阅读说明：本技术 厚壁铝基双金属轴承及制作方法 (Thick-wall aluminum-based bimetallic bearing and manufacturing method thereof ) 是由 尹忠慰 于 2021-07-16 设计创作，主要内容包括：本发明公开了一种厚壁铝基双金属轴承及制作方法,制作方法包括：除油处理、除锈处理、助镀处理、烘干处理、热浸镀处理、浇铸处理、保温处理及空冷,本发明工艺方法简单、制造成本低、适合于大批量生产。通过上述制作方法制得的厚壁铝基双金属轴承包括：钢背、与所述钢背相连的结合层以及与所述结合层相连的耐磨层,本发明厚壁铝基双金属轴承具有较高的强度和刚度,应用领域更加广泛,尤其可适用于风电、船舶等行业。(The invention discloses a thick-wall aluminum-based bimetallic bearing and a manufacturing method thereof, wherein the manufacturing method comprises the following steps: the invention has the advantages of simple process method, low manufacturing cost and suitability for mass production. The thick-wall aluminum-based bimetallic bearing prepared by the preparation method comprises the following steps: the thick-wall aluminum-based bimetallic bearing has higher strength and rigidity, has wider application field, and is particularly suitable for industries such as wind power, ships and the like.)

1. The thick-wall aluminum-based bimetallic bearing is characterized by comprising a steel back, a bonding layer connected with the steel back and a wear-resistant layer connected with the bonding layer.

2. A thick-walled aluminium-based bimetallic bearing as claimed in claim 1, wherein the bonding layer comprises or consists of: al and Fe.

3. A thick-walled aluminium-based bimetallic bearing as claimed in claim 1, wherein the bonding layer is Al₃Fe and Al₅Fe₂A metal mixture of (a).

4. A thick-walled aluminium-based bimetallic bearing as claimed in claim 1, wherein the wear layer comprises or consists of: al, Cu, Sn, Ni, Si, Fe, Mn, Ti, Pb, Zn, Mg.

5. A thick-walled aluminum-based bimetallic bearing as in claim 1, wherein said wear resistant layer comprises, in mass percent: 0.7-1.3% of Cu, 17.5-22.5% of Sn, 0.1% of Ni, 0.7% of Si, 0.7% of Fe, 0.7% of Mn, 0.2% of Ti and the balance of Al;

or Cu 0.8-1.2%, Sn 0.2%, Ni 0.2%, Si 1.0-2.0%, Fe 0.6%, Mn 0.3%, Ti 0.2%, Pb 0.7-1.3%, Zn 4.4-5.5%, Mg 0.6%, and the balance of Al.

6. A thick-walled aluminum-based bimetallic bearing as in claim 4, wherein the sum of Si, Fe, Mn in the contained composition of said wear resistant layer is not more than 1% by mass.

7. A thick-walled aluminium-based bimetallic bearing as in claim 1, wherein the bonding layer has a layer thickness of 5 to 30 microns.

8. A thick-walled aluminium-based bimetallic bearing as claimed in claim 1, wherein the steel backing has a layer thickness greater than that of the wear layer.

9. The manufacturing method of the thick-wall aluminum-based bimetallic bearing is characterized by comprising the following steps of:

step 1, preparing a steel back, and performing oil removal treatment and rust removal treatment on the surface of the steel back;

step 2, immersing the steel back subjected to oil removal treatment and rust removal treatment into a plating assistant agent for plating assistant treatment;

step 3, drying the steel back after the plating assisting treatment, wherein the surface of the steel back after the drying treatment is covered with a layer of anti-oxidation layer;

step 4, preparing molten alloy liquid, immersing the steel back with the surface covered with the anti-oxidation layer into the molten alloy liquid for hot dip coating treatment, and covering the surface of the steel back with an alloy layer after the hot dip coating treatment;

step 5, preparing a die, preheating the die, placing the steel backing covered with the alloy layer on the surface in the die, and pouring the molten alloy liquid in the step 4 into the die for casting treatment before the alloy layer is completely solidified; at the moment, a bonding layer is formed on the contact surface of the alloy layer and the molten alloy liquid, and the outer layer of the molten alloy liquid forms a wear-resistant layer;

and 6, taking the cast blank out of the die for heat preservation treatment, and air-cooling to obtain the thick-wall aluminum-based bimetallic bearing.

