CN110565006A - rod end joint bearing based on structure enabling material and preparation method - Google Patents
rod end joint bearing based on structure enabling material and preparation method Download PDFInfo
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- CN110565006A CN110565006A CN201910870914.6A CN201910870914A CN110565006A CN 110565006 A CN110565006 A CN 110565006A CN 201910870914 A CN201910870914 A CN 201910870914A CN 110565006 A CN110565006 A CN 110565006A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/08—Making cast-iron alloys
- C22C33/10—Making cast-iron alloys including procedures for adding magnesium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/04—Cast-iron alloys containing spheroidal graphite
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/06—Cast-iron alloys containing chromium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/10—Cast-iron alloys containing aluminium or silicon
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C9/00—Bearings for crankshafts or connecting-rods; Attachment of connecting-rods
- F16C9/04—Connecting-rod bearings; Attachments thereof
Abstract
the invention discloses a rod end joint bearing based on a structure enabling material, which comprises three parts, namely an inner ball sleeve, a middle clamping sleeve and a fisheye outer sleeve bolt, wherein the inner ball sleeve and the middle clamping sleeve are made of the structure enabling material. The invention is characterized in that graphite in the structure enabling material is used as a solid lubricant to replace PETF or aramid fabric in the traditional product, thereby eliminating hidden troubles of falling off, blocking and the like. According to the rod end joint bearing and the preparation method thereof, whether the color of the section just drawn by one step is uniform orange or not is observed, the components of molten iron are timely regulated and controlled to be within a tiny range of eutectic components, and the nodularity is remarkably increased; finally, annealing, rough machining, isothermal quenching and grinding are carried out on the section, the inner ball sleeve and the middle clamping sleeve which have mechanical properties equivalent to those of quenched and tempered steel and self-lubricating properties are prepared, and the rod end joint bearing is assembled.
Description
Technical Field
The invention belongs to the technical field of joint bearings, and particularly relates to a rod end joint bearing based on a structure enabling material.
Background
at present, a common rod end joint bearing on mechanical equipment is a spherical sliding bearing and consists of a spherical inner sleeve, a middle clamping sleeve and a fisheye outer sleeve bolt. The sliding contact surface of the inner sleeve and the middle clamping sleeve is a hinged inner spherical surface and an outer spherical surface, can rotate at any angle and swing within a certain angle range during movement, has an automatic aligning function, has strong tolerance on mechanical assembly and movement precision and large bearing capacity, and is widely applied to engineering machinery, automatic equipment, hydraulic cylinders, forging and pressing machine tools, military industry machinery, hydraulic machinery, joints of fixed-wing airplanes, spherical hinges of helicopters and roots of rotors.
The friction surface of the rod end joint bearing is difficult to coat and store lubricating grease. 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 gasket 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 solid lubricant on the inner spherical surface and the solid lubricant on the outer spherical surface of the inner sleeve replace 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 ball sleeve. 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.
it is known that the rod end joint bearing should have other properties such as self-lubrication, etc. in addition to the mechanical properties (tensile strength, hardness, toughness, elastic modulus, fatigue strength, etc.) that the general structural materials should have. The material with good mechanical properties and one or more other physical and chemical properties (self-lubricating, sound-absorbing, shock-absorbing, good heat-conducting, low-temperature-rising and the like) is called as a structural energized material. Namely, the structural material is endowed with the performances of self lubrication, sound absorption, shock absorption, good heat conduction, low temperature rise and the like on the basis of having enough mechanical properties. "
Disclosure of Invention
The invention aims to provide a rod end joint bearing based on a structure enabling material, and solves the problems that an existing rod end joint bearing is easy to fall off and tear a solid lubricating film, short in service life, large in clearance and poor in reliability.
It is another object of the present invention to provide a method of making a rod end knuckle bearing based on a structurally energized material.
The technical scheme adopted by the invention is that the rod end joint bearing based on the structure enabling material comprises three parts, namely an inner ball sleeve, a middle clamping sleeve and a fisheye outer sleeve bolt, wherein the inner ball sleeve and the middle clamping sleeve are made of the structure enabling material,
The inner ball sleeve material consists of the following components: c: 3.5% -3.7%, Si: 2.6-2.8%, 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 0.3 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;
The middle cutting ferrule comprises the following components: c: 3.3% -3.5%, Si: 2.8-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.1 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent.
