CN115194294B - Aluminum steel composite material and arc additive preparation method thereof - Google Patents

Abstract

The invention discloses an aluminum-steel composite material and an arc additive preparation method thereof. The material is composed of an aluminum alloy layer and a steel layer. The aluminum alloy layer contains the following weight percentages of each component: 20 to 23 wt.% Sn, 0.75 to 0.85 wt.% Cu, and 0.05 to 0.06 wt.% Si. , the balance is Al. The preparation process of this material is: (1) Preparing aluminum-tin alloy flux-cored wire material. (2) Arc additive the aluminum-tin alloy cored wire material to the surface of the steel plate to obtain an aluminum/steel composite material. Adopting the above technical solution, the present invention uses CMT arc additive technology as a new composite process of bearing alloy/steel. The prepared material has high bonding strength, uniform structure, excellent wear reduction and wear resistance and high load-bearing performance.

Description

An aluminum-steel composite material and its arc additive preparation method

Technical field

The invention relates to aluminum-steel composite materials and preparation methods, in particular to an aluminum-steel composite material and an arc additive preparation method thereof.

Background technique

Aluminum-based bearing alloy has high fatigue performance, strong load-bearing capacity, good adaptability, embeddedness, wear resistance, anti-seize ability and corrosion resistance. It is the main production of sliding bearings for light and medium load internal combustion engines. Material. Among them, Al-Sn bearing alloy is the most widely used. However, the current method of composite bearing alloy and steel backing has inevitable shortcomings: the bimetallic interface manufactured by the solid-solid phase composite method is basically mechanically bonded, and the bonding strength is low, which has a negative impact on the service life of the finished part; the solid-liquid composite method The phase compounding method is difficult to solve the problem of specific gravity segregation and affects the friction performance of bearing samples; semi-solid-solid phase compounding requires flux, surface preheating, mechanical stirring and other processes, which is complex to operate and difficult to produce in large quantities. Therefore, there is currently a lack of a bearing alloy composite method that can meet the requirements of high bonding strength, uniform structural composition, and high production efficiency.

CMT arc additive technology has flexible production, high product precision, and can be produced continuously; there is a high-temperature liquid phase during the molding process, which can produce metallurgical bonding; it also has the advantages of low heat input and no splash, and is very suitable for low-melting point metals such as aluminum alloys. . Current research on dissimilar metal welding of CMT aluminum steel focuses on the intermetallic compound layer that affects the bonding performance. The inhibitory effect of Si, Zn and other elements on the growth of the intermetallic compound layer has also been studied. However, the main purpose of these studies is to connect steel plates and aluminum plates to obtain a stronger joint; and they are blank on the impact of adding elements in bearing alloys such as Sn on bonding performance. In other words, CMT arc additives have not yet been used in the composite manufacturing of aluminum-based bearing alloy-steel.

Contents of the invention

Purpose of the invention: The present invention provides an aluminum-steel composite material with high bonding strength and good friction-reducing and wear-resisting properties and load-bearing properties.

Another object of the present invention is to provide an arc additive manufacturing method of the aluminum-steel composite material.

Technical solution: The aluminum-steel composite material of the present invention includes a steel layer and an aluminum-tin alloy layer covering the steel layer, and is characterized in that: in addition to the Fe-Al phase at the bonding interface between the steel layer and the aluminum-tin alloy layer There is also a Sn-containing layer. The aluminum alloy includes: Al, Sn, Cu and Si. The weight percentage of each component is: 20 to 23wt.% Sn, 0.75 to 0.85wt.% Cu, 0.05 to 0.06wt. % Si, the balance is Al; the aluminum-tin alloy layer is an aluminum-tin alloy flux-core wire prepared by mixing the components according to the above proportion, and the aluminum-tin alloy is welded by a CMT digital inverter welding power source The flux-cored wire is arc-added to the surface of the steel plate.

Further, the process parameters of the arc additive are: current 65A~95A, voltage 100% avp, argon gas flow 18~20L/min, swing amplitude 8mm, additive speed 7~10cm/min, swing frequency 1.0~ 4.0Hz.

Further, the preparation process of the aluminum-tin alloy cored wire is as follows: roll the 4043 aluminum alloy into a U-shaped cross-section, and then fill it with 800 mesh high-purity Sn powder and 1000-mesh high-purity Cu powder prepared according to dosage. Add it to the U-shaped strip material, roll it tightly with a rolling mill, and finally draw it to produce a composition of 20~23wt.%Sn, 0.75~0.85wt.%Cu, 0.05~0.06wt.%Si, and the balance is Al. Flux-cored wire with a diameter of 1.6mm.

The arc additive preparation method of aluminum-steel composite materials includes the following steps:

(1) Clean the steel back first, polish the surface to remove rust, wipe the surface with alcohol, dry it, and preheat the steel plate to 90~120℃;

(2) Using CMT digital inverter welding power source, arc additive the aluminum-tin alloy cored wire to the surface of the steel plate and obtain an aluminum-steel composite material containing Sn layer distributed on the aluminum-steel bonding interface.