10. A method of making a thick-walled aluminium-based bimetallic bearing as claimed in claim 9, characterised in that said step of forming is carried outThe plating assistant agent in the step 2 comprises the following components: KF.2H₂O、KCl、NiCl₂And H₂O。

Technical Field

The invention relates to the technical field of bearing processing, in particular to a thick-wall aluminum-based bimetallic bearing and a manufacturing method thereof.

Background

The common metal sliding bearing alloy materials mainly comprise babbitt metal, copper-based alloy and aluminum-based alloy. The microstructure of babbitt metal is a classical "dual phase structure" in which hard and brittle eutectic compound phases are distributed in a soft Sn or Pb matrix structure which provides good deformability and lubricity characteristics. The alloy has good embedding property, compliance, seizure resistance, friction reduction, low thermal expansion coefficient and good process performance, the hard eutectic compound phase can improve the wear resistance and mechanical strength of the alloy, but the strength of the matrix is very low, and the bearing capacity and fatigue strength of the matrix can be greatly reduced when the working temperature is increased to 100 ℃, so that the alloy can only be applied to small and light-load automobile engine bearing bushes or bushings. The copper-based alloy has higher fatigue strength than babbitt alloy, has better self-lubricating property after being added with certain soft metals such as tin, lead, cadmium, antimony, zinc, bismuth and the like, can meet the use requirements of modern high-speed high-load engines under various working conditions, but is poorer in embeddability, smoothness and seizure resistance than babbitt alloy. Zn and Cu elements are added into the aluminum-based alloy and are dissolved in the aluminum matrix in a solid solution manner, so that the solid solution strengthening effect can be achieved, and the Si element is added into the matrix, so that a hard Si particle phase can be formed, and the effect of strengthening the mechanical property of the alloy is achieved. On the other hand, addition of Sn to an aluminum alloy can form a soft Sn phase in the alloy matrix, thereby exhibiting good lubricating properties. Therefore, the aluminum alloy not only has good fatigue strength and bearing capacity, but also has high temperature resistance which is not possessed by babbit alloy. Because the aluminum alloy has higher comprehensive mechanical property, heat conduction property and good corrosion resistance, and has rich resources and low price, the aluminum-based bearing alloy is more and more widely applied.

At present, the aluminum-based bimetallic bearing is mainly prepared by a rolling composite method and a sputtering deposition method. The rolling composite method has higher requirements on equipment, large mechanical deformation and large energy consumption are required in the rolling process, a good metallurgical bonding interface can be formed after long-time diffusion annealing after rolling, the production flow is complex, and the rolling composite method is not suitable for mass production. In addition, the rolling and cladding method is only suitable for manufacturing the thin-wall bearing bush, the thickness of the aluminum alloy layer is 0.4-1.5mm, and the thickness of the steel backing is about 1-4 mm. The sputtering deposition method has high requirements on equipment, high preparation cost and low production efficiency, and the thickness of the prepared aluminum alloy layer is between several microns and dozens of microns, so the method is not suitable for mass production. Moreover, in the wind power and marine industries, the requirements for bearings include: high temperatures, large axial forces, large load variations and impacts are required, and therefore, thin-walled aluminum-based bearing shells are limited in their use in such industries.

Disclosure of Invention

The invention aims to provide a thick-wall aluminum-based bimetallic bearing and a manufacturing method thereof.

In order to achieve the purpose, the invention provides a thick-wall aluminum-based bimetallic bearing which comprises a steel back, a bonding layer connected with the steel back and a wear-resistant layer connected with the bonding layer.

Preferably, the bonding layer comprises or consists of: al and Fe.

Preferably, the bonding layer is Al₃Fe and Al₅Fe₂A metal mixture of (a).

Preferably, the wear resistant layer comprises or consists of the following elements: al, Cu, Sn, Ni, Si, Fe, Mn, Ti, Pb, Zn, Mg.

