JP2993829B2 - Rolling bearing and sliding bearing having heat resistance and corrosion resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant and corrosion-resistant rolling bearing and sliding bearing which can be used even at a temperature of 250 DEG C. or more. The present invention relates to a rolling bearing and a sliding bearing made of precipitation hardening type high silicon duplex stainless steel containing 0% silicon and having excellent toughness, heat resistance and corrosion resistance.

[0002]

2. Description of the Related Art Conventional bearing steel (JIS SUJ2)
Since the tempering temperature is low at 160 to 180 ° C, tempering softening occurs when exposed to a high temperature for a long time.
20 ° C. For this reason, high-speed steels having low softening during use, small dimensional change and high high-temperature hardness have been used. In recent years, if it is required to operate for a short time, 500 ° C. or even 800 ° C. is urgently required for practical use, but the current maximum operating temperature is 420 ° C.

In order to improve heat resistance, 1.3% Al
% C, 1.5% Cr bearing steel added to steel (MHT)
Rockwell hardness HRC60 up to tempering temperature 250 ° C
(Shore hardness HS81) or higher, and the high-temperature hardness is higher than that of SUJ2 up to about 300 ° C.
Since it softens to 5 (HS60), it cannot be said that it has heat resistance.

Accordingly, molybdenum-based high-speed steels (M50, M10, M2, M1, T1) are mainly used as heat-resistant bearing steels. However, since high-speed steels have a large amount of alloying elements, their thermal conductivity is low. Since it is much worse than carbon steel and has poor forgeability, sufficient time must be spent for heating and soaking, and the workability is very poor. In addition, M2, M with high hardness at high temperature
50 has good oxidation resistance up to 315 ° C.,
At the use limit of 26 ° C., the oxidation resistance is poor, and further, the corrosion resistance to chlorine cannot be expected.

[0005] As the corrosion-resistant bearing steel, there have been many 13Cr systems in the past, followed by 18Cr high-carbon systems and now 14Cr systems.
-4Mo. C easily forms carbides in the corrosion-resistant steel containing Cr, so that it becomes a grain boundary corrosion type and its corrosion resistance is reduced. In addition, 14 which is the current mainstream corrosion-resistant bearing steel
Cr-4Mo contains 0.95 to 1.20% C. The higher the Cr content, the better the oxidation resistance. However, if the Cr content is excessive, the stress corrosion cracking resistance decreases. The high-temperature hardness is, of course, lower than that of the above-mentioned heat-resistant bearing steel.

[0006] A high silicon toughness steel disclosed in Japanese Patent Publication No. 46-9536 has been known. This high silicon toughness steel has a C content of 0.08% or less,
%, Mn 5% or less, Ni 3 to 9%, Cr 6 to 15% and the balance Fe, and the sum of the contents of Ni and Mn is twice the Si content, and the Cr content is 2.5 times the Si content. The A ₃ transformation point is lowered to 750 ° C. or lower by adjusting the doubling as a target, and the crystal is refined to provide rich toughness equivalent to twice that of other tough special steels. Hereinafter, this high silicon toughness steel is referred to as “Silicolloy A1”. “Silicolloy” is a trade name of high silicon stainless steel manufactured by Nippon Silicolloy Industrial Co., Ltd., the present applicant.

Japanese Patent Publication No. 47-23056 discloses that a solution treatment is performed, and then aging is performed at 500 ° C., whereby a Vickers hardness of 5 is obtained without practically causing deformation.
An aging high silicon steel that hardens to more than 00 is disclosed.
This aging high silicon steel has a C content of 0.05% or less, and Si4-7.
%, Mn 3% or less, Ni 6-16%, Cr 12-20
%, V 4% or less, each 1% or less Ti, Al and each 4% or less Mo, W or C 1% or less respectively.
u, Co alone or in combination, the balance being Fe, the sum of the contents of Ni and Mn is twice the content of Si,
The content of r is adjusted to be three times the content of Si. Hereinafter, this aging high silicon steel is referred to as "Silicolloy C".
Called.

