JPH046785B2 - - Google Patents

Description

[Detailed description of the invention]

1. Field of Industrial Application The present invention relates to a wear-resistant sintered alloy, and more specifically, it is an improved wear-resistant sintered alloy suitable as a material for sliding parts used under severe conditions, such as valve seats of internal combustion engines. Regarding wear-resistant sintered alloys. 2. Prior Art In recent years, internal combustion engines have become smaller and have higher output, and in the case of gasoline engines, the fuel has shifted to unleaded gasoline or LPG has come to be used, so valve seats are under high load. However, as valve seats are now exposed to harsh conditions such as direct contact with the metal of a mating valve at temperatures of 700 to 800°C and being subjected to hot shock, the requirements for wear resistance of valve seats have become increasingly strict. It's coming. Additionally, diesel engines have higher combustion pressures and temperatures than gasoline engines, and the sulfur and vanadium in the fuel cause wear and tear accompanied by chemical corrosion, and valve seats are used under even harsher conditions. be done. Sintered alloys produced by powder metallurgy, especially iron-based sintered alloys, have recently been applied to machine parts materials because it is easier to form the desired metal structure than sintered lumber. Although the range has been expanded and many improvements have been made as material for valve seats, it has yet to be fully satisfied as a material for valve seats, especially in modern compact, high-output internal combustion engines. Not yet. 3. Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances. The purpose is to provide sintered parts. 4. Structure of the Invention The first invention has a structure in which titanium nitride particles with an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 μm. -3.0% by weight of carbon, 0.3-3.0% of nickel, 1.0-3.0% of copper, and 3.0-10.0% of cobalt, the balance being substantially iron, and 7% or less of pores Pertaining to wear-resistant sintered parts with a The second invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. One or more of carbon, 1 to 20% by weight chromium, 0.2 to 8.0% molybdenum, 0.5 to 3.0% tungsten, and 0.2 to 6.0% vanadium, the balance substantially consisting of iron, and chromium, molybdenum, The present invention relates to a wear-resistant sintered part that has a structure in which one or more of tungsten and vanadium are dispersed in the form of hard particles, and has a porosity of 7% or less. The third invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. One or more of carbon, 0.3 to 3.0 wt% nickel, 1.0 to 3.0 wt% copper, and 3.0 to 10.0 wt% cobalt, and 1 to 20 wt% chromium, 0.2 to 8.0 wt% molybdenum, 0.5 to 3.0 wt% tungsten. and 0.2～
6.0% by weight of one or more types of vanadium in a total of 40% by weight or less, the remainder substantially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium are dispersed to form hard particles. It pertains to wear-resistant sintered parts having a porosity of 7% or less. The fourth invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. one or more of carbon, 0.3 to 3.0% by weight nickel, 1.0 to 3.0% by weight copper, and 3.0 to 10.0% by weight cobalt, the remainder being substantially iron, and the pores are filled with a dissolving material. , relates to wear-resistant sintered parts having a porosity of 7% or less. A fifth invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. One or more of carbon, 1 to 20% by weight chromium, 0.2 to 8.0% molybdenum, 0.5 to 3.0% tungsten, and 0.2 to 6.0% vanadium, the balance substantially consisting of iron, and chromium, molybdenum, A resistant material having a structure in which one or more of tungsten and vanadium are dispersed in the form of hard particles, and the pores are filled with an infiltrating material and the porosity is 7% or less. Pertains to worn sintered parts. A sixth invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. One or more of carbon, 0.3 to 3.0 wt% nickel, 1.0 to 3.0 wt% copper, and 3.0 to 10.0 wt% cobalt, and 1 to 20 wt% chromium, 0.2 to 8.0 wt% molybdenum, 0.5 to 3.0 wt% tungsten. and 0.2～
