Classifications

• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
  • B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
  • B21J1/06—Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
  • B21J17/00—Forge furnaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
  • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
  • B21J5/02—Die forging; Trimming by making use of special dies ; Punching during forging
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
  • B21K3/00—Making engine or like machine parts not covered by sub-groups of B21K1/00; Making propellers or the like
  • B21K3/04—Making engine or like machine parts not covered by sub-groups of B21K1/00; Making propellers or the like blades, e.g. for turbines; Upsetting of blade roots
• • 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 present invention relates to a method for the production of forged components, in particular of components made of a TiAl alloy and preferably of components for gas turbines, preferably aircraft engines and in particular turbine blades for low pressure turbines.
• titanium aluminides or TiAl alloys Due to their low specific weight and their mechanical properties, components made of titanium aluminides or TiAl alloys are of interest for use in gas turbines, in particular aircraft engines.
• Titanium aluminides or TiAl alloys are hereby understood as meaning alloys which contain titanium and aluminum as main constituents, so that their chemical composition has constituents with the highest proportions of aluminum and titanium.
• TiAl alloys are characterized by the formation of intermetallic phases, such as y - TiAl or ⁇ 2 - Ti 3 Al, which give the material good strength properties.
• TiAl alloys are not easy to process and the microstructures of TiAl materials need to be precisely adjusted to achieve the desired mechanical properties.
• a method for producing forged TiAl - components is known, in which after the forging a two-stage heat treatment is carried out to set a desired structure.
• the documents DE 10 2015 103 422 B3 and EP 2 386 663 A1 disclose methods of manufacturing components TiAl alloys.
• a strain rate of 0.01-0.5 1 / s is also disclosed.
• an efficient method for forging components made of TiAl materials is to be provided, preferably for the production of components for turbomachines, such as stationary gas turbines or aircraft engines.
• the invention proposes to carry out a quasi-isothermal forging during the forging of components at high temperatures instead of an isothermal forging, so that the expense for the provision and operation of a high temperature forging die can be reduced.
• the forging die in which the forging is to take place, is preheated to a first temperature, which is lower than a second temperature, to which the preform, which is to be formed by forging, before Forging is heated.
• the two temperatures are chosen so that during the corresponding forging process, the surface temperature of the preform to be forged during the forging process does not fall below a minimum forging temperature and at the same time the die temperature of the forging die does not rise above a maximum die temperature.
• the burden of the forging die can be reduced on the one hand by a lower temperature of the forging die and thus directly by a lower temperature load and on the other hand by a higher temperature of the preform, which reduces the yield stress of the preform to be forged and thus the burden of the forging die by the forming during forging will be reduced.
• the first temperature for the preheating of the forging die and the second temperature for preheating the preform to be forged can be selected depending on the desired forging temperature of the corresponding component, the degree of deformation in the corresponding forging step, the forming speed and comparable forging parameters In order to achieve the desired effect of the lowest possible or not too high load of the forging die and a sufficiently high forging temperature of the entire preform to be forged.
• the forming speed at the beginning of the deformation of the component is comparatively high, for example. 0.5 1 / s, and is then continuously, preferably correlated, lowered with decreasing component or preform temperature.
• the forming speed can be chosen in particular such that by increasing the yield stress at decreasing Temperature of the component or the preform due to the forming speed no cracks or damage occur in the component or the preform.
• the forging die may be heated during forging to avoid temperature drop of the preform to be forged during forging.
• the values for the first and second preheating temperatures, ie the first temperature of the drop forging and the second temperature of the preform to be forged, can also be selected taking into account the heating of the forging counter.
• the heating of the forging die can be controlled or regulated in such a way that the minimum forging temperature for the preform is not undershot and the maximum die temperature for the forging die is not undershot.