[0008] This siliconloy C is the same as the siliconloy A described above.
1, the contents of Si, Ni and Cr were increased, and Mo, W, V and Co, and Cu and Ti were newly added.
And Al have been added to enhance age hardening characteristics, and have been developed for wear resistance with high hardness. Accordingly, since it is expensive as a whole because a large amount of expensive elements are used as compared with the above-mentioned Silicolloy A1, it is currently used only in limited products with high added value.

In addition, the above-mentioned silicoalloy A1 is improved to have a mixed state of a martensite phase and an austenite phase at room temperature, and desirable properties derived from both.
That is, a precipitation hardening type high silicon stainless steel having both toughness and corrosion resistance (JP-B-57-17070) has been developed. This precipitation hardening type high silicon stainless steel is C0.
05% or less, Si 2 to 4%, Mn 2% or less, Mo0.2
~ 1%, Cu0.5 ~ 3%, Ni5 ~ 10%, Cr8 ~
13% with the balance being Fe, twice the Cr content and Si
The sum of the contents was adjusted to 20 to 30%. Hereinafter, this precipitation hardening type high silicon stainless steel is referred to as “Silicolloy A2”.

[0010] The above-mentioned silico-alloys A1 and A2 are mainly used for structural purposes and are inexpensive and versatile as compared with silico-alloy C.
It is not as good. But still, Silicolloy A
2 was obtained by annealing at 650 ° C. and heat-treating by precipitation hardening at 480 ° C. to obtain Brinell hardness HB470 (Shore hardness HS65), and austenitic stainless steel (SUSXM15J1) at 900 ° C. and 310 ° C.
Brinell hardness H obtained by heat treatment by tempering
It is comparable to B500 (Shore hardness HS69).

[0011] Here, the hardness of Siliconolloy C is exemplified in the above-mentioned gazette.
After the solution was cooled at 50 ° C. for 30 minutes and cooled with oil, 500 ° C. × 1
In the case of heat treatment of air-cooling after aging and hardening for 6 hours, a Vickers hardness HV510 (Shore hardness HS67) is obtained.
In the case of heat treatment of air-cooling after age hardening at 16 ° C. × 16 hours, Vickers hardness HV615 (Shore hardness HS75) is obtained. Normally, the age hardening time is substantially proportional to the thickness of the steel material.
It is equivalent to just over 13 hours per m, far exceeding the standard working hours of the day (8 hours). In addition, it is not unusual for a steel material having a large thickness to be required to be continuously heat-treated day and night. As described above, since long-term heat treatment was conventionally required for age hardening, it is difficult to control the temperature during that time, and furthermore, it consumes a large amount of heat energy and has various problems such as a poor working environment. I have. In addition, 1250 ° C × 3
A solution heat treatment is performed to obtain a Vickers hardness HV500 (Shore hardness HS66) by aging hardening at 900 ° C for 4 hours and then air-cooling after solution-cooling and oil cooling for 0 minutes. Dimensional accuracy is significantly reduced due to thermal expansion and thermal strain. Therefore, in this case, machining such as cutting is finally required. However, since the hardness is high, it is difficult to perform such machining. Further, the conventional heat treatment did not provide a curing depth of 2 mm or more.

[0012]

SUMMARY OF THE INVENTION In view of the above-mentioned situation, the present invention aims to solve the problem by using a general-purpose and inexpensive precipitation-hardening high-silicon stainless steel (Silicolloy A2) developed for structural use. It has the heat resistance that enables it to be used continuously for a long time at a high temperature equal to or higher than conventional heat-resistant bearings, and at the same time has the toughness of the material and the same or higher corrosion resistance as conventional corrosion-resistant bearings Another object of the present invention is to provide a rolling bearing and a sliding bearing having corrosion resistance and excellent workability.