Preferably, the wear-resistant layer comprises the following components in percentage by mass: 0.7-1.3% of Cu, 17.5-22.5% of Sn, 0.1% of Ni, 0.7% of Si, 0.7% of Fe, 0.7% of Mn, 0.2% of Ti and the balance of Al;

or Cu 0.8-1.2%, Sn 0.2%, Ni 0.2%, Si 1.0-2.0%, Fe 0.6%, Mn 0.3%, Ti 0.2%, Pb 0.7-1.3%, Zn 4.4-5.5%, Mg 0.6%, and the balance of Al.

Preferably, in the containing composition of the wear-resistant layer, the sum of the mass percentages of Si, Fe, and Mn is not more than 1%.

Preferably, the layer thickness of the bonding layer is 5-30 microns.

Preferably, the layer thickness of the steel backing is greater than the layer thickness of the wear resistant layer.

In order to achieve the above object, the present invention further provides a method for manufacturing a thick-walled aluminum-based bimetallic bearing, the method comprising:

step 1, preparing a steel back, and performing oil removal treatment and rust removal treatment on the surface of the steel back;

step 2, immersing the steel back subjected to oil removal treatment and rust removal treatment into a plating assistant agent for plating assistant treatment;

step 3, drying the steel back after the plating assisting treatment, wherein the surface of the steel back after the drying treatment is covered with a layer of anti-oxidation layer;

step 4, preparing molten alloy liquid, immersing the steel back with the surface covered with the anti-oxidation layer into the molten alloy liquid for hot dip coating treatment, and covering the surface of the steel back with an alloy layer after the hot dip coating treatment;

step 5, preparing a die, preheating the die, placing the steel backing covered with the alloy layer on the surface in the die, and pouring the molten alloy liquid in the step 4 into the die for casting treatment before the alloy layer is completely solidified; at the moment, a bonding layer is formed on the contact surface of the alloy layer and the molten alloy liquid, and the outer layer of the molten alloy liquid forms a wear-resistant layer;

and 6, taking the cast blank out of the die for heat preservation treatment, and air-cooling to obtain the thick-wall aluminum-based bimetallic bearing.

Preferably, the plating assistant agent in step 2 comprises the following components: KF.2H₂O、KCl、NiCl₂And H₂O。

The beneficial effects of the above technical scheme are that:

compared with a rolled composite aluminum-based bearing bush, the invention has the beneficial effects that: 1) the process for preparing the aluminum-based bearing bush by rolling and compounding is complex, and the steps of pretreatment of a steel plate and an aluminum plate, rolling, heat treatment after rolling, edge shearing, straightening, edge rolling and the like are required; the process method of the invention only needs pretreatment, plating assistant, smelting, hot dipping and casting, and heat preservation and cooling to prepare the finished bearing bush, and the process is relatively simple; 2) the thickness of the aluminum-based bearing bush steel back prepared by the rolling composite process and the thickness of the aluminum layer are both limited, wherein the thickness of the steel back is between 1mm and 4mm, and the thickness of the aluminum alloy layer is between 0.4mm and 1.5 mm; the thickness of the steel back and the thickness of the aluminum layer of the aluminum-based bearing bush prepared by the invention are not limited theoretically, and the aluminum-based composite bearing bush with any thickness can be designed; 3) the aluminum-based bearing bush prepared by the rolling composite process has insufficient rigidity and high requirement on the processing precision of a bearing seat, and can only be applied to automobile engines and diesel engines generally, while the thick-wall aluminum-based bearing bush prepared by the invention has higher strength and rigidity and wider application field, and is particularly suitable for industries such as wind power, ships and the like.

Compared with the sputtering deposition of the aluminum-based bearing bush, the invention has the following effects: 1) the process for preparing the aluminum-based bearing bush by sputtering deposition has high requirements, and the steps of plating by using a magnetron sputtering deposition technology, adjusting the frequency and the temperature of a magnetron target and the like are required; the process method only needs pretreatment, plating assisting, smelting, hot dipping and casting, and heat preservation and cooling to prepare the finished bearing bush, and the process requirement is relatively low; 2) sputtering equipment used for preparing the aluminum-based bearing bush by sputtering deposition has high cost and low production efficiency, and is not suitable for mass production; the thick-wall aluminum-based bearing bush prepared by the invention has low cost and high efficiency, can be produced in large batch, has higher strength and rigidity, has wider application field, and is particularly suitable for industries such as wind power, ships and the like.