6.0% by weight of one or more types of vanadium in a total of 40% by weight or less, the remainder substantially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium are dispersed to form hard particles. The present invention relates to a wear-resistant sintered part, which has a structure in which the pores are filled with an infiltrating material and has a porosity of 7% or less. The seventh invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. One or more of carbon, 0.3 to 3.0 weight% nickel, 1.0 to 3.0 weight% copper, and 3.0 to 10.0 weight% cobalt, 0.1 weight% or less boron, 0.3 weight% or less phosphorus, and
The present invention relates to a wear-resistant sintered part containing 0.45% by weight or less of one or more types of sulfur in a total amount of 0.04 to 0.45% by weight, the balance being substantially iron, and having a porosity of 7% or less. The eighth invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. Carbon, 1 to 20% by weight chromium, 0.2 to 8.0% by weight molybdenum, 0.5 to 3.0% by weight tungsten, and 0.2 to 6.0% by weight vanadium, one or more of them, 0.1% by weight or less boron, 0.3% by weight or less phosphorus as well as
0.45% by weight or less of one or more types of sulfur in a total of 0.04 to 0.45% by weight, the balance essentially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium forming hard particles. The present invention relates to wear-resistant sintered parts having a porosity of 7% or less and having a structure in which the particles are dispersed. The ninth invention has a structure in which titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. One or more of carbon, 0.3 to 3.0 wt% nickel, 1.0 to 3.0 wt% copper, and 3.0 to 10.0 wt% cobalt, and 1 to 20 wt% chromium, 0.2 to 8.0 wt% molybdenum, 0.5 to 3.0 wt% tungsten. and 0.2～
6.0% by weight of one or more of vanadium in total not more than 40% by weight, boron not more than 0.1% by weight, phosphorus not more than 0.3% by weight, and
0.45% by weight or less of one or more types of sulfur in a total of 0.04 to 0.45% by weight, the balance essentially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium forming hard particles. The present invention relates to wear-resistant sintered parts having a porosity of 7% or less and having a structure in which the particles are dispersed. Next, each element and dispersed phase constituting the present invention will be explained. Regarding each element that makes up the base, if the carbon content is less than 0.3% by weight (hereinafter, numbers simply expressed as "%" represent weight%), the base is soft and lacks mechanical strength and wear resistance. If it exceeds 3.0%, the amount of carbides in the base will become too large and cause embrittlement, so it is preferably in the range of 0.3 to 3.0%. In the first, third, fourth, sixth, seventh, and ninth inventions, both nickel and copper are dissolved in the matrix to improve mechanical strength. Nickel is less than 0.3%,
If copper is less than 1.0%, the above effects will not be fully manifested,
Since the increase in the above-mentioned effects is not significant even when the content exceeds 3.0% in either case, it is preferable to set the content in the range of 0.3 to 1.0% for nickel and the range of 1.0 to 3.0% for copper. Cobalt, like nickel and copper, improves the mechanical strength of the matrix and also improves its mechanical strength at high temperatures. If the content is less than 3.0%, the above effect is insufficient, and even if it exceeds 10.0%, the increase in the above effect is not significant, so it is preferably in the range of 3.0 to 10.0%. In the second, third, fifth, sixth, eighth, and ninth inventions, a small portion of each of chromium, molybdenum, tungsten, and vanadium is dissolved in the matrix to improve mechanical strength; In particular, molybdenum increases high temperature strength. In addition, most of the other components form carbides with carbon or remain as undiffused hard particles, contributing to wear resistance. Chromium less than 1.0%, molybdenum less than 0.2%,
If the amount of tungsten is less than 0.5% and the amount of vanadium is less than 0.2%, the above effects will be insufficient; if the amount of chromium is less than 20%, molybdenum is less than 8.0%, tungsten is more than 3.0%, and vanadium is more than 6.0%, the This results in loss of compressibility. In particular, molybdenum makes the base brittle and impairs its mechanical strength. For the following reasons, chromium is 1.0-20%, molybdenum is 0.2-8.0%, tungsten is 0.5-3.0%,
