JPS60178041A - Method of sintering powdered alloy sheet and powdered alloy sheet fed to said method - 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 (Field of Industrial Application) The present invention relates to a method for sintering a powder alloy sheet and a powder alloy sheet used in the sintering method.

(Prior art) Conventionally, a powder alloy sheet is adhered to the surface of a metal substrate where wear resistance is required, and then this powder alloy sheet is heated and sintered to obtain a wear-resistant sintered layer. The technology is
It is well known as seen in Japanese Patent Publication No. 53-19540.

However, in the method of sintering a powder alloy sheet, when the powder alloy sheet is bonded to the lower surface, inclined surface, curved surface, etc. of a metal substrate, the above-mentioned temperature may be exceeded even during the process of heating to a high temperature state of about 1000°C, which is the sintering temperature. There is a possibility that adhesive strength such as Sea 1 to will not be able to reliably adhere to the surface of the metal substrate may not be obtained.

On the other hand, the special IWi proposed earlier by the applicant
The powder alloy sheet disclosed in the specification of No. 931125 is characterized by the fact that the adhesive that is mixed into the powder alloy sheet during heating and sintering or the gas that is generated when the adhesive used to bond the powder alloy sheet to the metal substrate is burned out. This may cause defects such as dents or bulges in the sintered layer.

That is, as the sintering process is shown in order in FIGS. 5A to 5D,
A powder alloy sheet S made by kneading alloy powder and a synthetic resin adhesive is adhered to the surface of the metal base M using an adhesive P (
(see FIG. 5A), and then heat-treated to a sintering temperature of about 1100°C. In the process of raising the temperature to this sintering temperature, 1
At a temperature of about 050°C, the surface of the powder alloy sheet S melts and exhibits a liquid phase e as shown in Figure 5B, and as gas is generated from this state, the powder alloy sheet S melts as shown in Figure 5C. A bulge f is formed in a part of the sintered layer, and when this trapped IC gas breaks the liquid phase e and ejects, the corresponding part becomes a liquid phase on the surface of the sintered layer after sintering is completed, as shown in Figure 5. On the other hand, due to the movement of , a defect remains as a dent d. Further, if the sintering is completed without tearing the bulge f, a protrusion remains on the surface, resulting in a problem that the bonding between the sintered layer and the metal base M becomes insufficient.

When the cause of the above phenomenon was investigated, it was found that gas generation occurs due to thermal decomposition of the adhesive and the resin component of the adhesive even at high temperatures near the sintering temperature. In other words, when a powder alloy sheet is bonded to a metal substrate with an adhesive and sintered by heating as described above,
The low-boiling point components of the adhesive and the adhesive begin to gasify and volatilize from around 600°C (=1), and high-boiling component gas begins to be generated at around 600°C (=1), but when the temperature rises to around 900°C, almost no gas is generated. It is clearly stated that when the temperature rises to approximately 1050°C, a liquid phase is generated as described above, and gas is generated again, and this gas escapes through the powder alloy sheet due to the presence of the liquid phase. The powder alloy sheet is trapped between the metal base and the sheet, and the generated gas increases the internal pressure, lifting the powder alloy sheet and causing it to swell.

The above phenomenon was discovered from the results of gas chromatograph measurements of the gas generated as the adhesive was heated to the sintering temperature. The measurement results are shown in Figure 6, and the analysis method was to use a gas chromatograph equipped with a pyrolysis device, and put a predetermined amount of sample (acrylic resin adhesive, sample amount: 24.11 mg) into a stainless steel column. 3
Heating was repeated for 5 minutes at each temperature in order of 00°C, 600°C, 900°C, and 1050°C, and the generated gas was collected using N2 gas as a carrier gas and analyzed and measured.

As seen in the results in Figure 6, at 300°C, low-boiling point gas was generated, at 600°C, high-boiling point gas was generated, and at 900°C, almost no gas was generated. At 1050° C., gas from the remaining organic components is generated as tar pitch. In the vicinity of this temperature of 1050°C, the powder alloy sheet begins to exhibit a liquid phase and sintering occurs from the surface, blocking the escape of gases generated from the adhesive and the adhesive of the powder alloy sheet, and the powder alloy sheet and the metal The sheet swells because gas accumulates between it and the substrate.