Drawings

Fig. 1 is a structural view of a thick-walled aluminum-based bimetallic bearing according to the first or second embodiment of the present invention;

FIG. 2 is a block diagram of a sector tile according to a third embodiment;

fig. 3 is a structural view of a thrust shoe of the third embodiment;

FIG. 4 is a view showing the construction of a curved tile according to the fourth embodiment;

FIG. 5 is a view showing the construction of the radial tiles of the fourth embodiment;

FIG. 6 is a graph showing the variation of the bonding strength curves of the finished products of this embodiment at different immersion plating times.

Reference numerals: a wear resistant layer 1; a bonding layer 2; a steel backing 3; a sector-shaped tile 4; a bearing seat 5; and arc-shaped tiles 6.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are only for the purpose of illustrating the present invention and are not to be construed as limiting the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As shown in fig. 1, the present invention provides a thick-walled aluminum-based bimetallic bearing comprising a steel backing 3, a bonding layer 2 connected to the steel backing 3, and a wear resistant layer 1 connected to the bonding layer.

The steel back 3 is preferably made of a workpiece made of steel-based metal materials such as 10 steel, 15 steel, 25 steel and the like, and the workpiece is cylindrical in shape.

The bonding layer 2 comprises or consists of the following elements: al and Fe. And the bonding layers 2 are connected to each other by a solution metallurgical connection, the bonding layers 2 being disposed on the outer surface of the steel back 3.

In this embodiment, the bonding layer 2 is Al₃Fe and Al₅Fe₂The thickness of the bonding layer 2 is 5-30 microns.

The wear resistant layer 1 comprises or consists of the following elements: al, Cu, Sn, Ni, Si, Fe, Mn, Ti, Pb, Zn, Mg. The wear-resistant layer 1 is arranged on one surface, deviating from the steel backing 3, of the combining layer 2, and the layer thickness of the steel backing 3 is larger than that of the wear-resistant layer 1.

Preferably, the wear-resistant layer 1 comprises the following components in percentage by mass: 0.7-1.3% of Cu, 17.5-22.5% of Sn, 0.1% of Ni, 0.7% of Si, 0.7% of Fe, 0.7% of Mn, 0.2% of Ti and the balance of Al;

or Cu 0.8-1.2%, Sn 0.2%, Ni 0.2%, Si 1.0-2.0%, Fe 0.6%, Mn 0.3%, Ti 0.2%, Pb 0.7-1.3%, Zn 4.4-5.5%, Mg 0.6%, and the balance of Al. Wherein, in the contained components of the wear-resistant layer 1, the sum of the mass percentages of Si, Fe and Mn is not more than 1%.

In this embodiment, the wear-resistant layer 1 is AlSn20Cu or alzn5si1.5cu1pb1mg.

In the present example, 10 steel, 15 steel, and 25 steel were selected as the steel backing 3, AlSn20Cu and alzn5si1.5cu1pb1mg were selected as the wear-resistant layer 1, and 20, 25, and 30 μm in thickness of the bonding layer 2 were selected for experimental comparison, and the results are shown in tables 1 and 2.

Steel backing	Wear resistant layer	Thickness of bonding layer (micrometer)	Bonding strength
				10 steel	AlSn20Cu	20	44
10 steel	AlSn20Cu	25	40
				10 steel	AlSn20Cu	30	35
15 steel	AlSn20Cu	20	43
				15 steel	AlSn20Cu	25	38
15 steel	AlSn20Cu	30	35
				25 steel	AlSn20Cu	20	42
25 steel	AlSn20Cu	25	40
				25 steel	AlSn20Cu	30	36

TABLE 1 bond strengths based on thickness of different steel backs and bond layers under AlSn20Cu wear layers