Vanadium is in the range of 0.2 to 6.0%, and from the viewpoint of compressibility, it is particularly preferable that the total amount of one or more of the alloying elements other than carbon is 40% or less. In addition, for the purpose of base reinforcement only, chromium, molybdenum, tungsten and vanadium are not added, 0.3-3.0% nickel, 1.0-3.0% copper and 3.0-3.0% copper.
One or more types of 10.0% cobalt may be contained (first, fourth, and seventh inventions). The titanium nitride particles dispersed in the matrix are hard and contribute to wear resistance. Its particle size is on average 2
It is preferable that the particle size is in the range of ~70 μm and the maximum particle size is 100 mesh (147 μm) or less. If the average particle diameter is smaller than 2 μm, it is difficult to uniformly disperse it, and if it exceeds 70 μm, it will damage the mating sliding parts and it will be difficult to cut it. The amount of dispersion is preferably in the range of 2 to 30% in terms of volume ratio (equal to area ratio under a microscope). Sintered alloys usually contain pores unless they are specifically treated to seal the pores, but the above-mentioned amount of dispersion is the amount of dispersion in the substance excluding the pores. This amounts to 1.5 to 20% by weight. The chemical composition of the entire sintered alloy in the third and sixth inventions configured as described above is 0.8 to 19.7% chromium, 0.24 to 3.0% nickel, 0.16 to 7.9% molybdenum, 0.4 to 3.0% tungsten, and 0.16 to 5.9%. 1% vanadium, 0.8-3.0% copper and 2.4-9.9% cobalt
Species or total of two or more species 39.4% or less, 0.24-3.0%
The composition consists of carbon, 1.16-15.5% titanium, 0.44-6.8% nitrogen, and the balance essentially iron. However, the above chemical composition does not include the components of the infiltrating material in the fourth, fifth, and sixth inventions. Also,
In the seventh, eighth, and ninth inventions, in addition to the above, one or more of boron, phosphorus, and sulfur is added in total.
Contains 0.04-0.45%. In the present invention, the porosity is set to 7% or less from the viewpoint of mechanical strength and wear resistance. In the fourth, fifth, and sixth inventions, the porosity is reduced by filling the pores with the infiltrating material. Copper or a copper alloy that has good wettability for both the iron base and titanium nitride particles, has the effect of fixing the titanium nitride particles, and dissolves in the iron base to strengthen it. is suitable. In the seventh, eighth, and ninth inventions, the porosity is reduced by liquid-phase sintering by the action of boron, phosphorus, and/or sulfur. Boron, phosphorus, and sulfur all have the effect of generating a liquid phase at the sintering temperature, and they partially generate a liquid phase during sintering, lowering the porosity and improving the mechanical strength of the sintered alloy. , improves the wettability of the titanium nitride particles and strengthens the bond between the base and the titanium nitride particles. In either case, if the content in the base is less than 0.04%, the above effects are not noticeable, and if it exceeds 0.45%, the above liquid phase will be excessively generated, worsening the dimensional accuracy of the sintered pair, and causing their embrittlement. The effect becomes apparent. Therefore, the total amount of one or more of these is preferably in the range of 0.04 to 0.45%. Note that, in order to prevent the above-mentioned embrittlement, the upper limits of the contents of boron, phosphorus, and sulfur are preferably 0.1%, 0.3%, and 0.45%, respectively. 5 Examples Example 1 First, an example of the first invention will be described. Mix the raw material powders with the chemical composition shown in Table 1 below as shown in Table 2 below, add 0.7% zinc stearate powder as a lubricant, mix for at least 20 minutes with a V-type mixer, and mix these powders as shown in Table 2 below. 6t/ ^cm2 of mixed powder
It was molded into an annular green compact with an outer diameter of 35.3 mm, an inner diameter of 28.7 mm, and a height of 9 mm at a molding pressure of .

