CN110629107A

CN110629107A - Radial spherical plain bearing based on structure enabling material and preparation method

Info

Publication number: CN110629107A
Application number: CN201910870927.3A
Authority: CN
Inventors: 许旸; 刘保建; 蒋百铃; 颜国君; 杜玉洲; 王旭; 翟瑞锋
Original assignee: Xian University of Technology
Current assignee: Xian University of Technology
Priority date: 2019-09-16
Filing date: 2019-09-16
Publication date: 2019-12-31

Abstract

The invention discloses a centripetal joint bearing based on a structure enabling material, which comprises a joint ball and an outer ring, wherein the joint ball and the outer ring are both prepared from the structure enabling material, and in the metallographic structure in the joint ball and the outer ring, a substrate is austeniteThe iron body and the graphite form are as follows: the diameter of the graphite sphere is less than or equal to 25 mu m, the spheroidization rate is 100 percent, and the density of the graphite sphere reaches 300-600 spheres/mm². In the preparation method, the color of the section bar drawn by one step is observed, the components of the molten iron are timely regulated and controlled to be within a tiny range of the eutectic components, the spheroidization rate is obviously increased, 100 percent spheroidized eutectic graphite is obtained, the sphere diameter of the graphite is less than or equal to 25 mu m, and the occurrence of large blocks of primary graphite is avoided; through rough machining and abrasive machining, prepare the joint ball that has self-lubricating nature and prepare outer ferrule, assemble and obtain radial spherical plain bearing, have the sound absorption shock attenuation, good heat conduction, and simple structure is compact, has better adaptability to various complicated operating condition.

Description

Radial spherical plain bearing based on structure enabling material and preparation method

Technical Field

The invention belongs to the technical field of radial spherical plain bearings, and particularly relates to a radial spherical plain bearing based on a structure enabling material, and a preparation method of the radial spherical plain bearing based on the structure enabling material.

Background

The radial spherical plain bearing is one of the spherical plain bearings, the sliding contact surface of the radial spherical plain bearing is a hinged inner spherical surface and an outer spherical surface, the radial spherical plain bearing can rotate at any angle and obliquely swing within the angle range of 0-45 degrees during movement, the radial spherical plain bearing has an automatic aligning function, can still normally work when the concentricity of a supporting shaft and a shaft shell hole is large, and has strong tolerance on mechanical assembly and movement precision and large bearing capacity. The radial spherical plain bearing has the advantages of compact structure, light weight, impact resistance, self lubrication, convenient use and maintenance, strong safety and reliability and the like, thereby being widely applied to engineering machinery, automatic equipment, hydraulic cylinders, forging and pressing machine tools and military machinery.

The above-mentioned structural features of the radial spherical plain bearing make it difficult to perform grease lubrication. In order to reduce the friction between the inner and outer spherical surfaces, pad-type self-lubricating spherical plain bearings have been developed. The bearing is characterized in that a layer of self-lubricating liner is adhered to the inner spherical surface of the cutting sleeve, and/or a layer of solid lubricant is sprayed on the spherical surface of the inner sleeve, and the sliding friction between the inner spherical surface and the outer spherical surface of the bearing replaces the direct friction on the surface of a friction pair. A common gasket and spray material today is polytetrafluoroethylene. However, the polytetrafluoroethylene has strict requirements on the adhesive and the bonding process, and has the hidden danger of falling off and tearing; the texture is soft, and the bearing can be gradually extruded out of the gap of the stress surface in the bearing swinging process; the hardness is low, the material is gradually thinned in the scraping and wearing process, and the wear-resisting service life is limited. And ceramics with high strength, high hardness and better antifriction and wear-resistant characteristics are also adopted as the material of the inner ring. However, the ceramic material has no toughness and large brittleness, so that the common application of the ceramic material is limited, and the ceramic material can only be used in occasions with small impact load.

In addition, the knuckle bearing used on the airplane needs to be in service at minus dozens degrees to minus hundred and ten degrees, and the heat-conducting property of the material is good in order to reduce the thermal stress.