Steel backing	Wear resistant layer	Thickness of bonding layer (micrometer)	Bonding strength
				10 steel	AlZn5Si1.5Cu1Pb1Mg	20	44
10 steel	AlZn5Si1.5Cu1Pb1Mg	25	42
				10 steel	AlZn5Si1.5Cu1Pb1Mg	30	35
15 steel	AlZn5Si1.5Cu1Pb1Mg	20	43
				15 steel	AlZn5Si1.5Cu1Pb1Mg	25	40
15 steel	AlZn5Si1.5Cu1Pb1Mg	30	30
				25 steel	AlZn5Si1.5Cu1Pb1Mg	20	40
25 steel	AlZn5Si1.5Cu1Pb1Mg	25	38
				25 steel	AlZn5Si1.5Cu1Pb1Mg	30	34

TABLE 2 bond strengths based on different thicknesses of steel backing and bond layer under AlZn5Si1.5Cu1Pb1Mg wear layer

In particular, the bonding strengths in tables 1 and 2 were measured according to ISO 4386-2-2012.

The invention also provides a manufacturing method for manufacturing the thick-wall aluminum-based bimetallic bearing, which comprises the following steps:

step 1, preparing a steel back, and performing oil removal treatment and rust removal treatment on the surface of the steel back.

The surface of the steel back needs to be subjected to oil removal and rust removal pretreatment, and if the surface of the steel back is not subjected to oil removal and rust removal treatment, oil stains and an oxidation film on the surface of the steel back can seriously hinder mutual diffusion between elements of molten alloy liquid and the steel back, so that a complete combined layer 2 cannot be formed subsequently, and the bearing is low in combination strength and poor in material performance.

In an exemplary embodiment, the oil removal process is: heating a 15 mass percent NaOH solution to 60-80 ℃, then immersing the steel back into the heated NaOH solution for 5-10min for degreasing, and then taking out the steel back to be cleaned by clear water to remove the residual NaOH solution on the surface of the steel back.

The invention adopts NaOH solution as degreasing liquid, and grease and sodium hydroxide are subjected to saponification reaction to generate higher fatty acid sodium and glycerin which can be mixed with water, thereby achieving the purpose of degreasing. The purpose of oil removal is to improve the wettability between the plating assistant agent and the steel backing in the subsequent plating assistant treatment. If the oil removal is not complete, the oil area of the steel backing has poor wettability, plating leakage is generated, and an oxidation film is generated after the plating leakage area is oxidized, so that mutual diffusion between elements of molten alloy liquid and the steel backing is hindered, the integrity of an intermediate metallurgical layer is further influenced, and the problem of poor bonding of the oxidation film area is caused.

In an exemplary embodiment, the descaling process is: the steel back after oil removal treatment is immersed in HCl with the concentration of 15% at normal temperature for 1-5min for rust removal, and then the steel back is taken out and cleaned by clear water to remove residual HCl solution on the surface of the steel back.

The invention adopts HCl solution as rust removing liquid, rust removal is carried out by acid cleaning, iron oxide reacts with HCl to generate FeCl₃Or FeCl₂And water, thereby achieving the effect of removing the oxide. The purpose of rust removal is to remove the residual oxide film on the steel backing. As mentioned above, the presence of the oxide film prevents interdiffusion between the steel and aluminum elements, affecting the integrity of the intermetallurgical layer, resulting in poor bonding of the oxide film regions.

And 2, immersing the steel back subjected to the oil removal treatment and the rust removal treatment into a plating assistant agent for plating assistant treatment.

And 3, drying the steel back subjected to the plating assisting treatment, wherein the surface of the steel back subjected to the drying treatment is covered with a layer of anti-oxidation layer.

