JPH04172140A - High tension brass fine diameter tube and its manufacture - Google Patents

Abstract

PURPOSE:To obtain excellent high temperature wear resistance, heat resistance, heat/fatigue resistance and heat conductivity and to prevent the central hole from being eccentric by specifying the composition of high tension brass fine diameter pipe. CONSTITUTION:The tube composition is, by weight, 60.0-64.0% Cu, 1.5-3.5% Al, 2.0-4.0% Mn, <=1.0% Cr, <=0.1% Ni, <=1.0% Pb, <=1.0% Fe, the balance Zn. Accordingly, the structure in which the intermetallic compound generated by mutually reacting the Mn-Si compound with Cr, Ni, Fe is distributed uniformly, and finely in the matrix which is improved in hardness by entering Zn into solid solution, is obtained. Therefore, the heat conductivity with Cu itself is not deteriorated especially, high temperature heat resistance is improved remarkably, and excellent heat resistance and heat fatigue resistance are obtained, further Al is entered into solid solution, so further excellent heat resistance especially in the oxidation atomosphere is displayed, and the cutting property and the comformability are improved by adding Pb.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-strength brass small-diameter pipe and a method for manufacturing the same, and particularly relates to a pipe for use in bearings of industrial machinery.

"Prior Art" An example of this type of bearing is a bearing for an automobile turbocharger. This bearing has a cylindrical shape with a small diameter, and the main shaft is supported within the bearing so as to be slidable in the radial direction.

The above bearings are usually made of bronze or brass, but in recent years, with the increase in performance and speed of engines,
As turbochargers become hotter, it is particularly desirable to develop bearings made of materials that have excellent high-temperature wear resistance, heat resistance, and thermal fatigue resistance.

By the way, in order to manufacture bearings made of special high-strength brass as mentioned above, basically it is difficult to cold-work this kind of high-strength brass, so it must be formed by warm drawing from a large-diameter pipe. However, in this case, drawing must be performed at a high temperature of 400° C. or higher, which poses problems in terms of equipment and lubrication.

Therefore, for boat fishing, after extruding a round bar, a hole is made in the center of the round bar by cutting.

"Problems to be Solved by the Invention" However, when drilling holes by cutting as described above, the above-mentioned high-strength brass ring has poor machinability (and sufficient precision cannot be obtained). In addition, since the holes are formed by cutting, work hardening cannot be expected and high strength cannot be obtained.

``Purpose of the Invention'' This invention was made in view of the above circumstances, and has excellent high-temperature wear resistance, heat resistance, thermal fatigue resistance, and thermal conductivity, as well as being able to prevent eccentricity of the hole in the center and having high strength. The purpose of the present invention is to provide a high-strength brass small-diameter pipe and a method for manufacturing the same.

"Means for Solving the Problems" In order to achieve the above object, the high-strength brass small diameter pipe according to claim 1 of the present invention has a cylindrical shape and has a component composition of Cu: 60.0 to 60.0. 64.0% by weight, Aa: 1.5-35
Weight %, Mn: 2, 0-4, 0 weight %, C
r: 1, 0% by weight or less, Ni: 1. Of! % or less, Pb: 1.0% by weight or less, Fe: 1, 0% by weight
Hereinafter, it consists of Zn; the rest.

Furthermore, the method for manufacturing a high-strength brass small-diameter pipe according to claim 2 includes:
The diameter of the high-strength brass pipe is reduced by press-welding two or more rolls or balls while rotating at 100 to 400°C to reduce the diameter of the high-strength brass pipe. The component composition is as follows: Cu: 60.0-64.0% by weight, /l: 1.5-3°5% by weight, M 12.0-4.0% by weight, Cr: 1.0
Weight % or less, N i: 1, 0 weight % or less, P b:
1, OfI weight% or less, Fe: 1.0 weight% or less,
In the high-strength brass small-diameter pipe of the present invention, a Mn-triacetate compound is added to the base material whose hardness has been improved by solid solution of Zn. Since the intermetallic compounds produced by the interaction with CrsNrsFe have a structure in which they coexist and disperse in a uniform and fine manner, the thermal conductivity provided by Cu itself is not impaired, and in particular, the intermetallic compounds The high temperature wear resistance is significantly improved by the action of 1. It also has excellent heat resistance and thermal fatigue resistance. Furthermore, by containing AQ, it is solid-dissolved in the base material and exhibits even more excellent heat resistance, especially in an oxidizing atmosphere. Furthermore, the addition of Pb improves machinability and conformability.