It is known that the radial spherical plain bearing should have mechanical properties (tensile strength, yield strength, hardness, toughness, elastic modulus, fatigue strength, etc.) required for general structural materials, and should also have other properties such as self-lubrication. The material with good mechanical properties and one or more other physical and chemical properties (such as sound absorption, shock absorption, good heat conduction, low temperature rise and the like) is called as a structural enabling material.

Disclosure of Invention

The invention aims to provide a radial spherical plain bearing based on a structural energizing material, which solves the problems that a traditional radial spherical plain bearing bonding lubricating film is easy to fall off and tear, and the service life and the reliability are poor.

Another object of the present invention is to provide a method for the preparation of a radial spherical plain bearing based on a structurally energized material.

The radial spherical plain bearing comprises a spherical joint and an outer ferrule, wherein the spherical joint and the outer ferrule are both prepared from the structural enabling material;

the joint ball consists of the following components: c: 3.5% -3.7%, Si: 2.6-2.9%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: not more than 0.2 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;

the outer ferrule comprises the following components: c: 3.3% -3.5%, Si: 2.9-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: not more than 0.1 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent.

The present invention is also characterized in that,

the internal microstructures of the joint ball and the outer ferrule are as follows: the diameter of the graphite sphere is less than or equal to 25 mu m; the nodularity in the section bar is 100 percent; the density of graphite nodules in the section bar reaches 300-²。

The invention adopts another technical scheme that the preparation method of the radial spherical plain bearing based on the structure enabling material comprises the following steps:

step 1, melting preset component materials into molten iron in an induction furnace when a ductile iron pipe or a solid bar used for drawing a joint ball by a vertical continuous casting method, wherein the preset component materials consist of the following components: c: 3.5-3.7%, Si: 1.6-1.8%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: less than or equal to 0.2 percent and the balance of Fe;

when a ductile iron pipe or a solid bar used for drawing an outer ring by a vertical continuous casting method is used, preset component materials are melted into molten iron in an induction furnace, and the preset component materials consist of the following components: c: 3.3-3.5%, Si: 1.8-2.1%, Mn: less than or equal to 0.15 percent, less than or equal to 0.015 percent, Cr: less than or equal to 0.1 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;

step 2, standing the molten iron for not less than 20min, drawing a section by using a vertical continuous casting method, pouring the molten iron in the step 1 into a ladle, and adding a nodulizer and an inoculant into the molten iron to ensure that the silicon content of the molten iron after inoculation and spheroidization is 2.6-2.9 percent and the residual magnesium content is 0.035-0.045 percent;

step 3, injecting the inoculated and spheroidized molten iron in the step 2 into a hearth of a continuous casting furnace, then flowing into a crystallizer to be condensed into a pipe or a bar, nesting with the front end of a seeding rod extending into the crystallizer, starting a drawing machine to carry out stepping drawing on the pipe or the bar by drawing the seeding rod to obtain a section;

observing the color uniformity of the section bar with one step drawn out from the crystallizer, if the section bar with one step is uniform orange red, continuously injecting the molten iron inoculated and spheroidized in the step 2 into a hearth of a continuous casting furnace to fill the crystallizer so as to continuously perform the drawing process; if the section bars of one step are distributed in a strip-shaped black-and-white alternative manner, adding the inoculant in the step (2) into a hearth of a continuous casting furnace for 1-2 times, adding the carburant into the electric furnace in the step (1), continuously drawing, and observing the color until the color is uniform orange;

step 4, after the drawing process in the step 3 is finished, carrying out metallographic detection and electron microscope detection on the obtained section;

step 5, after the metallographic detection and the electron microscope detection in the step 4 are finished, normalizing the section;

step 6, roughly processing the section bar processed in the step 5 into joint balls, reserving a grinding amount of 0.2-0.3mm, and then carrying out isothermal quenching treatment and grinding processing to obtain the required joint balls;

step 7, repeating the steps 1 to 5 to obtain an outer ferrule;

and 8, assembling the joint ball in the step 6 and the outer ring in the step 7 to obtain the required radial spherical joint bearing.

