JPH101736A - Disk brake rotor, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk brake rotor applicable, in particular, to large-sized truck, having high properties, and reduced in costs by specifying the composition of elements of flake graphite cast iron. SOLUTION: Flake graphite cast iron is used as a material suitable for disk brake rotor; however, it is necessary to improve thermal conductivity and lower Young's modulus in order to improve heat check resistance. The increase in C content suffices for the above purpose but deterioration in strength is brought about. Cr, therefore, is added, but the increase of the additive quantity of Cr causes formation of chill at the time of casting and deterioration in machinability. Accordingly, it is necessary to synthetically control the content of Cr and further the contents of Mn and Cr in order to facilitate control for preventing chilling, reduce costs, and produce the material suitable for use, in particular, in a large-sized truck. That is to say, Mn content and Cr content are controlled to <0.5% and >0.5-1.5% by weight ratio, respectively. Further, the sum total (α) of the contents of Mn and Cr is controlled so that 0.5%<=α<=1.5% by weight ratio is satisfied.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc for an automobile.
The present invention relates to a rake rotor and a method of manufacturing the same, and
For disk brakes optimal for brakes and its manufacture
About the method. 2. Description of the Related Art Disc brakes are integrated with wheels.
Press the friction material against both sides of the rotating rotor to increase the braking force.
Generated element, linear with pressure applied
As the braking force increases, stable braking can be obtained. General
In addition, as rotors for disc brakes for passenger cars,
(JIS) Made of flaky graphite of FC200 and FC250
Ordinary cast iron is mainly used. In recent years, passenger cars
As performance and output increase, rotors for disc brakes
About properties such as heat crack resistance, abrasion resistance, corrosion resistance
Improvement is being demanded. [0003] For example, Japanese Patent Publication No. 61-17900
Is a carbon equivalent (CE value) in a weight ratio: 3.8 to 4.5.
%: C: 2.8 to 4.0%, Si: 1.5 to
3.0%, Mn: 0.3-1.2%, P: 0.20% or less
Below, S: 0.06 to 0.25%, Cu: 0.15 to 3.
5%, Cr: 0.05-0.5%, Ni: 0.05-
0.5%, the balance of the composition of Fe and unavoidable impurities.
Slows the growth of the rust layer in various corrosive environments,
Suppresses the increase in oxidation of the rust layer, and furthermore, the layered peel resistance of the rust layer
By improving the components, for example, components such as disc brakes
There is disclosure of a corrosion-resistant cast iron that is effective as a material. [0004] Japanese Patent Publication No. 8-32944 discloses that
By weight ratio, C: 3.5 to 3.7%, Si: 1.40 to
1.72%, Mn: 0.5 to 0.8%, Mo: 0.4 to
1.2%, Ti: 0.05-0.10%, V: 0.02
0.35%, Ce: 0.01-0.05%, Cu:
0.20-2.0%, Cr: 0.05-1.0%
Flake black with the composition of the balance Fe and unavoidable impurities
Made of lead cast iron, heat cracking, braking, abrasion resistance and
Disc brake rotor is disclosed as having excellent strength
is there. Further, Japanese Patent Application Laid-Open No. 7-216495 discloses
Is C: 3.50-3.90%, Si: 1.60-2.
50%, Mn: 0.70 to 1.10%, P: 0.05%
, S: 0.06-0.12%, Cu: 0.6-1.
10%, Cr: 0.40 to 0.80%, Mo: 0.20
~ 0.50%, balance Fe and unavoidable impurities, CE value
By controlling the solidification rate as 4.1 to 4.75,
The mounting part is made of A-type graphite, D-type graphite or granular graphite.
One or a combination of the above, the sliding part is long A type graphite and C type
As a mixed structure of graphite, heat crack resistance, room temperature strength, heat conduction
Highly efficient disc brake rotor for automobiles
There is a disclosure. [0006] Currently, the maximum load capacity is 4
Large braking force for large trucks over 000kg
Drum brake that rotates with the wheels
Then, press the friction material stuck on the brake shoe,
The method of stopping the rotation of the drum by frictional force is generally adopted
I have. In recent years, however, even heavy trucks are lightweight.
