JPH11140509A - Manufacturing method of composite characteristic parts - Google Patents

Abstract

(57) [Abstract] The use of expensive high alloy powder can be minimized by utilizing the plastic deformation of the base ingot at high temperatures in densifying high alloy compacts. Becomes
A component having a sintered part with a high compaction density capable of maximizing the properties of the high alloy powder and having a high bonding strength between the base and the sintered part can be manufactured at low cost. PROBLEM TO BE SOLVED: To efficiently and inexpensively produce a composite part having excellent wear resistance has been difficult by a conventional method. SOLUTION: A high-alloy green compact and a smelting material serving as a substrate are primarily heated and bonded at a temperature equal to or higher than the melting point of the high-alloy powder x 0.5 times or more, so that the high-alloy compact can be produced in a short time without lowering the production efficiency The powder is reheated to a temperature of at least 0.5 times the melting point of the powder and processed (forged, pressed, rolled, extruded) into a shape close to the final part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite product comprising an ingot and a high-alloy green compact, and uses a plastic deformation of an ingot as a base to produce a high alloy powder having excellent wear resistance. And compacting the green compact, and joining the base and high alloy powder to improve the properties of the sintered body by densifying the sintered body, and by reducing the amount of high alloy powder used and the number of processes The present invention relates to a method for manufacturing a composite characteristic component having excellent wear resistance, which can reduce the manufacturing cost.

[0002]

2. Description of the Related Art For the purpose of reducing the cost of wear-resistant parts, use of high-alloy powders having excellent wear resistance only in the areas where wear resistance is required, and the use of inexpensive composite parts for the base material. Manufacturing is taking place. Here, for sintering the high alloy green compact,
Hot isostatic pressing is applied. For example, there are the following methods for producing a composite characteristic part in which a high alloy powder sintered body is arranged outside a cylindrical part by this method.

[0003] First, an ingot serving as a base is mounted in a metal container, and a high alloy powder is filled between the ingot and the metal container and canning is performed. This is sintered and diffusion-bonded by hot isostatic pressing. However, if the base is brought closer to the final component shape in advance, the process for removing the metal container used for canning becomes complicated. Further, when the substrate has a simple shape, the number of steps such as rolling, forging, and extrusion for increasing the final component shape is increased. Therefore, the production of the composite characteristic component using the hot isostatic pressing process requires a large amount of cost, and therefore, the components to which the process is applied are limited.

[0004] On the other hand, hot pressing, which is one of the prior arts, is also applied only to parts limited to special uses.
This is because hot sintering is performed at a high temperature for a long time in an inert gas apparatus, which is expensive for equipment and low in product production per unit time, making it unsuitable for mass production of general-purpose parts. This is one of the reasons for its narrow scope.

Further, as a method of plastically deforming an ingot material serving as a substrate, a method in which the ingot material and powder are pressed at room temperature and sintered at a high temperature has been devised. However, it is known that the compaction density after processing is not sufficiently high, and that the bonding strength between the powder and the ingot is low.

[0006] On the other hand, a high-alloy powder is filled in a metal tube of an ingot material serving as a base, and the mouth of the metal tube is sealed by welding.
After heating to a high temperature of 1000 ° C. or higher for about 1 hour, extruding, further rolling at 1000 ° C. or higher, and then performing a softening heat treatment to process into a final part shape, the quality of which is disclosed in JP-A-4-47022. Is disclosed. According to this method, it is possible to manufacture a composite characteristic part, but the heating time before extrusion is long, and a plurality of steps are added until the final part shape is processed, so that the productivity is low. There is.

[0007]

As explained in the prior art, it has been difficult to efficiently produce a composite part having excellent wear resistance by the conventional method. The purpose of the present invention is
It is an object of the present invention to provide a method for efficiently and inexpensively manufacturing a composite part having excellent wear resistance due to a densified powder sintered part and high bonding strength between the powder sintered part and an ingot.

[0008]

The present invention utilizes plastic deformation at a high temperature of an ingot as a base material in densifying a high-alloy green compact. In other words, the green compact and the ingot material serving as the substrate are primarily heated and bonded at a temperature equal to or higher than the melting point of the high alloy powder x 0.5 or more, and reheated in a short time without reducing the production efficiency. By simultaneously processing (forging, pressing, rolling, extruding) to a shape close to the part, the powder part can be uniformly densified, and a composite characteristic part with high bonding strength between the powder sintered part and the base can be manufactured. The present invention has been found.

