EP0514293B1 - Procédé de fabrication d'une pièce en alliage de titane comprenant un corroyage à chaud modifié et pièce obtenue - Google Patents

Procédé de fabrication d'une pièce en alliage de titane comprenant un corroyage à chaud modifié et pièce obtenue Download PDF

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Publication number
EP0514293B1
EP0514293B1 EP92420149A EP92420149A EP0514293B1 EP 0514293 B1 EP0514293 B1 EP 0514293B1 EP 92420149 A EP92420149 A EP 92420149A EP 92420149 A EP92420149 A EP 92420149A EP 0514293 B1 EP0514293 B1 EP 0514293B1
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EP
European Patent Office
Prior art keywords
equal
temperature
less
blank
beta
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP92420149A
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German (de)
English (en)
French (fr)
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EP0514293A1 (fr
Inventor
Bernard Champin
Bernard Prandi
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Compagnie Europeenne du Zirconium Cezus SA
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Compagnie Europeenne du Zirconium Cezus SA
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon
    • C22F1/183—High-melting or refractory metals or alloys based thereon of titanium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium

Definitions

  • the invention relates to a method for manufacturing a part made of cast and wrought titanium alloy, intended for example for compressor disks for aircraft propulsion systems, as well as the parts obtained.
  • a hot working of an ingot of said alloy is carried out, this hot working comprising a hot roughing into a hot blank, then a final working of at least a portion of this blank preceded by preheating at a temperature situated above the real beta transus of said hot-worked alloy, the ratio of this final working "S / s" (initial section / final section) is preferably greater than or equal to 2, then is carried out on the blank of part obtained by this final working a solution treatment then a tempering treatment.
  • the parts obtained have an ex-beta needle structure with alpha phase borders.
  • the Applicant has sought to obtain this improvement and more generally to improve the compromise of mechanical properties obtained on such a titanium alloy part.
  • This process is characterized in that the blank is cooled hot from its preheating temperature situated above the real beta transus up to a temperature for the start of final wrought lying below this real beta transus and above the temperature of appearance of the alpha phase under the conditions of said cooling of said blank.
  • the said final working is then carried out, thus exceeding the appearance of the alpha phase at the grain boundaries and breaking at least once the alpha border recrystallized between these grains.
  • the Applicant has found that when a Ti alloy part of the type studied is cooled from the beta domain, its beta grain structure is transformed into alpha below the real beta transus and in two successive phases: there are d 'first germination and growth of alpha phases at the joints of beta grains, then, for example 60 to 100 ° C lower depending on the alloy, an acicular alpha transformation in these grains.
  • the variation curve of the germination temperature of the alpha phases at the grain boundaries as a function of the speed or the cooling time of a sample can be determined by quenching dilatometry associated with micrographic observations.
  • the definition of the "real beta transus" and its experimental determination are also known from the aforementioned patent.
  • the forging ends either in (3) in the metastable beta domain (5), or in (3 ') in the domain (6) of germination and growth of the alpha phases at the grain boundaries.
  • the ductility is improved and at the same time the mechanical resistance properties, tested in the long direction, and the creep resistance at 400 ° C.
  • Preheating is carried out before final working with a double objective: to obtain good homogenization in the beta phase, nevertheless limiting the magnification of the beta grain.
  • the hot blank typically having at this stage a cross section of the order of 220 ⁇ 220 mm 2, it is preheated to at most 50 ° C. above the beta transus real, the chosen temperature being reached to the core for at most 2 h when this temperature does not exceed by more than 30 ° C said beta transus, and for at most 1 h when this temperature further exceeds said transus.
  • the temperature of the starting of working (9) is at least 10 ° C. above the temperature of appearance of the alpha phase. , that is to say above the curve (7) of FIG. 1. Assuming that this temperature (7) is poorly known, it is possible to adopt as a practical rule to locate the beginning of the working (7) less 50 ° C below the real beta transus (2), and preferably 10 to 30 ° C below this transus (2).
  • the curve (7) can be traversed in the first half of the final working both in forging between hot dies, maintaining a substantially constant temperature and ending in (11), as in forging with natural cooling between passes, giving for example a cooling speed of 5-10 ° C / min and ending in (10).
  • the soloution treatment after the final hot working is carried out in (alpha + beta) and preferably between "real beta transus-20 ° C” and “real beta transus- 100 ° C ", with particular preference for” transus beta -5 to 6 times the equivalent Mo ".
  • the tempering treatment is typically done between 500 and 720 ° C for 4h to 12h.
  • FIG. 1 already discussed, represents the phase diagram (time, temperature) of an alpha-beta titanium alloy, and locates there the final working in the prior art and in the invention.
  • FIG. 2 represents a micrographic section of a sample of the prior art at 1100 ⁇ magnification.
  • Figures 3 and 4 show x 500 and x 1100 micrographic sections of a "NC" sample according to the invention.
  • FIG. 5 represents a micrographic section x 500 of a sample of the same alloy forged outside the conditions of the invention.
  • FIG. 2 shows a fine border 14 of the alpha phase, diagonally in the figure, separating two ex-beta grains of needle-like alpha-acicular structure.
  • a second part PB was preheated to 970 ° C and then cooled to 930 ° C, the temperature at which the final working started to obtain the section of 130 mm x 100 mm, this working having ended at 850 ° C skin, or about 900 ° C at the heart of the workpiece blank.
  • the heat treatments following the final working were in each case: dissolving for 1 hour at 910 ° C followed by air cooling, then returning 8 hours at 710 ° C followed by air cooling also.
  • PA outside invention 945 820 12 128 PB according to the invention 935 860 20 144 PB differs from PA by a clear improvement of A% and of the toughness K lc , accompanied by an improvement of Rp0,2.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Forging (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Chemically Coating (AREA)
EP92420149A 1991-05-14 1992-05-11 Procédé de fabrication d'une pièce en alliage de titane comprenant un corroyage à chaud modifié et pièce obtenue Expired - Lifetime EP0514293B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9105988A FR2676460B1 (fr) 1991-05-14 1991-05-14 Procede de fabrication d'une piece en alliage de titane comprenant un corroyage a chaud modifie et piece obtenue.
FR9105988 1991-05-14