Arc additive process: spread the aluminum-tin alloy flux-cored wire from one side of the steel plate surface to the other side, connect the aluminum-tin alloy flux-cored wire to the positive pole of the power supply, and the steel plate to the negative pole of the power supply. After power is applied, an arc is generated between the two poles. , the wire is melted by the arc heat to form droplets, and the droplets are spread on the steel plate to form an additive belt, and an aluminum-steel composite material containing Sn layer distributed on the aluminum-steel bonding interface is obtained.

The current of the arc additive process is preferably 75A to 85A, the voltage is preferably 100% avp, and the swing frequency is preferably 1.5 to 2.5Hz.

Application of the aluminum-steel composite material in wear-resistant materials for sliding friction parts of light and medium-load internal combustion engines.

In order to form a Sn-containing layer on the bonding interface of the steel and aluminum layers in the aluminum-steel composite material, which not only has good friction and wear properties, but also improves the bonding strength between the steel and aluminum layers in the aluminum-steel composite material, the present invention uses the following aluminum alloy Welding wire, namely:

An aluminum-based alloy welding wire, including: Al, Si and Cu, characterized in that it also includes Sn, and the weight percentage of each component is: 20-23wt.% Sn, 0.75-0.85wt.% Cu, 0.05- 0.06 wt.% Si, balance Al.

The invention solves the problems in the traditional aluminum-based bearing alloy-steel composite process that the aluminum-steel bonding strength is low, the specific gravity of the alloy structure is segregated, and it is difficult to produce efficiently. We are the first to apply CMT arc additive technology to the manufacturing of aluminum-steel bearing strips, providing an aluminum-steel composite material and its arc additive preparation method, achieving high bonding strength, uniform structure, good wear reduction and wear resistance, and aluminum alloy Aluminum/steel composite strip that is clearly immiscible with steel structure.

specifically,

1. CMT arc additive technology was successfully used in the composite of aluminum-steel bearing strips, and a new method of composite of aluminum-steel dissimilar metals was obtained.

Traditional aluminum-based bearing alloy strip composite aluminum alloy-steel backing usually adopts solid-solid phase composite method, solid-liquid phase composite method and semi-solid-solid phase composite method. Among them, the bimetallic interface manufactured by the solid-solid phase composite method is basically mechanically bonded, and the bonding strength is low, which has a negative impact on the service life of the finished part; the solid-liquid phase composite method is difficult to solve the problem of specific gravity segregation, which affects the friction performance of the bearing sample; Semi-solid-solid composite requires processes such as flux, surface preheating, and mechanical stirring. The operation is complex and difficult to produce in large quantities. Existing aluminum-steel composite material preparation methods all have shortcomings that are difficult to overcome.

The physical properties of aluminum and steel are quite different, making it difficult to complete high-quality welding. Mainly because the density, linear expansion coefficient and thermal conductivity of aluminum alloy and steel are very different, stress concentration is easy to occur at the weld, leading to the initiation and expansion of cracks; and Al and Fe diffuse into each other and easily react at the interface to form Hard and brittle Fe-Al compounds, such as FeAl ₂ , FeAl ₃ , FeAl, Fe ₂ Al ₅ , etc. The thickness of these intermetallic compound layers is very large, which has a very negative impact on the mechanical properties.

The method in the present invention successfully realizes arc deposition of aluminum and steel, improves the bonding performance of aluminum-steel composite materials, and obtains a uniform alloy structure without segregation. At the same time, it requires few operating procedures and can meet the needs of high-efficiency continuous production.

2. In order to improve the bonding strength between aluminum alloy and steel in aluminum-based composite materials, the present invention prepares aluminum-based alloy welding wire containing Sn, in which Sn functions on the one hand as a soft point to reduce the composition of the hard Al matrix. wear-resistant materials to meet the friction and wear performance requirements of bearing alloys. On the other hand, a Sn-containing layer is formed at the aluminum-steel interface to inhibit the growth of the intermetallic compound layer, especially the Fe ₂ Al ₅ phase, thereby inhibiting the growth of the intermetallic compound layer. The bonding strength of aluminum-steel composite materials is improved (Figure 1). The present invention tested the bonding strength, and the bonding strength value increased from 43.6MPa to 113.8MPa (Figure 2).

During the arc deposition process, the flux-cored wire absorbs the arc and transforms into molten droplets that transfer to the steel plate. Sn and Al are not mutually soluble, and the density of Sn is greater than that of Al. The deposition on the back surface of the steel inhibits the reaction of Fe and Al, reducing the The growth rate of Fe ₂ Al ₅ thus limits the growth of the intermetallic compound layer. As the droplet cools, the Sn in it solidifies on the interface layer to form a Sn-containing layer.

3. The arc additive process of the present invention, through the CMT cold metal transfer technology low current (65A ~ 95A) arc additive process, it is easier to control the heat input, making the average heat input of the weld bead more uniform and controllable, and the arc deposition is obtained It has a dense, uniform and fine grain structure (Figure 3), so the additive layer has good friction-reducing, wear-resistant and load-bearing properties. At the same time, the matching between the current size, preheating temperature, swing frequency, swing amplitude, and pass overlap solves the problem of poor fluidity of liquid metal and difficulty in uniform forming of the additive layer, and obtains an additive layer with good forming performance ( Figure 4).