According to the present invention, by heating the component processed in this manner in a sintering furnace, it becomes possible to produce a composite characteristic component having a sintered portion having a sintered density of 98% or more. The bonding strength between the powder sintered part of these composite characteristic parts and the base ingot is determined by the plastic deformation of the ingot and mechanical caulking action by the powder biting into the ingot, and diffusion bonding of the powder and the ingot. Since the ingot is significantly higher than the case where the ingot is joined to the powder without plastic deformation, it can be applied to the production of various parts.

In the temperature range of the melting point of the high alloy powder × 0.5 or more, the high alloy green compact is consolidated while causing plastic deformation of the substrate, and the melting point of the high alloy powder × 0.7 or more. By performing sintering and diffusion bonding while causing plastic deformation of the substrate in the temperature range, it is possible to manufacture composite parts with sintered parts close to true density without going through the sintering process or hot isostatic pressing. Becomes

Here, the high alloy powder having excellent wear resistance is as follows:
Cold tool steel containing carbonitride, high speed steel, etc. are desirable,
It goes without saying that the type of powder is not limited as long as it has higher wear resistance than the base ingot and has the desired wear resistance. The average size of the powder was 1
It is desirable that the thickness is not more than 00 μm. The state of the powder in contact with the substrate may be either powder or green compact. The base ingot is preferably an Fe-based material, but can also be applied to Ni-based and Ti-based materials in consideration of heat resistance, corrosion resistance, and weight reduction of manufactured parts.

[0012] The primary heating temperature is set at 0.1 of the melting point of the high alloy powder.
5 times or more is desirable. It is necessary to bond the green compact and the ingot in a state where the green compact and the ingot are in contact with each other to prevent the green compact from falling off during the heating and further processing of the parts for further processing. That's why. Here, if the heating temperature is too low, the green compact cannot be bonded to the ingot. For this heating, it is desirable to use a sintering furnace whose atmosphere can be adjusted. However, heating may be performed in a vacuum furnace or in the air using a low to high frequency induction device.

[0013] The heating temperature at the time of working must be 0.5 times or more the melting point of the high alloy powder. At lower temperatures, the deformation resistance of the high alloy powder itself is high, so that the amount of plastic deformation is small, so that the contact area between the powders after processing does not increase, so that sintering does not sufficiently proceed, and the base becomes Since the deformation resistance of the ingot does not decrease, the amount of processing (working strain) of the base cannot be increased to the final part shape, and efficient production becomes difficult because the life of the mold is reduced.

If the reheating time up to the processing temperature exceeds 600 seconds, it is desirable to heat the parts within 100 seconds because the production efficiency of the parts is significantly reduced. The heating method is preferably a low to high frequency induction heating method. At this time, the heating atmosphere is preferably a vacuum or an inert gas atmosphere, but even in the air, the powder or the compact is exposed to the air. It does not matter if the contact surface between the green compact and the ingot is not exposed, or if it is partially exposed. When heating in the air, a Ti-based powder may be mixed into the high alloy powder for oxygen gettering.

The working method is desirably the final part shape by forging or a shape similar thereto, but rolling, extrusion, or wire drawing may be used. At this time, at least theoretically, a processing strain is applied so that the green compact has a true density.

After the above processing, plastic deformation is again caused in the substrate in the temperature range of not less than the melting point of the high alloy powder × 0.7, so that the powder sintered part and the joint part can be strengthened respectively. it can. However, when processing is performed by heating to a temperature lower than the melting point of the high alloy powder × 0.7, the effect of the repetitive processing is not recognized.

The processed product having the final part shape formed as described above is subjected to a necessary heat treatment, and the processed product conforming to the final part shape is subjected to heat treatment after being processed into the final part shape by cutting or grinding. Or after the necessary heat treatment, it can be processed into the final part shape by cutting or grinding. Here, the heat treatment includes quenching, tempering, annealing, sintering, HIP, and the like, and these may be combined.

[0018]

Example 1 Hot work tool steel (0.4% C-1.1% Si-
A base composed of 5.2% Cr-1.2% Mo-0.55% V) and a high-speed green compact (1.7% C-4.1% Cr-2.
0% Mo ), And then heated to 1150 ° C in a sintering furnace.
The temperature was set to 200 ° C., the base was plastically deformed by press working in a closed mold, and the high-speed green compact was compacted. This complex is
The high-speed steel was sintered by holding at 180 ° C. and 10 kg / cm ² for 1 hour. Furthermore, quenching from 1150 ° C to 550 ° C
After tempering, a cutting tip was produced by grinding.

