JPS58164704A - Production of sintered product - Google Patents

Abstract

PURPOSE:To produce sintered parts having excellent strength and mechanical properties by sintering the green compacts of metallic powder by heating, heating the surface layer parts of the resulted sintered bodies, passing said bodies through dies of a hot sizing device and making the surface layer parts compact. CONSTITUTION:Metallic powder is cold molded under pressure to form a green compact. The green compact is sintered by heating to obtain a sintered body. The body 1 is placed on the piston 6 of a product receiving cylinder 5, and is held in the coil of a high frequency induction heater 3 provided on the die 2 of a sizing device. High frequency electric current is conducted to the coil to heat the surface layer parts of the body 1 relatively deeply and quickly. The heated body 1 is forced downward with a punch 7 so as to be passed through the inside of the die 2 whereby the surface is plastically worked, the tooth profile is formed and the surface is sealed. Upon ending of the downward travel of the piston 6, a pusher 8 is operated to eject the product 9.

Description

[Detailed Description of the Invention] □ This appeal is related to the manufacturing method IIc of the 9th round sintered product that uses pottery powder as a lubricant to increase the strength of the surface layer of the round sintered product. □ Pressure molds the metal material. In recent years, the process of producing sintered crystals by sintering and shrinking at 90 degrees has made significant progress, and the sintered crystals have increased in strength and toughness.

In addition, OIl machines such as gears and rollers are required to have rounded surface layers that improve wear resistance and increase the strength of the surface layer.

However, sintered metal powder crystals have residual pores and therefore have low impact value, fatigue strength, elongation, and reduction of area.'The conventional method for improving the surface properties of sintered bodies is cold processing. Methods and methods are being used to lubricate low melting point metals.

In other words, the former has small dimensions, but the surface layer of the sintered body is processed through the inner surface of the sintered body to improve dimensional accuracy. The Ising method, the rolling tII && c type finish forming method, and the cold heat indium method in which the metal K11 ship body is inserted and re-pressed to improve dimensional accuracy? In the latter case, the pores of the sintered body are infiltrated with copper to seal them in order to improve the strength.

However, in the case of -consideration, the thickness of the densified material is not the same as the one layer with a strength of -1 at Ll-temporary, and the infiltration is carried out over the entire area in the case of post-coating, so more infiltration material than necessary is used. 9. It costs money, the manufacturing last is expensive, and the dimensions tend to be out of order.

In view of the current situation, this invention proposes a manufacturing method that aims to improve strength and unsightly properties by rapidly heating only the surface layer of a sintered body and subjecting only the surface layer to a black metal finish. It is something to do.

In other words, ζOa@ is produced by cold-pressing metal powder to form a green compact, then heating and sintering the surface layer of the sintered body, and then heating the sintered body through a hot sizing device. The gist is to densify the surface layer by sealing the surface of the combined body by cutting it into a die.

In the present invention, the method of producing a compact by pressure forming and the method of obtaining a sintered compact by sintering the powder compact are conventional methods. ' Also, metal powder can be made by any method such as water jet method, oil-fog method, etc.1, /: J, l: Especially when hardenability and toughness are required. Cr-hIi
N-based low alloy steel powder wheels etc. are used.

The surface of the sintered body before heating can be heated by any method, but induction heating using high-frequency current is most suitable for rapid heating, and can achieve relatively heavy heat in a short time. . In addition, in order to efficiently heat the surface, a high-frequency current is applied directly above the die of the hot sizing device.
It is preferable that the sintered body that has been rapidly heated using a device is passed through a die to uniformly process the surface.

The high-frequency current used varies depending on the object of the fired crystal, but frequencies 1 to IGKH can be used. Also, the heating temperature is 700~
The temperature is 1000℃, and the # of the densified layer in the surface layer is #! Saha 1-5
■ is obtained.

Note that the dimensions of the material depend on the shape of the fired crystal, but for example, in the case of a gear, if the diameter of the tip of the die is the diameter of the tip of the die, the outer diameter of the material is the radius, then the following formula is obtained: It is dtL to put together the whole thing.

1ζ (DI + Do) l 2≦Dw<D.

,,': ゛Also, the express heated deep gate is (Dv-Dx)/2+g
', and determined by the material and material density gKX
Dflru.

Next, the ζ08@0 embodiment will be described with reference to FIG. 11.

c &os-1Ma Qj-, Ct 0J811,
M, α28-1o, o, o a-1 remainder substantial kF@
steel powder consisting of and a small amount of Ome as a lubricant. 71 phosphate jI
Ilb, add graphite powder, add 9 raw materials to 6 / dOBi, add b and cold compress to create a compact with a density of 6.8t/s@o, siii, -* 511w, on si $ m m
9) Put the LIE powder into the furnace and heat it to igooo℃x
a.

Peng Jian, heat it and put it together to make a cylindrical body (gear material).

Then, show ζ0@Tate body 0) in the aa box! Ising equipment die (2)
) Hold a high-frequency current of 0 KHg in the 0-ring wheel and heat it for 0 seconds to set the temperature too ℃ and heat it! The combined oats were rapidly heated to a temperature of 5 km.

As shown in the figure below, the meet-in-vehicle installation is as follows: A gear layer (O〆 die) is attached to the stand (4), and immediately above it, a round high-frequency tsuba etc. In order to hold the body Q), install a direct IIC and install a large product receiving V cylinder (II).
Provided so that the O piston (.) moves up and down. punch(
7) is a rounded product in which the sintered body (1) is passed through a die.

In addition, the Detsu Vya (8) placed horizontally below the dice (2))
1 on the surface of the forest! The finished product (・) is extruded.

- If there is a difference Δ1 in the outer diameter of the glycobody (1) and the die (squeeze and OMK), apply high frequency induction to the surface layer and press down the astL round sintered body (1) with a punch (1). ) When passing through the inside, the surface is layered and the gears are formed.

The surface is sealed. Then, when the screw (screw 3) has finished descending, the deck shaft (8) operates to push out the finished product (2).

Note that the machining depth is appropriately set to the optimum conditions based on the time required for one rotation of the trout, and the inner diameter of the die, the outer diameter of the sintered body, and the dimensional difference Δ4.

In the present invention, as described above, the surface of the composite body is rapidly heated and subjected to plastic working, so that the remaining pores in the surface layer are sealed and the strength is improved. Moreover, since the heating is carried out in a short time, energy consumption is low and it is also useful for preventing surface oxidation.

[Brief explanation of drawings]

The drawing is an explanatory diagram showing an example of a heat-related Ising device for implementing ζOa@. In the figure, 1-III embroidery body, 8... die, 3... high frequency induction heating device, 1- punch, Δ1... dimensional difference. Applicant: Sumitomo Metal Industries, Ltd. 1. E, □ Yoshihisa, -7,i;i:・
・

Claims (1)

[Claims] 1) Metal powder is cold-press-molded to form a green compact, which is obtained by heating and heating in the 1st stage to heat the surface layer of the sintered body. A method for producing a fired crystal, characterized in that the surface of the monocycle is sealed by passing it through a closing chair of an Ising apparatus for thermal review, thereby densifying the surface layer. 2 Patent claim O@-1 Method for producing first spout crystals characterized by rapidly interrupting and heating a single bonded body amms with a high debris wave trout conduction a device installed directly above a mill injector device .