Then, the gas in this swollen portion expands and tears the sheet, and then the sheet portion becomes depressed. If depressions are formed on the surface, the thickness of the sintered layer will not be uniform, resulting in a large processing cost, requiring more powder alloy sheet cutting material than necessary, and since the sintered layer is a hard layer, the processing process will also take longer. It has the necessary defects.

(Object of the Invention) In view of the above circumstances, the present invention has been developed to maintain the adhesive strength, bonding strength, or In addition to having bonding properties, it also allows the gas generated when the adhesive and the adhesive of the powder alloy sheet are burned out to escape, making it easy to escape the gas and causing defects such as bumps or dents in the sintered layer. It is an object of the present invention to provide a method for sintering a powder alloy sheet that prevents degassing and a powder alloy sheet that is easily degassed.

(Structure of the Invention) The sintering method of the present invention involves preparing a powder alloy sheet formed by kneading a wear-resistant alloy powder with an adhesive made of acrylic resin, and bonding the powder alloy sheet with the surface of a metal substrate. The powder alloy sheet is adhered to the surface of the metal substrate through an adhesive layer of the same type as the above-mentioned adhesive, and then the powder alloy sheet is heated at a temperature of 150 to 380°C in a non-oxidizing atmosphere for 50 minutes.
After heating and holding for more than a minute, liquid phase sintering (including half-wave phase state)
The method is characterized in that a sintered layer is bonded and formed on the surface of the metal substrate.

In addition, the powder alloy sheet to be subjected to the method of sintering a powder alloy sheet of the present invention is formed by kneading an adhesive made of acrylic resin with an alloy powder having wear resistance, and the outer edge of the joint surface is It is characterized by forming an adhesive layer of the same type as the above adhesive.

(Effects of the Invention) According to the manufacturing method and the powder alloy sheet of the present invention, by partially adhering the powder alloy sheet to the surface of the metal substrate, the problem occurs when the adhesive and the adhesive of the powder alloy sheet are burned away. This makes it easier for gas to escape and reduces the amount of gas generated, so that even if the temperature rises and a liquid phase is generated on the surface of the powder alloy sheet, gas will not accumulate at the joint between the metal base and the powder alloy sheet. Therefore, it is possible to prevent defects such as bulges or depressions from occurring in the sintered layer, and the machining allowance is also reduced, thereby reducing material costs and machining costs.

In addition, when sintering the powder alloy sheet, after adhering the powder alloy sheet to the metal substrate and before liquid phase sintering,
By heating and holding at a temperature of 380°C for 5 minutes or more, the powder alloy sheet has good adhesion up to the sintering temperature, and the sintered layer made of the powder alloy sheet and the metal substrate are bonded well.
A sintered layer of excellent quality can be obtained by M bonding.

(Example) FIG. 1 is a perspective view showing a state before a powder alloy sheet is adhered to a gold J1 substrate in J3 according to an IM embodiment of the present invention.

A powder alloy sheet 2 formed by kneading a wear-resistant alloy powder with an adhesive made of acrylic resin is attached to the surface of an iron-based metal base 1, and a band-shaped (width) 3ms+), apply adhesive 3.3 of the same type as the above adhesive and partially seal.

After that, under a non-oxidizing atmosphere (inert gas atmosphere such as N2, Ar, etc., reducing atmosphere such as N2, vacuum atmosphere), 1
After heating and holding at a temperature of 50 to 380°C for 5 minutes or more, roughly under the above non-oxidizing atmosphere (inert gas atmosphere such as N2°Ar, reducing atmosphere such as 1-12, vacuum atmosphere), 9
Liquid phase sintering was performed at a temperature of 50 to 1150°C to bond and form a sintered layer having wear resistance on the surface of the metal base 1.

On the other hand, Figure N2 is a perspective view showing the state before the powder alloy sheet is adhered to the metal base in the actual IM aspect of the present invention.