In addition, in the method for manufacturing small-diameter high-strength brass pipes, rolls or balls rotate and revolve while pressing against the outer periphery of the pipe to reduce the diameter of the pipe, resulting in uniform wall thickness and To manufacture a high-strength brass small-diameter pipe with almost no eccentricity in the center hole.

Furthermore, since the pipe is subjected to compression processing, work hardening occurs and the structure becomes more uniform, resulting in a high-strength, high-strength brass small-diameter pipe. Note that the effect depending on the component composition is the same as above.

Here, the reason for limiting the component composition as described above will be explained.

(a) AQ2 ΔQ acid component is dissolved in the base material to increase strength,
In particular, it has the effect of further improving heat resistance in an oxidizing atmosphere, but if the content is less than 1.5% by weight, the desired effect of improving heat resistance cannot be obtained, whereas if it exceeds 3.5% by weight, , the thermal conductivity tends to decrease and the material becomes brittle, so its content is reduced to 1.5 to 3.5% by weight.
It was determined that

(b) Mn The Mn component combines with Si to produce a Mn-Si compound, and forms an intermetallic compound between this Mn-Si compound and Cr, Ni, and Fe to improve high-temperature wear resistance. However, if the content is less than 2.0% by weight, the desired high-temperature wear resistance cannot be ensured, while if it exceeds 4.0% by weight, the thermal conductivity decreases and the material quality deteriorates. Since this causes embrittlement, its content is set at 2.0 to 4.0% by weight.

(c) Si The Si component combines with Mn to produce an Mn-Si compound, which forms an intermetallic compound in the same manner as above and has the effect of improving high-temperature wear resistance, but the content is 0.
If the content is less than 5% by weight, the desired high-temperature wear resistance cannot be ensured, while if it exceeds 2.0% by weight, the thermal conductivity will decrease and the material will become brittle. was set at 15 to 2.0% by weight of O.

(cl) Cr, Ni%Fe These components each have the effect of forming an intermetallic compound with the above Mn-Si compound to improve high-temperature wear resistance, but when the content of each is 1°0 If it exceeds 1% by weight, it will not be alloyed even when melted and will remain as a metallic element, impairing the performance of the material, so the content should be set to 1.
The content was set at 0% by weight or less.

(e) Pb The Pb component has the effect of improving the machinability and conformability of the alloy, but if its content exceeds 1.0% by weight,
Since the strength decreases, its content is set at 1.0% by weight or less.

In addition, the temperature conditions during rolling were set at 100 to 400°C because if the temperature is less than 100°C, cracks will occur in the pipe, whereas if it exceeds 400°C, the pipe made of high-strength brass will This is because the material becomes too soft and the shape of the manufactured high-strength brass small-diameter pipe becomes unstable.

"Example" An embodiment of the present invention will be described below with reference to the drawings.

Using a normal high frequency melting furnace, in a graphite crucible, the component composition was changed to Cu: 60.0-64.0% by weight, AQ: 1.5-
3.5% by weight, Mn: 2, 0-4, 0% by weight
, Cr: 1.0% by weight or less, Ni: 1.0% by weight or less,
A high-strength brass molten metal adjusted to Pb: t, o weight % or less, Fe: 1, 0 weight % or less, Zn remaining is melted, cast into a mold to produce a billet, and extruded into this billet. A high-strength brass pipe (outer diameter: 35111°, inner diameter: 27++ mm) was manufactured by applying the following steps.

Next, the pipe 1 is subjected to a rolling process to reduce the diameter of the pipe 1. Before explaining this rolling process, the rolling process apparatus will be explained.

