JPH0347932A - Copper-base sintered alloy excellent in wear resistance at high temperature - Google Patents

Abstract

PURPOSE:To improve wear resistance and seizure resistance in particular by incorporating specific amounts of Mn, Si, one or more elements among Fe, Ni, and Co, and O2 to a Cu-Zn alloy and specifying structure and the amount of pores, respectively. CONSTITUTION:The alloy has a composition consisting of, by weight, 5-25% Zn, 0.1-3% Mn, 0.1-2% Si, 0.1-3% of one or more elements among Fe, Ni, and Co, 0.01-0.5% O2, and the balance Cu and also has a structure in which fine oxides and intermetallic compounds are uniformly dispersed in a matrix and also pores are distributed by 1-15vol.%. In the above alloy, it is necessary that pores are contained by the amount not less than the lower limit, and, when the amount of pores exceeds the upper limit, strength and thermal conductivity are decreased and heat resistance is deteriorated, and further, seizure resistance and wear resistance are also reduced. As to the amounts of Mn, Si, Fe, etc., the amounts not less than the lower limits are required, respectively, from the viewpoint of improving seizure resistance and wear resistance, and, on the other hand, seizure resistance is deteriorated and attacks on mating materials are increased when the amounts of Mn and Si exceed the upper limits, respectively, and further, seizure resistance is deteriorated when the amounts of Fe, etc., exceed the upper limits, respectively. As to O2 content, the amount not less than the lower limit is necessary from the viewpoint of improving wear resistance, and, the grain size of oxides is coarsened and attacks on mating materials are increased when O2 content exceeds the upper limit.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a copper-based sintered alloy that has excellent wear resistance under any conditions from room temperature to high temperature, and in particular has excellent wear resistance under high temperature conditions. The present invention relates to a copper-based sintered alloy that has excellent properties, and is suitable for use as guide bushings for internal combustion engines, bearings for turbochargers, and the like.

[Conventional technology]

Conventionally, a copper-based melt-produced alloy having a typical composition of Cu-28%2n-6%Ag in weight percent (hereinafter % indicates weight percent) has been used to manufacture the above-mentioned various members.

[Problem to be solved by the invention]

However, when the above-mentioned conventional copper-based alloys are used from relatively low to high temperatures, seizure occurs, especially at high temperatures, and there are problems with wear resistance.

With the recent increase in output in internal combustion engines, the sliding parts of internal combustion engines are exposed to even higher temperatures than before, so copper-based alloys, which do not cause seizure and have excellent wear resistance, especially at high temperatures, are used. The development of this was strongly desired.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors focused particularly on the conventional copper-based sintered alloys mentioned above, and developed a copper-based sintered alloy that has significantly superior seizure resistance and wear resistance. As a result of research, we found that Zn: 5-25%, Mn: 0.1-3%, Si: 0.1-2%, and one or more of Fe, Ni, and Co.
．． 1 to 3%, oxygen: 0.01 to 0.5%, and if necessary, (a) AR: 0.1 to OJ%, (b) 1 of Cr, Mo, and W. Species or two or more species: 0.1 to 2%, a composition containing any one or two of the above (a) to (b), with the remainder consisting of Cu and inevitable impurities,
In addition, copper-based sintered alloys, which have a structure in which fine oxides and intermetallic compounds are uniformly dispersed in the matrix and pores are distributed at a volume ratio of 1 to 15%, have improved wear resistance at room temperature and high temperature. Furthermore, they found that the presence of fine oxides and pores in the matrix improves the seizure resistance at high temperatures.

This invention was made based on this knowledge, and the copper-based sintered alloy of this invention has the above composition.
In the matrix, oxides distributed within the particle size range of 1 to 40 ttn are uniformly dispersed at an area ratio of 0.1 to 7%, and
Intermetallic compounds distributed within the particle size range of ~25t1m
It is uniformly dispersed with an area ratio of ~8%, and further has an area ratio of 1 to 40%. cm
It has a structure in which pores within the particle size range of 1 to 15% by volume are uniformly distributed, and the presence of these oxides and intermetallic compounds in the matrix significantly improves wear resistance at room and high temperatures. The presence of particles and pores in the base material significantly improves the seizure resistance at high temperatures.