[0019]

Comparative Example 1 Hot work tool steel (0.4% C-1.1% Si-
A base composed of 5.2% Cr-1.2% Mo-0.55% V) and a high-speed green compact (1.7% C-4.1% Cr-2.
0% Mo-14.8% W-5.1% V-7.9% Co)
1 was installed as shown in FIG. 1, carbon steel heated to 1200 ° C. was inserted into the hole of the base, and the temperature of the base was 1000
° C (30 seconds after inserting carbon steel)
Then, the substrate was plastically deformed by press working in a closed mold, and the high-speed green compact was compacted. This complex was heated at 1180 ° C, 1
The high-speed steel was sintered by holding at 0 kg / cm ² for 1 hour.
Furthermore, after quenching from 1150 ° C. and tempering to 550 ° C., a cutting tip was produced by grinding.

[0020]

Comparative Example 2 Table 1 shows the results of intermittent cutting using the tips shown in Example 1 and Comparative Example 1 and a general-purpose HSS tip (Comparative Example).

[0021]

[Table-1] Work material: SCM440 (hardness: 280 HV), work material shape: φ90 mm, 7 grooves of 10 mm width Cutting speed: 150 m / min, depth of cut: 1.5 mm,
Feed: 0.3 mm / rev Life criterion: Cutting time (min) until flank wear reaches 0.2 mm

[0022]

Example 2 A base made of a Ti alloy (6.2% Al-4.1% V-balance Ti) and a cold tool steel compact (2.8% C
-17% Cr-2.9% Mo-0.3% V) as shown in FIG. The vicinity of the powder filling of the adhesive product taken out of the above was heated to 1200 ° C. in 5 seconds by high-frequency induction heating and pressed to deform the base plastically, thereby consolidating the cold tool steel powder. After that, quenching from 1200 ° C and tempering at 580 ° C
A tappet was produced by grinding the sintered part.

[0023]

Comparative Example 3 A base made of a Ti alloy (6.2% Al-4.1% V-balance Ti) and a cold tool steel compact (2.8% C
-17% Cr-2.9% Mo-0.3% V) as shown in FIG. 2, and then heats the vicinity of the powder filling to 1200 ° C. in 20 seconds by high-frequency induction heating. It was plastically deformed and the cold tool steel powder was consolidated. After that, quenching from 1200 ° C and tempering at 580 ° C
A tappet was produced by grinding the sintered part.

[0024]

Comparative Example 4 The tappets shown in Example 2 and Comparative Example 3
General-purpose sintered high-speed steel (2.1% C-4.0% Cr-5.9)
% Mo-14.0% W-5.5% V-11.9% Co)
The carburized case hardened steel (0.2% C-1.1% Cr-0.15%
The results of an abrasion test performed using a tappet brazed to Mo) (Comparative Example 4) are shown in Table-2. In addition, the roughness on the tappet crown surface was within 0.3a.

[0025]

[Table-2] Number of cam contacts: 5000 rpm, load surface pressure: 1.5 GP
a, Endurance time: 150 hours

[0026]

Embodiment 3 Ni alloy (18.2% Cr-2.9% Mo)
-52% Ni- balance Fe and high-speed green compact (1.7% C-4.1% Cr-2.0% Mo-14.8)
% W- After the installation, the product was heated to 1150 ° C. in a sintering furnace, and the adhesive product taken out of the furnace was subjected to high-frequency induction heating for 1200 seconds in 5 seconds.
℃, plastic deformation of the substrate by pressing,
The high-speed green compact was compacted. Further, immediately after reheating to 1200 ° C. in 5 seconds by high-frequency induction heating, the base was plastically deformed by press working to increase the compaction density of the high-speed green compact. Subsequently, quenching was performed from 1200 ° C. and tempered at 540 ° C., and the sintered portion was ground to obtain a cylindrical radial bearing shape.

