RU2630142C1 - Method of producing metallic fidstock - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method involves mechanical mixing the metal powder and binder. Powder based on a metal selected from Fe, Ti, Al in the amount of 95-97% by weight is used as the metal powder, and paraffin and wax in the amount of 3-5% by weight are used as the binder %. Paraffin and wax are taken in the ratio from 95:5 to 90:10.

EFFECT: production of metal feedstock, products of which have high uniformity in density, hardness and strength.

3 cl, ex 5

Description

The invention relates to PIM technologies, and in particular to methods for producing metal feedstock.

A known method of obtaining a suspension of metal powders for the manufacture of preforms from powder multicomponent materials (Ru 2442675, B22F 9/04, publ. 02.20.2012), including the preparation of a mixture of metal powders, mixing a mixture of metal powders and an aqueous solution of polyvinyl alcohol, while as a source of powder use a powder of a multicomponent highly alloyed alloy 60X20U, which is pre-crushed in the presence of a 96% solution of ethanol in a high-energy mill to a particle size of 0.6-1.4 microns, the resulting powder is mixed with iron powder with a particle size of 3.5 microns in the mixers for 24-32 hours to obtain a mixture of metal powders with a relative particle density of 0.5-0.6. EFFECT: obtaining a sedimentation-stable suspension of metal powders for the manufacture of multicomponent powder materials.

A disadvantage of the known invention is the low degree of particle packing - not more than 60%. This does not allow to obtain dense non-porous products after sintering due to the large amount of introduced plasticizer.

The most widely used materials for PIM technology were raw materials under the Catamold trademark of BASF (Germany) (US 6228508, B22F 3/22, B22F 7/06, B23K 20/10, publ. 8.05.2001). Catamold's product range ranges from pure iron alloys and low alloy steels to high alloy, stainless steels and oxide ceramics. Homogenized mixtures of fine metal powders and a polymer thermoplastic binder (binder) are used as feedstock (granulate or feedstock). Catamold materials use a polyacetal-thermoplastic polymer as a binder, which is removed by thermal degradation at a temperature of about 110 ° C in the presence of a catalyst - nitric acid vapor.

However, these materials require a long binder removal cycle due to the need to maintain a low rate of destruction of the polyacetal in order to avoid destruction of the compact by gases released during the decomposition of the binder.

The technical problem of the invention is the development of a method for producing metal feedstock. Products obtained from feedstock by the proposed method have high uniformity in density, hardness and strength.

The specified technical result is achieved in that the method for producing metal feedstock involves mechanical mixing of a metal powder and a binder, while powders based on a metal selected from the group: Fe, Ti, Al are used as a powder, and paraffin and wax are used as a binder, with the following ratio of components, mass. %:

metal based powder, selected from the group: Fe, Ti, Al 95-97 binder 3-5,

while paraffin and wax are taken in a ratio of from 95: 5 to 90:10.

In the proposed method, metal powders are pre-subjected to mechanical activation for 24 hours with the addition of stearic acid in an amount of 5% of the binder. Mixing of the starting components is carried out at the boiling point of water in a steam bath.

Disclosure of the invention

The proposed method for producing metal feedstock involves mechanical mixing of a powder based on a metal selected from the group: Fe, Ti, Al, and paraffin and wax taken respectively as a binder are used: powder 95-97 wt. % and a binder of 3-5 mass. %, while paraffin and wax are taken in a ratio of from 95: 5 to 90:10.

In the proposed method, the selected metal powders are pre-subjected to mechanical activation for 24 hours with the addition of stearic acid in an amount of 5 mass. % of the binder.

The preliminary activation of the metal powder is carried out to further improve the compaction of the particles, as well as to achieve a degree of uniformity of particle size. Stearic acid is added to surface activation of the metal powder.

In this case, paraffin and beeswax are taken in a ratio of from 95: 5 to 90:10 for fluid stock flow.

These optimal qualitative and quantitative ratios of metal powders and a binder (paraffin and wax) within the stated limits in the proposed metal feedstock were achieved as a result of experimental studies of the authors.

The implementation of the invention

To implement the invention, the authors used a powder based on a metal selected from the group: Fe, Ti, Al, solid petroleum paraffin (P-2) and beeswax.

A powder similar in composition to a metal powder of grade 20X13 is obtained from:

- a mixture of powders 30X13 (73.7%), FeC (22.25%), Cr (4.05%) or

- a mixture of powders FeC (85.67%), Cr (13.00%), Mn (0.60%), Ni (0.60%), C (0.13%).

The selected metal powder is mechanically activated in a drum mill with the addition of stearic acid. The mechanical treatment provides a reduction in the particles of the metal powder and increases its surface activity, which improves the fluidity of the feedstock and, accordingly, leads to more efficient filling of the injection mold (compaction).

Next, the activated metal powder is mixed with a heated binder component.

To do this, a steam bath is heated to the boiling point of water, paraffin and beeswax, taken in the declared quantitative proportions, are placed in a ceramic crucible.

