is 2-3 hours, the temperature of the aging heat treatment is 450-600 ℃ and the heat preservation time is 6-8 hours.

Description

Segregation-free high-strength Ti6Al6V2Sn titanium alloy forging and preparation method thereof Technical Field The invention belongs to the technical field of titanium alloy material processing, and relates to a segregation-free high-strength Ti6Al6V2Sn titanium alloy forging prepared by adopting free forging and a preparation method thereof. Background Titanium alloy plays an important role in the fields of aerospace, ocean engineering, weapon engineering, petrochemical engineering and the like by virtue of the characteristics of light weight, high strength, corrosion resistance and wear resistance. The Ti6Al6V2Sn titanium alloy is an (alpha+beta) two-phase titanium alloy which is obtained by adding beta stabilizing elements V, fe, cu and neutral element Sn on the basis of the Ti6Al4V titanium alloy. Compared with Ti6Al4V titanium alloy, the Ti6Al6V2Sn titanium alloy has more excellent heat treatment strengthening performance and tensile strength, and simultaneously has good hardenability and heat stability, thus having obvious advantages in the application of large-size structural members. However, the method is limited in the smelting process, the equilibrium distribution coefficients of Cu and Fe elements are greatly different from those of Ti elements, and segregation is easily generated in the processing process of Ti6Al6V2Sn titanium alloy, so that beta spot defects are formed. The defects can cause the uniformity degradation of internal tissue structures and the reduction of batch stability, and seriously affect the performance and the service life of the Ti6Al6V2Sn titanium alloy serving as a large-specification forging. Therefore, ti6Al6V2Sn titanium alloy is commonly used for manufacturing small-sized components such as plates, small-sized forgings, bars or fasteners at present, the application requirements of large-sized structural forgings are difficult to meet, and the application prospect of the Ti6Al6V2Sn titanium alloy in high-end fields such as aerospace and ocean engineering is severely restricted. Therefore, there is a need to develop a large-sized Ti6Al6V2Sn titanium alloy forging and a method for manufacturing the same to solve the above problems. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a non-segregation, high-strength and large-specification Ti6Al6V2Sn alloy forging and a preparation method thereof. Firstly, on the design of Ti6Al6V2Sn titanium alloy components, binary intermediate alloys such as titanium copper, titanium iron and the like are used for replacing simple substances such as copper, iron and the like, the content of Cu and Fe elements in the alloy is reduced, the segregation and beta spot defects generated in the smelting process are reduced, secondly, in the forging process, a forging mode combining multiple-firing upsetting and two-phase region reversing upsetting and drawing is adopted, the direction of a tissue structure and a metal streamline is optimized, a uniform and fine forging structure is obtained, the reduction of the mechanical properties of a forging to a certain extent caused by the reduction of the content of Cu and Fe elements is compensated, and finally, a composite heat treatment process of high-temperature water-cooling solid-dissolving and aging of an upper two-phase region is adopted, so that the strength of the large-size Ti6Al6V2Sn titanium alloy forging is further improved, and certain plasticity is maintained. The method is characterized in that the primary alpha phase in the alloy forging stock is partially dissolved at a high temperature, a high-proportion metastable beta phase is formed in a matrix, a proper amount of primary alpha phase is reserved as a nucleation site, and the metastable beta phase in the forging stock is largely decomposed in a subsequent low-temperature aging heat treatment stage, so that a large number of secondary alpha phases are formed in the forging stock. The Ti6Al6V2Sn titanium alloy forging with no segregation, uniform tissue structure and high and strong specification is finally prepared by a composite heat treatment process of casting ingot composition design, a forging mode of combining large deformation upsetting forging and reversing upsetting and high-temperature cold-solidification and aging, and has important engineering significance. In order to achieve the above purpose, the present invention provides the following technical solutions: in the first aspect, the invention discloses a segregation-free high-strength Ti6Al6V2Sn titanium alloy forging, the thickness of the Ti6Al6V2Sn titanium alloy forging is 350-420 mm, the width is 420-470 mm, the length is 3200-4400 mm, the room temperature tensile strength is more than or equal to 1035MPa, the specified plastic elongation strength is more than or equal to 965MPa, and the elongation is more than or equal to 12%. In a second aspect, the invention discloses a preparation method of a non-segregation hig