JPS6334201B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves assembling a powder compact made of a component that produces a liquid phase during sintering so that it contacts a metal member only on a curved line or a straight line, and placing it in a vacuum or non-oxidizing atmosphere without applying pressure. The present invention relates to a sintering and joining method characterized in that liquid phase sintering and joining are performed simultaneously by heating once. Generally, methods for joining sintered bodies to metal members include:
There are welding methods, brazing methods, diffusion bonding methods, etc. The welding method requires high hardness, and in the case of a sintered body with low toughness, cracks may occur due to thermal shock, making it unusable. The brazing temperature of silver solder and copper solder is about 600 to 900°C, and although the brazing temperature is not high, on the other hand, when you want to use it as a high-temperature heat-resistant member, it melts and peels off from the brazed part and cannot be used. In addition, the brazing strength is not necessarily high, and there are concerns about the strength of the brazed portion, so there is a problem that it cannot be used in cases where it is necessary to withstand a large load. Next, the diffusion bonding method is a method commonly used for bonding steel materials, etc., and bonding is generally performed by heating at about 1000 to 1300° C. to cause diffusion. However, this method
In order to make sufficient contact between the sintered body and the metal member, it is necessary to match the surface shapes of the sintered body and the metal member, and to make the surface roughness of the joint surface extremely fine.
In order to eliminate unbonded surfaces, heating is sometimes required under a load for a long time, and there are also problems such as increased cost and deterioration of properties due to reheating of the sintered body during diffusion bonding. For this reason, methods have been proposed that take advantage of shrinkage during sintering and place a green compact coaxially around the outer periphery of steel or cemented carbide, and then join them by a single sintering heating process, but all of these methods have an annular shape. It can only be used when joining the powder compact, and there are problems such as cracking of the sintered compact unless the inner diameter of the green compact is strictly controlled within a certain range. The powder green compact is made into a sintered compact with substantially 100% true density, the shape of these sintered compacts is maintained in the desired shape, and the sintered compact is properly joined to the part of the metal member to be joined. , and in order to bond the sintered body with strong bonding strength without causing breakage or the like, it is difficult to satisfy all these conditions simply by placing the green compact on the surface of the metal member. The reason for this is
Due to the appearance of a liquid phase when the powder compact is heated, it becomes vertical,
The powder compact, which undergoes large contraction in all horizontal and height directions and progresses in sintering as it shrinks, moves on the metal member by the amount of contraction, causing the final sintered compact to move away from the final joining position. If a partial sintering bond occurs between the base material and the base material at a certain point during shrinkage due to sintering, and this bonding force is stronger than the shrinkage force of the sintered compact, the sintered compact will shrink. This may lead to breakage and cause the joint position to be misaligned. In particular, these problems become more serious as the size of the sintered body becomes larger. The purpose of the present invention is to propose a method for solving the above-mentioned problems, and it is possible to join only the necessary parts instead of the entire circumference of a cylindrical body, etc., and the surface of the metal member can be The object of the present invention is to provide a method that can join even curved surfaces. The present invention will be explained in more detail below. The material of the powder compact used in the present invention is 1000~
It is preferable to use one that produces a eutectic liquid phase at a temperature of 1350°C.