The invention is also characterized in that:
The graphite form and distribution in the microstructure of the inner ball sleeve and the middle cutting sleeve are as follows: the diameter of graphite nodules within 12mm from the surface layer of the profile is less than or equal to 25 mu m, and the density of the graphite nodules is more than or equal to 400 graphite nodules per mm2the spheroidization rate is 100 percent; the density of graphite nodules which are 12mm away from the surface is more than or equal to 300 graphite nodules per mm2。
the hardness of the inner ball sleeve is not less than HRC 50; the hardness of the middle cutting sleeve is HRC 38-42.
The invention adopts the technical scheme that a preparation method of a rod end joint bearing based on a structure energizing material comprises the following steps:
step 1, melting preset component materials into molten iron in an electric furnace, wherein the preset component materials comprise the following components: c: 3.5% -3.7%, Si: 1.4-1.6%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.3 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent; after molten iron is melted in an induction furnace, pouring about 300Kg of molten iron into a ladle, and adding an inoculant and a nodulizer into the ladle molten iron so as to ensure that the final silicon content of the molten iron after inoculation and nodulizing is 2.6-2.8 percent and the residual magnesium content is 0.04-0.05 percent;
step 2, injecting the inoculated and spheroidized molten iron in the step 1 into a hearth of a continuous casting furnace through a ladle, then flowing into a crystallizer to be condensed into a tube shell or a bar, nesting with the front end of a crystal guiding rod extending into the crystallizer, starting a drawing machine to carry out stepping drawing on the tube or the bar by drawing the crystal guiding 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, continuously injecting the molten iron inoculated and spheroidized in the step 1 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 1 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 3, after the drawing process in the step 2 is finished, carrying out metallographic detection and electron microscope detection on the obtained section;
Step 4, after the metallographic detection and the electron microscope detection in the step 3 are finished, annealing the section;
Step 5, after the treatment of the step 4, roughly processing the section into an inner ball sleeve semi-finished product, and reserving a grinding amount of 0.2 mm;
step 6, sequentially carrying out isothermal quenching treatment and grinding processing on the semi-finished product of the inner ball sleeve in the step 5 to obtain the inner ball sleeve;
Step 7, repeating the steps 1-6 to obtain a middle cutting sleeve matched with the inner ball sleeve; the middle cutting ferrule comprises the following components: c: 3.3% -3.5%, Si: 2.8-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.1 percent, residual magnesium content of 0.04 percent and the balance of Fe.
step 8, selecting a fisheye outer sleeve bolt made of medium carbon steel or martensitic stainless steel materials, wherein the size of an inner hole of the fisheye outer sleeve is in transition fit with the size of an outer circle of the middle cutting sleeve manufactured in the step 7; pressing the middle clamping sleeve obtained in the step (7) into a fisheye inner hole of the fisheye outer sleeve bolt matched with the middle clamping sleeve, so that the middle clamping sleeve and the fisheye outer sleeve bolt are in transition fit; and (4) sleeving the inner ball sleeve in the step 6 into the middle clamping sleeve manufactured in the step 7, pressing two end faces of the middle clamping sleeve through a rotary rolling process, enabling the inner wall of the middle clamping sleeve to be plastically deformed to hold the inner ball sleeve, enabling the end face of the middle clamping sleeve to be plastically deformed outwards, clamping the bevel chamfer of the fisheye outer sleeve bolt hole, and completing assembly to obtain the rod end joint bearing.
The present invention is also characterized in that,
In the step 1, 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;
in the step 2, the recarburizer is graphite, coke or wood carbon.
The qualified standards of the metallographic detection and the electron microscope detection in the step 3 are as follows: the diameter of graphite nodules within 12mm from the surface layer of the profile is less than or equal to 25 mu m, and the density of the graphite nodules is more than or equal to 400 graphite nodules per mm2The spheroidization rate is 100 percent; the density of graphite nodules which are 12mm away from the surface is more than or equal to 300 graphite nodules per mm2。
the annealing treatment in the step 4 comprises the following specific operations: and (3) preserving the heat of the section material qualified in the step (3) for 90-120min at 875-885 ℃, cooling the section material in a furnace to below 600 ℃, and then cooling the section material in air to room temperature.