As a measure to meet the demand for
Adoption is under consideration. Disc break on heavy truck
When adopting a key, disc brakes
Used in harsh conditions, such as when the surface temperature of the
Therefore, high heat crack resistance and wear resistance are required.
It becomes important. Improve properties such as heat crack resistance and wear resistance
Manufacturing process such as casting process and subsequent heat treatment process
It is truly appropriate to have a high degree of control and
It is not a technical solution. The present invention has been made in view of the above problems in the prior art.
Heat treatment in the manufacturing process, etc.
Cracks at low cost without complicating the process
Properties such as wear resistance and abrasion resistance, and
Management to prevent chilling, and manufacturing costs
To reduce the use of expensive raw materials
Disc brakes, especially for heavy trucks
Rotor and its manufacturing method, that is, high performance and low cost
Disc brake rotor and method of manufacturing the same
The purpose is to do. Means for Solving the Problems The present inventors have proposed a brake system.
Has abrasion resistance when used repeatedly.
Disk brake rotor with a damping capacity
Flake graphite cast iron is advantageous for inexpensive production.
Of knowledge. Further, the present inventors have developed such flaky graphite cast iron.
Various studies focused on the characteristics of
The present invention has been made based on such knowledge. That is,
In order to improve the heat crack resistance of the brake rotor, heat
It is necessary to improve the conductivity and lower the Young's modulus.
Therefore, it is necessary to increase the carbon content. I
However, when the carbon content is increased, the strength decreases.
There is a problem. Therefore, reducing this strength reduction
Cr is added in order to suppress an increase in growth property. Only
While increasing the Cr content while casting, chill (eutectic
And the machinability deteriorates. This casting
Simplified management to prevent chilling in the process,
Reduce manufacturing costs, especially for large truck disc drives.
In order to manufacture rake rotors at low cost,
Amount, and also the Mn and Cr contents, must be comprehensively controlled.
It is necessary. [0011] In order to solve the above-mentioned problem, the present invention is described in claim 1.
Disk brake rotors have a Mn content by weight ratio.
Less than 0.5%, more than 0.5% and 1.5% or less of C
It is made of flaky graphite cast iron containing r. [0012] In order to solve the above-mentioned problem, a second aspect is provided.
Disk brake rotors contain Mn and Cr
Is controlled to 0.5% ≦ α ≦ 1.5% by weight.
Flake graphite cast iron. According to a third aspect of the present invention, the above-mentioned object is attained.
The disc brake rotor has a weight ratio of C: 3.7
To 4.2%, Si: 1.5 to 3.0%, Mn: 0.5%
, Cr: more than 0.5% and 1.5% or less, Cu: 2.
It is made of flake graphite cast iron containing 0% or less.
You. [0014] In order to solve the above-mentioned problem, the present invention is described in claim 4.
The disc brake rotor has a weight ratio of C: 3.8
To 4.1%, Si: 2.0 to 2.7%, Mn: 0.2 to
0.4%, Cr: 0.55 to 1.0%, Cu: 0.5 to
1.5% flaky graphite cast iron
You. [0015] In order to solve the above-mentioned problem, a fifth aspect of the present invention is provided.
The disk brake rotor according to any one of claims 1 to 4
The disk brake rotor according to any one of the above,
Include more than 0.5% and less than 3.0% Ni by weight.
And features. [0016] In order to solve the above-mentioned problem, a sixth aspect of the present invention is provided.
The disk brake rotor according to any one of claims 1 to 4
The disk brake rotor according to any one of the above,
Include more than 0.5% and less than 2.0% Ni by weight
And features. [0017] In order to solve the above-mentioned problem, the present invention is described in claim 8.
The disk brake rotor according to any one of claims 1 to 7
The disk brake rotor according to any one of the above,
It is for heavy trucks. According to a ninth aspect of the present invention, in order to solve the problem,
The manufacturing method of the rotor for disc brakes is flake graphite casting.
In the manufacturing method of iron disc brake rotor
Thus, the amount of Cr is controlled according to the amount of Mn in the raw material, and Mn and C
r is 0.5% ≦ α ≦ 1.5% (weight
(Amount ratio). [0020] In order to solve the above-mentioned problem, the invention is described in claim 10.
The manufacturing method of the above-mentioned disk brake rotor is described in claim 9.