[Table]

[Table] Next, these green compacts were heated at 15°C in an AX gas atmosphere.
Heating to 850-950℃ with a heating rate of min, at this temperature
Performed a 60-minute hold-out process, followed by 5
Heated to 1120℃ at a heating rate of ℃/min.
Hold for 90 minutes to sinter, cool to near room temperature at a cooling rate of 30°C/min, then heat to 700°C again for 60 minutes.
After holding for a minute, it was cooled at a cooling rate of 20°C/min. The thus obtained annular sintered body was subjected to rotary casting to increase the density (lower the porosity). The outline of the rotary casting apparatus used is shown in Figs. 1 and 2, in which the die 1 is elastically supported on the die base 2 by an elastic body (spring, urethane resin, etc.) 3a. A lower punch 4 is provided in the circular hollow hole at the center of the die 1 so as to slide up and down in sliding contact with the die 1, and inside the annular lower punch 4, a core 5 whose head is connected to the lower punch 4 is provided. The lower part of the core 5 is supported on the base of the lower punch 4 via an elastic body (same as above) 3b, and the side surface 1 of the hollow hole of the die 1
The sintered body R to be forged is inserted into the annular die groove 6 formed by the upper end 4a of the lower punch 4 and the head side surface 5a of the core 5. The upper punch 7 is cylindrical and the end is a right circular cone with an apex angle of θ.The conical surface is in flat contact with the top surface of the die and core, and the central axis of the cylinder is OB at α=(180−θ).
It is tilted by 1/2° with respect to the center line OA of the die groove 6 and is supported by a spherical bearing (not shown), and is oscillated around the axis OA by a drive device (not shown). The thickness of the stopper 8 which is placed on the die base and limits its rising height is determined by the compressed height of the sintered compact, and the adjusting screw 10 screwed into the die 1 through the die base 2 is adjusted so that the height of the die 1 is horizontal. adjust the
The depth of the annular die groove can be adjusted by the collar 10a. Base plate 11 for attaching the die base
is moved up and down by a fluid pressure cylinder (not shown), and the lower punch 4 is moved up and down. The base of the lower punch 4 is connected to the piston rod 1 of a second hydraulic cylinder (not shown).
It is designed so that it can be moved up and down independently of the base plate 11 connected to 2. Since the structure is as described above, the base plate 11 is first lowered, and the sintered body R is inserted into the annular die groove 6 so that its upper surface is slightly below the die surface. When the die 1 is raised by the upper punch 7, the upper surface of the die 1 comes into contact with the conical pressing surface of the upper punch 7. When the center axis OB of the upper punch 7 is rotated around the center line OA by an angle α, the curved surface of the cone rotates with its generatrix sequentially touching the die surface around the apex O. When the base plate 11 is further raised by the hydraulic cylinder, the die 1 and the core 5 are pressed against the conical surface of the upper punch 7 by the elasticity of the elastic body 3a or 3b, and the lower punch 4 is raised together with the base plate 11. Therefore, the sintered body R in the annular die groove 6 is pushed up inside the groove, its upper surface is pressed against the conical curved surface of the upper punch, and as the base plate 11 rises, it is subjected to pressing force by the upper punch. Compressed. When the base plate 11 continues to rise and the stopper 8 touches the lower surface of the die 1, the base plate 11 stops rising and the lower punch 4 also stops rising. The upper punch 7 continues to rotate for a while, and when the sintered body R is compressed to the same height as the die surface, the pressing force of the upper punch no longer acts, so after a predetermined period of time, the fluid pressure cylinder of the base plate 11 is reversed. After actuating and lowering the base plate 11 to a predetermined position, when the piston 12 connected to the lower punch 4 is raised, the sintered body R is pushed upward from the die groove 6, and is removed from the forging machine by a take-out lever (not shown). carried outside. Sintered bodies whose porosity has been lowered using such equipment will have minute cracks inside, so in order to eliminate these, the sintered body must be heated at 15°C/min in an RX gas atmosphere.
Heat to 700-950℃ at a heating rate of
Heat to, hold at this temperature for 50 minutes, then 30-10
Re-sintering was performed by cooling to near room temperature at a cooling rate of °C/min. The analytical values and porosity of the sintered body subjected to the above treatment are as shown in Table 3 below.