The present inventors have already disclosed a boride or complex boride-based hard sintered alloy containing Fe and a B content of 3 to 20% (Tokuko Sho
54-27818, Special Publication Showa 56-8904, Special Publication Showa 56-15773,
Since it is a material that undergoes liquid phase sintering (Japanese Patent Publication No. 56-37281, Japanese Patent Application Laid-Open No. 58-67842), it will mainly be explained in detail below. The hard sintered alloy and powder used in the present invention are B
Contains 3 to 20% of Fe, and at least 10% of Fe. B forms a hard phase of boride or complex boride and is dispersed therein, imparting high hardness and wear resistance. It also plays an important role in sintering the powder compact and firmly bonding it to the metal member without applying pressure. The amount of hard phase is 40-95%. The hardness of the sintered body ranges from HR _A 80 to 93,
If the hardness can be lowered to around HR _A 77, the B content can be lowered to 2%. The boride components forming the hard phase are Mo, W,
These are group a, a, and a group elements such as Ti, V, Nb, Ta, Zr, and Hf, and iron group metal elements such as Fe, Cr, Co, Ni, and Mn. When C or carbides or nitrides are added, they mainly form a hard phase. The binder phase surrounding the hard phase provides strength and toughness to the sintered body, and is made of an Fe-based alloy component. Depending on the amount of Cr, Ni, Mo, W, Co, Cu, Mn, etc. added, these may exist in the hard phase, the binder phase, or both phases, and play a role in imparting corrosion resistance, heat resistance, and strength to the sintered body. . The particle size of the powder used is 350 meshes (44μ) or less, preferably 500 meshes (25μ) or less, and more preferably an average particle size in the range of 0.3 to 3μ. The reason for this is to increase the bonding force between the powders when compacting the powder so that the powder compact does not chip or lose its shape, and also to allow the sintering reaction to occur smoothly, resulting in a virtually true density with fewer pores. To obtain a sintered body, to maintain high mechanical properties of the sintered body such as hardness, transverse rupture strength, and wear resistance, and to increase the bonding strength with metal parts and not leave defects such as pores at the bonding interface. It is of fundamental importance to ensure that If the powder particle size is 100 mesh (150 μ) to 325 mesh or coarser than 500 mesh, many pores remain in the sintered body, and it is not possible to obtain a sintered body with true density, resulting in resistance. Strength such as rupture strength decreases, and pores remain at the bonding interface, making it impossible to obtain a strong bonded body. In order to make the powder fine, a wet ball mill, a vibrating ball mill, an attritor, or an equivalent grinding means using a solvent such as alcohol or acetone is used. As the powder becomes finer, it becomes more susceptible to oxidation, so it is preferable to use appropriate amounts of paraffin, stearic acid, zinc stearate, etc. After drying and granulating the finely pulverized powder above, pressure is applied.
The powder is compacted into the desired shape at 100 to 3000Kg/cm ² , preferably 150 to 2000Kg/cm ² , and the density of the powder is 3.2 to 5.6.
g/cm ³ is preferably in the range of 3.4 to 5.1 g/cm ³ .
This is 38-67% of the true density sintered body, preferably 40
In the range of ~60%. If the density of the green compact is less than 3.2 g/cm ³ , the strength of the green compact will be insufficient, and the green compact may break during operations such as handling and transportation.
In addition, cracks and holes are likely to occur during sintering, and the bonding is often insufficient and unstable. Green density is
When it exceeds 5.6g/ ^cm3 , a small amount of oxide remains on the powder surface, CO gas caused by this oxide,