• minimum preform forging temperature is meant the lowest preform temperature at any location, and in particular at any surface location during forging.
• minimum forging temperature means the absolute lowest value at any location of the preform at any time during the forging process.
• minimum preform forging temperature can be understood to mean a minimum temporal and / or local average.
• maximum die temperature is preferably understood to mean the absolute highest temperature at any location in the forging die, particularly at the surface of the die at any time during forging. Alternatively, however, the maximum die temperature may also be defined as a maximum local and / or temporal average.
• the difference between the first and second temperature may be at most 320 ° C, preferably at most 200 ° C and in particular at most 150 ° C. With these difference ranges a compromise can be made between the highest possible difference for a very efficient use of a forging die at a high forging temperature and the smallest possible difference for the maintenance of uniform and homogeneous forging conditions over the entire preform to be forged.
• the forging die is maintained in a temperature range of 1100 ° C ⁇ 10 ° C prior to forging and / or during forging.
• the forging die material can be more stable in strength and creep, and less in wear, which can increase its life.
• the forging preform may be brought to a temperature of 1230 ° C ⁇ 8 ° C, for example, with a soak time of between 45-60 minutes, preferably in a rotary hearth furnace.
• the yield stresses are significantly lower, so that the burden of the forging counter can be significantly reduced and the forging time can be shortened.
• the throughput can be increased at the same time with a lower load on the forging counter.
• the minimum forging temperature and maximum die temperature may be the same, such that the forging preform moves from the second temperature and the drop forging moves from the first temperature toward a common limit temperature during the forging operation.
• the minimum forging temperature and the maximum die temperature may differ from one another and, for example, have differences of not more than ⁇ 50 ° C., preferably not more than ⁇ 25 ° C. In this case, preferably, the minimum forging temperature is higher than the maximum die temperature.
• the preform to be forged which is preheated in a preheating furnace, in particular a rotary hearth furnace, is transferred directly from the preheating furnace into the forging die immediately before the forging process. If the forging deformation takes place under a protective gas atmosphere, the preheating furnace and the transfer of the preform to be forged can be carried out from the preheating furnace to the forging die under a protective gas atmosphere to avoid lock operations or the like.
• the forging method according to the invention is particularly suitable for TiAl materials and components produced therefrom and for components of turbomachines, such as stationary gas turbines or aircraft engines, in particular TiAl materials, in which, for example, forging temperatures in the range of over 1200 ° C are advantageous.
• forged components made of TiAl alloys in particular for gas turbine components, such as low-pressure turbine turbine blades, are mainly with Niobium and molybdenum alloyed titanium aluminide alloys. Such alloys are also referred to as TNM alloys.
• an alloy of 42 to 45 atomic percent aluminum, 3 to 5 atomic percent niobium, and 0.5 to 1.5 atomic percent molybdenum may be used, the remainder being titanium.
• the aluminum content may be selected in the range of 42.8 to 44.2 atomic percent aluminum, while 3.7 to 4.3 atomic percent of niobium and 0.8 to 1.2 atomic percent of molybdenum may be alloyed.
• the alloy may be alloyed with boron in the range of 0.05 to 0.15 atomic percent boron, more preferably 0.07 to 0.13 atomic percent boron.
• the alloy may include unavoidable impurities such as carbon, oxygen, nitrogen, hydrogen, chromium, silicon, iron, copper, nickel and yttrium, the content of which is ⁇ 0.05% by weight of chromium, ⁇ 0.05% by weight of silicon, ⁇ 0.08 wt% oxygen, ⁇ 0.02 wt% carbon, ⁇ 0.015 wt% nitrogen, ⁇ 0.005 wt% hydrogen, ⁇ 0.06 wt% iron, ⁇ 0.15 wt% copper, ⁇ 0.02 wt% nickel and ⁇ 0.001 wt% yttrium , Further constituents may be contained individually in the range of 0 to 0.05 percent by weight or in total from 0 to 0.2 percent by weight.
• unavoidable impurities such as carbon, oxygen, nitrogen, hydrogen, chromium, silicon, iron, copper, nickel and yttrium, the content of which is ⁇ 0.05% by weight of chromium, ⁇ 0.05% by weight of silicon,

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Forging (AREA)

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• 2017
  • 2017-07-14 DE DE102017212082.7A patent/DE102017212082A1/de not_active Withdrawn
• 2018
  • 2018-05-25 EP EP18174307.1A patent/EP3427858A1/fr not_active Withdrawn
  • 2018-07-12 US US16/034,198 patent/US20190017158A1/en not_active Abandoned

Patent Citations (3)

Non-Patent Citations (1)

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