The specific operation of the isothermal quenching treatment of the inner ball sleeve in the step 6 is as follows: preserving the heat of the semi-finished product of the inner ball sleeve treated in the step 5 for 40-60min at 890-910 ℃; then soaking in a nitrate tank with the temperature range of 255-265 ℃ for quenching, preserving heat for 40-60min, taking out, air-cooling to room temperature, and removing the salt stain by using clear water.
and 7, the intermediate cutting sleeve isothermal quenching treatment is specifically operated as follows: preserving the temperature of the intermediate ferrule semi-finished product at 890-910 ℃ for 40-60 min; then soaking in a nitrate tank with the temperature range of 325-335 ℃ for quenching, preserving heat for 40-60min, taking out, air-cooling to room temperature, and removing the salt stain by using clear water.
The invention has the beneficial effects that: a rod end joint bearing based on a structure enabling material and a preparation method thereof are disclosed, wherein whether the color of a section 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 eutectic components, the spheroidization rate is remarkably increased, nearly 100% spheroidized eutectic graphite is obtained, the diameter of a graphite sphere is less than or equal to 25 mu m, and the mechanical property damage caused by large blocks of nascent graphite is avoided; finally, annealing, rough machining, isothermal quenching and grinding are carried out on the section bar, an inner ball sleeve and an intermediate clamping sleeve which have mechanical properties equivalent to those of quenched steel and quenched and tempered steel and self-lubricating properties are prepared, and the rod end oscillating bearing is assembled and obtained.
Drawings
FIG. 1 is a schematic representation of a rod end knuckle bearing based on a structurally energized material of the present invention;
FIG. 2 is a cross-sectional view of a small rod end knuckle bearing (inner ball sleeve outer diameter ≤ 60mm) based on a structural energizing material according to the present invention;
FIG. 3 is a cross-sectional view of a large rod end knuckle bearing (inner ball sleeve diameter > 60mm) based on a structural energizing material of the present invention;
FIG. 4 is a schematic illustration of a continuous casting of a profile at a eutectic composition in a method of making a rod end knuckle bearing based on structurally energized material of the present invention;
FIG. 5 is a schematic color representation of a continuous cast profile with off-eutectic composition according to a method of making a rod end joint bearing of the present invention;
FIG. 6 is an SEM image of an electron microscope scanning inspection performed during a rod end spherical plain bearing manufacturing method according to the present invention;
FIG. 7 is a graphite morphology diagram of metallographic examination in a method of manufacturing a rod end spherical plain bearing according to the present invention;
FIG. 8 is a graph illustrating isothermal quenching of the inner ball sleeve in a method of manufacturing a rod end spherical plain bearing according to the present invention;
FIG. 9 is a graph illustrating austempering of the intermediate cutting ferrule in the method of manufacturing a rod end oscillating bearing of the present invention.
In the figure, 1, a rod end joint bearing, 2, an inner ball sleeve,
3. a middle cutting sleeve 31, a middle cutting sleeve upper body 32, a middle cutting sleeve lower body,
4. A fish eye is sleeved with a bolt, 5, a connecting piece.
Detailed Description
the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
the invention relates to a rod end joint bearing based on a structure enabling material, and as shown in figures 1 and 2, the rod end joint bearing 1 comprises three parts, namely an inner ball sleeve 2, a middle clamping sleeve 3 and a fisheye outer sleeve bolt 4. The rod end joint bearing 1 is mainly used for swinging motion and is an important part capable of depending on self structural materials for lubrication, and comprises an inner ball sleeve 2 with self-lubrication and a middle clamping sleeve 3, and a fisheye outer sleeve bolt 4 prepared by a conventional process. The insert surface of the inner ball sleeve 2 is in slidable contact with the inner spherical surface of the middle clamping sleeve 3, the inner ball sleeve 2 can rotate in any angle and swing within a certain angle range, the automatic aligning function is achieved, tolerance of mechanical assembly and movement precision is high, and bearing capacity is high.