In FIG. 1, numerals 21... are rolled balls;
Reference numeral 22 denotes a radial holding member that holds the force of the rolled ball 21 in the radial direction. Four rolled balls 21 are rotatably arranged at equal intervals around the pipe l in a radial holding member 22, and this radial holding member 22 is attached to a first frame 23 and a first frame 23. It is held between two frame bodies 24. Further, the radial holding member 22 is composed of an inner ring 25 made of carbide-containing metal, and an outer ring 26 that backs up the inner ring 25.

The first frame 23 and the second frame 24 have a large-diameter recess 23a and a large-diameter recess 23a for fitting into the outer periphery of the radial holding member 22 and holding the radial holding member 22 at coaxial positions thereof. A large-diameter recess 24a is formed, and a small-diameter recess 23 coaxial with the large-diameter recess 23a and large-diameter recess 24a is formed inside the large-diameter recess 23a and large-diameter recess 24m.
b and 24b are formed. And small diameter recess 2
3b and the small diameter recess 24b are provided with a first axial holding member 27 and a second axial holding member 28, respectively, which regulate the axial position of the rolled ball 21. These axial holding members 27, 28 are formed in an annular shape and are formed to be sufficiently larger than the outer diameter of the pipe l. Further, a through hole 23c having a diameter continuous with the inner circumferential surface of the first axial holding member 27 is formed inside the small diameter recess 23b in the first frame 23. A through hole 24c is formed inside the small diameter concave portion 24b of the body 24, coaxially with the small diameter four portions 24b. A shaping die 29 is fitted into the through hole 24c to trim the outer circumferential surface of the pipe l which has been rolled with the rolling ball 24 and reduced in diameter. Movement to the right side in the figure is restricted.

In the rolling device having the above configuration, a holder (not shown) is fitted into the frame 23, 24, and the pipe 1 is rotated around the centerline of the pipe 1 by an electric motor or the like via this holder. .

In order to reduce the diameter of the pipe l using the rolling device configured as described above, first, the frames 23 and 24 are rotated at 60 Orpm, and the pipe l is fed through the through hole 23c between the rolling balls 21... Speed 4. Insert at 5 m/sin. In addition, at this time, the distance between the rolled balls 21 and 21 provided at opposing positions with the pipe 1 in between is 2.
0! Codfish set. Then, the rolled balls 21... rotate and revolve around the outer circumference of the pipe 1, and come into pressure contact with the outer circumferential surface of the pipe 1, thereby increasing the outer diameter of the pipe 1 by 2.
The diameter is reduced to 0ff11. Note that the temperature at this time was 20
Set to 0℃.

Next, the distance between the rolled balls 21 and 21 is set to 1.
After setting the diameter to 2 mm+, the pipe l whose outer diameter has been reduced to 20+ m is again pushed into the rolling balls 21 through the through hole 23c at a feeding speed of 4 m/+in. At this time, a cylindrical mandrel lO having a diameter of 7 sv is inserted into the pipe 1 and positioned at a portion facing the rolled balls 21 .

Here, this mandrel lO is rotatably supported by a rod 11, and by supporting this rod 11 by a support means (not shown), the mandrel 10 is positioned at a position facing the rolled balls 21... It has become.

Then, rolled balls 21...
While rotating and revolving around its axis, it comes into pressure contact with the outer peripheral surface of the pipe 1, and the inner peripheral surface of the pipe 1 comes into pressure contact with the mandrel 10. As a result, the outer diameter of the pipe 1 is reduced to 12i+m, and the inner diameter is reduced to 71. Note that the temperature at this time is set to 200°C.

In this way, the diameter of the reduced pipe 1 is uniform, the hole in the center has almost no eccentricity, and the rolled ball 2
1..., work hardening occurs, the structure becomes uniform, and high strength is obtained. By the way, the tensile strength of the pipe L reduced in diameter by the above method is 6.
5 kgf/mm”.

Moreover, the component composition of the pipe 1 is Cu:60.
0-64.0% by weight, lj: 1.5-3.5% by weight, M
n: 2.0 to 4.0% by weight, Cr: 1.0% by weight or less,
Ni: 1.0% by weight or less, Pb: 1.0% by weight or less, F
Since e: 1.0% by weight or less and Zn: the remainder, it has excellent high-temperature wear resistance, heat resistance, thermal fatigue resistance, and thermal conductivity.