[Table] In the table, No. 1 to 9 are examples in which titanium nitride particles are dispersed, and No. 41 is a comparative example with a low nickel content.
No. 42 is a comparative example in which titanium nitride particles were not dispersed. To explain the base structure of these sintered bodies,
Nos. 1 to 9 and No. 42 have a structure made of sorbite. The structure of these sintered bodies is shown in FIG. 3 as a 400x micrograph, taking No. 5 as an example. As mentioned above, No. 5 cannot recognize hard phases such as carbides in the base at the above magnification, and the base 15
is made of sorbite, and has a structure in which titanium nitride particles 17 that appear white (appear yellow under a microscope) are dispersed. Part 18 that looks black
are pores, and due to the rotary forging, the number of pores is smaller than that of general sintered alloys. A valve seat having an outer diameter of 35 mm, an inner diameter of 29.5 mm, and a chamfer of 1.2C (width of contact 17 mm) was chamfered at one end on the inner peripheral side was machined from the sintered body, and a wear test was performed. The test equipment is shown schematically in Figure 4.
1 is a valve seat holder 2 provided on the cylinder head 22
3 and is fixed to the cylinder head via the valve seat retainer 23. A valve drive main body 24 is fixed to the lower part of the cylinder head 22, and the valve 30 is
The rod portion 30a is vertically movably inserted into the valve guide 25 attached to the valve drive body 24 so that the valve face abuts the chamfered surface of the valve seat 21. The tip of the valve rod portion 30a is in pressure contact with the cam 29a of the camshaft 29, which is fitted into the bearing 28 provided in the valve drive unit main body 14 by the coil springs 27a and 27b.
It is accommodated in 6. The valve 30 has its rod portion 3
It is held by a claw 26a provided on the valve receiver 26 near the tip of the valve receiver 26, and is fixed to the valve receiver 26. With this structure, when the camshaft 29 is rotated by a drive device (not shown), the valve 30 fixed to the valve receiver 26 moves up and down, causing the valve face to impact the chamfered surface of the valve seat 21. I started hitting it repeatedly. The load is determined by appropriately selecting the coil springs 27a and 27b. A gas burner 31 is arranged above the valve 30, and a thermocouple 33 is inserted into a hole drilled in the valve seat holder 23 so that the hot junction of the thermocouple 33 comes into contact with the valve seat 21 to adjust the temperature of the valve seat 21. is detected, and a control circuit (not shown) controls the flow from the nozzle 34 to the cylinder head 22.
The valve seat 21 is maintained at a predetermined temperature by adjusting the amount of compressed air blown onto the valve seat 21. Further, the surface temperature of the bulb 30 is measured using a radiation thermometer 32.
The surface temperature of the valve 30 is maintained at a predetermined temperature by adjusting the amount of propane gas supplied to the gas burner 31 by a control circuit (not shown). Using such a testing device, we held the valve surface temperature at 750°C and the valve seat temperature at 450°C, conducted a test for 10 hours at a camshaft rotation speed of 2500 rpm, and a coil spring load of 40 kg, and measured the amount of wear on the valve seat. was calculated from the amount of sinking of the reference valve. The valve was made of 21-4N steel and the valve face was filled with Stellite No. 6. The number of strikes on the valve and valve seat is 1.5×10 ⁷ times. In addition to the valve seats No. 41 and No. 42 mentioned above, the valve seat for comparison is No. 4, which is made of heat-resistant steel SLH4.
46 and 1.35%C, 1.21%Si, 0.42%Mn, 13.1%
Also added was No. 47 made of high chromium white cast iron having a chemical composition of Cr, 0.36% Mo, and the balance substantially Fe. The test results are shown in FIG. From the same figure, the valve seat made of the sintered alloy of the present invention having a titanium nitride phase in its structure clearly shows a greater amount of wear than any of the comparative valve seats, as well as compared to the comparative valve seat made of sintered lumber. It can be seen that it is small and extremely wear resistant. Nos. 41, 42, 1, 2, and 3 have the same base material with a volume ratio of titanium nitride of 0, 15, 5, 15, and 25.
%, and the amount of wear decreases as the amount added increases. From these results, it can be seen that the addition of titanium nitride significantly improves wear resistance. Further, titanium nitride is chemically stable and does not decompose even when heated to the sintering temperature in the sintering process. Example 2 Next, an example of the second invention will be described. The raw material powders having the chemical composition shown in Table 1 were blended as shown in Table 4 below, and a low porosity annular sintered body was obtained in the same manner as in Example 1 above. The analytical values and porosity of these sintered bodies are shown in Table 5 below.

【table】

[Table] No.43 is a comparative example with low molybdenum content, No.44
is a comparative example in which titanium nitride particles were not dispersed. The base of these sintered bodies has a structure in which hard ferroalloy particles containing carbide formed by bonding with carbon are dispersed in the sorbite ground. The same abrasion test as in Example 1 was conducted on these annular sintered bodies, and the results are also shown in FIG. Example 3 Next, an example of the third invention will be described. The raw material powders having the chemical composition shown in Table 1 were blended as shown in Table 6 below, and a low porosity annular sintered body was obtained in the same manner as in Examples 1 and 2. The analytical values and porosity of these sintered bodies are shown in Table 7 below.