[0013]

According to the present invention, there is provided a rolling bearing comprising an inner ring, an outer ring, a rolling element and a cage, wherein the carbon content is 0.05% or less, and 3.0% or less. ~
5.0% silicon, 2% or less manganese, 5-10%
Precipitation hardening type high silicon alloy comprising nickel of 6%, 12% (excluding 12%) of chromium, 0.2% to 1% of molybdenum, 0.5% to 3% of copper, and the balance of iron. Using stainless steel, at least the inner ring and the outer ring are formed, and the distance between the inner ring and the outer ring is regulated by a retainer made of metal or heat-resistant synthetic resin, and the space is regulated by precipitation hardening type high silicon duplex stainless steel or A heat-resistant and corrosion-resistant rolling bearing comprising a plurality of ceramic rolling elements was constructed.

Then, the precipitation hardening type high silicon duplex stainless steel is rapidly cooled at a temperature of 900 to 1000 ° C. for a predetermined time, then cooled at a temperature of 600 to 700 ° C. for a predetermined time. At least an inner ring and an outer ring are formed and formed from the steel in a state of being heated to a solution heat temperature of 〜1150 ° C. and quenched, and each of the parts is maintained at a temperature of 420 to 520 ° C. for at least 10 minutes or more per 1 cm thickness. It is a preferred embodiment that a plurality of rolling elements are arranged while being age-hardened and the distance between the inner ring and the outer ring is regulated by a retainer.

Further, after being formed from the precipitation hardening type high silicon duplex stainless steel and subjected to the age hardening treatment, at least the surface layer of the rolling element is subjected to ion nitriding or surface hardening treatment for coating TiC or TiW. Is more preferable.

A sliding bearing comprising an inner ring and an outer ring, comprising 0.05% or less of carbon, 3.0% to 5.0% of silicon, 2% or less of manganese, and 5% to 10% of manganese. Nickel and 6-12% (but not 12%) chromium,
An inner ring and an outer ring are formed using a precipitation hardening type high silicon duplex stainless steel composed of 0.2 to 1% molybdenum, 0.5 to 3% copper, and the balance iron, and the inner and outer rings are formed. A sliding bearing having heat resistance and corrosion resistance, which is fitted so as to be able to slide directly on each other, is constructed.

Further, it is preferable that the sliding bearing is also subjected to the same age hardening treatment and surface hardening treatment as those of the rolling bearing.

[0018]

The heat-resistant and corrosion-resistant rolling bearing and sliding bearing of the present invention having the above-mentioned contents are conventionally known precipitation hardening type high silicon duplex stainless steels, that is, 0.05%.
The following carbon, 3.0-5.0% silicon, 2% or less manganese, 5-10% nickel, 6-12% (but not 12%) chromium, 0.2% At least the inner ring and the outer ring are formed using a precipitation hardening type high silicon duplex stainless steel composed of １1% molybdenum, 0.5-3% copper, and the balance iron, and relatively hardened by a special age hardening treatment. It is cured in a short time, and the surface hardness is converted to Shore hardness HS.
5 to 80 to provide the required surface hardness and toughness for the bearing, and the age hardening temperature (420 to 520)
C)), it has both the heat resistance that allows long-term continuous use at high temperatures up to ℃) and the excellent corrosion resistance inherent in the material.

The reason for using each element and the reason for its mixing ratio are described in detail in the above-mentioned Japanese Patent Publication No. 57-17070. In the present invention, in particular, chromium is used for the purpose of reducing the cost of the material. Is set to 12% or less (however, 12% is not included). Needless to say, it is preferable to set the content of other elements other than iron as small as possible. In the present invention, the strength and toughness, heat resistance and corrosion resistance are guaranteed by using the precipitation hardening type high silicon duplex stainless steel having the above-mentioned compounding ratio, so how to increase the surface hardness,
The main focus is on whether it can be put into practical use as a bearing by deepening the hardening depth. However, in general, there is a disadvantage that the working becomes difficult when the surface hardness of the material becomes high, but for this problem, it is fortunate that the bearing steel used in the present invention is a precipitation hardening type.