[0027]

Comparative Example 5 Ni alloy (18.2% Cr-2.9% Mo)
-52% Ni- balance Fe and high-speed green compact (1.7% C-4.1% Cr-2.0% Mo-14.8)
% W-5.1% V-7.9% Co) as shown in FIG. 3, heated to 1200 ° C. in 10 seconds by high frequency induction heating, plastically deformed the base by press working, and The body was compacted. Furthermore, immediately with high-frequency induction heating, 2
The substrate was heated to 1200 ° C. in 0 second and pressed again to plastically deform the base, thereby increasing the compaction density of the high-speed powder. Then quenched at 1200 ℃ and tempered at 540 ℃
The sintered part was ground to form a cylindrical radial bearing.

[0028]

Comparative Example 6 The radial bearing test pieces shown in Example 3 and Comparative Example 5 and M50 (0.78% C-0.3% Si-4.
The results of a rolling fatigue test performed using a radial bearing (Comparative 6) made of 1% Cr-4.2% Mo1.0% V) are shown in Table-3.

[0029]

[Table-3] Surface pressure: 5.2 GPa, number of revolutions: 1800 rpm, lubricating oil: automatic fluid, oil temperature: 180 ° C. Life judgment: number of repetitions leading to the establishment of 10% cumulative damage

[0030]

Embodiment 4 Carbon steel (0.2% C-0.25% Si-
0.5% Mn-balance Fe and a high speed green compact (1.5% C-0.2% Si-4.1% Cr-5.0%)
Mo-3. Then, the adhesive product taken out of the furnace was heated to 1200 ° C. in 5 seconds in the vicinity of powder filling by high-frequency induction heating, and the substrate was plastically deformed by press working to consolidate the high-speed powder. After that, it was immediately reheated to 1200 ° C. in 5 seconds by high-frequency induction heating and pressed to deform the substrate plastically, thereby increasing the compaction density of the green compact. Subsequently, quenching was performed from 1180 ° C. and tempered at 540 ° C., and the sintered portion was ground to form a tooth profile of the gear.

[0031]

Comparative Example 7 Carbon steel (0.2% C-0.25% Si-
0.5% Mn-balance Fe and a high speed green compact (1.5% C-0.2% Si-4.1% Cr-5.0%)
Mo-3.1% V) was installed as shown in FIG. 4, the vicinity of powder filling was heated to 1200 ° C. in 10 seconds by high-frequency induction heating, the base was plastically deformed by press working, and the high-speed powder was compacted. It has become. Then, quenching from 1180 ° C, 5
After tempering at 40 ° C., the sintered portion was ground to form a gear tooth profile.

[0032]

Comparative Example 8 Table 4 shows the results of a gear fatigue test using the gears shown in Example 4 and Comparative Example 7 and the gear carburized with case hardened steel (Comparative Example 8).

[0033]

[Table-4] Tooth profile: Normal tooth, Module: 2.5, Number of teeth: 28 Lubricating oil: Automatic fluid, Oil temperature: 90 ° C Fatigue limit: 10 Root bending stress of undamaged gear after repeated ⁷ times

[0034]

According to the present invention, it is possible to minimize the amount of expensive high alloy powder used, and to provide a sintered part having a high compaction density so that the characteristics of the high alloy powder can be maximized. In addition, it is possible to produce a component having a high bonding strength between the base and the sintered part at a high yield and at a low cost. In addition, the application of such composite characteristic parts is achieved by, for example, reducing the size and weight of the parts themselves due to the excellent characteristics of the high alloy powder sintered part, thereby reducing the size of the mechanical structure to which the parts are applied. And lightening are also possible. Furthermore, when applied to tools and the like, the effect is great from the viewpoint of economic efficiency and resource saving.

[Brief description of the drawings]

FIG.

FIG. 2

FIG. 3

FIG. 4

Claims (2)

[Claims] 1. A compact made of a high alloy powder having excellent wear resistance and a smelting material serving as a base, wherein the high alloy green compact and the base are in contact with each other. Primary heating at a temperature of 0.5 times or more to bond them together, reheating in a short time without lowering production efficiency, and consolidating the high alloy compact while causing plastic deformation on the base A method for producing a composite characteristic component, comprising: 2. A compact made of a high alloy powder having excellent wear resistance and a smelting material serving as a base, wherein the high alloy green compact and the base are in contact with each other. Primary heating at a temperature of 0.5 times or more to bond them, reheating in a short time without lowering the production efficiency, compacting the high alloy compact while causing plastic deformation on the base, Furthermore, a method for producing a composite characteristic part, characterized in that sintering and diffusion bonding are performed while causing plastic deformation of a substrate in a temperature range of melting point of high alloy powder × 0.7 or more.