In this example, on the surface of the metal base 1 at the position where the powder alloy sheet 2 is to be bonded, there are 6
Adhesive 4.4... is applied in spots (diameter 3+u), and the powder alloy sheet 2 is partially adhered to the surface of the metal base 1 using the adhesive 4.4..., and then , the powder alloy sheet 2 is heated and sintered in the same manner as above to form a wear-resistant sintered layer on the metal base 1 by 316'H@dj TA
- The adhesives 3 and 4 are shown in FIG.
It may be applied in a band-like manner on the surface of the metal base 1 corresponding to the outer edge of the powder alloy sheet 2 at the adhesion position, or in dots on the outer edge of the powder alloy sheet 2 in FIG.

By changing the application area (width or number of adhesive strips in Figure 1, diameter or number of dotted adhesive in Figure 2) of adhesive 3.4, the adhesive nozzle can be adjusted. can be changed, but it is sufficient that the powder alloy sheet 2 adheres to the metal base 1 without falling off during sintering and transportation, and should be as small as possible. is preferable in terms of reducing the amount of gas generated.Also, since it is difficult to remove gas from the central part of the powder alloy sheet 2, it is preferable to avoid adhesion in this central part.Furthermore, the adhesive 3, 4 may be applied in liquid form or may be formed into a sheet.

The powder alloy sheet 2 contains po, 5 to 2.5% by weight.

C1,5-4.5% by weight, Mo2,5-10.5
weight%.

C" 85-97% by volume of wear-resistant eutectic alloy powder consisting of ≦10% by weight, balance Fe, and powder particle size of 150 mesh or less
and 15 to 3% by volume of an acrylic resin adhesive dissolved in a solvent are kneaded, then rolled and cut into a predetermined shape.

Furthermore, if a specific example is shown and explained, Pl, 2
Weight%, Mo 4.9tMt%, Cr 6.2fi
sfJi%.

97% by weight (91% by volume ω%) of wear-resistant eutectic alloy powder having a structure of C1.9% by weight, Si 0.4% by weight, and the balance being Fe, with a particle size of 200 mesh or less, and an acrylic resin adhesive 3
% by weight (9% by volume) and wet kneading by adding toluene,
A sheet with a density of 4.60/cn+3 and a thickness of 1.5 ml1 was formed by roll rolling, and this was
Cut into a size of 111m x 1 Bmm and a thickness of about 30mm.
It was adhered to the surface of a steel metal substrate with an acrylic resin adhesive made of the same material as above (the application locations were as in the embodiment described above), and the following heat treatment was performed.

Maejo WJ! <Under H2 gas atmosphere) ■→■→■■ Temperature increase rate 10℃/min → 300℃×60 minutes■ Temperature increase rate 15
°C/min → 1060 °C x 15 minutes ■ Heating rate 5 °C/min →
After the above heat treatment at 1090℃ x 20 minutes, slow cooling (cooling rate 6℃)
/min) to obtain a wear-resistant sintered layer bonded to the surface of the metal substrate. Furthermore, no defects such as swelling or depressions were observed in this sintered layer.

J3. In the above heat treatment, the temperature of 1060°C in (2) is maintained for 15 minutes because the temperature rise of the powder alloy sheet 1~ housed in the sintering furnace is uneven in each part, so it is necessary to make it uniform. This is done for the purpose of achieving this, and is not necessary when there is little storage space and the temperature is uniform.

Here, the above powder alloy sheet will be explained in more detail. The above sintering method basically involves rolling and forming a mixture of alloy powder and synthetic resin adhesive into a sheet shape, partially adhering it onto a metallic body, and sintering it to form a wear-resistant alloy layer on the surface. It forms the

Usually, resin adhesives (adhesives) are heated at 200 to 300℃.
However, as the temperature rises further, the adhesive burns out, evaporates, loses its function as an adhesive, and cannot be bonded to the base material. ! 4
1, 'TI, = + R11' T 121 Neo (11&;I i?ii A'+ 50 When the weight of the powder alloy sheet, such as a curved surface or a downward facing surface, acts on the adhesive surface with the base material is unable to support the weight of the powder alloy sheet and may peel or fall off from the base material.Particularly in equipment where vibrations or shocks do not apply to the workpiece, adhesive strength with the base material is not required as much. However, in meshbelt type or pusher continuous sintering furnaces, vacuum sintering furnaces, etc., vibrations and shocks during transportation are unavoidable.

