JPS58153702A - Formation of molded alloy parts from metal particle or chemical particle of alloy components - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to methods and molding compositions for forming alloy parts from alloying components and/or compounds containing these alloying components.

Conventionally, parts have been formed from metal alloys by various methods. For example, parts can be obtained by manufacturing a mounting block and processing it into a desired shape and size. Method F is clearly expensive since the cost of the final part varies depending on the required part accuracy and the number of required machining steps. That is, the more complex the part, the higher the cost of the final part.

Moreover, there is also the disadvantage that all alloy materials that do not form parts are scrapped and discarded.

Another conventional method is to utilize particles of alloy material and form the particles into parts using conventional press and sinter metallurgy techniques. However, these methods did not give satisfactory results. Furthermore, attempts have been made to mold parts from mixtures of powders of alloys or powders of the metal components themselves used to obtain the desired alloy in appropriate proportions, but these methods do not involve oxidation on the particle surface. There is a disadvantage that objects are easily formed and the sintering operation is easily hindered. Therefore, it is possible to form highly accurate parts from metal alloys that have all the advantages of conventionally machined parts, while also having the additional advantages of improved part structure integrity and reduced final part costs. Providing a method is strongly desired.

The above needs can be achieved by the method of the present invention for forming precision molded parts of metal alloys from binders and small particles of metals and/or compounds containing the metal components of the desired metal alloy. .

The desired alloy can be obtained by mixing the metals and/or metal compounds @ required to produce the desired alloy in a predetermined ratio. The smaller the diameter of the particles of the metals and/or alloys used, the better, preferably in the range of 10 microns to 10 microns. These particles are mixed with a suitable binder to form a uniform mass.

To form a part, this mixture is made into a green body by any known method, the binder is removed from the green body, and the binder-removed green body is heated at a temperature above the firing temperature of the metal used but in a processing atmosphere. to sufficiently reduce all metal compounds, but raise the temperature to a high enough temperature to prevent oxidation of the metal. By holding this temperature, the process is carried out on the reducing side of the equilibrium curve of the furnace atmosphere for the metals being alloyed and fired, and this process operation is often based on the relationship between the dew point of the atmosphere and the current temperature (W). adjusted. Holding a green body in this atmosphere for a light minute removes virtually all metals and/or metals.
Or metal compounds become pure metal. Next, by raising the temperature of the thread at a firing temperature of 1 and maintaining the system temperature at the firing temperature of the metal concerned while keeping the thread in the reduction region of the equilibrium curve until 1-1 firing is completed, the fired parts will be can get. The fired part exhibits the properties of a homogeneous alloy, and the desired alloy is formed.

The present invention will be explained in more detail below.

In order to form precision parts from metal alloys, it is first necessary to use a suitable molding composition.

The molding composition according to the invention comprises small particles of metals or compounds containing the metal components necessary to form the desired alloy and which can be reduced or converted to base metals under the conditions of 4. Formed using small particles. When a compound is used, the amount of the compound to be used is determined based on the metal content in the compound required for the intended alloy so that the final alloy contains a specified amount of metal. The particle size is about 10 microns or less, and the smaller the particle size, the better. The preferred particle size range is 0 microns to 10 microns.

However, in the case of pure metals, for example, certain metals such as chromium become more explosive if the particle size is made very small, so when used in metallic form, the particle size of these pure metals should be within the range L. It is necessary to use it on the inner large diameter side. On the other hand, when metal compounds, especially oxides, are used, the surface energy of these compounds is 1 to 1 compared to that of pure metals.
Being so small, these compounds can be made into very small particle sizes, below a fraction of a micron, and can be used in the above size range with virtually no risk compared to the pure metal itself. I can do it. Father, the necessary alloys and metal components are usually not available, and even if they were available, they would be expensive and uneconomical. Therefore, small particles of suitable metals and/or compounds are mixed into a homogeneous mass with suitable known binders such as paraffin wax, carnauba wax, polyethylene, etc. and mixtures thereof.

The binder and metal and/or metal compound composition is then formed into the desired shape to form a green body.
The binder is removed from the body by all conventional methods. The binder-removed Gre-7 body is placed in a suitable reducing or other atmosphere, usually an oxygen-free dry hydrogen oven, kill/etc. -C All metal compounds are converted to pure metals 1- And if pure metals are used, these should be kept in a pure metal state. The dew point in the furnace is determined by the reduction range of all half-curves of the oxides of the metals and/or compounds used in the production of alloys or the conditions in the system (the father is Cr2O). , if the drawing contains Cr2U
, 1jlil to the right of the curve. For example, if we use a hydrogen atmosphere and form stainless steel with Cr2O, iron and nickel, and operate without changing the atmosphere, the entire operation will be Cr, on the right side of the 0° curve in the drawing, already reduced. Maintain the dew point of the system as done in the area.