The components of the binder melt and mix until a homogeneous consistency. Then, the previously activated metal powder obtained is added to the crucible with a binder. The metal powder is mixed with a bunch of ceramic spatula at the boiling point of water in a steam bath until a homogeneous consistency. After acquiring uniformity, the resulting feedstock is cooled in air.

Example 1

A metal powder is used, similar in composition to the powder of grade 20X13, obtained from a mixture of powders 30X13 (73.7%), FeC (22.25%), Cr (4.05%).

For 100 g of the finished feedstock, 95 g of metal powder is taken, stearic acid is added in an amount of 0.25 g. The metal powder is activated in a drum mill for 24 hours. Next, a steam bath is heated to the boiling point of water, paraffin 4.5 g and wax 0.5 g are placed in a ceramic crucible. The components of the binder are melted and mixed to a homogeneous consistency. Then, the previously activated metal powder obtained is added to the crucible with a binder. Metal powder in an amount of 95 g is mixed with a binder at a boiling point of water (100 ° C) in a steam bath until a homogeneous consistency. After acquiring uniformity, the resulting feedstock is cooled in air.

Example 2

A metal powder is used, similar in composition to the powder of grade 20X13, obtained from a mixture of powders:

FeC (85.67%), Cr (13.00%), Mn (0.60%), Ni (0.60%), C (0.13%).

Per 100 g of finished feedstock, 97 g of metal powder are taken, stearic acid is added in an amount of 0.15 g. The metal powder is activated in a drum mill for 24 hours. Then a steam bath is heated to the boiling point of water, paraffin 2.75 g and wax 0.25 g are placed in a ceramic crucible. The components of the binder are melted and mixed until a homogeneous consistency. Then, the previously activated metal powder obtained is added to the crucible with a binder. A metal powder in the amount of 97 g is mixed with a binder at the boiling point of water (100 ° C) in a steam bath until a homogeneous consistency. After acquiring uniformity, the resulting feedstock is cooled in air.

Example 3

A metal powder is used, similar in composition to the powder of grade 20X13, obtained from a mixture of powders FeC (85.67%), Cr (13.00%), Mn (0.60%), Ni (0.60%), C ( 0.13%).

96 g of metal powder are taken per 100 g of ready feedstock, stearic acid is added in an amount of 0.20 g. The metal powder is activated in a drum mill for 24 hours. Next, a steam bath is heated to the boiling point of water, paraffin 3.8 g and wax 0.2 g are placed in a ceramic crucible. The components of the binder are melted and mixed to a homogeneous consistency. Then, the previously activated metal powder obtained is added to the crucible with a binder. A metal powder in the amount of 96 g is mixed with a binder at the boiling point of water (100 ° C) in a steam bath until a homogeneous consistency. After acquiring uniformity, the resulting feedstock is cooled in air.

Example 4

Use a metal powder obtained from a mixture of powders Ti (94%), V (6%).

For 100 g of the finished feedstock, take 95 g of the metal powder, add stearic acid in an amount of 0.25 g. The metal powder is activated in a drum mill for 24 hours. Next, a steam bath is heated to the boiling point of water, 4.75 g paraffin and 0.25 g wax are placed in a ceramic crucible. The components of the binder are melted and mixed to a homogeneous consistency. Then, the previously activated metal powder obtained is added to the crucible with a binder. A metal powder in the amount of 96 g is mixed with a binder at the boiling point of water (100 ° C) in a steam bath until a homogeneous consistency. After acquiring uniformity, the resulting feedstock is cooled in air.

Example 5

Al powder (100%) was used.

For 100 g of the finished feedstock, 95.5 g of metal powder are taken, stearic acid is added in an amount of 0.225 g. The metal powder is activated in a drum mill for 24 hours. Next, a steam bath is heated to the boiling point of water, paraffin 4.15 g and wax 0.35 g are placed in a ceramic crucible. The components of the binder are melted and mixed until a homogeneous consistency. Then, the previously activated metal powder obtained is added to the crucible with a binder. Metal powder in the amount of 95.5 g is mixed with a binder at the boiling point of water (100 ° C) in a steam bath until a homogeneous consistency. After acquiring uniformity, the resulting feedstock is cooled in air.

Products obtained from the proposed metal feedstock have the following characteristics: hardness 270 ± 10 MPa, yield strength 250 ± 10 MPa, porosity 6 ± 1%, ultimate tensile strength 600-700 MPa.

Claims (5)

1. A method of producing a metal feedstock, comprising mechanically mixing a metal powder and a binder, characterized in that the powders are based on powders based on a metal selected from the group: Fe, Ti, Al, and paraffin and wax are used as a binder in the following ratio of components , wt.%: metal based powder, selected from the group: Fe, Ti, Al 95-97 binder 3-5, while paraffin and wax are taken in a ratio of from 95: 5 to 90:10. 2. The method according to claim 1, characterized in that the metal powder is pre-subjected to mechanical activation for 24 hours with the addition of stearic acid in an amount of 5 wt.% From the binder. 3. The method according to claim 1, characterized in that the mixing of the starting components is carried out at a boiling point of water in a steam bath.