Alternatively, it becomes difficult for the pores existing between the powder particles to escape, and these tend to remain in the center of the sintered body, degrading the mechanical properties of the sintered body. The powder compact made under the above conditions is left standing and sintered so that it contacts the metal member only on a straight line or curved line, but the radius of curvature on the side of the powder compact to be joined is not bonded. It is important that the radius of curvature be larger than the radius of curvature of the member being used. Regarding how large it should be, it is important that while the green compact is heated and shrinks and reaches almost true density, contact starts from a position closer to the first contact point to a farther side, and vice versa. If the size is at least the minimum size, the bonding will be complete and no problems such as breakage or cracks will occur. If the shrinkage rate of the powder compact during sintering is k%, the radius of curvature of the joined side of the powder compact is Rmm, and the outer diameter of the metal member is Dmm, then R>D/2 (1-K/100 ) It is more preferable if the following relationship is maintained. Further, the radius of curvature R can be up to infinity (that is, a straight line). (See FIG. 5) Furthermore, when joining to a flat plate, the radius of curvature R may take a negative value. Even in the case of a curved surface whose radius of curvature is not constant, the compact size may be calculated based on the maximum radius of curvature so that the above relationship can be maintained. The basic method of assembling the powder compact to the metal member is to lay the metal member horizontally and place the powder compact on top of it. By doing so, the powder compact comes into contact with the metal member under its own weight at the same time as sintering. If necessary, the metal member can be placed on an inclined surface and the powder compact can be placed on the inclined surface. In this case as well, for joining with metal parts,
It is necessary to apply the weight of the powder compact. The angle of inclination of the metal part is up to 60°, preferably up to 45°. As a result of various experiments regarding the metal parts used,
Ordinary steel such as JIS standard SS material, SC material, SB material, STB material, SUJ material, SCM material, SK material, SKS material, SKD
low-alloy steel such as SKH material, SUS material, SUH material, structural steel, tool steel, stainless steel, heat-resistant steel,
Fe-based materials such as high-speed steel, cast steel, and cast iron can be used, and all of them can provide strong bonding strength with a shear strength of 35 to 50 Kg/mm ² and a bending strength of about 100 Kg/mm ² or more. The shear strength of connections such as silver brazing is 20 to 25 kg/
It is about ^mm2 . Next, the heating conditions for bonding will be described.
Vacuum, reducing or non-oxidizing atmosphere can be used as the heating furnace atmosphere, but vacuum is preferable in consideration of ease of reducing small amounts of oxides such as B, Cr, and Ti, prevention of oxidation during heating, and other workability. is more preferable. When using a vacuum furnace, the degree of vacuum is in the range of 1 to 10 ^-5 torr, preferably 10 ^-1 to ^{10 -4} torr. Vacuum degree is 1torr
In the following, oxides such as B, Cr, and Ti are generated on the powder surface, so the lower limit is 1 torr, preferably 10 ^-1 torr. In addition, the reduction of the above-mentioned oxides such as B, Cr, and Ti is almost done at temperatures up to 10 ^-4 torr, and raising the degree of vacuum above 10 ^-5 torr is expensive in terms of equipment, so the upper limit is 10 -4 torr. ^-5 torr preferably 10 ^-4 torr. Reducing atmosphere or non-oxidizing atmosphere is
H ₂ , N ₂ , Ar gas, a gas containing a small amount of CO or CO ₂ , or a mixed gas atmosphere thereof;
In order to prevent oxidation of Cr etc. or to reduce these oxides, lower the oxygen potential and keep the dew point below -10°C. Next, the heating temperature varies depending on the powder composition, but
It is in the range of 1150-1350°C, preferably 1180-1300°C. The density of the powder compact used in the present invention is 38 to 67% of the true density, and the density is 99% of the true density by sintering.
% or more, the true density is essentially 100%, although it contains a small amount of unavoidable impurities. B or B compound and Fe contained in the powder at 3 to 20% during sintering,
A eutectic liquid phase occurs between Ni, Cr, Co, etc. at temperatures above 1150°C, resulting in a sintered body with almost 100% true density, but B or B compounds in the sintered body are removed during sintering. , Fe or contained Cr, Ni, Co in iron, steel or alloy steel of metal parts within the same sintering temperature range.