Next, comparative examples will clarify the effects of the above embodiments according to the present invention.

(Comparative Example 1) A diameter of 14I was obtained from a billet with the same composition as in the above example.
After producing an extruded round bar, the diameter was reduced to 12s by cutting.
A pipe was manufactured by drilling a hole with an inner diameter of 7 mm in the center of this round bar using a drill. The thickness deviation between the outer diameter and inner diameter was measured and was 0.3.
A deviation of 11 occurred.

In addition, when the tensile strength of this pipe was measured, it was found to be 55.
kgr/mm'', which was lower than that of the above example.

(Comparative Example 2) Outer diameter 35s from a billet with the same composition as in the above example
U+, manufactured an extruded pipe with an inner diameter of 27 mm.

This extruded pipe was warm drawn at 400°C for 10 passes to reduce the outer diameter by 14.5111 mm, and then warm drawn at 400°C for 2 PasS using a mandrel, with an outer diameter of 121N and an inner diameter of 7mm. manufactured pipes. When the eccentricity of the hole was measured, the length of the hole was l
There was a shoulder deviation of 0.3 compared to 000xxj. Also, when we measured the tensile strength of this pipe, it was 57 kg.
r/am'', which was slightly improved compared to Comparative Example 1, but lower than that of the above example.

Nao, in the above embodiment, the ball 21 and
... was used, but a cylindrical roll may be used instead. Rolls are used to reduce the diameter of relatively large-diameter pipes, and balls are used to reduce the diameter of small-diameter pipes, but the boundary between them is set at the diameter of the pipe after the reduction is 20 cm.

"Effects of the Invention" As explained above, the high-strength brass small-diameter pipe of the present invention is excellent in high endurance abrasion resistance, heat resistance, thermal fatigue resistance, and thermal conductivity. It is effective as a bearing for turbochargers in automobiles, and can satisfactorily handle use under harsh conditions associated with higher performance and higher speeds, and maintains excellent performance over a long period of time. can demonstrate.

Furthermore, according to the method of manufacturing a small diameter high-strength brass pipe of the present invention, the roll or ball rotates and revolves while pressing against the outer circumference of the pipe to reduce the diameter of the pipe, so that the wall thickness is uniform. In addition, it is possible to manufacture a small-diameter high-strength brass pipe with almost no eccentricity in the center hole, and since the pipe is subjected to compression processing, work hardening occurs and the structure becomes more uniform, resulting in high strength and high strength. A small diameter brass pipe can be obtained.

In addition, since it is a compression process in which the diameter is reduced by being compressed by rolls or balls, less energy is required for plastic deformation than in drawing process, and deformation can be easily performed.
When performing warm processing, processing at low temperatures is possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rolling device for carrying out the method of manufacturing a small-diameter high-strength brass nozzle according to the present invention. 1...Pipe, 21...Rolled ball.

Claims (2)

[Claims] (1) It has a cylindrical shape and its component composition is Cu:60
．． 0 to 64.0% by weight, Al: 1.5 to 3.5% by weight,
Mn: 2.0 to 4.0% by weight, Cr: 1.0% by weight or less, Ni: 1.0% by weight or less, Pb: 1.0% by weight or less,
A high-strength brass narrow-diameter pipe characterized by Fe: 1.0% by weight or less, Zn: the remainder. (2) Two or more rolls or balls are pressed against the outer periphery of a high-strength brass pipe at 100 to 400°C.
The diameter of the above-mentioned pipe is reduced by subjecting it to a rolling process, and the composition of the above-mentioned high-strength brass is as follows: Cu: 60.0-64.0% by weight, Al: 1.5-3.
5% by weight, Mn: 2.0-4.0% by weight, Cr: 1.0
% by weight or less, Ni: 1.0% by weight or less, Pb: 1.0% by weight or less, Fe: 1.0% by weight or less, and Zn: the remainder. Production method.