Next, the reason why the composition and pores of the copper-based sintered alloy of the present invention are limited as described above will be explained.

(a), pores are distributed on the sliding surface and have the effect of improving seizure resistance, especially at high temperatures, but this effect cannot be obtained at less than 1% by volume; If the distribution exceeds %, not only the strength will decrease, but also the heat resistance will deteriorate due to the decrease in thermal conductivity, and the seizure resistance at high temperatures will decrease.
It is also undesirable because it reduces wear resistance.

Therefore, the distribution amount of pores was determined to be 1 to 15% by volume.

(b), Zn Zn forms a matrix together with Cu and has the effect of improving the strength and toughness of the alloy, and also combines with oxygen to form an oxide, improving seizure resistance at high temperatures and at room and high temperatures. It has the effect of improving the wear resistance of, but if it is less than 5%, it has no effect, while if it is contained more than 25%,
As the thermal conductivity decreases, the seizure resistance at high temperatures also decreases.

Therefore, the Zn content was set at 5 to 25%.

(c), Mn and St These components combine with each other to form an intermetallic compound that is finely dispersed in the matrix, and some Mn is solidly dissolved in the matrix and forms a copper-based sintered alloy. It has the effect of improving strength,
Furthermore, St is W, Mo.

Alternatively, these components combine with Cr to form a hard and fine intermetallic compound, which has the effect of improving wear resistance and seizure resistance at room temperature and high temperature.
Less than 1% has no effect; on the other hand, Mn has 3%, S
If i is contained in excess of 2%, it is not preferable because the seizure resistance decreases and the aggressiveness toward the other party increases.

Therefore, the MH content was determined to be 0.1 to 3%, and the Sl content was determined to be 0.1 to 2%.

(d) Oxygen Oxygen combines with Cu, Zn, and St, as well as AI, W, Mo, and Cr contained as necessary, to form an oxide that is uniformly and finely dispersed in the base material, and at room temperature and It has the effect of improving wear resistance at high temperatures, especially by improving seizure resistance and heat resistance, but if it is less than 0.01%, it has no effect; If the content exceeds .5%, the grain size of the oxide will not only become coarse, exceeding 40% (the area ratio will exceed 7%, which will reduce the strength and toughness of the alloy). It increases the opponent's aggressiveness and is not desirable.

Therefore, the oxygen content is 0. Previously set at ~0.5%.

(e), Fe, Ni and C.

All of these components are dispersed in the matrix to improve the strength and toughness of the alloy, and combine with Cu and optionally contained AI, W, Mo, and Cr.
Forms fine intermetallic compounds that are dispersed in the base material, improving wear resistance and heat resistance, and is also effective in seizure resistance, but if the content is less than 0.1%, the desired On the other hand, if the content exceeds 3%, the toughness and thermal conductivity will decrease, resulting in deterioration of seizure resistance, which is not preferable.

Therefore, the content of Fe, Nj and CO is 0.1
It was set at ~3%.

(f), AI AI not only forms a matrix with high strength and toughness together with Cu and Zn, but also combines with oxygen to form an oxide, which has excellent seizure resistance at high temperatures and resistance at room and high temperatures. It has the effect of improving wear resistance, but its content is 0.
If the content is less than 1%, the desired effect cannot be obtained, while if the content exceeds 0.3%, the thermal conductivity will decrease and the seizure resistance will deteriorate, which is not preferable.

Therefore, the content of A and Q was set at 0.1 to 0.3%.