The inner ball sleeve material consists of the following components: c: 3.5% -3.7%, Si: 2.6-2.8%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.3 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;
the middle cutting ferrule comprises the following components: c: 3.3% -3.5%, Si: 2.8-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.1 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent.
the graphite form in the microstructure of the inner ball sleeve 2 and the middle cutting sleeve 3 is as follows: the diameter of graphite nodules within 12mm from the surface layer of the profile is less than or equal to 25 mu m, and the density of the graphite nodules is more than or equal to 400 graphite nodules per mm2The spheroidization rate is 100 percent; the density of graphite nodules which are 12mm away from the surface is more than or equal to 300 graphite nodules per mm2。
The hardness of the inner ball sleeve 2 is not less than HRC 50; the hardness of the middle cutting sleeve 3 is HRC 38-42.
As shown in figure 3, a cross-sectional view of the rod end joint bearing 1 is provided when the diameter of the inner ball sleeve 2 is larger than or equal to 100mm, and the middle cutting sleeve 3 is composed of an upper middle cutting sleeve body 31 and a lower middle cutting sleeve body 32, and is formed by connecting the fisheye outer sleeve bolt 4 with the middle cutting sleeve through a plurality of connecting pieces 5, wherein the connecting pieces 5 can be pins and have a fastening effect.
the small rod end joint bearing 1 is assembled by the following method: pressing the middle clamping sleeve 3 into the fisheye outer sleeve bolt 4 to enable the middle clamping sleeve 3 to be in transition fit with the fisheye outer sleeve bolt 4; manually installing the inner ball sleeve 2 into the middle cutting sleeve 3 so that the inner ball sleeve 2 can be movably sleeved in the middle cutting sleeve 3; pressing the upper end surface and the lower end surface of the middle cutting sleeve 3 through special 'opening-blasting' equipment and a mould so that the middle cutting sleeve 3 is inwards plastically deformed to hold the inner ball sleeve 2 and outwards plastically deformed to clamp a chamfer groove of the fisheye outer sleeve bolt 4; the tightness degree of the inner ball sleeve 2 and the middle cutting sleeve 3 is adjusted through a three-point correction machine, so that the inner ball sleeve 2 can move freely in the middle cutting sleeve 3.
The press machine is a hydraulic press, and can also be a screw press or a crank press and the like. The press machine mainly applies strong pressure to the metal blank to enable the metal to generate plastic deformation so as to hold the ball sleeve and clamp the inner hole of the fisheye sleeve; three gyro wheels that have the symmetric distribution on the three-point type correction machinery, two gyro wheels in the below are fixed, and pressure can be adjusted from top to bottom to a gyro wheel in the top, puts into the middle of three gyro wheels with circular workpiece, compresses tightly slightly, and reciprocating rotation can make the oval deviation of circular workpiece man-hour reduce, makes rod end joint bearing 1's interior outer sphere better laminate, nimble rotation and swing.
the large rod end joint bearing (the outer diameter of an inner ball sleeve is more than 60mm) cannot enable the middle clamping sleeve to hold the inner ball sleeve by a 'deep hole' method, and needs to be assembled by the following method: dividing the middle cutting sleeve into a middle cutting sleeve upper body 31 and a middle cutting sleeve lower body 32, turning an inner spherical surface with 0.2mm in advance, and drilling 4 screw holes by matching with the fisheye outer sleeve bolt 4; the upper body and the lower body of the middle clamping sleeve are fixed well by a screw hole and a screw which are matched and drilled, and an inner spherical surface is ground on the inner spherical surface grinding machine. The assembly process is as follows: detaching the middle bayonet sleeve upper body 31 from the fisheye outer sleeve bolt; then the inner ball sleeve 2 is arranged in the fisheye outer sleeve bolt 4, namely, is arranged on the middle cutting sleeve lower body 32; finally, the middle clamping sleeve upper body 31 is arranged in the fisheye outer sleeve bolt 4 and fixedly connected by 2 pins 5.
The spherical surface of the inner spherical sleeve 2 of the rod end joint bearing 1, which is contacted with the middle cutting sleeve 3, does not need to depend on a gasket, and only depends on the graphite exposed on the inner spherical surface of the middle cutting sleeve and the surface of the inner spherical sleeve and the graphite smeared before assembly as a solid lubricant. The graphite is non-volatile, the friction coefficient is small, the shearing resistance is strong, and the wear resistance is good. The graphite is not oxidized until 325 ℃, the use temperature is high, the self-lubricating rod end oscillating bearing 1 can be in service at the temperature below 230 ℃, the lubrication is reliable, and the service life is prolonged by times.