In order to solve the above-mentioned problem of increasing the surface hardness and improving the workability, the inventors of the present invention have conducted three-stage heat treatments sequentially in a specific temperature range based on experience accumulated over many years and repeated experiments. It was found that the problem could be solved by performing machining during this time. That is, as shown in FIG. 1, a known precipitation hardening type high silicon duplex stainless steel ingot is first rolled or cast by a steelmaking process of a base material to form a steel material having a shape close to a final part, and then a raw material is formed. A first heat treatment step for tempering steel, a second heat treatment step (solution treatment) for producing a supersaturated solid solution that is the basis of age hardening, a machining step for mechanically processing into a predetermined part shape, and thereafter aging The third heat treatment step for curing is performed.

The first heat treatment step is performed at 900 to 1000
C., preferably at 950.degree. C. for a given time (at least 10 minutes per cm of steel thickness), then quenched in oil phase and then at a temperature of 600-700.degree. C., preferably 65.degree.
After maintaining the temperature at 0 ° C. for a predetermined time (at least 1.5 hours per 1 cm of the thickness of the steel material), the steel material is subjected to gas phase cooling (air cooling) to temper the steel material. Note that the temperature is not necessarily limited to the above-mentioned values because there is a fluctuation of about ± 5% due to a measurement error of the temperature measuring device or a temperature setting error of the heating device. The same applies to the temperature value described later.

In the second heat treatment step, 950 to 1150
The solution is heated to a solution temperature of about 10 ° C., preferably about 1050 ° C., and then rapidly cooled (water-cooled). The time required for this heating is sufficient until the steel material rises to a substantially uniform temperature inside. By the second heat treatment step, the surface hardness of the steel material becomes 35 to 45 in terms of Shore hardness HS. The surface hardness in this state is most suitable for machining, so that machining with high accuracy and excellent surface finish can be performed.

In the third heat treatment step, the steel material has a thickness of 1 cm.
Age hardening is carried out at a temperature of 420 to 520 ° C, preferably 460 to 480 ° C, for at least 10 minutes or more. Even if the time spent in the third heat treatment step is limited to 7 hours or less, it is possible to sufficiently age harden a steel material having a thickness of about 30 cm. After the third heat treatment step, the surface hardness increases to 65 to 80 in terms of Shore hardness HS. Here, since the hardness and the hardening depth increase substantially in proportion to the age hardening time, it is natural that a necessary and sufficient age hardening time is ensured. 1 heat treatment step
What can be done within the average working hours per day is a remarkable fact, and the hardness at a depth of 3 mm from the surface can be converted to a Shore hardness HS of 60 or more.

As described above, the precipitation hardening type high silicon duplex stainless steel material is subjected to the first heat treatment step and the second heat treatment step, and then mechanically processed to a predetermined product shape by a machining step. The third heat treatment step is performed. Therefore, after the first heat treatment step and the second heat treatment step involving a heat treatment at a high temperature close to 1000 ° C. that causes thermal deformation of the steel material, the surface hardness of the steel material is 35 to 45 in terms of Shore hardness HS. Since machining is performed in a state of hardness,
Processing is easy, and after the processing, a third heat treatment step involving a low-temperature heat treatment is performed as a heat treatment at about 500 ° C., so that the processed material has very little thermal deformation, and has high precision and high hardness (surface hardness is Shore hardness). It is possible to provide a bearing of 65 to 80) in terms of HS.

The rolling bearing is formed of the above precipitation hardening type high silicon duplex stainless steel and subjected to an age hardening treatment. At least the rolling element, and for the sliding bearing, ion nitriding or TiC or Ti
By performing the surface hardening treatment for coating W, the surface hardness can be further increased.