The present invention is also characterized in that,

and 4, the metallographic detection and electron microscope detection standards are as follows:

the diameter of the graphite sphere is less than or equal to 25 mu m; the nodularity in the section bar is 100 percent; the density of graphite nodules in the section bar reaches 300-²The specific density of graphite nodules within 15mm from the surface layer of the profile is more than or equal to 400 graphite nodules per mm²(ii) a The density of graphite nodules which are 15mm away from the surface is more than or equal to 300 graphite nodules per mm²。

The normalizing treatment in the step 5 specifically comprises the following steps:

and (3) preserving the heat of the qualified section at 875-.

Step 6, isothermal quenching treatment: preserving heat for 40-60min at 890-910 ℃, then immersing into a nitrate tank with the temperature range of 255-265 ℃ for quenching, and preserving heat for 40-60 min; taking out and air-cooling to room temperature, and removing the salt stain by using clear water.

In the step 7, the outer ring isothermal quenching treatment comprises the following steps: preserving heat for 30-60min at 890-910 ℃, then immersing into a nitrate tank with the temperature range of 325-335 ℃ for quenching, and preserving heat for 40-60 min; taking out and air-cooling to room temperature, and removing the salt stain by using clear water.

In the step 2, the inoculant is 75# ferrosilicon or ferrosilicon containing strontium, or ferrosilicon containing barium, or ferrosilicon containing zirconium or silicon-barium alloy;

the nodulizer is rare earth magnesium, yttrium heavy rare earth or magnesium alloy;

in the step 2, the recarburizer is graphite, coke or wood carbon.

The invention has the beneficial effects that: according to the preparation method of the self-lubricating radial spherical plain bearing, whether the color of a section which is just drawn out by a step is uniform orange red or not is observed, the components of molten iron are timely regulated and controlled to be within a tiny range of the eutectic components, the spheroidization rate is remarkably increased, nearly 100% spheroidized eutectic graphite is obtained, the diameter of the graphite sphere is less than or equal to 25 microns, the situation that large blocks of primary graphite are generated to cause damage to mechanical properties is avoided, and finally, the self-lubricating radial spherical plain bearing is prepared, the outer ring is prepared and assembled through rough machining and grinding machining.

Drawings

FIG. 1 is a schematic structural view of a radial spherical plain bearing based on a structurally energized material of the present invention;

FIG. 2 is a cross-sectional view of a radial spherical plain bearing based on a structurally energized material of the present invention;

FIG. 3 is a schematic color diagram of a spherical plain end and an outer race made of eutectic composition according to the method of the present invention;

FIG. 4 is a schematic color diagram of a spherical plain bearing and an outer race made by the method of the present invention, with off-eutectic composition;

FIG. 5 is a surface topography diagram of a scanning electron microscope during the preparation of the joint ball and the outer race in the method for preparing the radial spherical plain bearing according to the present invention;

FIG. 6 is a surface topography diagram of metallographic examination when a spherical plain knuckle and an outer race are prepared in the method for preparing a radial spherical plain bearing according to the present invention;

FIG. 7 is a graph showing isothermal quenching curves in the production of a spherical plain end bearing according to the present invention;

FIG. 8 is a graph showing the isothermal quenching curve in the outer race production in the radial spherical plain bearing production method of the present invention;

FIG. 9 is a schematic structural view of the spherical plain end and the outer ring of the method for manufacturing the radial spherical plain bearing of the present invention before pressing;

FIG. 10 is a schematic view of a structure of a spherical plain end and an outer race of the manufacturing method of the radial spherical plain bearing according to the present invention;

FIG. 11 is a schematic structural view of another outer race in the method for manufacturing a radial spherical plain bearing according to the present invention;

fig. 12 is a sectional view taken along line a-a in fig. 11.

In the figure, 1 is a radial spherical plain bearing, 2 is a spherical plain,

3. an outer race, 31, an outer race upper body, 32, an outer race lower body,

4. the bolt is fixed on the upper die, the pin is fixed on the lower die, the bolt is fixed on the pin, the bolt is fixed on the bolt, the upper die is fixed.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The radial spherical plain bearing 1 is mainly used for performing inclined rotary motion within a certain angle range, and is an important part which can be lubricated by a self-structural material. As shown in fig. 1 and 2, the self-lubricating angular contact bearing 1 includes a contact ball 2 and an outer race 3. The outer spherical surface of the joint ball 2 is in slidable contact with the inner spherical surface of the outer ferrule 3, the joint ball 2 can rotate at any angle and swing within a certain angle range, the automatic aligning function is achieved, the tolerance on mechanical assembly and motion precision is high, and the bearing capacity is high.