In the method for manufacturing a rotor for a disc brake described in
The rotor for disc brakes is
It is a rotor for brakes. Hereinafter, a rotor for a disc brake according to the present invention will be described.
And the reasons for limiting the ranges of the respective components will be described. (1) C (carbon): 3.7 to 4.2%, preferably
Preferably, C: 3.75 to 4.1% C improves the thermal conductivity and damping rate of cast iron, and
Active ingredient that lowers the cracking rate and improves heat crack resistance
And at least 3.7 to deposit the desired graphite.
% Or more is required. On the other hand, it contains more than 4.2%
If it has, the flowability of the molten metal decreases and castability deteriorates.
In both cases, coarse graphite is crystallized, and the strength is reduced. Follow
C: 3.7 to 4.2%. Preferably, C:
It is set to 3.8 to 4.1%. (2) Si (silicon): 1.5 to 3.0%,
Preferably, Si: 2.0 to 2.7%, Si precipitates good flake graphite and complicates the manufacturing process.
Low cost and good wear resistance
Therefore, it is good to contain at least 1.5% or more.
No. On the other hand, if the content of Si exceeds 3.0%,
Si is dissolved in the base structure of cast iron to improve any characteristics
Does not contribute to Therefore, Si: 1.5 to 3.0%.
You. Preferably, Si: 2.0 to 2.7%, more preferably
More specifically, Si: 2.1 to 2.5%. (3) Mn (manganese): less than 0.5%,
Preferably, 0.2-0.4% Mn is the pearlite forming element as generally known.
And at the same time, it is a chilling promoting element. Mn is 0.5%
The above is the management to prevent chilling in the casting process
Complexity, increasing manufacturing costs and
This is not desirable because the site transformation temperature decreases. Mn content
In order to reduce the amount to less than 0.2%, generally the
Material management or raw material processing is required, and
Construction costs rise. However, the content of Mn was 0.2%
In the case above, the range of raw materials that can be used is
Extremely wide, and to that extent in the casting process.
Problem of complicated management to prevent chilling
Does not occur. From this viewpoint, Mn: 0.2 is preferable.
To 0.4%. (4) Cr (chromium): more than 0.5%
1.5% or less, preferably Cr: 0.55 to 1.0
%, Most preferably Cr: 0.75 to 1.0% Cr is heated by the operation of the disc brake rotor.
Ferrite in the base structure when
Suppress thermal expansion deformation due to In addition, components that increase hardness
Min. And contained by more than 0.5%.
Do not complicate the heat treatment process in the manufacturing process.
The hardness can be improved at low cost. On the other hand, C
If more than 1.5% of r is contained,
Management to prevent chilling becomes complicated, and manufacturing costs
Rises. Therefore, Cr: more than 0.5% and 1.5% or less
Below. Preferably, Cr: 0.55 to 1.0%,
More preferably, it is set to 0.75 to 1.0%. (5) The total content α of Mn and Cr:
0.5% or more and 1.5% or less Cr is formed by the disc brake rotor as described above.
Suppresses ferrite formation of matrix structure when heated by heating
And suppresses thermal expansion deformation due to ferrite formation
The product of improving heat crack resistance and increasing hardness
Although it has an extreme function, if it is contained beyond the limit
Is complicated in management to prevent chilling in the casting process.
Has the passive function of increasing production costs.
I do. At the same time, when Mn is contained in excess of the limit,
The management to prevent chilling in the casting process is complicated
And the production cost rises. Therefore, the content of each of Cr and Mn
For disc brakes, depending on the amount considered separately
Management to prevent chilling in the rotor casting process
Can be simplified and the increase in manufacturing costs can be suppressed.
Therefore, the contents of Cr and Mn must be comprehensively examined.
No. Especially in the present invention, thermal conductivity and damping rate are improved.
As well as lowering Young's modulus to improve heat crack resistance
From the viewpoint of making the C content 3.7% or more,
The strength decreases due to carbonization. Therefore, in the present invention
Is the result of comprehensive examination of the contents of Cr and Mn.
The total α of the contents of Mn and Cr is 0.5% by weight.
≦ α ≦ 1.5%. To do that
In the casting process of rotors for disc brakes
Strength level can be secured while preventing chilling
You. Particularly, the raw material of the rotor for the disc brake
The content of Mn contained in is not always constant.