The preparation method of the self-lubricating rod end oscillating bearing 1 mainly comprises the steps of preparing an inner ball sleeve 2 and a middle clamping sleeve 3. The preparation process will be described in detail below. The fisheye outer-sleeved bolt 4 is prepared by adopting medium carbon steel or martensitic stainless steel (used under the light corrosion prevention requirement) and a conventional process because the fisheye outer-sleeved bolt does not need to have self-lubricating property.
the invention relates to a preparation method of a rod end joint bearing based on a structure enabling material, which comprises the following steps of:
Step 1, melting preset component materials into molten iron in a medium-frequency induction furnace, wherein the preset component materials consist of the following components: c: 3.5% -3.7%, Si: 1.4-1.6%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.3 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent; according to the vertical continuous casting process, a part (about 300Kg) of molten iron is poured into a ladle, and a nodulizer and an inoculant are added into the molten iron in the ladle, so that the final silicon content of the inoculated and nodulized molten iron is less than or equal to 2.6-2.8 percent, and the content of residual magnesium is 0.04-0.05 percent;
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 will crystallize graphite in the molten iron into spherical shapes. The inoculant is 75# ferrosilicon or ferrosilicon containing strontium, or ferrosilicon containing barium, or silicon-barium alloy; 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.
And 2, injecting the inoculated and spheroidized molten iron in the step 1 into a hearth of a continuous casting furnace through a ladle, then flowing into a crystallizer to be condensed into a tube shell, and condensing and nesting with the front end of a seeding rod extending into the crystallizer in advance. Starting a drawing machine to lift and draw the crystal bar, and carrying out step-by-step lifting on the tube shell (the step pitch is 40-50mm) to obtain a section;
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 4, continuously injecting the molten iron inoculated and spheroidized in the step 1 into a hearth of a continuous casting furnace to fill the crystallizer so as to continuously perform the drawing process; as shown in FIG. 5, if the section bar with one step is distributed in a strip-shaped black-and-white alternate distribution, and the molten iron component deviates from the eutectic component, the inoculant in the step 1 is 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 of the section bar is changed into uniform orange red, which generally needs 3-5 min.
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.
Drawing a ductile iron hollow section by using vertical continuous casting equipment to be used as a blank for preparing an inner ball sleeve 2 (the outer diameter is more than or equal to 60 mm); if the outer diameter of the inner ball sleeve 2 to be manufactured is less than 60mm, the blank of the continuous casting ductile iron is a solid bar, and the molten iron is condensed into a bar in a crystallizer and can be drawn on horizontal continuous casting equipment.
And 3, after the drawing process in the step 2 is finished, carrying out metallographic detection and electron microscope detection on the obtained section, wherein the standard is as follows: the diameter of graphite nodules within 12mm from the surface layer of the profile is less than or equal to 25 mu m, and the density of the graphite nodules is more than or equal to 400 graphite nodules per mm2the spheroidization rate is 100 percent; the density of graphite nodules which are 12mm away from the surface is more than or equal to 300 graphite nodules per mm2。
As shown in fig. 6, 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. 7, the spheroidization rate of graphite is close to 100%, the graphite is uniformly distributed, and the graphite nodules are uniform and consistent in shape and size. By metallographic detection, whether the section bar reaches 100% eutectic graphite or not can be roughly detected, no primary graphite is required, and the nodularity approaches or reaches 100%.
Step 4, after the metallographic detection and the electron microscope detection in the step 3 are finished, annealing the section; the normalizing treatment comprises the following specific operations: and (3) preserving the heat of the section material qualified in the step (3) for 90-120min at 875-885 ℃, cooling the section material in a furnace to below 600 ℃, and then cooling the section material in air to room temperature. Columnar crystal, dendrite and cast residual stress of the material can be eliminated through the normalizing process.