The radial spherical plain bearing 1 has two types: the outer diameter of a joint ball 2 is less than or equal to 60mm and is marked as a small centripetal joint bearing; the other joint ball 2 with the outer diameter larger than 60mm is a large radial spherical joint bearing. The main differences are: the outer ring 3 of the small radial spherical plain bearing is integrated, while the outer sleeve of the large radial spherical plain bearing is split.

A radial spherical plain bearing based on a structure enabling material comprises a spherical joint 2 and an outer ferrule 3, wherein the spherical joint 2 and the outer ferrule 3 are both prepared from the structure enabling material;

the joint ball 2 is composed of the following components: c: 3.5% -3.7%, Si: 2.6-2.9%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: not more than 0.2 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;

the outer ferrule 3 consists of the following components: c: 3.3% -3.5%, Si: 2.9-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: not more than 0.1 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent.

The internal microstructures of the joint ball 2 and the outer ferrule 3 are as follows: the diameter of the graphite sphere is less than or equal to 25 mu m; the nodularity in the section bar is 100 percent; the density of graphite nodules in the section bar reaches 300-². The fine, dense and round graphite nodules disperse the stress strain acting between the graphite nodules and the matrix structure when the part is deformed by stress, so the fatigue strength and the fatigue life of the part are obviously improved and reach or exceed the level of common quenched steel.

The spherical surface of the joint ball 2 contacted with the outer ring 3 does not need to depend on a gasket, only depends on the graphite exposed on the surface of the material as a solid lubricant, the graphite begins to be oxidized until 325 ℃, the use temperature is higher, and the self-lubricating centripetal joint bearing 1 can be used at the temperature below 230 ℃.

The invention relates to a method for preparing a radial spherical plain bearing based on a structure enabling material, which comprises the following steps:

when a ductile iron pipe or a solid bar used for drawing an outer ring by a vertical continuous casting method is used, preset component materials are melted into molten iron in an induction furnace, and the preset component materials consist of the following components: c: 3.3-3.5%, Si: 1.8-2.1%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: less than or equal to 0.1 percent and the balance of Fe, wherein the sum of the mass percentages of the components is 100 percent, and the carbon content is 99.95 to 100 percent of theoretical carbon equivalent;

step 2, standing the molten iron for not less than 20min, drawing a section by using a vertical continuous casting method, pouring the molten iron in the step 1 into a ladle, and adding a nodulizer and an inoculant into the molten iron to ensure that the residual magnesium content of the molten iron after inoculation and spheroidization is 0.035-0.045%;

the inoculant can promote graphitization, reduce chilling tendency, improve graphite morphology and distribution, increase eutectic group number, and refine matrix structure, and generally inoculate for 5-8 min. The nodulizer is used for crystallizing graphite in molten iron into spheres. The inoculant is 75# ferrosilicon or ferrosilicon containing strontium or ferrosilicon containing barium; the nodulizer is rare earth magnesium, yttrium heavy rare earth or magnesium alloy.

The preparation of the molten iron into eutectic components has four advantages: firstly, 100% of eutectic graphite can be obtained only when molten iron in the range of eutectic components is solidified, and the occurrence of primary graphite (the volume of primary graphite nodules is larger or very large) is avoided, so that the diameters of all graphite nodules are ensured to be less than or equal to 25 mu m; secondly, only the graphite spheres crystallized under the eutectic composition and the eutectic temperature grow rapidly on the basal plane due to the maximum supercooling degree, the maximum difference of latent heat of crystallization between the graphite crystal edges and the {1000} basal plane, so that the highest roundness, namely the highest spheroidization rate (nearly 100%), is achieved, and the high and low spheroidization rate and the sphere diameter have decisive influence on the material performance; austenite dendritic crystals crystallized with graphite nodules simultaneously during eutectic reaction block and disorder micro-area flow of molten iron, so that the graphite nodules floating along with the micro-area flow of the molten iron are not arranged in series, and anisotropy of mechanical properties of materials is avoided; and fourthly, the molten iron is directly cooled to the eutectic temperature from the actual temperature, so that intersection with a liquid phase line is avoided, the supercooling degree is improved, the phase change power is increased, the nucleation rate is increased, the density of graphite spheres is improved, and the volume of the graphite spheres is reduced.