On the other hand, there is no problem between room temperature and 200°C, where the adhesive has strong adhesive strength, but at higher temperatures and temperatures around 700°C, where sintering of the metal powder begins, strong vibrations and I! If an i-impact is applied, the powder alloy sheet will peel off if the adhesive has a weak bonding force due to carbonized carbon.

Regarding the above point, as mentioned above, wear-resistant eutectic alloy powder 85~
After kneading 97% by volume and 15 to 3% by volume of an acrylic resin adhesive, a rolled or extruded powder alloy sheet is adhered to an iron base material using an acrylic resin adhesive with adhesive properties. 150-380℃ in non-oxidizing atmosphere
, preferably between 200 and 350°C! up to temperature, 4
In J, Sea Urchin C, which is heated at a temperature increase rate of 0°C/min or less and held at this humidity for more than 5 minutes, low boiling point components volatilize from around 120°C, and thermal decomposition polycondensation reaction starts from around 200°C. occurs, and a tar pitch-like substance is produced. Since this tar pitch-like substance has adhesive properties, it can provide adhesive strength that can withstand vibrations and impacts caused by transportation at temperatures of 300° C. or higher.

In this test, the above phenomenon will be explained along with the test results shown in FIG. 3. MOIO, 5% by weight, (: r2.5% by weight).

P2.4% by weight, C3.6% by weight, balance [e] 48.5ml of ternary eutectic alloy powder with a grain size of 11150 mesh or less, 5US410 (7) Powder with a grain size of U150 mesh or less 48. 5% by weight and 3% by weight (9% by volume) of acrylic resin were wet-kneaded with acetone and rolled to a density of 4.8g/cm3. The acrylic resin adhesive sheet 1- (same as above) was made into a 2 mm thick sheet and cut into 1 cm x 1 cm. At this time, the weight of the powder alloy sheet was approximately 0.96 g, so the adhesive surface had a weight of 0.960 g.
/cm2 shear)j is acting, and if the adhesive strength is greater than this value, the powder alloy sheets 1 to 1 will not fall off.

In Figure 3, sample ■ is an untreated sample heated in a nitrogen gas atmosphere and subjected to high-temperature shear tests at various temperatures. 300℃ due to the adhesive softening at ℃
Becomes 0g/cmz or less. Furthermore, thermal decomposition of the acrylic resin begins at about 200°C, and its strength decreases as it decomposes.At about 400°C, it decomposes rapidly and its strength drops significantly, causing the powder alloy sheet to fall off. .

Here, it is considered that the powder alloy sheet could not withstand the shear force due to gravity, so it can be inferred that the shear surface strength was about 10/cm2 or less.

On the other hand, samples It, III, and IV were heated in advance in a hydrogen gas atmosphere at a heating rate of 10°C/min, and each
Heat treatment was performed for 00°C x 60 minutes, 250°C x 60 minutes, and 380°C x 60 minutes, and the sample was then slowly cooled to room temperature and heated again, and a high-temperature shear test was conducted at each temperature. 4
The strength gradually decreases up to 00°C due to the presence of unreacted resin. When the temperature exceeds 400°C, the unreacted resin evaporates, and the carbonization of the tar-like substance progresses with heating, resulting in a decrease in adhesive strength. However, 700℃
When the temperature exceeds 1000°C, the strength increases as the solid phase sintering of the alloy powder progresses, but when the temperature approaches 1000°C, a liquid phase crystallizes due to the eutectic component, and the liquid phase component diffuses into the base material. As the material solidifies again, the strength of the bearing surface increases significantly.

(If the temperature is raised continuously like sample ①, 3
There is a possibility that it will fall off at temperatures exceeding 80°C, but sample n
, tn, and iv, which have been heat-treated in advance, are bonded without any drop in m2.

