JPS591778B2 - Manufacturing method of coarse-grained superalloy blocks by powder metallurgy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to produce a coarse-grained block from a superalloy by powder metallurgy, the present invention involves compressing a powder mixture into a green shape at high temperature and isostatic pressure, and then subjecting it to coarse-graining heating. Relating to a method of forming a strainer block.

In superalloys, a block from which the structure has a grain size of about 100 μm produced by powder metallurgy has a higher temperature at a temperature of 1000 °C or more than a block produced by spacing metallurgy and whose structure has a grain size of 1000 μm or more. It is known to have little strength.

To date, powder metallurgy has not been able to produce blocks whose structure has an average grain size of 100 μm or more, and it has therefore not been possible to produce high heat-resistant blanks using powder metallurgy.

Nevertheless, in fact, certain high temperature resistant blocks,
For example, it is often advantageous if turbine blades can be manufactured from superalloys using powder metallurgy instead of molten metallurgy.

The object of the invention is to create a method with which blocks with a coarse-grained structure can be produced by powder metallurgy.

According to the invention, this task is achieved by first strain-hardening particles of the monodisperse oxide-free powdered alloy or its components in a grinding device; loading and compressing the powdered alloy components mixed in the alloying ratio into a green form, and - heating the blank obtained in this way to a coarse-grained form at a temperature between the recrystallization temperature and the solidus temperature; This is solved by

The invention will be explained in detail below with reference to a schematic system diagram.

This causes strain hardening 3 of the superalloy particles 1, which are in powder form, or the alloy component particles 2, which are also in powder form (superalloys are defined in ASTM A:DS 9E).

When the alloy component 2 in powder form is strain hardened 3, it is simultaneously mixed 3' mechanically.

This powder is then charged 4 into a mild steel mold and shaped in the mold into a green shape 5 corresponding to a block.

This green form 5 is hot isostatically compressed 6 into a blank 7 in a press under a protective gas, preferably argon.

Such compression is known (Keramische
Zeitschrift, Volume 9 (1971), 51
0-514 pages).

In order to subsequently form a blank 9, this blank 7 is subjected to coarsening heating 8 under protective gas in a conventional heating furnace.

The method according to the invention will be explained in detail below using examples.

Example 1 To form a block of nickel-based austenitic superalloy, the following metal or alloy powders were mixed together in the following weight ratios and particle sizes.

(Weight%) Particle size (μm) CO,042,3 Co 8.5 2.3C
r 16.0 9. OMo
1.75 3.2W
2.6 0.5 Ta 1.75 6.5Nb
O,9012,5 AJ* 3.4 8~9 Ti*3.4 B* 0.01 7,.

. 1,■°〜. Ni remainder 4.8 (*marks are added as Ni pre-alloy.

) The particles are mixed and/or subsequently passed through an attritor (Attritor, US Pat.
91362) in an argon atmosphere,
Mixed mechanically at the same time.

This powder was then loaded into a mild steel mold and shaped in the mold to correspond to a block.

This green form was then hot isostatically compressed under an argon atmosphere to form a blank.

A pressing pressure of 3000 bar, a pressing time of 1 hour and a pressing temperature of 1050°C, where the pressing temperature is γ'
It was within the solution temperature range.

This blank was then subjected to coarsening heat under argon protective gas to form blocks.

This is then continued for 3 hours to exceed the recrystallization temperature12
Exposure to a temperature of 70°C followed by air cooling.

The temperature range from 900° C. to heating temperature (1270° C.) was reached quickly, ie within 15 minutes, until temperature equilibrium was reached in the blank.

The particle size obtained in the block was 1200 μm.

Example 2 To form a block of nickel-based austenitic superalloy, the following metal or alloy powders were mixed together in the following weight ratios and particle sizes.

(Weight %) Particle size (μm) Cr 19 9 AJ* 1.2 T i *2.4 8~9 Zr* 0.07 B* 0.007 Ni balance 4.8 (*marked is added as Ni pre-alloy) The particles are mixed and/or subsequently passed through a milling device (U.S. Pat. No. 3,591) for 48 hours.
No. 362) strain hardening in a medium argon atmosphere and mechanical mixing at the same time.

This powder was then loaded into a mild steel mold and shaped in the mold to correspond to a block.

The green form was then compressed under an argon atmosphere at high temperature and isostatic pressure to form a blank.

The pressing pressure was 3000 bar, the pressing time was 1 hour and the pressing temperature was 900° C., the pressing temperature being in the range of the γ' solution temperature.

This blank was then subjected to coarsening heat under argon protective gas to form blocks.

This is further continued for 30 minutes to exceed the recrystallization temperature12
Exposure to a temperature of 40°C followed by air cooling.