observing the color uniformity of the section bar with one step drawn out from the crystallizer, and if the section bar with one step is uniform orange as shown in figure 3, continuously injecting the inoculated and spheroidized molten iron into a hearth of a continuous casting furnace to fill the crystallizer so as to continuously perform the drawing process; as shown in fig. 4, if the section bar with one step pitch is distributed in a strip-shaped black-and-white alternate mode, and the molten iron component deviates from the eutectic component, the inoculant in the step 1 needs to be added into the hearth of the continuous casting furnace for 1-2 times, and the carburant is added into the electric furnace in the step 1 until the color is changed into uniform orange red, wherein the process generally needs 3-5min, and if the molten iron component is in the hypereutectic component zone, the carbon-silicon equivalent of the subsequent molten iron needs to be timely reduced.

If the standing time of the molten iron in the electric furnace is too long, the molten iron is decarburized, and a carburant needs to be added into the electric furnace. The carburant is graphite, or coke, or wood carbon.

The continuous casting furnace is preferably a vertical continuous casting furnace, and a parallel continuous casting furnace can be selected according to different profiles. Wherein the drawn hollow pipe (the outer diameter is more than or equal to 80mm) or the solid bar (the outer diameter is less than 80 mm).

And 4, after the drawing process in the step 3 is finished, carrying out metallographic detection and electron microscope detection on the obtained section. And 4, the metallographic detection and electron microscope detection standards are as follows: the diameter of the graphite sphere is less than or equal to 25 mu m; the nodularity in the section bar is 100 percent; the density of graphite nodules in the section bar reaches 300-²The specific density of graphite nodules within 15mm from the surface layer of the profile is more than or equal to 400 graphite nodules per mm²(ii) a The density of graphite nodules which are 15mm away from the surface is more than or equal to 300 graphite nodules per mm²。

As shown in fig. 5, it can be seen that the graphite nodule has uniform and consistent shape and size, and the spheroidization rate is close to 100%. If all indexes do not meet the detection standard, the material needs to be prepared again. Metallographic examination is used as prejudgment before a scanning electron microscope, and as shown in fig. 6, it can be seen that the spheroidization rate of graphite is nearly 100%, the graphite is uniformly distributed, and the graphite nodules are uniform and consistent in shape and size.

And 5, after the metallographic detection and the electron microscope detection in the step 4 are finished, normalizing the section. The normalizing treatment in the step 5 specifically comprises the following steps: and (3) preserving the heat of the qualified section at 875-.

And 6, roughly processing the section bar processed in the step 5 into joint balls, reserving a grinding amount of 0.2-0.3mm, and then carrying out isothermal quenching treatment and grinding processing to obtain the required joint balls. Step 6, isothermal quenching treatment: preserving heat for 40-60min at 890-910 ℃, then immersing into a nitrate tank with the temperature range of 255-265 ℃ for quenching, and preserving heat for 40-60 min; taking out and air-cooling to room temperature, and removing the salt stain by using clear water.

As shown in fig. 7, when the effective thickness of the joint ball 2 is greater than 15mm, t is the time required for the super-thick portion to extend, i.e., t is 0.5 × super-thick portion (mm), and t is min. Keeping the temperature of the joint ball 2 at 890-910 ℃ for more than 30 min; immersing the joint ball 2 into a nitrate tank with the temperature range of 255-265 ℃ for quenching, and preserving heat for 40-60 min; taking out the quenched joint ball 2, air-cooling to room temperature, and removing the salt stain by using clear water. After isothermal quenching treatment, the hardness of the joint ball 2 is HRC46-50, and the hardness range ensures that the joint ball 2 has higher strength and wear resistance.