Furthermore, in order to elucidate the above-mentioned phenomenon, an experiment was conducted as shown in Fig. 4. In this experiment, the acrylic resin necking agent [7acrylic acid] Nisdel-acrylic acid copolymer] was used in a nitrogen gas atmosphere +/
Shows the decrease in ff1ffl when heated in Jl air. J3, the A depletion rate up to each temperature described later is 15° C./min. Approximately 10% of the acrylic resin binder decomposes at 300°C, and when heated further, it rapidly decomposes at around 400°C.
Approximately 90% will decompose.

On the other hand, in a nitrogen gas atmosphere, the temperature was increased to 300°C along the heating characteristic a.
In sample A heated for 60 minutes, about 40% decomposed due to heating in a non-oxidizing atmosphere and the remaining about 6
0% undergoes a thermal decomposition polycondensation reaction and turns into a tar pitch-like substance. This tar pitch-like substance causes 4
It is considered that the adhesive has an adhesion temperature of 00 to 700°C, that is, a retention temperature of 00 to 700°C.

In addition, in sample B heated at 400°C for 60 minutes according to the heating characteristics, about 90% decomposed and the formation of tar pitch-like substances, which are required to have adhesive strength at temperatures above 400°C, is reduced. In addition, the powder alloy sheet may fall off. Furthermore, the lifting platform of sample C, which was heated to 500°C x 60 minutes after achieving thermal characteristic C (7 Jl), was
The same thing holds true for ℃×60 minutes. As mentioned above, at high temperatures of 400°C or higher, where rapid resin decomposition occurs, the contribution of the generated tar pitch-like substances becomes dominant, and it is thought that this will continue up to nearly 700°C (q) where in-phase sintering of the alloy powder begins. It will be done.

In order to confirm the formation of the above-mentioned tar pitch-like substance, elemental analysis was performed on acrylic resin adhesives held at 300°C for 60 minutes in a nitrogen gas atmosphere and then heated at 500°C and 700°C. The weight percent of the C element and the H/C atomic ratio for hydrogen and hydrogen are shown below. Sample 1 was heated at 500°C, and Sample 2 was heated at 700°C.

Cl-1' H/C Sample 1 91.7% 5.9% 0.17 Sample 295.
2% 1.4% 0.18 Here, pitches are generally referred to as l=I/O atomic ratios ranging from 1.0 or more for asphalts to 0.5 to 0.5 for coal tar pitches.
It is up to 0.6.

J, in the case of sample 1, l''/c is 0.17,
It was confirmed that tar pitch-like substances remained. Trial 1'312 ta, l-1/C 0.18 ta V),
As the M X' conversion progresses, the tar pitch-like substance decreases, but at around this humidity, full bending sintering begins and a transition to a strong metallic bond occurs.

In addition, in the heat treatment of the powder alloy sheet before sintering, the heating atmosphere is inert gas such as nitrogen gas or argon gas, hydrogen gas, etc. to prevent oxidation of the alloy powder and acrylic resin adhesive. It is necessary to carry out in a non-oxidizing atmosphere such as a reducing gas or a vacuum. In addition, the heating rate was increased to 40
℃/min or less is because if the heating rate exceeds 40℃/min, the low-boiling fish in the acrylic resin adhesive will rapidly volatilize, which may damage the powder alloy sheet or cause air bubbles on the adhesive surface. This is to prevent this from occurring and falling off. Then, the heating temperature is set to 150 to 380°C, preferably 200 to 380°C.
The reason why the temperature is 350°C is because below 150°C, the amount of undecomposed adhesive increases, and when heated above 380°C, rapid decomposition occurs, and the amount of tar pitch-like substances produced is small. At high temperatures, the adhesive strength decreases and the powder alloy sheet may fall off. On the other hand, when the temperature exceeds 380°C, the adhesive rapidly decomposes, and the amount of tar pitch-like substances that contribute to adhesion is small, resulting in powder. This is because the alloy sheet may fall off. Furthermore, the retention time is 5
The optimal time for heating for more than 120 minutes varies depending on the heating temperature, but if it is less than 5 minutes, the amount of tar pitch-like substances produced will be small and the adhesion will be insufficient, and heating for more than 120 minutes is not economical. Therefore, it is preferable to set each of the above conditions within such ranges since good processing can be performed.