It appears that a eutectic liquid phase is partially formed between the powder compact and the like, and it is thought that the sintering of the powder compact itself and the strong bonding between the sintered compact and the metal member proceed almost simultaneously. Although the sintered compact shrinks significantly compared to the powder compact by 12 to 27% in size and 33 to 62% in volume, by selecting the above sintering temperature and the time described later, A sintered body having the desired size and shape is obtained without deformation, and a strong bond with a shear strength of 35 kg/mm ² or more is achieved with the bonding member. When a powder compact is brought into contact with a round bar or tube only in a straight line or curved line, it maintains accurate dimensions and shape after sintering, the joining position is accurate, and the shear strength is extremely high. It is interpreted that the bonding with the metal member is performed after sintering occurs with large dimensional shrinkage. For example, in the case of joining onto a rod or tube as shown in Figures 1 and 2, the green compact shrinks and becomes a sintered body with almost 100% true density, and the radius is reduced or the rod or tube is joined by the action of gravity. It is thought that the bonding occurs when the material comes into contact with the pipe or pipe. As mentioned above, the first technical idea of the present invention is
The powder compact is placed in a positional relationship such that only a portion of the powder compact is in contact with the iron, steel, or alloy steel member that is the joining metal member, with a gap, and the powder compact's own weight acts on it. Second, the B content is 3-20
%, and by using finely pulverized powder, the powder itself undergoes liquid phase sintering with 100% true density due to B, while at the same time partially forming a eutectic liquid phase with the metal components, B The purpose of this method is to reduce and remove oxides on the surface of metal members and perform a cleaning action, thereby making diffusion bonding extremely easy. In normal diffusion bonding, a large pressurizing load is applied to ensure sufficient bonding, but in the method of the present invention, only the weight of the powder compact is sufficient, and no pressurizing is necessary. Despite the extremely large dimensional shrinkage of 12 to 27%, only at the final stage of completion of sintering is the metal member surface and sintered body placed in full contact with each other to complete diffusion bonding. This completely prevents the surface of the sintered body during sintering from shifting from its final position on the surface of the metal component due to movement due to contraction, and the phenomenon of cracks and ruptures in the sintered body due to partial bonding. virtually 100 mm in position while maintaining the desired dimensions and shape.
% true density and bonding can be performed simultaneously. Next, the heating temperature is within the above temperature range,
Below 1150℃, a sintered body with true density cannot be obtained, many pores remain, and the bonding strength with metal parts is low, causing peeling, so the lower limit is 1150℃,
Preferably it is 1180°C. On the other hand, if the heating temperature is too high, the bonding strength with the metal member will be sufficient, but the shape of the sintered body will collapse, making it impossible to obtain a sintered body with the desired shape and dimensions, so the upper limit of the temperature is
The temperature is 1350°C, preferably 1300°C. Next, the heating time at 1150-1350°C is 5-90 minutes. Sintering and bonding reactions proceed quickly, so if you slow down the rate of heating to the above temperature, you can reach the above soaking temperature and achieve the desired purpose at the same time.
There may be cases where the sintering or bonding strength is insufficient, so
The lower limit is set to 5 minutes. If the powder compact or metal member is large, or if the amount to be processed is large, there may be a delay in local temperature rise or uneven temperature, so the upper limit of the soaking time is set at 90 minutes. Next, the rate of temperature increase in the temperature range from the appearance of a liquid phase to sintering is important, and must be kept below 20°C/min. If the temperature increase rate is too high, the bonding position may become inaccurate or the bonding to a curved surface may be insufficient, so the temperature is preferably 20° C./min or less. As described above, in the method of the present invention, there is no need to apply a load to increase the bonding strength during the sintering and bonding heat treatment, and contact with the powder green body's own weight is sufficient. Prior to performing the sintering and joining process, it is desirable that the surface of the metal member be subjected to a process such as shot blasting, turning, grinding, etc. to remove black scale. Irregularities created on the bonding surface due to blasting or the like affect the bonding strength. If the surface roughness is Rmax60μ or more, it is necessary to increase the heating temperature to maintain bonding strength, and if the heating temperature is increased, the shape of the sintered body cannot be obtained. Therefore, the surface roughness is Rmax60μ or less, preferably
The thickness is preferably 30μ or less, more preferably 10μ or less. Good bonding strength can be obtained even with a mirror finish with a lower limit of about 0.2μ, but usually up to about 0.8μ is sufficient. If necessary, the surface of the metal member is degreased with a solvent, or pretreatment such as alkaline cleaning or pickling is performed. By using the manufacturing conditions described above, it is possible to simultaneously complete a sintered body that maintains desired dimensions and shape, and a strong bonding of the sintered body to a metal member. The area to be bonded can be changed as necessary. If the heating temperature is high and the metal parts require tempering heat treatment to remove the effects of heating, semi-sintering heat treatment or solution heat treatment may be applied after sintering and joining, depending on the material of the metal parts used. Heat treatments such as chemical treatment, quenching, tempering, distortion removal, and depositing treatment can be performed. These heat treatments can be accomplished extremely economically in a single heating and cooling process by immediately performing the desired heating and cooling operations using _N2 gas or the like in the same furnace after the sintering and bonding process. Alternatively, heat treatment may be performed in a separate furnace after cooling to room temperature. During these heat treatments, the bonding temperature between the sintered body and the metal member is high and the bonding strength is sufficiently high, so problems such as peeling are unlikely to occur, and changes in mechanical properties such as hardness and transverse rupture strength of the sintered body are avoided. Almost never occurs. For example, semi-hardening heat treatment is performed at 880 to 1000℃ for 10 to 30 minutes.