[0026]

Next, the details of the present invention will be further described based on examples. First, in the precipitation hardening type high silicon duplex stainless steel used in the present invention, the silicon content is specified to be 3.0 to 5.0% from a practical viewpoint. The carbon content is specified to be 0.05% or less, which can sufficiently be achieved in a normal steel making process, because an increase in carbon content causes not only a decrease in toughness but also a reduction in corrosion resistance. Since manganese does not contribute significantly to the hardening of precipitation hardening stainless steel, it is specified to be 2% or less, which is a normal specification range for stainless steel. Molybdenum and copper are added for the purpose of increasing corrosion resistance. However, since molybdenum is an expensive and powerful ferrite-forming element, its use is restricted to 1%.
It is suppressed below. Copper acts as a precipitation hardening element and also as an austenite forming element, and its ferrite suppressing action is about one-third of that of molybdenum.
Therefore, the content is set to 3% or less, which is three times the amount of molybdenum, for the purpose of suppressing generation of fallite by molybdenum. Further, copper significantly impairs hot workability due to the increased amount thereof, so the upper limit is kept at 3%. Furthermore,
The lower limits of molybdenum and copper are specified as 0.2% molybdenum and 0.5% copper in order to ensure corrosion resistance.

In the above composition ranges of carbon, manganese, copper and molybdenum, the content of nickel is reduced to 5 in order to maintain the characteristics of the precipitation hardening type high silicon duplex stainless steel and to minimize the material cost. The content is set to 6 to 12% (excluding 12%) while setting to 10% to 10%. Here, the reason why the content of chromium is excluded from 12% is that the content of chromium in the above-mentioned siliconcolloy C is 12 to 20%, and the material cost is reduced as compared with siliconolloy C.

Next, a description will be given of the results of examining mechanical properties after actually preparing a sample and performing heat treatment. The sample was 0.019% carbon, 3.43 silicon.
%, Manganese: 1.00%, nickel: 6.45%, chromium: 10.68%, an appropriate amount of molybdenum and copper, and a composition consisting of iron and cast into a columnar shape having a diameter of 280 mm (mother) Steel making process). First, the sample was maintained at a temperature of 920 ° C. for a predetermined time, then rapidly cooled in an oil phase, then maintained at a temperature of 660 ° C. for a predetermined time, and then air-cooled (first heat treatment step). Next, 1050-1
After heating to a temperature of 100 ° C., the oil phase was rapidly cooled to perform a solution treatment (second heat treatment step). Then, the surface was cut with a lathe to smooth the surface and formed into a perfect cylinder (a machining process). Lastly, after maintaining at a temperature of 480 ° C. for 6 hours for age hardening, it was cooled (third heat treatment step).

Table 1 shows samples according to the bearing of the present invention,
The results of measuring the mechanical properties of SUH660 and SUS321 as comparative materials are shown.
No. 0, Silicoroy A by the conventional heat treatment
No. 2 and the characteristics of Silicolloy C described in JP-B-47-23056 are also described.

[0030]

[Table 1]

Here, in Sample 1 according to the present invention in Table 1, the upper heat treatment shows the first heat treatment step, the lower heat treatment shows the second and third heat treatment steps together, and the lower mechanical properties Is a measured value after the first to third heat treatment steps.

As for the curing depth after the age hardening treatment, for example, it is shown in Table 1 that the surface hardness of a cylinder having a diameter of 280 mm has been increased to 78 in Shore hardness HS. H at a depth of 4.9 mm from the surface
S71, HS56 at 15.4 mm, HS at 20 mm
HS53 at 51 and 30 mm, HS52 at 40 mm,
HS56 at 50mm, HS57, 70m at 60mm
The actual measurement is HS51 at m, HS50 at 80 mm, and HS51 at 90 mm. Therefore, depth 3 from the surface
Based on the fact that the hardness in mm is achieved at HS60 or more and the curing depth cannot be increased to 2 mm or more by the conventional heat treatment, it can be understood that the curing method by the heat treatment used here can significantly increase the curing depth.