step 5, after the treatment of the step 4, roughly processing the section into an inner ball sleeve semi-finished product, and reserving a grinding amount of 0.2 mm;
Step 6, sequentially carrying out isothermal quenching treatment and grinding processing on the semi-finished product of the inner ball sleeve in the step 5 to obtain the inner ball sleeve;
As shown in fig. 8, the austempering treatment is specifically performed by: when the effective thickness of the semi-finished product of the inner ball sleeve 2 is less than 15mm, the austenitizing heat preservation time needs 40 minutes; when the effective thickness of the semi-finished product of the inner ball sleeve 2 is larger than 15mm, t is the time required to be prolonged by the super-thick part, namely t is 2 multiplied by the super-thick part (mm), and t is min. Keeping the temperature of the semi-finished product of the inner ball sleeve 2 at 890-910 ℃ for more than 40min, then soaking the semi-finished product into a nitrate tank with the temperature range of 255-265 ℃ for quenching, and keeping the temperature for 40-60 min; taking out the quenched semi-finished product of the inner ball sleeve 2, air-cooling to room temperature, and removing the salt stain by using clear water. After isothermal quenching treatment, the hardness of the inner ball sleeve 2 is HRC46-50, and the hardness range ensures that the inner ball sleeve 2 has higher strength and wear resistance. After the inner ball sleeve is stressed in service, stress induced hardening occurs in the surface layer micrometers of the inner ball sleeve, the hardness is increased to be more than HRC58, and the inner ball sleeve is more wear-resistant. Because the graphite and cementite in the material are fine and dense, the curvature radius is small, and the dissolution speed to the surrounding matrix is high, in the isothermal quenching process: 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 1-6 to obtain an intermediate cutting sleeve matched with the inner ball sleeve (the contents of C, Si, Mn and Cr are adjusted);
as shown in fig. 9, the intermediate sleeve 3 after rough machining is austempered. Preserving the temperature of the semi-finished product of the middle cutting sleeve 3 for more than 40min at 890-910 ℃; immersing the middle cutting sleeve 3 into a nitrate tank with the temperature range of 325-335 ℃ for quenching, and preserving heat for 40-60 min; taking out the quenched semi-finished product of the middle cutting sleeve 3, air-cooling to room temperature, and removing the salt stain by using clear water. After isothermal quenching treatment, the hardness of the middle cutting sleeve 3 is HRC 38-42, the middle cutting sleeve has medium strength and also has plastic deformation capacity, and the sufficient plastic deformation amount is ensured without generating cracks when subsequent assembly processes such as 'opening explosion' or 'circle locking' (namely the middle cutting sleeve 3 clamps the spherical inner ball sleeve 2).
if the split type middle clamping sleeve (31, 32) is manufactured, the quenching hardness can be improved after the screw hole is drilled.
Step 8, pressing the middle clamping sleeve 3 into the fisheye outer sleeve bolt 4 to enable the middle clamping sleeve 3 to be in transition fit with the fisheye outer sleeve bolt 4; manually pressing the inner ball sleeve 2 into the middle cutting sleeve 3 so that the inner ball sleeve 2 is movably sleeved in the middle cutting sleeve 3; pressing the upper end surface and the lower end surface of the middle cutting sleeve 3 through special 'opening-exploding' equipment so that the middle cutting sleeve 3 is inwards plastically deformed to hold the inner ball sleeve 2 and outwards plastically deformed to clamp a chamfer groove of the fisheye outer sleeve bolt 4; the tightness degree of the inner ball sleeve 2 and the middle cutting sleeve 3 is adjusted through a three-point correction machine, so that the inner ball sleeve 2 can move freely in the middle cutting sleeve 3. For the self-lubricating rod end oscillating bearing 1 with the diameter of the inner spherical sleeve being more than or equal to 60mm, the middle cutting sleeve 3 is divided into an upper body and a lower body, the upper body and the lower body are directly turned and ground into an inner spherical surface, the excircle is in transition fit with the fisheye outer sleeve bolt 4, the lower body 32 of the middle cutting sleeve is pressed into the fisheye outer sleeve bolt 4 and is arranged into the inner spherical sleeve 2, and then the upper body 31 of the middle cutting sleeve is pressed into the fisheye outer sleeve bolt 4 to ensure that the; four screw holes are drilled on the side surface of the fisheye outer sleeve bolt 4 in advance, and the fisheye outer sleeve bolt 4 is fastened with the upper body and the lower body of the middle clamping sleeve 3 by four connecting pieces 5.