In order to make it less than 0.2%, generally the raw materials for that
Management or raw material processing is required.
The strike rises. However, the content of Mn is merely 0.5%
It is not difficult to manage to less than, manage so
The range of raw materials that can be used is extremely wide
Become. Therefore, Mn is contained in a range of less than 0.5%.
The total content of Mn and Cr according to the Mn content of the raw material
The amount of Cr should be determined from the viewpoint of determining the sum α.
And a pipe for preventing chilling in the casting process.
Simplicity and reduce overall manufacturing costs.
it can. (6) Cu (copper): 2.0% or less, preferably
In other words, Cu: 0.5-1.5% Cu is similar to Cr and Mn in the base structure of cast iron.
-Light stabilizing element, rotor for disc brake
Strength required in the manufacturing process
To achieve low cost without complicating the process
To 2.0% or less. On the other hand, over 2.0%
In the manufacturing process to prevent a decrease in toughness, especially elongation
Process such as heat treatment becomes complicated and costs increase. Follow
To 2.0% or less. Preferably, 0.5 to 1.5
%. (7) Ni (nickel): more than 0.5%
3.0% or less, preferably, Ni: more than 0.5%;
0% or less Ni forms a solid solution in ferrite
Strengthen. Therefore, heat treatment to strengthen the base, etc.
Required to simplify the manufacturing process and reduce manufacturing costs
Ni is contained according to. Particularly in the present invention, heat transfer
Improve conductivity and damping rate and lower Young's modulus
From the viewpoint of improving the heat crack resistance, the C content is 3.7.
% Or more to compensate for the decrease in strength due to high carbonization.
Simplifies process management to improve strength,
Is an important issue. Ni content
If less than 0.5%, manufacture heat treatment to strengthen the base
The process becomes complicated, and even if the content exceeds 3.0%,
Simplify manufacturing processes such as heat treatment to strengthen the base
Effect is saturated and Ni itself is expensive
Therefore, it is rather expensive and disadvantageous. Therefore, N
i: More than 0.5 and less than 3.0%. Preferably, N
i: More than 0.5% and 2.0% or less. (8) P (phosphorus): 0.05% or less When P is contained in a large amount, a phosphorus eutectic structure (stedite) is generated.
And the machinability decreases. Therefore, P: 0.05%
The following is assumed. (9) S (sulfur): 0.08 to 0.12% S can simplify a manufacturing process such as a heat treatment for securing strength.
At least 0.08%
Is desirable. In particular, in the present invention, the thermal conductivity and the attenuation
It improves heat crack resistance by improving and lowering Young's modulus.
From the viewpoint of improvement, the C content is set to 3.7% or more.
To compensate for the decrease in strength due to high carbon
Process management to reduce manufacturing costs.
Is an important issue. However, S exceeds 0.12%
When included, manufacturing processes such as heat treatment to ensure strength
On the contrary, it becomes complicated and the manufacturing cost increases. Therefore, S:
0.08 to 0.12%. DETAILED DESCRIPTION OF THE INVENTION Example 1 Composition shown in Table 1 (However, unavoidable impurities are omitted)
The disc brake rotor was cast. [Table 1] [Table 2] The as-cast test piece of the obtained cast material was drawn.
Tensile strength, thermal conductivity, 900 ° C x 10 cycles after heating
The expansion coefficient and Vickers hardness were examined. Table 2 shows the results.
Shown in Further, the metal structure after the heating test was examined. In FIG.
Metallographic examination of the disk brake rotor of Example 1-1
A microscopic photograph is shown in FIG.
FIG. 3 shows a metallographic micrograph of the disk of Comparative Example 2.
4 shows a metallographic micrograph of a brake rotor. As shown in Table 2, Example 1 of the present invention
1 to 3 according to the disk brake rotor
For example, a tensile strength of 215 MPa or more in an as-cast state,
A thermal conductivity of 6 W / m · K or more has been obtained.
Is clearly higher than the disc brake rotor of Comparative Example 1.
Excellent. Moreover, the discs of Embodiment 1-1 to Embodiment 1-3
The brake rotor is hardened after heating at 900 ° C for 10 cycles.