The temperature range from 900 °C to the heating temperature (1240 °C) is controlled rapidly until the blank reaches temperature equilibrium, i.e. 1
Achieved within 5 minutes.

The particle size obtained in the product was 1100 μm.

Example 3 To form a block of ferritic superalloy, the following metals or alloys were mixed together in the following weight ratios and particle sizes.

(Weight %) Particle size (μm) Co 1 5 ferroorom 30 30 FeAJ (Fe65%) 8 15Zr
O,058 Nb O,29 Fe Balance 7 The particles were mixed and/or subsequently milled in a milling apparatus (U.S. Pat. No. 3,591) for 24 hours.
No. 362) strain hardening in a medium argon atmosphere and mechanical mixing at the same time.

This powder was then loaded into a mild steel mold and shaped in the mold to correspond to a block.

The green form was then compressed under an argon atmosphere at high temperature and isostatic pressure to form a blank.

The pressing pressure was 3000 bar, the pressing time was 1 hour and the pressing temperature was 1000°C.

This blank was then subjected to coarsening heat under argon protective gas to form blocks.

This is further continued for 30 minutes to exceed the recrystallization temperature13
Exposure to a temperature of 20°C followed by air cooling.

The temperature range from 1000° C. to heating temperature (1320° C.) was reached quickly, ie within 15 minutes, until the blank reached temperature equilibrium.

The particle size obtained in the blocks averaged about 1000 μm.

Example 4 To form a block of nickel-based austenitic superalloy, the following composition: (% by weight)
Particle size (μm) C015 Cr 10 Af 5.5 Ti 4.75 Mo 3 130
CO,02 B O,15 Zr 0.06 Ni The remaining fine powder was strain hardened in an argon atmosphere in a milling apparatus (US Pat. No. 3,591,362) for 48 hours.

This powder was then loaded into a mild steel mold and shaped in the mold to correspond to a block.

The green form was then compressed at high temperature and isostatic pressure under an argon atmosphere to form a blank.

The pressing pressure was 3000 bar, the pressing time was 1 hour and the pressing temperature was 900° C., the pressing temperature being in the range of the γ' solution temperature.

This blank was then subjected to coarsening heat under argon protective gas to form blocks.

This is further continued for 30 minutes to exceed the recrystallization temperature12
Exposure to a temperature of 90°C followed by air cooling.

The temperature range from 900 °C to the heating temperature (1290 °C) is controlled rapidly until the blank reaches temperature equilibrium, i.e. 1
Achieved within 5 minutes.

The particle size obtained in the block was on average 1000 μm.

According to another example, blocks of cobalt-based austenitic superalloys having grain sizes generally greater than 1000 μm were produced in the manner described above.

In general, the present invention allows a blank to be hot-pressed simultaneously to the finished dimensions of a block, so that the block has:
The advantage is that there are no subsequent cutting or non-cutting work operations.

Another advantage of the present invention is that if the dimensions of the blank after hot isostatic pressing are larger than the finished dimensions of the block, the blank can be easily forged prior to coarsening heating to achieve the target block size. It is to be considered as the dimension.

[Brief explanation of the drawing]

The drawing is a system diagram illustrating the method according to the invention. 1... Alloy powder, 2... Alloy component powder, 3... Strain hardening, 3'... Strain hardening and mixing, 4...・Powder loading into mild steel mold, 5.
・・・・・・Green shape, 6：High temperature isostatic pressure compression, T・
... Blank, 8 ... Coarse graining heating, 9.
...Bujitsuku.

Claims (1)

[Claims] 1. In order to produce blocks with a coarse grained structure from superalloys by powder metallurgy, the powder mixture is compressed into a green shape at high temperature and equal static pressure, and then heated to coarsen the grains to form blocks. superalloy powder or powder mixed in an alloy ratio, in which particles of the dispersed oxide-free powdered alloy or its components are initially strain hardened in an attrition device and then strain hardened particles; Coarse-grained structure superstructure characterized by loading and compressing the alloy components of Manufacturing method of alloy blocks by powder metallurgy. 2. A method for producing a coarse-grained superalloy block by powder metallurgy according to claim 1, wherein the superalloy is a ferritic superalloy. 3. A method for producing a coarse-grained superalloy block by powder metallurgy according to claim 1, characterized in that the superalloy is an austenitic superalloy based on nickel or cobalt. 4. A method for producing a coarse-grained superalloy block by powder metallurgy according to claim 3, characterized in that the high-temperature isostatic compression is carried out within the range of the γ' solution temperature. 5 When heating the blank to coarsen it, it becomes 900% within 15 minutes.
4. A method for producing a coarse-grained superalloy block by powder metallurgy according to claim 3, characterized in that the block is heated from .degree. C. to a heating temperature.