The plating assistant treatment can activate the surface of steel, promote the wetting between the alloy liquid and the steel base and react during hot dipping, and improve the quality of the plating layer. Combining the step 2 and the step 3, the function of the plating assistant agent mainly comprises the following aspects:

1. isolation: after plating assisting treatment and drying treatment, a salt film anti-oxidation layer is hung on the surface of the steel back surface, the surface of the steel back is separated from air, and further oxidation of the clean steel base surface obtained by degreasing and pickling is prevented;

2. infiltration: the surface tension of the steel backing and the molten alloy liquid is reduced, and the infiltration capacity of the molten alloy liquid on the surface of the steel base is improved;

3. purification effect: in the plating assistant treatment process, the plating assistant agent can remove impurities such as residual iron salt, oxides and the like on the back surface of the steel, and in the subsequent hot dipping treatment process, the salt film oxidation-resistant layer formed through the plating assistant treatment can generate chemical reaction with various harmful impurities in the molten alloy liquid to remove the impurities in the form of scum;

4. activation: the salt film oxidation-resistant layer formed by plating-assisting treatment and drying treatment can be quickly decomposed at the temperature of subsequent hot dipping treatment to generate a series of chemical reactions, so that the surface of the steel backing is further activated, the normal reaction process of the aluminum-iron alloy is promoted, and a plating layer with firm adhesion is obtained.

In an exemplary embodiment, the plating-assist process is: and (3) preheating the plating assistant agent to 60-80 ℃, immersing the steel back subjected to oil removal treatment and rust removal treatment in the step (1) into the plating assistant agent, and keeping for 2-7 min for plating assistant. The invention adopts water-soluble salt solution as plating assistant, and the water-soluble salt solution comprises KF & 2H₂O、KCl、 NiCl₂And H₂O。

In an exemplary embodiment, the drying process is: and taking the steel back subjected to plating assistant treatment out of the plating assistant agent, baking the steel back at 100-250 ℃, keeping for 5-20 min, and drying.

And 4, preparing molten alloy liquid, immersing the steel back with the surface covered with the salt film anti-oxidation layer into the molten alloy liquid for hot dip coating, and covering the surface of the steel back with an aluminum alloy layer after the hot dip coating.

In an exemplary embodiment, a molten alloy is melted by placing a pure aluminum ingot in a medium frequency induction melting furnace and heating to 730 ℃, then adding an Al-Cu or Al-Si intermediate alloy, finally adding low melting point metals such as pure tin or pure Zn according to different application scenes of a bearing bush, after all the substances are fully melted, uniformly stirring by using a graphite rod, adding 0.3 wt% of a refining agent according to the mass of the melted metals for refining and degassing, and finally uniformly scattering a covering agent on the surface of the melt. Wherein, the addition of Sn is 6-40% by mass of the total metal to be smelted, and the Al-Sn alloy obtained after the Sn is added has the characteristics of excellent wear resistance, corrosion resistance and embeddability, and simultaneously has relatively high bearing capacity and fatigue strengthIt is widely applied to engines of automobiles, tractors, ships and the like. The addition amount of Zn is 3-5%, and the Al-Zn alloy obtained after Zn is added has high bearing capacity and can be applied to heavy-duty bearings. In the present invention, the refining agent may be a conventional refining agent known in the art, and the main component of the refining agent is C₂Cl₆、KCl，K₃AlF₆Etc., the coating agent may also be a conventional coating agent known in the art, whose main component is KCl, NaCl, Na₃AlF₆And the like. The invention prepares the components of the aluminum alloy through smelting treatment to obtain the predetermined aluminum alloy melt, and finishes the preparation work.

Before hot dipping treatment, a smelting spoon is used for removing the covering agent on the surface of the aluminum alloy melt to expose bright aluminum alloy melt, the steel back dried in the step 3 is immersed into the aluminum alloy melt, the covering agent is scattered, and hot dipping treatment is carried out for 1min-10min at the temperature of 700-760 ℃.

In the hot dipping process, the steel back is dipped into an aluminum alloy melt (aluminum liquid), the plating assistant agent reacts with the oxide to remove the surface oxide, the aluminum alloy melt is infiltrated with the steel back, the aluminum element in the aluminum alloy melt and the iron element in the steel back are diffused mutually, and an aluminum alloy layer is formed at a contact interface.

And 5, preparing a mould, preheating the mould, placing the steel backing with the surface covered with the aluminum alloy layer in the mould, and pouring the molten alloy liquid obtained in the step 4 into the mould for casting treatment before the aluminum alloy layer is completely solidified.