In the isothermal quenching process of the present invention, since graphite in the material is fine, has a small radius of curvature and a high dissolution rate: the austenitizing time and the austempering time are short, and are shortened by about 1/3 compared with the austenitizing holding time and the austempering time of the traditional ADI quenching.

Step 7, repeating the steps 1 to 5 to obtain an outer ferrule; and 7, outer ring isothermal quenching treatment: preserving heat for 30-60min at 890-910 ℃, then immersing into a nitrate tank with the temperature range of 325-335 ℃ for quenching, and preserving heat for 40-60 min; taking out and air-cooling to room temperature, and removing the salt stain by using clear water.

When the outer ferrule is prepared, a hollow pipe (the outer diameter is more than or equal to 60mm) or a solid bar (the outer diameter is less than 60mm) is drawn out.

And carrying out isothermal quenching treatment on the outer ring 3 after rough machining. An isothermal quenching process curve, as shown in fig. 8, the outer ferrule 3 is insulated at 890-910 ℃ for more than 30 min; immersing the outer ring 3 into a nitrate tank with the temperature range of 325-; and taking out the quenched outer ring 3, air-cooling to room temperature, and removing the salt stain by using clear water. After the isothermal quenching treatment, the hardness of the outer ring 3 is HRC38-42, the outer ring 3 is in the hardness range, has medium strength and also has the capacity of plastic deformation, and the sufficient plastic deformation amount is ensured when subsequent assembly processes are carried out, such as 'opening explosion' or 'circle embracing' (namely the outer ring 3 clamps the spherical joint ball 2), but cracks are not generated.

The assembly is mainly carried out by the following method: coating graphite powder on the surfaces of the joint ball 2 and the outer ring 3; installing the lower cushion mould 7 into the constraint sleeve 8; putting the joint ball 2 into a lower cushion mould 7; the outer ferrule 3 is arranged in the restraining sleeve 8; the outer ring 3 is pressed down by a press machine and an upper pressing die 6, so that the lower part of the outer ring is plastically deformed, the joint ball 2 is held, and the inner spherical surface and the outer spherical surface are jointed; the outer ring 3 which holds the joint ball 2 is put on a three-point roller press to rotate, and the ovality and the gap between the inner ring 3 and the outer ring 3 are adjusted to ensure that the two are in dynamic fit precision. The arrow direction is the direction of depression as shown in fig. 9 and the assembled charge is as shown in fig. 10.

The press may be a hydraulic press, but may also be a screw press or a crank press. The press plastically deforms the metal primarily by applying a strong pressure to the blank to grip the joint ball.

For a radial spherical plain bearing with a larger size, if the integral outer race 3 is to hold the spherical plain 2, large-size plastic deformation is required, cracks are easy to generate, in addition, the elastic recovery of materials caused by large deformation is larger, and difficulty is brought to the control of the fit clearance, so a combined structure is adopted, namely, the outer race 3 is divided into an upper body and a lower body, namely an outer race upper body 31 and an outer race lower body 32, the accurate positions of the upper body and the lower body are fixed by two pins 4, the upper body and the lower body are ensured not to be dislocated, and the upper body and the lower body are fastened into a whole by four bolts 5, as shown in fig. 11 and.

The self-lubricating radial spherical plain bearing 1 depends on graphite as a lubricant during working. The blank material of the structure energizing material is nodular cast iron containing a large number of graphite nodules (300-²) The graphite crystal is easy to generate interlayer cleavage, and atoms on the same layer are not easy to separate, so that the graphite presents a flaky structure and has lubricating property. According to the joint ball 2 and the outer ring 3 manufactured by the invention, the self-lubricating radial spherical joint bearing 1 is processed and assembled according to the industry standard, the outer ring 3 is in contact friction with the joint ball 2 at the initial stage of the service process, the bare graphite (and the graphite coated during assembly) on the spherical surface is scraped off by the micro-convex body on the grinding surface, and the graphite film is adsorbed on the whole friction surface by the micro-lamellar tendrilled cloth to form a graphite film. In microcosmic view, the pits on the surfaces of the inner and outer ferrules are filled with thicker graphite, and the contact area of the microprotrusions is only provided with a plurality of graphite crystal sheets. The graphite film has small internal friction coefficient, plays a role in lubrication, isolates dual friction surfaces, and avoids welding which is easy to occur during low-speed heavy-load sliding friction, thereby avoiding adhesion abrasion. Because the graphite has stable property and is oxidized at the temperature of more than 325 ℃, the graphite can exist for a long time at normal temperature. Obviously, a series of drawbacks and limitations (extruded, worn quickly, detached and torn, etc.) such as those of the PTFE lining type spherical plain bearing do not exist in the self-lubricating spherical plain radial bearing 1, and the reliability and life of use will be extended.