(g), W, Mo and Cr0 These components all combine with Fe, Ni and Co to form fine intermetallic compounds dispersed in the matrix,
It also combines with oxygen to form fine oxides, which have the effect of improving wear resistance and seizure resistance, but if the content is less than 0.1%, the desired effect cannot be obtained. On the other hand, if the content exceeds 2%, the toughness decreases, which is not preferable.

Therefore, the content of W, Mo and Cr is 0.1~
It was set at 2%.

The copper-based sintered alloy of the present invention may contain P, Mg, Sn, and Pb as unavoidable impurities, but if the total content is 1.5% or less, the alloy properties will not be impaired in any way. Therefore, its content can be tolerated.

〔Example〕

Next, the copper-based sintered alloy of the present invention will be specifically explained with reference to Examples.

As raw material powder, Cu
-5% Zn alloy powder, Cu-30% Zn alloy powder, Cu
Powder, Zn powder, AI? powder, Si powder, Mo powder, W
Prepare powder, C powder, Fe powder, Ni powder, and Co powder, blend these raw material powders, and mix with a V-type mixer for 3
After being pulverized and mixed for a period of time, it is press-molded into a green compact at a predetermined pressure within the range of 5 to 7 tons/c+a', and the dew point is 20℃ to 20℃.
Sintering is carried out at a predetermined temperature within the range of 850 to 950 °C for 1 hour in hydrogen gas at -30'C.
After holding at a predetermined temperature within the range of 0℃ for 1 minute, pressurization is performed again.Outer diameter: 63mm, inner diameter = 54mm for crushing load measurement.
Invention Cu-based sintered alloy 1 consisting of a ring having dimensions of m1m% thickness: 8m+* and having the composition shown in Table 1
~30. and comparative Cu-based sintered alloys 1~! 3, and for wear measurement, diameter: 10 cm, height: 30 mrs
Round bar with dimensions and outer diameter: 12 mm, inner diameter = 6 mm,
Cu-based sintered alloys 1 to 30 of the present invention and comparative Cu-based sintered alloys 1 to 13, each consisting of a pipe having a length of 45IIIM, were manufactured.

Furthermore, conventional Cu-based alloys having the compositions shown in Table 1 were manufactured by melting and casting using a conventional melting method to form rings, round rods, and pipes having the above-mentioned dimensions.

The Cu-based sintered alloys 1 to 30 of the present invention all had a structure in which fine oxides and intermetallic compounds were uniformly dispersed in the base material.

In addition, all of Comparative Cu-based sintered alloys 1 to 13 have a component content or a pore content (those marked with * in Table 1) outside the scope of the present invention. It is something that

Next, for the purpose of evaluating the strength and toughness of various Cu-based sintered alloys obtained as a result, the ring was divided into three parts, one of which was used as a sample, and the crushing load at room temperature was measured. In addition to the results shown in Table 1, the following abrasion test was conducted for the purpose of evaluating the abrasion resistance at high temperatures.

Wear test I A round 2 bar with the above diameter = lOLII + 1, height: 30 + am was processed to make a pin with a diameter of 1.5 mm, and a chromium-plated SUH material disc was prepared as a mating material, and the above disc was While heating the disc to 620°C with a burner from the back side, it was rotated at a circumferential speed of 2.1 m/see, while the above pin was pressed against the disc with a load of 8 kg, and 5W-30 oil was dropped. A pin-on-desk friction and wear test was performed to evaluate the high-temperature synchronization characteristics with respect to the mating material by sliding a sliding distance of I5km, and using a torque meter to examine the occurrence of seizure based on changes in the generated torque. and use these results as the first
Shown in the table.

Wear test ■ Outer diameter above: 12mm, inner diameter = 6mm, length: 45mm
Various inventive Cu-based sintered alloys, comparative Cu-based sintered alloys, and conventional Cu-based alloys were fabricated from pipes having the following dimensions: outer diameter: 11 mm, inner diameter: 6.5++ ms, length: 45 mm. Various invention C consisting of pipes having
Samples of a u-based sintered alloy, a comparative Cu-based sintered alloy, and a conventional Cu-based alloy were manufactured, while 3 4 SUH material was used as a counterpart material and was salt chromed.
8.42ml5 A round bar with length: 150mm was prepared.