Publications (2)

Publication Number Publication Date
EP0514293A1 EP0514293A1 (fr) 1992-11-19
EP0514293B1 true EP0514293B1 (fr) 1995-08-02

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EP92420149A Expired - Lifetime EP0514293B1 (fr) 1991-05-14 1992-05-11 Procédé de fabrication d'une pièce en alliage de titane comprenant un corroyage à chaud modifié et pièce obtenue

Country Status (7)

Country Link
US (2) US5264055A (ja)
EP (1) EP0514293B1 (ja)
JP (1) JPH0798989B2 (ja)
AT (1) ATE125881T1 (ja)
CA (1) CA2068556A1 (ja)
DE (1) DE69203791T2 (ja)
FR (1) FR2676460B1 (ja)

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FR2707111B1 (fr) * 1993-06-30 1995-08-18 Cezus Procédé de contrôle de copeaux et/ou fragments métalliques pour en éliminer des inclusions plus absorbantes aux rayons X .
FR2715410B1 (fr) * 1994-01-25 1996-04-12 Gec Alsthom Electromec Procédé de fabrication d'une pièce en alliage de titane et pièce en alliage de titane ainsi fabriquée et produit semi-fini en alliage de titane.
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Also Published As

Publication number Publication date
DE69203791D1 (de) 1995-09-07
FR2676460B1 (fr) 1993-07-23
ATE125881T1 (de) 1995-08-15
JPH0798989B2 (ja) 1995-10-25
CA2068556A1 (fr) 1992-11-15
FR2676460A1 (fr) 1992-11-20
EP0514293A1 (fr) 1992-11-19
JPH05148599A (ja) 1993-06-15
US5304263A (en) 1994-04-19
US5264055A (en) 1993-11-23
DE69203791T2 (de) 1995-12-14

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