By heating in _N2 gas and cooling at a cooling rate of 20 to 50°C/min, the crystal grain size and mechanical properties of the metal member can be restored, and the hardness, transverse rupture strength, and structure of the sintered body change. There isn't. For stainless steel
It may be combined with soaking at 1000 to 1150°C followed by quenching with _N2 gas. The hard sintered alloy bonded metal body of the present invention not only has high hardness and strength as a hard sintered alloy and has excellent wear resistance, but also has excellent corrosion resistance, heat resistance at high temperatures, and oxidation resistance. Because of its high strength, it can be used in a wide range of applications as a composite material for general wear-resistant materials, corrosion-resistant wear-resistant materials, and heat-resistant wear-resistant materials. For example, one or many pieces are arranged on a metal member such as a flat plate, cylinder, or rod, and are joined together to form guide plates, guide rods, earth, sand, or shot blasts for the parts through which ferrous or non-ferrous plates, wires, rods, or pipes pass. Scraping plates, plates, and wear-resistant members for transportation means such as conveyors for conveying coal, coke, ore, glass, cement, etc., attachments for furnace pipes for coal ovens, fluidized bed boilers, etc. Yuerosion prevention linings, side pump casings and blades, screw conveyor blade wear-resistant linings, wear-resistant parts against molten Zn, mines, etc.
Wear resistance of the hard alloy of the present invention for civil engineering, construction machinery, steel, non-ferrous metals, paper, chemicals, wood machinery and metal processing industries, etc.
It can be widely used in fields where corrosion resistance and heat resistance can be utilized. The above-mentioned pulverization of the powder, virtually 100% true densification based on the compacting pressure of the powder, the density of the powder compact, and the amount of shrinkage of the sintered compact due to heating, and the assembly of the metal member and the powder compact On the other hand, the description of the surface roughness of a metal member can be similarly applied to Ni- and Co-based B-containing powders and liquid-phase sintered alloys containing a large amount of C, Si, and P. In the case of a Ni-based alloy powder containing as much as 2 to 4% of B, Si, or C, the liquid phase appearance temperature decreases to about 1050°C. If the liquid phase sintering temperature exceeds 1350℃, the metal parts are likely to deform during heating.