When the assembled rod end joint bearing 1 works, under the action of external force, the inner ball sleeve 2 and the middle cutting sleeve 3 are made of structure energizing materials, and graphite is exposed on the inner spherical surface and the outer spherical surface which are mutually rubbed. Cleavage easily occurs between the crystal layers of the graphite, and atoms in the same layer are not easy to separate, so that the graphite presents a flaky structure and has lubricating property. The friction coefficient of graphite in the atmosphere is 0.05-0.19, and the higher the humidity is, the lower the friction coefficient is. Graphite does not begin to oxidize until 325 ℃, which is much higher than the service temperature of polytetrafluoroethylene, 165 ℃. The rod end joint bearing 1 prepared by the invention can be in service at the temperature below 230 ℃, at the initial stage of the service process, the middle cutting sleeve 3 is in contact friction with the inner ball sleeve 2, the bare graphite on the spherical surface is scraped off by the microprotrusions on the opposite grinding surface, and the graphite is adsorbed on the whole friction surface by the micro lamellar tendrilled cloth to form a graphite layer 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 the gluing which is easy to occur during low-speed heavy-load sliding friction, thereby avoiding the adhesive wear. 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. The contact spherical surface of the inner ball sleeve and the middle cutting sleeve is not adhered with lubricating materials such as PTFE and the like, only graphite with exposed surfaces is used as a solid lubricant, the structure is simple, the manufacture is convenient, the hardness of the friction spherical surface is improved, and the wear resistance, the fatigue resistance and the use reliability are realized.
Claims (9)
1. a rod end joint bearing based on a structure enabling material is characterized in that the rod end joint bearing (1) comprises three large parts, namely an inner ball sleeve (2), a middle cutting sleeve (3) and a fisheye outer sleeve bolt (4), the inner ball sleeve (2) and the middle cutting sleeve (3) are made of the structure enabling material,
the inner ball sleeve (2) is made of the following components: c: 3.5% -3.7%, Si: 2.6-2.8%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.3 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent;
the middle clamping sleeve (3) comprises the following components: c: 3.3% -3.5%, Si: 2.8-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.1 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent.
2. A rod end knuckle bearing based on structurally energized material according to claim 1, characterized in that the graphite morphology and distribution in the microstructure of the inner ball sleeve (2) and middle ferrule (3) is: the diameter of graphite nodules within 12mm from the surface layer of the profile is less than or equal to 25 mu m, and the density of the graphite nodules is more than or equal to 400 graphite nodules per mm2the spheroidization rate is 100 percent; the density of graphite nodules which are 12mm away from the surface is more than or equal to 300 graphite nodules per mm2。
3. A rod end knuckle bearing based on a structurally energized material according to claim 1, characterized in that the hardness of the inner ball sleeve (2) is not less than HRC 50; the hardness of the middle clamping sleeve (3) is HRC 38-42.
4. A method of manufacturing a rod end knuckle bearing based on a structurally energized material according to any one of claims 1-3, comprising the steps of:
Step 1, melting preset component materials into molten iron in an electric furnace, wherein the preset component materials comprise the following components: c: 3.5% -3.7%, Si: 1.4-1.6%, Mn: less than or equal to 0.3 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.3 percent, residual magnesium content of 0.04 percent and the balance of Fe, wherein the sum of the mass percent of the components is 100 percent; after molten iron is melted in an induction furnace, pouring about 300Kg of molten iron into a ladle, and adding an inoculant and a nodulizer into the ladle molten iron so as to ensure that the final silicon content of the molten iron after inoculation and nodulizing is 2.6-2.8 percent and the residual magnesium content is 0.04-0.05 percent;
step 2, injecting the inoculated and spheroidized molten iron in the step 1 into a hearth of a continuous casting furnace through a ladle, then flowing into a crystallizer to be condensed into a tube shell or a bar, nesting with the front end of a crystal guiding rod extending into the crystallizer, starting a drawing machine to carry out stepping drawing on the tube or the bar by drawing the crystal guiding 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, continuously injecting the molten iron inoculated and spheroidized in the step 1 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 1 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 3, after the drawing process in the step 2 is finished, carrying out metallographic detection and electron microscope detection on the obtained section;
Step 4, after the metallographic detection and the electron microscope detection in the step 3 are finished, annealing the section;
Step 5, after the treatment of the step 4, roughly processing the section into an inner ball sleeve semi-finished product, and reserving a grinding amount of 0.2 mm;
step 6, sequentially carrying out isothermal quenching treatment and grinding processing on the semi-finished product of the inner ball sleeve in the step 5 to obtain the inner ball sleeve;
step 7, repeating the steps 1-6 to obtain a middle cutting sleeve matched with the inner ball sleeve; the middle cutting ferrule comprises the following components: c: 3.3% -3.5%, Si: 2.8-3.2%, Mn: less than or equal to 0.15 percent, P: less than or equal to 0.015%, S: less than or equal to 0.01 percent, Cr: less than or equal to 0.1 percent, residual magnesium content of 0.04 percent and the balance of Fe.