The degree is Vickers hardness of 330 Hv or more. Against this
The disk brake rotor of Comparative Example 1 was 900 ° C. × 1
Hardness after 0 cycle heating is 150Hv in Vickers hardness
This clearly shows that the hardness has been reduced. I
It should also be noted that the data of Example 1-1 to Example 1-3 are different.
The disc brake rotor is heated at 900 ° C for 10 cycles.
Comparative Example 1 has an expansion coefficient of 0.25% or less.
Disc brake rotor is 900 ° C x 10 cycles
The fact that the coefficient of expansion after heating reaches 1.35%
You. As described above, the disc brakes of Examples 1-1 to 1-3 are used.
In the rotor, the hardness decreases after 900 ° C x 10 cycles of heating,
That is, the degree of softening is extremely small, and
Although the degree is extremely small, the disc
For rotors for heating, the softness after heating at 900 ° C for 10 cycles
And expansion and deformation are remarkable. This is the implementation shown in FIG.
In Examples 1-1 to 1-3, no ferrite was generated.
The disk brake rotor of Comparative Example 1 shown in FIG.
Corresponds to the occurrence of ferrite. This
This is because the disk brake rotor of Comparative Example 1 has a Cr content.
Is less than 0.5% and 0.02%.
This is because the formation of ferrite in the weave is not suppressed. That is, in Embodiments 1-1 to 1-3,
In the rotor for disc brake shown, 900 ° C × 10 size
No ferrite was generated even after the
No softening and expansion deformation caused by the occurrence of
In terms of rotors for disc brakes for heavy trucks
And has sufficient performance. In contrast, the data of Comparative Example 1
900 ° C x 10 cycles for disc brake rotor
After heating, generation of ferrite was observed,
Softening and expansion deformation due to the occurrence have occurred. But
As a disk brake rotor for heavy trucks
Insufficient performance. Further, as shown in Table 2, the Cr of Comparative Example 2
The disc brake rotor having a content of 1.6% is:
Tensile strength is 291MPa, thermal conductivity is 46W / m
K, the data of Examples 1-1 to 1-3 of the present invention.
Both tensile strength and thermal conductivity are higher than disk brake rotors.
Excellent. Moreover, the discs of Examples 1-1 to 1-3 were not used.
The brake rotor is heated at 900 ℃ for 10 cycles.
The hardness is 390 Hv or less in Vickers hardness.
On the other hand, the rotor for the disc brake of Comparative Example 2 was 900 ° C ×
The hardness after 10 cycles of heating is 440H in Vickers hardness
v, and it is not recognized that there is a marked decrease in hardness.
No. In addition, the disc blur of the embodiment 1-1 to the embodiment 1-3 is different.
Expansion coefficient after heating at 900 ℃ for 10 cycles
Is 0.20% or more, whereas the disc of Comparative Example 2 is
The brake rotor expands after heating at 900 ° C for 10 cycles.
The tension ratio is 0.08%, and the disc brake of Comparative Example 2
The rotor material for the disk is the disk drive of Example 1-1 to Example 1-3.
The expansion deformation is extremely small compared to the rake rotor. This
900 ° C. for the disk brake rotor of Comparative Example 2.
× Decrease in hardness after 10 cycles of heating, ie, degree of softening
Is extremely small, and the degree of expansion deformation is also extremely small
The disk brake rotor of Comparative Example 2 contains Cr.
The amount reaches 1.6%, and the base tissue ferri
This is due to the strong suppression of gasification. However, in the comparative example 2 shown in FIG.
Metallographic microscopy of as-cast specimens of a brake rotor.
The photograph shows the occurrence of chilled tissue. Such chill organization
Of the disc brake rotor becomes brittle due to the presence of
Is obvious, processing becomes extremely difficult, and it is solved
In order to achieve this, heat treatment of complicated processes is performed after casting, or
Or very highly controlled to prevent chilling
Casting process must be adopted, which leads to higher costs
Is inevitable. So compare in that respect
The disc brake rotor shown in Example 2 has a high performance house cost.
The present invention provides a rotor for a disc brake of the present invention.
I can not adopt it against the purpose. Thus, for the disc brake of Comparative Example 2
Chill structure in microstructure micrograph of as-cast rotor specimen
The occurrence of cracks is observed in the disc brake of Comparative Example 2.