Next, the steel making process and the machining process of the base material will be explained a little. In the steelmaking process of the base material, pure iron with extremely low carbon content was difficult to obtain in the past, so it was manufactured by vacuum melting to limit the contamination of carbon in the steelmaking process. The availability has made it easier to use a vacuum melting furnace. As a result, the steelmaking process has been greatly simplified, and steelmaking by rolling, forging or casting has become possible. Furthermore, precision casting by the lost wax method or the like has become possible, and the production of precision parts has become easy. For the machining, the first and second
The hardness after the heat treatment process is relatively low (HS35-4
Since processing is performed in the state of 5), cutting and grinding can be easily performed by a general-purpose machine tool, for example, a lathe, a drilling machine, a milling machine, and the like, like ordinary stainless steel.

Therefore, on the premise that the above-mentioned heat treatment is performed, a rolling bearing or a sliding bearing is manufactured using the precipitation hardening type high silicon duplex stainless steel having the above composition. In the bearing of the present invention, at least the inner ring and the outer ring are formed of a precipitation hardening type high silicon duplex stainless steel, and the other parts are formed of a material having appropriate heat resistance and corrosion resistance according to the use environment. Especially,
In a rolling bearing, it is also preferable from the viewpoint of bearing performance that the rolling elements are made of ceramics, but the rolling elements made of ceramics are expensive and the product becomes expensive. Further, since the cage is not particularly required to be strong, it may be made of a material whose strength is slightly reduced at a high temperature. , Phenolic resin, nylon,
A synthetic resin such as PTFE can be used. Of course,
It is economical to form all the parts constituting the bearing from precipitation hardening type high silicon duplex stainless steel in terms of heat resistance and corrosion resistance.

After the above-mentioned age hardening treatment is performed, the surface hardness of the surface layer of the component is further increased by performing ion nitriding or surface hardening treatment for coating TiC or TiW or SiC, This surface hardening treatment and various conventionally known ones can be used.

Next, a specific example of the bearing will be briefly described. Although known as a bearing structure, a rolling bearing suitable for high-speed rotation and low load as shown in FIGS. 2 to 4 and a sliding bearing suitable for low-speed rotation and high load as shown in FIGS. Is exemplified. First, FIGS. 2 and 3 show radial bearings in which a plurality of rolling elements 4,... Are inserted between concentrically arranged inner races 1 and outer races 2 having different diameters with a retainer 3 at equal intervals. 2 shows a ball bearing using a ball as the rolling element 4, and FIG. 3 shows a roller bearing using a roller as the rolling element 4. FIG. 4 shows an inner ring 1 having a diameter substantially equal to that of the inner ring 1 arranged coaxially.
A thrust bearing in which a plurality of rolling elements 4,... Are inserted in a state of being positioned at equal intervals by a retainer 3 between the rolling element 4 and the outer ring 2 is shown.

The sliding bearings shown in FIGS.
A radial sliding bearing suitable for low-speed rotation and use of a high load, having a structure in which an inner ring 5 and an outer ring 6 are slidably fitted to each other, and having a convex spherical sliding surface 7 on the outer peripheral surface of the inner ring 5. And a concave spherical sliding surface 8 is formed on the inner peripheral surface of the outer ring 6, and the inner ring 5 is formed on one axial side of the sliding surface 8.
A pair of notches 9, 9 which can be loosely inserted in the sliding surface 7 of the inner ring 5 in a state where the axial direction of the inner ring 5 is perpendicular to the axial direction of the outer ring 6 is formed to face the diameter portion. That is, in order to insert the inner ring 5 into the outer ring 6, the diameter of the sliding surface 7 of the inner ring 5 is notched while the axial direction of the inner ring 5 is orthogonal to the axial direction of the outer ring 6. After the inner ring 5 is inserted through the
The inner ring 5 and the outer ring 6 are concentrically and coaxially rotated by 0 degrees. In this fitting state, the inner ring 5 does not come off the outer ring 6 in the axial direction, and the sliding surfaces 7 and 8 are in sliding contact with each other. The sliding bearing of the present invention is applicable not only to the above-described radial sliding bearing but also to a thrust sliding bearing.

