A multilayer metal sheet for thin-walled sliding bearing

Abstract

The invention discloses a multilayer metal sheet for a thin-walled sliding bearing, comprising a first structural layer, an interlayer and a second structural layer, wherein the first structural layer is attached to the upper surface of the interlayer and the second structural layer is attached to the lower surface of the interlayer. The key points of the technical solution are as follows: through experimental verification, a 5-10 micron thick aluminum (or aluminum-copper alloy) coating layer obtains an intermediate phase transition layer of about 3 microns under certain process conditions, and the aluminum intermediate layer is well bonded to a steel matrix. Through a multilayer alloy structure, a continuous casting and rolling method can be used to improve the bonding strength of the steel / copper interface. Since the liquid phase copper alloy diffuses faster into the steel matrix and has a greater solubility, this may make the liquid phase composite steel / copper bimetallic bonding strength higher, and fatigue resistance and load-bearing performance better.

Description

Technical Field

[0001] The invention relates to the field of thin-walled sliding bearings, in particular to a multi-layer metal sheet for thin-walled sliding bearings. Background Art

[0002] The traditional internal combustion engine shaft sleeve and bearing material base material is steel / copper bimetallic material. Compared with steel / aluminum bimetallic material, its fatigue resistance and load-bearing performance are better, and it is mainly used in heavy-load conditions such as diesel engines. In order to further improve the material's load-bearing performance, the traditional lead-containing copper alloy is replaced by lead-free copper alloy, and various alloys such as copper-tin-nickel, copper-tin-bismuth, and copper-aluminum have been developed. The strength of the copper alloy as the intermediate layer is constantly improving. However, the bonding problem between steel / copper dissimilar metals is still very prominent, especially in the process of bimetallic composite using powder metallurgy. The insufficient diffusion of steel / copper dissimilar atoms in the solid phase still greatly affects its bonding strength.

[0003] The continuous casting and rolling method can improve the bonding strength of the steel / copper interface. Since the liquid copper alloy diffuses faster into the steel matrix and has greater solubility, this may be the main reason for the higher bonding strength, fatigue resistance and load-bearing capacity of the liquid composite steel / copper bimetal. However, this process is not easy to control and there is even a risk of copper-steel grain boundary corrosion.

[0004] Thin-walled sliding bearings mainly refer to internal combustion engine sleeves or bearings. Thin-walled sliding bearings use multi-layer metal plates as the base material for sleeves and bearings, which play an important role in the fatigue resistance and load-bearing performance of these key components of internal combustion engines.

[0005] With the improvement of energy conversion efficiency requirements of internal combustion engines, the explosion pressure of the combustion chamber increases, and the overall operating temperature of the engine rises, higher requirements are placed on the fatigue resistance and load-bearing performance of bearings and sleeves. Traditional thin-walled sliding bearing substrates often cannot meet the use requirements, and the copper alloy layer cracks and peels off. Therefore, the present invention provides a multi-layer metal sheet for thin-walled sliding bearings to solve the above problems. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, thin-walled sliding bearings belong to multi-field coupling conditions such as stress, temperature, and friction. Copper / steel bimetal is usually used as the base material to meet various performance requirements, but it is also easy to have the problem of bonding cracking between the two metals. The purpose of the present invention is to provide a multi-layer metal plate for thin-walled sliding bearings to solve the problems raised in the background technology.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions:

[0008] A multilayer metal sheet for a thin-walled sliding bearing comprises a first structural layer, an interlayer and a second structural layer. The first structural layer is attached to the upper surface of the interlayer, and the second structural layer is attached to the lower surface of the interlayer.

[0009] Furthermore, the thickness of the interlayer is 5-10 microns, the interlayer is an aluminum-copper alloy, and the copper content in the aluminum-copper alloy is 0.3-1.5% by weight.

[0010] Furthermore, the second structural layer is made of steel material. The second structural layer is low-carbon steel with a carbon content lower than 0.15%. The steel material has good structural strength.

[0011] Furthermore, there is a transition zone less than 3 microns at the interface between the interlayer and the second structural layer, and the aluminum content in the transition zone is not less than 10%, or an aluminum-copper alloy is used, and the aluminum element and the iron element are easy to diffuse to form an intermediate phase, which conforms to the principle of forming a stable bonding layer by general brazing connection.

[0012] Furthermore, the copper layer of the first structural layer is tin bronze or lead bronze to ensure that the copper layer can be effectively attached to the surface of the interlayer.

[0013] Furthermore, alloy elements such as Ni, Sn, Cu, and Ag were added to the interlayer respectively. By comparison, it was found that the addition of Cu can increase the diffusion rate between the copper layer and the intermediate layer. There are very few defects on the intermediate layer / copper interface, and the bonding strength reaches above 320 MPa, which is significantly higher than the bimetallic material without an intermediate layer. When the copper content is too high, the diffusion reaction between the intermediate layer and the steel is insufficient, there is no obvious diffusion reaction layer, and the effect of the intermediate layer is weakened.