Rotor not only contains 1.60% Cr,
Containing 0.29% of Mn, and the total content of Mn and Cr
The sum α is as high as 1.89%. Next, Examples 1-1 to 1 shown in Table 1 are shown.
-3 disk brake rotor and comparative examples 3 to 5
C content per as-cast test piece of rotor for brake
And the relationship between thermal conductivity, Young's modulus and damping rate.
Inspected. FIG. 4 shows the relationship between the C content and the thermal conductivity.
FIG. 5 shows the relationship between the C content and the damping rate and Young's modulus.
As shown. From the relationship between the C content and the thermal conductivity in FIG.
As the C content increased, the thermal conductivity increased.
And disc brakes of Examples 1-1 to 1-3
It is clear that there is a remarkable difference in thermal conductivity
You. FIG. 5 shows the C content, the decay rate, and the Young's content.
From the relationship graph of the rate, the damping rate improves as the C content increases.
C: From 3.7% or less, the slope of the change in the decrease of the damping ability is
On the other hand, Young's modulus is also high at C: less than 3.7%
The change becomes steeper. Comparative Example 3 and Example 1
In the disk brake rotor of -1 to 1-3,
It can be seen that there is a remarkable difference between the damping capacity and the Young's modulus. On the other hand, Comparative Example containing more than 4.2% of C
4 and 5 have low flowability of the molten metal and good castability.
There was no. Thus, it contains more than 4.2% of C.
The flowability of the molten metal decreases and the castability deteriorates.
The strike rises. Heat conductivity, damping rate, Young's modulus
What examination results and the fluidity of the molten metal during casting, that is, castability
From the viewpoint of preventing the rise of manufacturing cost due to the deterioration of
Content is 3.7-4.2%. Next, with the compositions shown in Table 3, the examples of the present invention and
An as-cast test piece of a comparative disk brake rotor was prepared.
And conduct tensile test to investigate the relationship between Cr content and tensile strength
Was. FIG. 6 shows the results of the tensile test. [Table 3] FIG. 6 shows that the Cr content increased over 0.5%.
It can be seen that the tensile strength increases as the addition increases. Meanwhile, the pair
According to the results of weaving observation, the Cr content exceeds 1.5%
And chill tissue increases. Next, Examples 2-1 to 2-4 and
Heating and cooling the as-cast test pieces after casting of Comparative Examples 6 and 7
Change (growth) and hardness when repeating
Was examined by the following two types of heating tests. 1. "900 ° C x 10 cycle" test Large trucks brake many times from high-speed running to stopping
From normal temperature to 900 ° C.
Temperature and hold for 10 seconds, then cool to 500 ° C in 400 seconds
10 cycles of heating and cooling (“900 ° C. × 10
Cycle)) 2. "700 ° C x 1h" test heavy trucks continuously apply brakes down hill
Heat at 700 ° C for 1 hour, assuming that
(Indicated as “700 ° C. × 1 h”). After each of the above tests
Cr content and expansion coefficient [(elongation after heating / length before heating)
.Times.100 (%)] and hardness. So
FIG. 7 shows the relationship between the Cr content and the coefficient of expansion, and FIG.
Fig. 4 shows the relationship between Cr content and Vickers hardness (Hv).
Shown. As shown in FIG. 7, heating was performed at 900 ° C. for 10 cycles.
And 700 ° C. × 1 h heating,
As the r content increases, the degree of expansion due to ferrite
It can be seen that the so-called growth property is lowered. I
However, if the Cr content exceeds 1.5%, further expansion occurs.
No decrease in the growth rate was observed, and growth was
It can be seen that the suppression saturates. Also heating at 700 ° C for 1 hour
When the Cr content exceeds 0.5%, the expansion coefficient becomes almost 0.
% And expands even if the Cr content exceeds 0.75%
No effect of decreasing the rate was seen, and the inclusion of Cr
Growth suppression saturates. FIG. 8 shows that 900 ° C. × 10 cycles
After heating for 1 hour and after heating at 700 ° C for 1 hour,
When the content is 0.5% or less, Vickers hardness (Hv) is added.
Notably lower than Vickers hardness before heating (Hv330)
ing. On the other hand, the Cr content is 0.5%, especially 0.75%.