【table】

【table】

【table】

[Table] No. 45 is a comparative example in which titanium nitride was not dispersed. Base No. 33 has hard particles formed by CMC powder (pre-alloyed powder) shown in Table 1 and hard particles containing molybdenum carbide produced by combining molybdenum with carbon dispersed in the sorbite ground. It has become an organized organization. Bases No. 34, 35, 36, and 37 are shown in Table 1.
It has a structure in which spherical hard particles formed by STL (Stellite) spray alloy powder are dispersed. These annular sintered bodies were subjected to wear tests in the same manner as in Example 1, and the results are also shown in FIG. No. 25, 26, 27 with almost constant nickel content,
28 data, it can be understood that chromium, molybdenum, tungsten, and vanadium have the same effect on improving wear resistance. Furthermore, from the data for Nos. 26, 29, and 30 where the molybdenum content was kept approximately constant, it can be understood that nickel, copper, and cobalt have the same effect on improving wear resistance. Furthermore, compared to Comparative Examples No. 42, 44, and 45 in which titanium nitride particles were not dispersed, the examples of the first, second, and third inventions all showed significantly less wear, and titanium nitride particles The effect of dispersion on improving wear resistance is remarkable. Comparative example No.
46 and 47 have the largest amount of wear. Example 4 Next, examples of the fourth, fifth, and sixth inventions will be described. The annular sintered body obtained in the same manner as in Examples 1, 2, and 3 (however, the sintering temperature was 1150°C) was
Insert it into the mold used for green compact molding, and place it on top of it.
2.46%Mn, 3.82%Fe, 2.20%Zn, 0.6%Si, 0.06
An annular green compact formed by molding fused copper powder (FIPA-3) with a particle size of -100 mesh at a molding pressure of 3t/ ^cm2 , consisting of %Al and the balance Cu, was placed and heated to 1130℃ for 40 minutes. The pores of the sintered body were filled with the fused copper to lower the porosity. The analytical values and porosity of the sintered body after infiltration are as shown in Section 8 below.
As shown in Table 9, Table 10. The numbers representing the sintered bodies are shown in Tables 2, 4, and 6.
The numbers corresponding to are shown with "-2" added. The percentage of Cu is No. 4-2 and No. 6- in Table 8.
2 and No. 9-2 and No. 29-2 and No. 32- of Table 10
2. For No. 35-2, No. 36-2, and No. 38-2, it is the sum of the Cu values in Tables 3 and 7 in the sintered body skeleton and the Cu that filled the pores. , Cu% of other sintered bodies is the amount of Cu filling the pores.

【table】

【table】

[Table] The structure of these sintered bodies (without corrosion) is shown in Fig. 6 as a 400x micrograph, taking No. 30-2 as an example.
Melted copper 36 has entered the gap between the iron base 35,
Titanium nitride particles 37 are observed therein. 38
There are still a few pores remaining. The same wear test as in Example 1 was conducted on the above sintered body. The test results are shown in FIG. 4th, 5th, whose porosity was reduced by infiltration;
The sintered alloy based on the sixth invention shows even better results than the sintered alloys of Examples 1, 2, and 3 whose porosity was reduced by rotary casting. Example 7 Next, examples of the seventh, eighth, and ninth inventions will be described. In addition to the raw material powder shown in Table 1, ferroboron (Fe-B) powder (-250 mesh) containing 21.0% B, ferrophosphor (Fe-B) powder containing 26.6% P
P) Powder (-250 mesh) and molybdenum disulfide (MoS ₂ ) powder with a purity of 99% or more (average particle size 2μ)
m) and blended as shown in Table 11, Table 12 and Table 13 below to obtain a mixed powder, and from this mixture, an annular green compact was prepared in the same manner as in Examples 1 to 6 above. And so.

【table】

【table】

【table】

【table】

【table】

[Table] These green compacts were heated to 1050°C at a heating rate of 10°C/min in a vacuum furnace, held at this temperature for 15 minutes, and then heated to 1200°C at a heating rate of 5°C/min. The material was sintered by holding for 60 minutes at a cooling rate of 40°C/min to 950°C, and then nitrogen gas was blown into the furnace to cool it to near room temperature at a cooling rate of 300°C/min. The analytical values of boron, phosphorus and sulfur and the porosity of the sintered body thus obtained are shown in Tables 14, 15 and 15 below.
As shown in Table 16. The analytical values of components other than those listed above were almost the same as the analytical values of Nos. 1 to 38 shown in Tables 3, 5, and 7 corresponding to the No. in the same table.