Step 8, selecting a fisheye outer sleeve bolt made of medium carbon steel or martensitic stainless steel materials, wherein the size of an inner hole of the fisheye outer sleeve is in transition fit with the size of an outer circle of the middle cutting sleeve manufactured in the step 7; pressing the middle clamping sleeve obtained in the step (7) into a fisheye inner hole of the fisheye outer sleeve bolt matched with the middle clamping sleeve, so that the middle clamping sleeve and the fisheye outer sleeve bolt are in transition fit; and (4) sleeving the inner ball sleeve in the step (6) into the middle clamping sleeve manufactured in the step (7), and pressing two end faces of the middle clamping sleeve to enable the inner wall of the middle clamping sleeve to be plastically deformed to hold the inner ball sleeve, so that the end faces of the middle clamping sleeve are plastically deformed to clamp the bevel chamfer of the fisheye outer sleeve bolt hole, and completing assembly to obtain the rod end joint bearing.
5. A rod end knuckle bearing based on a structure enabling material according to claim 4, characterized in that the inoculant in step 1 is 75# Si-Fe or Sr-Si-Fe or Ba-Si-Fe alloy;
The nodulizer is rare earth magnesium, yttrium heavy rare earth or magnesium alloy;
The recarburizing agent in the step 2 is graphite, coke or wood carbon.
6. A rod end oscillating bearing based on a structurally energized material according to claim 4, characterized in that the passing standards of metallographic examination and electron microscopy examination in step 3 are: the diameter of graphite nodules within 12mm from the surface layer of the profile is less than or equal to 25 mu m, and the density of the graphite nodules is more than or equal to 400 graphite nodules per mm2The spheroidization rate is 100 percent; the density of graphite nodules which are 12mm away from the surface is more than or equal to 300 graphite nodules per mm2。
7. A rod end knuckle bearing based on structurally energized material according to claim 4, wherein the annealing process of step 4 is specifically performed by: and (3) preserving the heat of the section material qualified in the step (3) for 90-120min at 875-885 ℃, cooling the section material in a furnace to below 600 ℃, and then cooling the section material in air to room temperature.
8. A rod end knuckle bearing based on structurally energized material according to claim 4, wherein the step 6 inner ball sleeve austempering process is specifically operative to: preserving the heat of the semi-finished product of the inner ball sleeve treated in the step 5 for 40-60min at 890-910 ℃; then soaking in a nitrate tank with the temperature range of 255-265 ℃ for quenching, preserving heat for 40-60min, taking out, air-cooling to room temperature, and removing the salt stain by using clear water.
9. a rod end knuckle bearing based on structurally energized material according to claim 4, wherein the step 7 intermediate ferrule austempering process is specifically operative to: preserving the temperature of the intermediate ferrule semi-finished product at 890-910 ℃ for 40-60 min; then soaking in a nitrate tank with the temperature range of 325-335 ℃ for quenching, preserving heat for 40-60min, taking out, air-cooling to room temperature, and removing the salt stain by using clear water.
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| CN111482564A (en) * | 2020-03-31 | 2020-08-04 | 包头钢铁（集团）有限责任公司 | Method for judging cause of transverse crack on corner of plate blank surface |
| CN112210718A (en) * | 2020-09-28 | 2021-01-12 | 西安理工大学 | High-thermal-conductivity and anti-melting-loss iron-based material for aluminum alloy die-casting die and preparation method thereof |
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| CN112210718A (en) * | 2020-09-28 | 2021-01-12 | 西安理工大学 | High-thermal-conductivity and anti-melting-loss iron-based material for aluminum alloy die-casting die and preparation method thereof |
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Application publication date: 20191213 |