%, After 900 ° C. × 10 h cycle heating,
Vickers hardness after heating is slightly higher than before heating
After heating at 700 ° C for 1h, before heating
Vickers hardness and Vickers hardness after heating and almost
no change. From the above results, select the Cr content appropriately.
By suppressing the decrease in hardness, the wear resistance can be improved
You can see that you can. As shown in FIG.
From the viewpoint of eliminating it, Cr is 0.55%, especially
It is better to be 0.75% or more. Cr in the as-cast test piece after the above casting
The relationship between the content and various properties is summarized below. 1. Tensile strength as Cr content exceeds 0.5%
Is improved. 2. If the Cr content exceeds 1.5%, the chill structure increases.
You. 3. 900 ° C x 10 cycle heating and 700 ° C x 1
Growth rate decreases with increasing Cr content in both h heating
You. 4. 900 ° C x 10 cycle heating and 700 ° C x 1
When the Cr content exceeds 1.5% for both heating and heating,
No decrease is seen. 5. By heating at 700 ° C for 1 hour, the Cr content is reduced to 0.5%.
If it exceeds, the expansion coefficient becomes almost 0%, and the Cr content becomes 1
%, The effect of lowering the expansion coefficient is not seen. 6. After heating at 900 ° C. for 10 cycles,
And after heating at 700 ° C for 1h, the Cr content is 0.5%
Below, Vickers hardness (Hv) is the Vickers before heating
Hardness (Hv330). 7. If the Cr content exceeds 0.5%, 900 ° C. × 10
In h cycle heating, Vickers hardness after heating is
Slightly higher than after heating at 700 ° C for 1h
Has almost no change in Vickers hardness before heating. 8. If the Cr content exceeds 0.75%, 900 ° C. × 1
In 0h cycle heating, Vickers hardness after heating is heated
It becomes slightly higher than before, and after heating at 700 ° C for 1 hour,
Vickers hardness after heating is hardly changed from before heating. From the above, the heat treatment in the manufacturing process
Process without complicating the process, etc.
Improved properties such as crack resistance and wear resistance.
Management to prevent chilling,
That Cr itself is expensive.
From the comprehensive point of view of saving its usage from
The r content should be more than 0.5 and 1.5% or less,
In particular, various heat effects are reliably eliminated and Cr
In terms of saving on usage by avoiding the use of,
It is preferably set to 0.55 to 1.0%, particularly 0.7 to 1.0%.
It is understood that the content is preferably set to 5 to 1.0%. [0054] Example 3 Next, using the compositions shown in Table 4, the samples of Examples of the present invention and Comparative Examples were prepared.
Prepare an as-cast test piece of the rotor for the brake, and conduct a tensile test.
An experiment was conducted to examine the relationship between the Ni content and the tensile strength. That
FIG. 9 shows the results of the tensile test. [Table 4] As shown in FIG. 9, the ratio not containing Ni
The disk brake rotor of Comparative Example 8 and 0.5% or more of N
Discs of Examples 4-1 to 4-4 containing i
Difference of more than 20MPa in tensile strength for brake rotor
It can be seen that this occurs. Also, as the Ni content increases,
The fact that the tensile strength is improved is also recognized. Therefore
From the above results, when the Ni content is less than 0.5%, 220%
Improve tensile strength to ensure tensile strength of MPa or more
It is necessary to perform heat treatment for the purpose of
Results in more complicated manufacturing processes and higher costs
You can see that. On the other hand, when the Ni content exceeds 2.0%,
260MPa or more strength for disc brake
Exceeding the strength required for rotor materials, Ni itself
Considering that it is very expensive,
Rotor material for disc brakes for large trucks
In order to achieve the object of the present invention,
Issues arise. Therefore, Ni (Ni
Is greater than 0.5% and less than or equal to 3.0%, preferably
It is better to exceed 0.5% and 2.0% or less. The above description of each embodiment of the present invention
Akira, for each disk brake rotor of the embodiment,
I will explain the characteristics of the as-cast condition after casting
In the manufacturing process, chilling prevention control and heat
It does not directly explain the characteristics after processing is performed.
No. However, the rotor for a disc brake of the present invention
However, it complicates processes such as heat treatment in the manufacturing process.