Conventional sliding bearings are made of white metal, copper-lead alloy, aluminum alloy, bronze, etc. as a bearing alloy. In addition, cast iron, iron-based or copper-based sintered alloy, Ni-based, Co-based And W-based heat- and wear-resistant alloys are used. In particular, as a material having heat resistance, a heat-resistant wear-resistant alloy is used, but a two-layer material lined with a back metal uses centrifugal casting, flame spraying, plasma spraying, etc., but the manufacturing process is complicated, The corrosion resistance is insufficient. There are ceramics, but they are very expensive. On the other hand, the sliding bearing of the present invention can be made of a single material of precipitation hardening type high silicon duplex stainless steel having heat resistance and corrosion resistance.

The bearing described above is an example for explaining the present invention, and the present invention is not limited to the above-described bearing structure, but can be applied to bearings having various structures. is there. Further, the bearing of the present embodiment is for the rotary motion, but the present invention is for supporting the linear motion, for example, a roller or a ball-shaped rolling slide or a sliding slide used in a high-temperature, corrosive atmosphere. It can be easily inferred that the present invention can be similarly applied to a guide device such as a moving tool.

[0040]

According to the heat-resistant and corrosion-resistant rolling bearing and sliding bearing of the present invention described above, a general-purpose and inexpensive precipitation-hardening high silicon stainless steel (Silicolloy A2) developed for structural use can be used. Since the components such as the inner ring and the outer ring are formed by using the material, it is possible to provide a bearing having the toughness, corrosion resistance and heat resistance of the material at the same time.

In particular, by forming a part by precipitation hardening type high silicon stainless steel and then subjecting it to age hardening to produce a bearing, the surface hardness is high and the hardening depth is deep, which is equal to or higher than that of a conventional bearing. It has excellent high temperature properties, excellent corrosion resistance, and excellent workability. For example, heat resistance equivalent to high-speed steel, which is a heat-resistant bearing steel, and corrosion resistance equal to or higher than that of 14Cr-4Mo, which is a corrosion-resistant bearing steel, are simultaneously provided. After a first heat treatment step and a second heat treatment step involving a heat treatment at a high temperature close to 1000 ° C.,
Moreover, the surface hardness of the steel material is 35 in terms of Shore hardness HS.
Since machining is performed in a hardness state of about 45 to about 45, it is significantly superior to high-speed steel, and a third heat treatment step involving a low-temperature heat treatment of about 500 ° C. is performed after the processing. High precision with minimal thermal deformation. In particular, it is a noteworthy feature that it has heat resistance that allows long-term continuous use at high temperatures up to the age hardening temperature (420 to 520 ° C). Furthermore, the corrosion resistance and stress corrosion cracking resistance of solutions containing sulfuric acid, nitric acid or chloride ions have already been demonstrated, and the corrosion resistance is satisfactory. Therefore, it can be said that a bearing using the precipitation hardening type high silicon stainless steel of the present invention is a truly ideal bearing.

Further, the rolling bearing is formed of the above precipitation hardening type high silicon duplex stainless steel and subjected to age hardening treatment, and at least the rolling element is used. TiC or Ti
By performing the surface hardening treatment for coating W, the surface hardness can be further increased, and the characteristics equivalent to or higher than those of the conventional bearing can be obtained in terms of the surface hardness.

Further, although it has been known that a precipitation hardening type high silicon duplex stainless steel has excellent mechanical properties, it is slightly inferior to bearing steel in terms of hardness, and has a higher hardness than bearing steel. Due to the high cost, bearings made of precipitation hardening type high silicon duplex stainless steel have not found practical value, and no bearings made of precipitation hardening type high silicon duplex stainless steel have existed until now. By applying a special aging and expensive treatment according to the invention, the last difficulty such as a significant improvement in surface hardness has been eliminated, heat resistance and corrosion resistance are comparable to all ceramic bearings, impact resistance and price are all ceramics It is now possible to provide better bearings than bearings.

[Brief description of the drawings]

FIG. 1 is a block diagram showing steps of a method for manufacturing a bearing according to the present invention.