It is difficult to apply this method to powders whose liquid phase sintering temperature exceeds 1350°C. As mentioned above, when using powder of about -100 mesh, such as those used for general sintering such as normal Fe-based alloys and Ni-based alloys, it is 99% or more,
A sintered body with substantially 100% true density cannot be obtained, but a sintered body with a lower density remains, and pores remain, and the number of pores at the bonding interface with the metal member increases, and the bonding strength decreases. , can be used depending on the purpose. Examples of the present invention will be shown below. Example 1 Mo powder 44 in 10% B, 13% Cr, FeBal. powder
%, Ni powder 3%, Fe powder 6%, graphite powder 0.3%, and paraffin 6% are mixed, wet-pulverized in a vibrating ball mill to an average particle size of 1.5 μm, and after drying, a semi-cylindrical green compact with a density ratio of 51% is obtained. (outer surface radius 44 mm, inner radius 40 mm), and this compact was placed on a round bar of SS41 and SUS405 with an outer diameter of 60 mm and a surface roughness of Rmax 6 μm (Fig. 1 A). Sintering and bonding was carried out at 1275°C for 20 minutes in a vacuum of ×10 ^-3 torr. (Figure 1B)
The density of the sintered body was 8.2 g/cm ³ , with no pores observed and substantially 100% true density. A specimen was cut out from this, and the shear strength was measured using a method similar to the JIS G061 clad steel shear strength test. As a result, the joint strengths shown in Table 1 were obtained. The hardness of the sintered body was H _R A87, and the bonding interface was strong with a diffusion layer.

[Table] Example 2 13% B, 5% Cr, FeBal. Mo powder 50 to powder
%, Ni powder 3%, Fe powder 4%, graphite powder 0.4% and paraffin 5% were mixed and the average particle size was determined using a ball mill.
Wet-pulverize to 1.3 μm, dry, and press to form a semi-cylindrical compact with a density ratio of 48% (outer surface radius 51 mm, inner radius 47 mm).The outer diameter of this compact is placed horizontally on a flat surface.
It was placed on a 76 mm steel pipe (surface roughness Rmax 10-30 μm), and the whole (Fig. 2A) was sintered and bonded in a vacuum of 4.5×10 ⁻² torr at 1250° C. for 20 minutes. (FIG. 2B) After sintering and bonding, the sintered body was completely bonded to the metal member, and microscopic observation of the bonded surface confirmed that there were no pores at the interface. In addition, no pores were observed in the sintered body, and the hardness was H _R A90. The bonding strength is
It was 46Kg/ ^mm2 . Example 3 Using the same powder as in Example 2, a cylindrical powder compact with a density ratio of 45% (outer radius 46.5 mm, inner radius 31.5
mm), and the green compact was placed on a SUS410 round bar with an outer diameter of 50.5 mm and a surface roughness of Rmax 10μ (Fig. 3A), and the whole body was placed in a vacuum of 2 × 10 ^-3 torr. 1250
Sinter bonding was performed at ℃ for 20 minutes. (Figure 3B) A rectangular parallelepiped of 8 mm x 4 mm x 25 mm was cut out from this sintered joint and a three-point bending test was conducted using the joint surface as the load point. As a result, the bonding strengths shown in Table 2 were obtained.

[Table] Example 4 Using the same powder as in Example 2, a cylindrical shaped powder compact (outer radius 35 mm, inner radius 31.5 mm, Fig. 4A)
is placed on a 45° bent pipe with an outer diameter of 50.5 mm without any gaps in the pipe axial direction (Fig. 4B), and the overall temperature is 4.5 × 10 ^-2 torr.
Sinter bonding was carried out in a vacuum at 1250℃ for 20 minutes. After sintering and joining, as shown in FIG. 4C, the sintered bodies were completely joined to the metal member with spaces between them. Example 5 Using the same powder as in Example 2, the width was 15 mm and the length was 100 mm.
A plate-shaped green compact with a thickness of 3 mm and a thickness of 3 mm was molded, and this green compact was placed on a steel pipe with an outer diameter of 76 mm and a surface roughness of Rmax 15μ (Fig. 5A) ^. Sinter bonding was performed at 1250°C for 20 minutes in a vacuum of ³ torr. (Figure 5B)
After sintering and joining, the sintered body was completely joined to the metal member, and it was confirmed that the joint did not separate even if deformed by a radial crushing test. Example 6 Using the same powder as in Example 1, a semi-cylindrical powder compact with a density ratio of 50% (outer surface radius 35 mm, inner radius 31.5 mm,
15mm width) using a press, and this green compact is
Placed on a steel pipe (carbon content 0.09%) with an outer diameter of 50.5 mm and a surface roughness of Rmax 10 μm, and the overall temperature was 3.5 × 10 ^-3 torr.