Low-cost properties such as heat-resistant cracking and abrasion resistance
To improve and prevent chilling in the casting process
Simplifies management, reduces manufacturing costs, and
Being a cast material that can save the usage of various raw materials
This means that the purpose of the present invention is
Since it is in the point of providing a rotor for key and its manufacturing method,
It is an important factor in achieving this goal. As described in detail above, the present invention
The brake brake rotor has a Mn content of 0.5 by weight.
%, Containing more than 0.5% and 1.5% or less of Cr.
Consisting of flaky graphite cast iron, or alternatively Mn and Cr
Is 0.5% ≦ α ≦ 1.5% by weight.
3.7% because it is made of flaky graphite cast iron
By using high carbon cast iron containing C as described above,
Do not particularly complicate processes such as heat treatment in the process.
And improved properties such as heat crack resistance and abrasion resistance at low cost
Pipe for preventing chilling in the casting process
Simplifies processing, reduces manufacturing costs, and
It can save the usage of the fee. The disk brake rotor according to the present invention.
Is especially difficult for large trucks with severe operating conditions compared to passenger cars.
For small and medium-sized trucks and passengers
It has excellent effects when applied to cars. The disk brake rotor of the present invention
The manufacturing method is for disc brakes made of flake graphite cast iron.
In the method of manufacturing the rotor, C
r is controlled so that the sum α of the contents of Mn and Cr is 0.
5% ≦ α ≦ 1.5% (weight ratio)
High carbon cast iron containing more than 3.7% C
Made of discs with excellent properties such as heat crack resistance and abrasion resistance
Chilling prevention management in the manufacturing process of brake rotors
Low cost without complicating processes such as heat treatment and heat treatment
Can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a metal micrograph (× 400) showing a metal microstructure after repeated heating and cooling of Example 1-1. FIG. 2 is a metal micrograph (× 400) showing a metal microstructure of Comparative Example 1 after repeated heating and cooling. FIG. 3 is a metal micrograph (× 400) showing a metal microstructure of Comparative Example 2 after repeated heating and cooling. FIG. 4 is a diagram showing the relationship between the C content and the thermal conductivity. FIG. 5 is a diagram showing a relationship between a C content, an attenuation rate, and a Young's modulus. FIG. 6 is a diagram showing the relationship between Cr content and tensile strength. FIG. 7 is a graph showing the relationship between the Cr content and the coefficient of expansion after repeated heating and cooling. FIG. 8 is a graph showing the relationship between the Cr content and Vickers hardness after repeated heating and cooling. FIG. 9 is a diagram showing the relationship between the Ni content and the tensile strength.

Claims (1)

Claims: 1. A flaky graphite cast iron having a Mn content of less than 0.5% by weight and containing more than 0.5% and less than 1.5% of Cr. Disc brake rotor. 2. A disk brake rotor made of flaky graphite cast iron in which the total content α of Mn and Cr is controlled to 0.5% ≦ α ≦ 1.5% by weight. . 3. The weight ratio of C: 3.7 to 4.2%, S
i: 1.5 to 3.0%, Mn: less than 0.5%, Cr:
A rotor for a disc brake, comprising flaky graphite cast iron containing more than 0.5% and 1.5% or less and Cu: 2.0% or less. 4. C: 3.8 to 4.1% by weight, S:
i: 2.0 to 2.7%, Mn: 0.2 to 0.4%, C
A disk brake rotor made of flaky graphite cast iron with r: 0.55 to 1.0% and Cu: 0.5 to 1.5%. 5. The disk brake rotor according to claim 1, further comprising Ni in an amount of more than 0.5% and not more than 3.0% by weight. 6. The rotor for a disk brake according to claim 1, wherein the rotor contains Ni in an amount of more than 0.5% and not more than 2.0% by weight. 8. The disk brake rotor according to claim 1, wherein the rotor is for a heavy truck. 9. A method for manufacturing a disk brake rotor made of flaky graphite cast iron, wherein the amount of Cr is controlled in accordance with the amount of Mn of the raw material, and the total sum α of the contents of Mn and Cr is:
A method for manufacturing a rotor for a disc brake, characterized in that 0.5% ≦ α ≦ 1.5% (weight ratio) is controlled. 10. The method of manufacturing a disk brake rotor according to claim 9, wherein the disk brake rotor is a large truck disk brake rotor.