Insert the round bar that is the mating material into the pipe hole that is the specimen, heat one end of the round bar that is the mating material with a burner, and set the atmospheric temperature at one end to 550°C, and apply a load to press the sample against the mating material. : While pressing with 6 kg and dropping 5W-30 oil, stroke the round bar that is the mating material in the axial direction of the pipe hole that is the sample.Slide distance: 15 mm, 40
A wear test was conducted under the conditions of sliding at 00 strokes/min for 30 minutes, the amount of wear was measured, and the presence or absence of seizure and the surface condition of the mating material were observed. The results are shown in Table 1. .

Regarding the surface condition of the mating material, those with no scratches are marked O, those with some scratches due to burn-in are marked Δ, and those with wear scratches on the surface are marked X. They were distinguished by

〔Effect of the invention〕

From the results shown in Table 1, Cu-based sintered alloys 1 to 1 of the present invention
30 has much better wear resistance and seizure resistance than conventional Cu-based prepared alloys, and
As seen in U-based sintered alloys 1 to 13, if any of the constituent components and pores are out of the scope of the present invention, the wear resistance, seizure resistance, or attack property at high temperatures, or at room temperature It is clear that at least one of the strength and toughness at the bottom is inferior.

As mentioned above, the Cu-based sintered alloy of the present invention has wear resistance and synchronization characteristics at high temperatures, so it can be used satisfactorily as a structural member of various devices that are exposed to high temperatures associated with high output. In practical use, it exhibits excellent performance over a long period of time, resulting in excellent industrial effects.

Claims (4)

[Claims] (1) Zn: 5-25%, Mn: 0.1-3%, Si: 0.1-2%, one or more of Fe, Ni, and Co: 0
．． 1 to 3%, oxygen: 0.01 to 0.5%, and the rest is Cu and unavoidable impurities (weight%), and fine oxides and intermetallic compounds are uniformly distributed in the matrix. A copper-based sintered alloy having excellent wear resistance at high temperatures and having a structure in which pores are dispersed and distributed at 1 to 15% by volume. (2) Zn: 5-25%, Mn: 0.1-3%, Si: 0.1-2%, one or more of Fe, Ni, and Co: 0
．． 1 to 3%, oxygen: 0.01 to 0.5%, and further contains Al: 0.1 to 0.3%, with the remainder consisting of Cu and unavoidable impurities (more than 1% by weight) ), and a copper-based sintered bond with excellent wear resistance at high temperatures, characterized by having a structure in which fine oxides and intermetallic compounds are uniformly dispersed in the matrix and pores are distributed at 1 to 15% by volume. Money. (3) Zn: 5-25%, Mn: 0.1-3%, Si: 0.1-2%, one or more of Fe, Ni, and Co: 0
．． 1 to 3%, oxygen: 0.01 to 0.5%, and further contains one or more of Cr, Mo, and W: 0.
1 to 2%, with the remainder being Cu and unavoidable impurities (wt%), and fine oxides and intermetallic compounds are uniformly dispersed in the matrix, and pores are 1 to 15% by volume. A copper-based sintered alloy with excellent wear resistance at high temperatures, characterized by a distributed structure. (4) Zn: 5-25%, Mn: 0.1-3%, Si: 0.1-2%, one or more of Fe, Ni, and Co: 0
．． 1 to 3%, oxygen: 0.01 to 0.5%, and further contains: Al: 0.1 to 0.3% One or more of Cr, Mo, and W: 0.
1 to 2%, with the remainder being Cu and unavoidable impurities (wt%), and fine oxides and intermetallic compounds are uniformly dispersed in the matrix, and pores are 1 to 15% by volume. A copper-based sintered alloy with excellent wear resistance at high temperatures, characterized by a distributed structure.