FIG. 2 is a partially broken perspective view of a radial ball bearing showing an example of a rolling bearing according to the present invention.

FIG. 3 is a partially broken perspective view of a radial roller bearing showing an example of a rolling bearing according to the present invention.

FIG. 4 is a partially broken perspective view of a thrust ball bearing showing an example of a rolling bearing according to the present invention.

FIG. 5 is an exploded perspective view of a radial slide bearing showing an example of the slide bearing according to the present invention, with a part cut away.

FIG. 6 is a partially broken perspective view of the radial sliding bearing in the assembled state.

[Explanation of symbols]

 Reference Signs List 1 inner ring 2 outer ring 3 cage 4 rolling element 5 inner ring 6 outer ring 7 sliding surface 8 sliding surface 9 notch

Claims (6)

(57) [Claims] 1. A rolling bearing comprising an inner ring, an outer ring, a rolling element, and a cage, wherein 0.05% or less of carbon and 3.0%
-5.0% silicon, 2% or less manganese, 5-10
% Nickel, 6 to 12% (excluding 12%) chromium, 0.2 to 1% molybdenum, and 0.5 to 3%
At least an inner ring and an outer ring are formed by using a precipitation hardening type high-silicon duplex stainless steel composed of copper and the balance iron, and a metal or heat-resistant synthetic resin-made cage is provided between the inner ring and the outer ring. A heat-resistant and corrosion-resistant rolling bearing comprising a plurality of rolling elements made of precipitation hardening type high silicon duplex stainless steel or ceramics. 2. The precipitation hardening type high silicon duplex stainless steel is rapidly cooled at a temperature of 900 to 1000 ° C. for a predetermined time, and then cooled at a temperature of 600 to 700 ° C. for a predetermined time. At least an inner ring and an outer ring are formed and formed from the steel in a state of being heated to a solution heat temperature of 〜1150 ° C. and quenched, and each of the parts is maintained at a temperature of 420 to 520 ° C. for at least 10 minutes or more per 1 cm thickness. 2. The heat-resistant and corrosion-resistant rolling bearing according to claim 1, wherein a plurality of rolling elements are arranged with the cage being regulated between the inner ring and the outer ring by age hardening. 3. A method comprising forming the precipitation hardening type high-silicon duplex stainless steel and subjecting it to age hardening treatment and then subjecting at least the surface layer of the rolling element to ion nitriding or surface hardening treatment for coating TiC or TiW. Claim 1 or 2
A rolling bearing having the described heat resistance and corrosion resistance. 4. A plain bearing comprising an inner ring and an outer ring, wherein 0.05% or less of carbon, 3.0 to 5.0% of silicon, 2% or less of manganese, and 5 to 10% of Nickel and
6-12% chromium (excluding 12%) and 0.2%
Using a precipitation hardened high silicon duplex stainless steel consisting of ~ 1% molybdenum, 0.5-3% copper, and the balance iron,
A sliding bearing having heat resistance and corrosion resistance, wherein an inner ring and an outer ring are formed, and the inner ring and the outer ring are fitted so as to be able to directly slide on each other. 5. The precipitation hardening type high silicon duplex stainless steel is rapidly cooled at a temperature of 900 to 1000 ° C. for a predetermined time, and then cooled at a temperature of 600 to 700 ° C. for a predetermined time. An inner ring and an outer ring are formed from the steel in a state of being heated to a solution heat temperature of ~ 1150 ° C and rapidly cooled.
The heat-resistant and corrosion-resistant sliding bearing according to claim 4, wherein the inner ring and the outer ring are fitted so as to be able to directly contact each other while being kept at a temperature of 420 to 520 ° C for not less than 0 minutes for age hardening. 6. An inner ring and an outer ring which are formed of the precipitation hardening type high silicon duplex stainless steel and subjected to age hardening treatment, are subjected to ion nitriding or surface hardening treatment for coating TiC or TiW. A sliding bearing having heat resistance and corrosion resistance according to claim 4 or 5.