Sinter bonding was carried out in a vacuum at 1250℃ for 20 minutes. After sintering and joining, it was confirmed that the sintered body did not separate from the metal member and was completely joined to the metal member even when the sintered metal was deformed to the point of rupture through a radial crushing test. In addition, when a JIS No. 12 test piece was cut out from this bonded metal body and a tensile test was performed, the yield point was 15 kg/
mm ² , tensile strength of 35 Kg/mm ² , and elongation of 44%, the crystal grains of the metal member were coarsened. The normalized heat-treated specimen heated at 950℃ for 20 minutes in N ₂ gas and then cooled at 40℃/min had a yield point of 26Kg/mm ² , a tensile strength of 39Kg/mm ² , and an elongation of 43%. The mechanical properties of the previous metal part were restored, and the crystal grains were also restored to their pre-treatment state.
The hardness of the sintered body did not change at H _R A87.

[Brief explanation of drawings]

1, 2, 3, 4, and 5 are drawings showing embodiments of the present invention.
Figure A, Figure 2 A, Figure 3 A, Figure 4 B and Figure 5
Figure A is a diagram showing how to assemble the compact and the metal member. Figure 1B, Figure 2B, Figure 3B, Figure 4
FIG. C and FIG. 5B are drawings showing the sintered and joined state. 1...Powder compact, 2...Metal member, 3...Sintered compact.

Claims (1)

[Scope of Claims] 1. A powder green body made of a component that generates a liquid phase during sintering is used, and the radius of curvature of the side to be joined of the powder green body is made larger than the radius of curvature of the metal members to be bonded. , and heated in vacuum or in a non-oxidizing atmosphere in a state in which the powder compact is assembled so that it contacts the metal member only in a straight line or a curved line,
A sintering and joining method characterized by performing liquid phase sintering of the powder compact and at the same time performing diffusion joining using a eutectic liquid phase between the powder compact and a metal member. 2 An object whose metal member has a curved surface consisting of an arc such as a cylinder, a cylinder, a semi-cylindrical shape, an ellipse, etc.
The sintering and joining method according to claim 1, wherein the longitudinal direction is straight or curved. 3. The sintering and joining method according to one of claims 1 to 2, wherein the metal member is iron, carbon steel, alloy steel, or tool steel. 4. In one claim selected from claims 1 to 3, wherein the powder green compact contains one or more of B, Sl, P, and C, and the sintering temperature is 1000°C to 1350°C. The described sinter bonding method. 5 The powder compact has a B content of 3 to 20% and at least
Contains 10% or more of Fe, and after sintering has a hard phase of 40 to 95% mainly composed of boride or complex boride,
The particle size of the powder that becomes the hard sintered alloy consisting of the binder phase that binds the hard phases is set to 350 mesh (44μ) or less, and the powder is compacted to have a compact density of 38 to 67%.
The powder compact is heated to 1150 to 1350°C in a vacuum heating furnace at 1 to 10 ^-5 torr with a part of the powder compact in contact with a metal member such as iron, steel, or alloy steel.
A patent claim that provides a sintered body with a dimensional shrinkage rate of 12 to 27% by heating and cooling to a sintered body with a true density of 99% or more and substantially 100%, and at the same time provides a strong bond with the metal member. 1 selected from the range 1 to 4 of
The sintering joining method described in paragraph 1. 6. The sintering and joining method according to one of claims 1 to 5, wherein the joining member is subjected to tempering heat treatment in a cooling process after sintering or once cooled and then reheated.