[0014] In summary, the present invention has the following beneficial effects:

[0015] 1. Through experiments and verification, a 5-10 micron thick aluminum (or aluminum-copper alloy) coating layer can obtain an intermediate phase transition layer of about 3 microns under certain process conditions. The aluminum intermediate layer is well bonded to the steel matrix. Through the multi-layer alloy structure, the continuous casting and rolling method can improve the bonding strength of the steel / copper interface. Since the liquid copper alloy diffuses faster into the steel matrix and has a greater solubility, this may make the liquid phase composite steel / copper bimetallic bonding strength higher, fatigue resistance and load-bearing better;

[0016] 2. Alloy elements such as Ni, Sn, Cu, and Ag are added to the interlayer respectively. By comparison, it is found that the addition of Cu can increase the diffusion rate between the copper layer and the intermediate layer. There are very few defects on the intermediate layer / copper interface, and the bonding strength reaches more than 320MPa, which is significantly higher than the bimetallic material without an intermediate layer. When the copper content is too high, the diffusion reaction between the intermediate layer and the steel is insufficient, there is no obvious diffusion reaction layer, and the effect of the intermediate layer is weakened. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an overall structural diagram of a multilayer metal sheet for a thin-walled sliding bearing of the present invention.

[0018] In the figure, 1, first structural layer; 2, interlayer; 3, second structural layer. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0020] The same parts are denoted by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the drawings, and the words "bottom" and "top", "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0021] Reference Figure 1 As shown, a multilayer metal sheet for thin-walled sliding bearings in a preferred embodiment of the present invention includes: a first structural layer 1, an interlayer 2 and a second structural layer 3, wherein the interlayer 2 is an aluminum-copper alloy, the first structural layer 1 is attached to the upper surface of the interlayer 2, and the second structural layer 3 is attached to the lower upper surface of the interlayer 2, the thickness of the interlayer 2 is 5-10 microns, and the copper content in the aluminum-copper alloy is 0.3-1.5% by weight, and the second structural layer 3 is a steel material, which has good structural strength and improves support.

[0022] However, the bonding strength of aluminum cladding on the steel surface is not high, and it is even very easy to produce thermal cracks along the bonding surface. The main reason for cracking is that the interface between the intermediate phase of the existing double-layer structure and the two metals is too high. One is to change the method of coating aluminum on the steel surface, especially the temperature of the substrate; the second is to control the thickness of the coated aluminum, which controls the reaction rate of aluminum and steel and the stress formed by the intermediate phase. Through experiments, it is verified that a 5-10 micron thick aluminum (or aluminum-copper alloy) coating layer obtains an intermediate phase transition layer of about 3 microns under certain process conditions. The aluminum intermediate layer is well bonded to the steel substrate. There is a transition zone of less than 3 microns at the interface between the interlayer 2 and the second structural layer 3, and the aluminum content in the transition zone is not less than 10%. Or an aluminum-copper alloy is used, and the aluminum element and the iron element are easy to diffuse, and an intermediate phase can be formed, which is in line with the principle of forming a stable bonding layer by general brazing connection. The second structural layer 3 is low-carbon steel with a carbon content of less than 0.15%.

[0023] The copper layer of the first structural layer 1 is tin bronze or lead bronze. In order to ensure that the copper layer can effectively adhere to the surface of the interlayer 2, alloy elements such as Ni, Sn, Cu, and Ag are added to the interlayer 2 respectively. By comparison, it is found that the addition of Cu can increase the diffusion rate between the copper layer and the intermediate layer. There are very few defects on the intermediate layer / copper interface, and the bonding strength reaches more than 320MPa, which is significantly better than the bimetallic material without an intermediate layer. When the copper content is too high, the diffusion reaction between the intermediate layer and the steel is insufficient, there is no obvious diffusion reaction layer, and the effect of the intermediate layer is weakened.

[0024] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A multilayer metal sheet for a thin-walled sliding bearing, characterized in that: The invention comprises a first structural layer (1), an interlayer (2) and a second structural layer (3), wherein the first structural layer is attached to the upper surface of the interlayer (2). layer (1), a second structural layer (3) being attached to the lower surface of the interlayer (2); The thickness of the interlayer (2) is 5-10 microns, and the interlayer (2) is an aluminum-copper alloy. The copper content in the alloy is 0.3-1.5% by weight; The second structural layer (3) is made of steel material, and the second structural layer (3) is low-carbon steel with a carbon content lower than 0.15%; There is a transition zone of less than 3 micrometers at the interface between the interlayer (2) and the second structural layer (3). The aluminum content in the transition zone is not less than 10%.

2. The multilayer metal sheet for thin-walled sliding bearing according to claim 1, characterized in that: The copper layer of the first structural layer (1) is tin bronze or lead bronze.

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