Before the casting treatment, the mold is placed in a furnace at 400 ℃ for preheating, so as to prevent casting failure caused by too fast heat loss of the melt in the casting process. The preheating temperature is preferably 400 ℃, the preheating temperature is too low, and the casting failure or casting defect can be caused by the too fast heat loss of the melt in the casting process; and the energy consumption is obviously increased when the preheating temperature is too high.

After the hot dipping in the step 4 is finished, removing the covering agent on the surface, exposing the bright aluminum alloy melt, quickly taking out the steel back, fixing the hot dipped steel back in the preheated mold within 30s, and casting the steel back by using the aluminum alloy melt in the step 4, wherein the casting temperature is 700-760 ℃.

In the casting treatment process, before the fixed steel back is taken out within 30s and cast, the aluminum alloy layer formed on the surface of the steel back in the step 4 hot dipping treatment is not solidified, and the newly poured aluminum alloy melt with higher temperature and the aluminum alloy layer which is not solidified on the surface of the steel back are fused and solidified mutually to form the composite material with the steel-metallurgical bonding layer-aluminum alloy structure. The steel is a steel backing 3, the metallurgical bonding layer is a bonding layer 2, and the aluminum alloy structure is a wear-resistant layer 1.

In this example, the casting temperature is preferably 750 ℃. If the casting temperature is too low, the aluminum alloy melt in the casting process in the step 5 and the unset aluminum alloy layer on the back surface of the steel in the step 4 are difficult to be completely fused, so that delamination is generated, and the bonding strength is reduced; and too high casting temperature increases energy consumption and causes coarse aluminum alloy structure.

Further, the hot dip plating temperature is preferably 730 ℃. If the hot dipping temperature is too low, the salt film anti-oxidation layer can react completely only in a long time, and the metallurgical bonding layer is thin and the bonding force is poor easily due to the too low temperature; if the hot dip coating temperature is too high, the surface of the steel back is covered with a layer of incompletely solidified aluminum, the surface oxidation is serious, the aluminum is easy to remain on a bonding surface during subsequent casting, the bonding strength is influenced, and on the other hand, a metallurgical bonding layer is too thick, the brittleness of the bonding layer is increased, and the bonding force is reduced. Meanwhile, if the hot dipping time is too long, the metallurgical bonding layer is too thick, the brittleness of the bonding layer is increased, and the bonding force is poor; if the plating assistant time is too short, the metallurgical bonding layer is thin and the bonding force is poor. In the embodiment, 4 immersion plating times are selected from 1min to 10min for comparison under the premise that the hot dip plating temperature is 730 ℃. In this example, the preferred ranges are 1min, 3min, 5min and 10min, and the results are shown in Table 3 and FIG. 6.

Immersion plating time	1min	3min	5min	10min
					Thickness of bonding layer	5 micron	10 micron	20 micron	30 micron

TABLE 3 thickness of bond layer at different immersion plating times

And 6, taking the cast blank out of the die for heat preservation treatment, and performing air cooling to finish the process.

And (5) placing the blank after the casting in the step 5 in an oven at the temperature of 200-400 ℃ for 1-2 h, and then carrying out air cooling to obtain the thick-wall aluminum-based bimetallic bearing. The heat preservation process after the casting can ensure the uniform shrinkage of the aluminum alloy in the solidification process, and avoid the cracking of a bonding interface caused by the generation of larger thermal stress. If the heat preservation temperature is too low or the heat preservation time is too short, the tendency of cracking of the bonding layer is improved, and even delamination is caused when the bonding layer is severe; and too high holding temperature or holding time process can cause coarse grains of the alloy and reduce the performance of the material.

Example two

The invention provides a method for manufacturing a thick-wall aluminum-based bimetallic bearing in the embodiment, which comprises the following steps:

step 1, designing a size to process a steel backing and a matched casting mold;

wherein, the size of the steel backing needs to be reserved with machining allowance of 1mm-2 mm.

Step 2, carrying out oil removal treatment and rust removal treatment on the surface of the steel backing;

wherein, deoiling treatment includes: heating a 15% NaOH solution to 70 ℃ by adopting a water bath kettle, then soaking the steel back into the NaOH solution, keeping for 8min, taking out, and cleaning with clear water to remove residual NaOH on the surface of the steel back;

the rust removal treatment comprises: and (3) at normal temperature, immersing the steel back into a 15% HCl solution, keeping for 3min, taking out, and cleaning with clear water to remove residual HCl on the surface of the steel back.