Equilibrium curves for iron and Ninocur oxides are shown for Cr,0
．． It is located completely to the left of the curve.

The temperature in the oven is then raised to a high enough temperature to cause the appropriate chemical reactions to occur, such as reducing or converting all the metal compounds to pure metals, or reducing or converting the metal compounds to the metals themselves. In this case, the dew point of the system should be on the right side of the curve shown. Once all the metal compounds used have been reduced or converted into pure metals, there is a homogeneous mixture of small particles of metal throughout the compact, from which the binder has already been removed due to the very small particle size. Whether the reduction reaction has been completed can be determined by monitoring the dew points at the inlet and outlet of the furnace. That is, while the oxides are present, moisture is generated from the reduced or fired compact, so in an airtight system after all the oxides have been reduced, the exhaust dew point becomes equal to or higher than the population dew point. Thereafter, the temperature of the system is gradually raised to the firing temperature of the alloy, and the dew point of the yarn is maintained in the reduction range as described above.

, 111° for the required time, the metal particles will diffuse into each other and the desired alloy will be obtained. The atmosphere during firing may be neutral or vacuum. The furnace is then shut down, the final part is cooled to room temperature, and the finished product is removed from the furnace.

The time required to reduce all compounds to base metals will vary depending on the type of materials used, atmosphere, temperature, and size and shape of the part. Typically, the part thickness is 0.127CrIL(o,
Sintering the part on the right side of the equilibrium curve for 1 hour per 5 in. o is sufficient to reduce all compounds to pure metal.

Furthermore, better results can be obtained by the method described in -F than when the raw material powder itself consists of the target alloy.

Generally speaking, alloys also oxidize on their particle surfaces, so it is not possible to sinter them sufficiently and appropriately from an economical point of view.However, in the method of the present invention, oxidation of the entire metal surface is substantially prevented, so even if the surface is oxidized, This is thought to be because it is also reduced to a pure metal alloy.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example ■ 200g of nickel powder with a particle size of 2 to 4 microns
・1420g of iron powder with a particle size of 2 to 4 microns and a particle size of 1
．． Mixed with 560 g of 5 micron chromium oxide.

Further, 70.5 g of paraffin wax and 70 g of polyethylene were added to these materials, and 2
Mixed for an hour. Homogeneous blocks of various materials were used to form test bars in an injection molding machine. The bar was removed from the molding machine and the green body was placed on an absorbent material made of ashless paper in an oven.The body was gradually heated to 200C and held at 200C for 3 hours to remove the binder from the green body. Removed.

After the binder was removed from the green body, the green body was placed in a furnace. The inside of the furnace has a dew point of -5c+ at 1 atm.
, +c (-75°F) hydrogen was supplied and recycled. The furnace temperature was increased to 787.8 U (1
Gradually increase the temperature to 450°F (3.3°C per minute).
The temperature was gradually increased to 926.7C (1700F) at a rate of 6F (6F) and held at this temperature for 5 hours. Then,
1260C (2300°F) as quickly as possible while keeping the dew point 5.6C (10°F) below the dew point equilibrium curve.
and held at this temperature for 1 hour. The dew point within the system was continuously plotted, as shown in the accompanying drawings. Next, the furnace was stopped and allowed to cool to room temperature, after which the rods were removed and inspected. The rod was entirely homogeneous stainless steel and non-magnetic.

Example ■ 2151 g of 316L stainless steel powder with a particle size of 10 microns or less, 70°5 gb of paraffin wax, 50 g of polyethylene, 2 pieces of pure refined candelilla wax
A homogeneous mass of each material was obtained by mixing for 2 hours with 0 g and 150 U of stearic acid. This homogeneous mass was used to mold a test companion using an injection molding machine. The rod was removed from the molding machine and the green body was placed on an absorbent material made of ashless paper in an oven, heated gradually to 200C and held at 200C for 3 hours to remove the binder components. After removing the binder from the green body, the green body was placed in a furnace.

Hydrogen with a dew point of -59.4U (-75°F) is supplied and circulated into the furnace at 1 atm, and the temperature is increased by 3.3C (6'F) per minute.
) at a rate of 787.8C (1450°F) and then at a rate of 3.3C (6°F) per minute to 926.
Gradually raise the temperature to 70°C (1700°F) and hold at this temperature for 5 hours. Next, the dew point was set to 5.6 using a flaw point equilibrium curve.
C (10°F) low (-1 as quickly as possible)
The temperature was raised to 260C (2300°E")-E and maintained at this temperature for 10 hours. After the furnace was stopped and allowed to cool to room temperature,
4#! was taken out and inspected. The rod was entirely homogeneous stainless steel and non-magnetic. The density of the rod was 97% of Renx Denless Steel 316L.