In addition, it goes without saying that the alloy powder of the powder alloy sheet must have wear resistance when heated and sintered, but since the adhesiveness of acrylic resin adhesives has a temperature limit, It is preferable that the freezing temperature is as low as possible.

From this point of view, it is preferable to use a wear-resistant eutectic alloy powder, particularly a Fe-MC-based ternary eutectic alloy powder, as the #4 wear-resistant alloy powder, and M is preferably Mo, B, and It is preferable to use any one type of P or a combination thereof. In particular, using P means FJ as well as C.
It is preferable because it has strong diffusivity to J'jfA.

Specifically, the alloy powder is heated at 1f at 1000 to 1150°C.
It is preferable that the liquid phase is 10 to 50% by volume in a range of 11 degrees, and that the liquid phase has excellent wettability to the base material.

If the liquid phase m is less than 10% by volume, there will be insufficient liquid phase and effective bonding with the base material will not be possible, and if it exceeds 50% by volume, the liquid phase will be excessive and will exhibit fluidity and maintain the required shape. become unable.

In addition, cr and v are secondary elements that improve the strength and wear resistance of the Fe'-M-C ternary eutectic alloy.

W, Nb, Ta, and Ti are effective elements, and Si, Ni, and Mn are also elements useful for improving various performances, and are preferably added.

Further, the powder particle size is a factor that greatly affects the porosity of the sintered layer, and is preferably set to 150 mesh or less. When the particle size increases beyond 150 mesh, the porosity increases accordingly, impairing the wear resistance of the sintered layer.

The blending ratio of the acrylic resin used as the adhesive and the alloy powder is 3 to 15% by volume of the adhesive, and the remainder is the alloy powder. If the amount of adhesive is less than 3% by volume, the adhesiveness will be insufficient and the powder alloy sheet will become brittle, making it impossible to secure the necessary flexibility of the sheet, and if the amount of adhesive exceeds 15% by volume, The resin content becomes excessive, which adversely affects porosity and the like, and at the same time makes it impossible to bond to the base material. Further, the powder alloy sheets 1 to 1 have some self-adhesiveness and C is also good, and those containing an adhesive of 12% by volume or more have self-adhesiveness.

[Brief explanation of drawings]

Fig. 1 is a perspective view, not showing the state before the powder alloy sheet is attached to the metal base in J3, according to one embodiment of the present invention, and Fig. 2 is a perspective view of another embodiment of the present invention. A perspective view showing the state before the powder alloy sheet 1- is bonded to the metal substrate.
A characteristic diagram showing the relationship between shear strength and warm melon. Figure 4 shows the weight loss when acrylic resin adhesive is heat-treated in the range of 300 to 500°C and then heated in a nitrogen gas atmosphere.
Characteristic diagrams. Figures 5A to 5D are explanatory diagrams showing the sintering process in order and the occurrence of defects. Figure 6 is a gas chromatograph showing the generation of gas as the acrylic resin adhesive is heated to the sintering temperature. It is a graph showing the results measured by. 1...Metal base 2...Powder alloy sheet 3.4...Adhesive

Claims (2)

[Claims] (1) A method for forming a sintered layer bonded to the surface of a metal substrate, in which a powder alloy sheet is prepared by kneading a wear-resistant alloy powder with an adhesive made of acrylic resin. The powder alloy sheet is adhered to the metal substrate surface by partially interposing an adhesive layer similar to the above adhesive between the powder alloy sheet and the metal substrate surface, and then the powder alloy sheet is heated for 150 minutes in a non-oxidizing atmosphere. A method for sintering a powder alloy sheet, which comprises heating and holding at a temperature of ~380°C for 5 minutes or more, followed by liquid phase sintering to form a sintered layer on the surface of a metal substrate. (2) A powder alloy sheet used to form a sintered layer bonded to the surface of a gold substrate by liquid phase sintering, and this powder alloy sheet is made of abrasion-resistant alloy powder and acrylic resin. A method for sintering a powder alloy sheet characterized by forming an adhesive layer of the same type as the adhesive on the outer edge of the bonding surface. powder alloy sheet.