【table】

【table】

【table】

【table】

[Table] The structure of these sintered bodies is given as an example of No. 31-B.
A 400x micrograph is shown in Figure 8. Eutectic phase 4 formed by solidifying the liquid phase generated by Fe-Cr-C-B multi-component eutectic during sintering in the sorbite base 45
6 was observed, and a structure in which titanium nitride particles 47 were further dispersed was observed. The black portion 48 is a pore, and the number of the pores is smaller than that of a general sintered alloy due to the liquid phase sintering due to the action of boron. The same wear test as in Examples 1 and 2 was conducted on the above sintered body. The test results are as shown in FIG. 9, and show comparable good results as the test results in Example 2 shown in FIG. The present invention has been explained above using a valve seat as an example.
In addition to valve seats, the range of application is wide, such as internal combustion engine parts such as rocker arms, tappets, piston rings, and other mechanical parts such as rotary compressor vanes. 6 Effects of the Invention As explained above, the wear-resistant sintered alloy of the present invention has the above-mentioned chemical composition and structure, so it has extremely excellent wear resistance and is suitable for use from overhaul to subsequent overhaul of internal combustion engines and other mechanical devices. The present invention has great industrial utility value by extending the so-called open period period.

[Brief explanation of drawings]

1 and 2 are sectional views of the main parts of the rotary casting apparatus, with FIG. 1 showing the state in which the sintered body has been inserted, and FIG. 2 showing the state in the final stage of forging. Figures 3, 6 and 8
All figures are micrographs at 400x magnification showing the structure of the wear-resistant alloy according to the present invention. FIG. 4 is a sectional view of the main parts of the valve seat wear test device. Figure 5,
Both FIG. 7 and FIG. 9 are graphs showing the results of the wear test. In addition, in the symbols shown in the drawings, 1...die, 2...die base, 3a, 3b...elastic body,
4... Lower punch, 5... Core, 6... Annular die groove, 7... Upper punch, 8... Stopper, 9...
Guide rod, 10... Adjustment screw, 10a... Collar,
11... Base plate, 12... Piston, R... Annular sintered body, 13... Core fixing pin, 14... Mounting collar, 15, 35, 45... Solvite base, 1
7,37,47...Titanium nitride particles, 18,3
8,48...pore, 36...melted copper, 46...
Fe-Cr-C-B eutectic phase, 21...Valve seat, 22
... Cylinder head, 24 ... Valve drive unit body, 35 ... Valve guide, 27a, 27b ...
Coil spring, 29...camshaft, 30...valve,
30a... Valve rod part, 31... Gas burner, 32... Radiation thermometer, 33... Thermocouple, 3
4... Compressed air nozzle.

Claims (1)