Claims

1. A radial spherical plain bearing based on a structure enabling material is characterized by comprising a joint ball (2) and an outer ferrule (3), wherein the joint ball (2) and the outer ferrule (3) are both prepared from the structure enabling material;

the joint ball (2) consists of the following components: c: 3.5% -3.7%, Si: 2.6-2.9%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: not more than 0.2 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;

the outer ring (3) consists of the following components: c: 3.3% -3.5%, Si: 2.9-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: not more than 0.1 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent.

2. A radial spherical bearing based on a structurally energized material according to claim 1, characterized in that the inner microstructures of the joint ball (2) and the outer race (3) are both:

the diameter of the graphite sphere is less than or equal to 25 mu m; the nodularity in the section bar is 100 percent; the density of graphite nodules in the section bar reaches 300-²。

3. A method for the production of a radial spherical plain bearing based on a structurally energized material, as claimed in claim 1 or 2, characterized in that it comprises the following steps:

when a ductile iron pipe or a solid bar used for drawing an outer ring by a vertical continuous casting method is used, preset component materials are melted into molten iron in an induction furnace, and the preset component materials consist of the following components: c: 3.3-3.5%, Si: 1.8-2.1%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.015 percent, Cr: less than or equal to 0.1 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;

step 2, standing the molten iron for not less than 20min, drawing a section by using a vertical continuous casting method, pouring the molten iron in the step 1 into a ladle, and adding a nodulizer and an inoculant into the molten iron to ensure that the silicon content of the molten iron after inoculation and spheroidization reaches 2.6-2.9 percent and the residual magnesium content is 0.035-0.045 percent;

observing the color uniformity of the section bar with one step drawn out from the crystallizer, if the section bar with one step is uniform orange red, continuously injecting the molten iron inoculated and spheroidized in the step 2 into a hearth of the continuous casting furnace to fill the crystallizer so as to continuously perform the drawing process; if the section bars of one step are distributed in a strip-shaped black-and-white alternative manner, adding the inoculant in the step (2) into a hearth of a continuous casting furnace for 1-2 times, adding the carburant into the electric furnace in the step (1), continuously drawing, and observing the color until the color is uniform orange;

step 7, repeating the steps 1 to 5 to obtain an outer ferrule;

4. A method for preparing a radial spherical plain bearing based on a structure enabling material according to claim 3, wherein the metallographic examination and the electron microscope examination in the step 4 are as follows:

5. A method for the manufacture of a radial spherical bearing based on a structurally energized material as claimed in claim 3, characterized in that said normalizing treatment of step 5 consists in:

and (3) preserving the heat of the qualified section at 875-.

6. A method for the production of a radial spherical bearing based on a structurally energized material according to claim 3, characterized in that the step of austempering treatment of step 6: preserving heat for 40-60min at 890-910 ℃, then immersing into a nitrate tank with the temperature range of 255-265 ℃ for quenching, and preserving heat for 40-60 min; taking out and air-cooling to room temperature, and removing the salt stain by using clear water.

7. A method for the manufacture of a radial spherical bearing based on a structural energizing material according to claim 3, characterized in that in step 7, the step of austempering the outer race: preserving heat for 30-60min at 890-910 ℃, then immersing into a nitrate tank with the temperature range of 325-335 ℃ for quenching, and preserving heat for 40-60 min; taking out and air-cooling to room temperature, and removing the salt stain by using clear water.

8. A rod end knuckle bearing based on a structurally energized material according to claim 3, wherein the inoculant in step 2 is 75# Si-Fe or Sr-Si-Fe or Ba-Si-Fe alloy;

the recarburizing agent in the step 2 is graphite, coke or wood carbon.