3, immersing the steel back subjected to the oil removal treatment and the rust removal treatment in the step 2 into a plating assistant agent, performing plating assistant treatment for 5min at 70 ℃, then taking out the steel back, drying the steel back for 10min at 150 ℃, and covering a salt film anti-oxidation layer on the surface of the workpiece subjected to the drying treatment;

the plating assistant agent is prepared from the following raw materials in parts by weight based on 1L of solution: 61.9g KF.2H₂O、38.7g KCl、19.4g NiCl₂The balance being H₂O, the concentration of the prepared plating assistant agent is 120 g/L.

Step 4, preparing molten alloy liquid;

placing a pure aluminum ingot in a medium-frequency induction melting furnace, heating to 730 ℃ for melting, then adding Al-Cu alloy until the Al-Cu alloy is melted, adding 20% of low-melting-point metal pure Sn, after all the substances are fully melted and uniformly stirred by a graphite rod, adding a refining agent accounting for 0.3% of the weight of the melted metal for refining and degassing to obtain an aluminum alloy melt, and uniformly scattering a covering agent on the surface of the aluminum alloy melt.

And step 5, preheating the die in a furnace at 400 ℃ in advance.

And 6, removing the covering agent on the surface of the aluminum alloy melt in the step 4 by using a smelting spoon to expose the bright aluminum alloy melt, immersing the steel back of which the surface is covered with a salt film anti-oxidation layer in the step 3 into the aluminum alloy melt, uniformly scattering the covering agent on the surface of the aluminum alloy melt, and carrying out hot dip plating treatment at 730 ℃ for 5 min.

And 7, after the hot dipping treatment is finished, removing the covering agent on the surface, exposing the bright aluminum alloy melt, taking out the steel back from the aluminum alloy melt (at the moment, the surface of the steel back is covered with a layer of aluminum alloy layer which is not completely solidified) and fixing the steel back in the mold, and pouring the aluminum alloy melt into the mold within 30s for casting treatment, wherein the casting temperature is 750 ℃.

And 8, placing the blank cast in the step 7 in an oven at 300 ℃ for 1h, and then air-cooling to prepare the thick-wall aluminum-based bimetallic bearing.

The bonding strength of the double metal layer of the bearing of this example was tested to 44MPa according to ISO 4386-2-2012.

The thick-walled aluminum-based bimetallic bearing manufactured by the present embodiment is a radial bearing (see fig. 1).

EXAMPLE III

The steps 1 to 7 of this embodiment are the same as those of the embodiment.

And 8, placing the blank cast in the step 7 in an oven at 300 ℃ for 1 hour, and then cooling in air.

Step 9, processing the cooled blank into fan-shaped tiles 4 (see fig. 2), and fixing the fan-shaped tiles on a bearing block 5 to manufacture the thick-wall aluminum-based bimetallic bearing;

the fan-shaped tile and the bearing seat can be fixedly connected in a threaded mode, a threaded hole is formed in the steel back side, and the fan-shaped tile is fixed on the bearing seat through a screw penetrating through the threaded hole.

The thick-walled aluminum-based bimetallic bearing manufactured by the present embodiment is a thrust pad (see fig. 3).

Example four

The steps 1 to 7 of this embodiment are the same as those of the embodiment.

And 8, placing the blank cast in the step 7 in an oven at 300 ℃ for 1 hour, and then cooling in air.

Step 9, processing the cooled blank into arc-shaped tiles 6 (see fig. 4), and fixing the arc-shaped tiles on a bearing block 5 to manufacture the thick-wall aluminum-based bimetallic bearing;

the arc-shaped tile and the bearing seat can be fixedly connected in a threaded mode, a threaded hole is formed in the steel back side, and a screw penetrates through the threaded hole to enable the arc-shaped tile to be fixed on the bearing seat.

The thick-walled aluminum-based bimetallic bearing manufactured in the embodiment is a radial tile (see fig. 5).

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.