[Scope of Claims] 1. Titanium nitride particles having an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the base has a structure of 0.3 to 3.0% by weight. % carbon, 0.3 to 3.0 weight % nickel, 1.0 to 3.0 weight % copper, and 3.0 to 10.0 weight % cobalt, and the remainder substantially consists of iron, and has a porosity of 7% or less Wear-resistant sintered parts. 2 Titanium nitride particles with an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the matrix contains 0.3 to 3.0% by weight of carbon, 1 to 20 One or more of the following: chromium, molybdenum, molybdenum, tungsten, and vanadium (by weight%) A wear-resistant sintered part that has a structure in which a species or two or more species are dispersed to form hard particles, and has a porosity of 7% or less. 3. Titanium nitride particles with an average particle diameter of 2 to 70 μm have a structure in which titanium nitride particles with an average particle size of 2 to 70 μm are dispersed in a matrix with an area ratio of 2 to 30% excluding pores, and the base contains 0.3 to 3.0% by weight of carbon, 0.3 to 3.0 One or more of the following: by weight% nickel, 1.0-3.0% by weight copper, and 3.0-10.0% by weight cobalt, and 1-20% by weight chromium, 0.2-8.0% by weight molybdenum, 0.5-3.0% by weight tungsten, and 0.2-20% by weight.
6.0% by weight of one or more types of vanadium in a total of 40% by weight or less, the remainder substantially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium are dispersed to form hard particles. Wear-resistant sintered parts with a porosity of 7% or less. 4 Titanium nitride particles with an average particle size of 2 to 70 μm have a structure in which titanium nitride particles with an average particle size of 2 to 70 μm are dispersed in a matrix with an area ratio of 2 to 30% excluding pores, and the base contains 0.3 to 3.0% by weight of carbon, 0.3 to 3.0 One or more of the following: 1.0 to 3.0 weight % copper, and 3.0 to 10.0 weight % cobalt, the remainder being substantially iron, and the pores are filled with an infiltrating material, and the porosity is 7. % or less wear-resistant sintered parts. 5 Titanium nitride particles with an average particle size of 2 to 70 μm have a structure in which they are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the matrix contains 0.3 to 3.0% by weight of carbon, 1 to 20 One or more of the following: chromium, molybdenum, molybdenum, tungsten, and vanadium (by weight%) A wear-resistant sintered part having a structure in which the species or two or more species form hard particles and are dispersed, and the pores are filled with an infiltrating material and the porosity is 7% or less. 6. Titanium nitride particles with an average particle diameter of 2 to 70 μm have a structure in which titanium nitride particles with an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the matrix contains 0.3 to 3.0% by weight of carbon, 0.3 to 3.0% by weight. One or more of the following: by weight% nickel, 1.0-3.0% by weight copper, and 3.0-10.0% by weight cobalt, and 1-20% by weight chromium, 0.2-8.0% by weight molybdenum, 0.5-3.0% by weight tungsten, and 0.2-20% by weight.
6.0% by weight of one or more types of vanadium in a total of 40% by weight or less, the remainder substantially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium are dispersed to form hard particles. A wear-resistant sintered part having a structure in which the pores are filled with an infiltrating material and the porosity is 7% or less. 7 Titanium nitride particles with an average particle size of 2 to 70 μm have a structure in which titanium nitride particles with an average particle size of 2 to 70 μm are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the matrix contains 0.3 to 3.0% by weight of carbon, 0.3 to 3.0% by weight. One or more of the following: 1.0 to 3.0% by weight of copper, 3.0 to 10.0% by weight of cobalt, 0.1% by weight or less of boron, 0.3% by weight or less of phosphorus, and
A wear-resistant sintered part comprising 0.45% by weight or less of one or more types of sulfur in a total of 0.04 to 0.45% by weight, the balance being substantially iron, and having a porosity of 7% or less. 8 Titanium nitride particles with an average particle size of 2 to 70 μm have a structure in which they are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the matrix contains 0.3 to 3.0% by weight of carbon, 1 to 20 One or more of the following: chromium, 0.2 to 8.0% by weight, molybdenum, 0.5 to 3.0% tungsten, and 0.2 to 6.0% vanadium, 0.1% by weight or less boron, 0.3% by weight or less phosphorous, and
0.45% by weight or less of one or more types of sulfur in a total of 0.04 to 0.45% by weight, the balance essentially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium forming hard particles. A wear-resistant sintered part that has a porosity of 7% or less and has a porosity of 7% or less. 9 Titanium nitride particles with an average particle diameter of 2 to 70 μm have a structure in which they are dispersed in a matrix in an area ratio of 2 to 30% excluding pores, and the matrix contains 0.3 to 3.0% carbon by weight, 0.3 to 3.0% by weight. One or more of the following: by weight% nickel, 1.0-3.0% by weight copper, and 3.0-10.0% by weight cobalt, and 1-20% by weight chromium, 0.2-8.0% by weight molybdenum, 0.5-3.0% by weight tungsten, and 0.2-20% by weight.
6.0% by weight of one or more of vanadium in total not more than 40% by weight, boron not more than 0.1% by weight, phosphorus not more than 0.3% by weight, and
0.45% by weight or less of one or more types of sulfur in a total of 0.04 to 0.45% by weight, the balance essentially consisting of iron, and one or more types of chromium, molybdenum, tungsten, and vanadium forming hard particles. A wear-resistant sintered part that has a porosity of 7% or less and has a porosity of 7% or less.