As detailed above, in the present invention, the fungal component constituting the alloy can be converted into a base metal itself in the form of granules by hand, or can be converted into a base metal at a temperature below -F above the firing temperature of the metal particles during formation of the alloy. Parts can be made from all kinds of alloys if the granules of the compound are large enough.

Although the invention has been described in terms of preferred embodiments, it will be appreciated that many changes and modifications will be readily apparent to those skilled in the art and the invention is not limited to the preferred embodiments described above.

[Brief explanation of the drawing]

The drawing is Cr, 0. , Fe20B, W'02 and MoO2 are graphs showing the dew point of hydrogen at 1 atm ("F) versus furnace temperature. Specially assigned to Lytic Cayman Patents Ltd.
Patent Attorney Toshiaki Morisaki 11.1

Claims (1)

[Scope of Claims] (1) A method for forming molded parts of metal alloys directly from individual metals and/or compounds containing the metal components of the target alloy, comprising: (a) in the target alloy; mixing small particles of a substance selected from the group consisting of metals and/or metal compounds in an amount corresponding to the weight percent of the individual metals present with a suitable binder to form a homogeneous mixture of binder and particles; (C) removing the binder from the compact; (d) constantly maintaining the dew point of the atmosphere on the reducing side of the dew point equilibrium curve for all metals forming the target alloy; while placing the compact from step (C) under reducing atmosphere and temperature conditions to convert all compounds into metallic form, and (e) in a calcination atmosphere to reduce the dew point of the atmosphere to form the target alloy. A method for forming the alloy molded part comprising the step of firing the molded body from step (d) under reducing atmosphere and temperature conditions while always maintaining the dew point equilibrium curve on the reducing side for all metals. (2) The method according to claim 1, wherein the particles are oxides of metals forming the target alloy. (3) The method according to any one of claims 1 and 2, wherein the particles have a diameter of about 10 microns or less. (4) The method according to claim 3, wherein the particles are comprised of chromium oxide, iron oxide, and nickel oxide. (5) The method according to claim 3, wherein the particles are comprised of chromium oxide, iron, and nickel. (6) The method according to claim 3, wherein the particles are comprised of chromium oxide, iron oxide, and nickel. (Force) The method according to claim 3, wherein the particles are composed of chromium oxide, iron and nickel oxide. 18) Direct metal production from individual metals and/or compounds containing the metal components of the target alloy A method of forming an alloy molded part, the method comprising: (a) a total of the individual metals present in the LJ alloy; (b) Form the mixture into a predetermined shape; (c)
nf+ A+4 by/da was removed from the molded body, and (
d)], in order to make all the compounds and liquefied metals in IIi into pure gold, the molded bodies from L1 & 1(c) were placed in a prepared atmosphere, and the above 6. -I-
(e) Convert all the compounds and all the hard metal acids and arsenics during the IJ visit into pure metals, while always keeping them on the pupil side of the dew point curve. The above molding (4) from soil &i (C) is fired in an atmosphere, and the dew point of the atmosphere is kept at 11N, which is the point equilibrium curve for all the metals forming the gold. 7. A method for forming the alloy molded part, comprising the step of firing the alloy molded part. (9) The method according to claim 8, wherein the particles are oxides of metals forming the target alloy. OQ The method of any of claims 8 and 9, wherein the particles have a diameter of about 10 microns or greater. OI) A method according to claim 1O, wherein the particles consist of chromium oxide, iron oxide and nickel oxide. 0'4 The method of claim 1O, wherein the particles consist of chromium oxide, iron and nickel. (g) The method according to claim 10, wherein the particles are comprised of chromium oxide, iron oxide, and nickel. 11. The method according to claim 10, comprising α4 Ail particles of chromium, iron and nickel oxide. (a) mixing small particles of said alloy with a suitable binder to form a homogeneous mixture of binder and particles; (b) Ai
(c) removing the Ail binder/da from the molded body; (J) molding the Ail mixture into a prescribed shape;
While keeping the dew point of the atmosphere on the reduction side of the dew point equilibrium curve for all categories of the lid, the molded body from (C) is heated to the raw atmosphere and heated. Conditions FV apparatus converts all the compounds into metallic state, and (e) in the firing atmosphere Af, the dew point of the atmosphere is reduced to 1 for all the metals placed.Dew point-IL penalty curve reduction 111
11. A method for forming the alloy molded part consisting of ``process (d) to completely recycle the molded product under L1 raw atmosphere and temperature conditions. 16. A method according to claim 15, wherein the micron is less than about 1 micron.