Beneficial effects: Compared with the existing technology, the present invention has the following advantages: the present invention uses CMT arc additive technology as a new composite process of bearing alloy/steel, and the prepared materials have high bonding strength, uniform structure, and excellent wear-reducing resistance. Abrasion resistance and high load-bearing performance.

Description of the drawings

Figure 1 Sn-containing layer at the aluminum/steel joint;

Figure 2 The bonding strength between the aluminum alloy layer and the steel matrix at different currents;

Figure 3 Internal organization of the additive layer;

Figure 4 Appearance of the additive layer.

Detailed ways

Example 1:

The arc additive process includes the following steps:

(1) First prepare the aluminum-tin alloy cored wire: roll the 4043 aluminum alloy into a U-shaped cross-section, and then add 800 mesh high-purity Sn powder and 1000-mesh high-purity Cu powder prepared according to dosage into the U-shaped The strip material is rolled tightly with a rolling mill and finally drawn to produce a composition of 20~23wt.%Sn, 0.75-0.85wt.%Cu, 0.05~0.06wt.%Si, the balance is Al, and the diameter is 1.6mm flux-cored welding wire.

(2) Then clean the steel back, grind the surface with a grinder to remove rust, wipe the surface with alcohol, dry it and fix it to the workbench, and preheat the steel plate to 100°C;

(3) Then, the aluminum-tin alloy cored wire arc is added to the surface of the steel plate through the CMT digital inverter welding power supply. The welding wire is perpendicular to the substrate. The arc additive process parameters are: current 75A, voltage 100% avp, argon gas flow 20L/min, swing amplitude 8mm, additive speed 10cm/min, swing frequency 2.5Hz. The above-mentioned new aluminum-tin additive layer has average formability and a bonding strength of 55.1MPa.

Example 2:

The arc additive process includes the following steps:

(1) First prepare the aluminum-tin alloy cored wire: roll the 4043 aluminum alloy into a U-shaped cross-section, and then add 800 mesh high-purity Sn powder and 1000-mesh high-purity Cu powder prepared according to dosage into the U-shaped The strip material is rolled tightly with a rolling mill and finally drawn to produce a composition of 20~23wt.%Sn, 0.75~0.85wt.%Cu, 0.05~0.06wt.%Si, the balance is Al, and the diameter is 1.6mm flux-cored welding wire.

(2) Then clean the steel back, grind the surface with a grinder to remove rust, wipe the surface with alcohol, dry it and fix it to the workbench, and preheat the steel plate to 100°C;

(3) Then, the aluminum-tin alloy cored wire arc is added to the surface of the steel plate through the CMT digital inverter welding power supply. The welding wire is perpendicular to the substrate. The arc additive process parameters are: current 80A, voltage 100% avp, argon gas flow 20L/min, swing amplitude 8mm, additive speed 10cm/min, and swing frequency 2.5Hz. The above-mentioned new aluminum-tin additive layer has good formability and a bonding strength of 95.7MPa.

Example 3:

The arc additive process includes the following steps:

(1) First prepare the aluminum-tin alloy cored wire: roll the 4043 aluminum alloy into a U-shaped cross-section, and then add 800 mesh high-purity Sn powder and 1000-mesh high-purity Cu powder prepared according to dosage into the U-shaped The strip material is rolled tightly with a rolling mill and finally drawn to produce a composition of 20~23wt.%Sn, 0.75~0.85wt.%Cu, 0.05~0.06wt.%Si, the balance is Al, and the diameter is 1.6mm flux-cored welding wire.

(2) Then clean the steel back, grind the surface with a grinder to remove rust, wipe the surface with alcohol, dry it and fix it to the workbench, and preheat the steel plate to 100°C;

(3) Then, the aluminum-tin alloy cored wire arc is added to the surface of the steel plate through the CMT digital inverter welding power supply. The welding wire is perpendicular to the substrate. The arc additive process parameters are: current 85A, voltage 100% avp, argon gas flow 20L/min, swing amplitude 8mm, additive speed 10cm/min, swing frequency 2.5Hz. The above-mentioned new aluminum-tin additive layer has good formability and a bonding strength of 113.8MPa.

Example 4:

The arc additive process includes the following steps:

(1) First prepare the aluminum-tin alloy cored wire: roll the 4043 aluminum alloy into a U-shaped cross-section, and then add 800 mesh high-purity Sn powder and 1000-mesh high-purity Cu powder prepared according to dosage into the U-shaped The strip material is rolled tightly with a rolling mill and finally drawn to produce a composition of 20-23wt.% Sn, 0.75-0.85wt.% Cu, 0.05-0.06wt.% Si, the balance is Al, and the diameter is 1.6mm flux-cored welding wire.

(2) Then clean the steel back, grind the surface with a grinder to remove rust, wipe the surface with alcohol, dry it and fix it to the workbench, and preheat the steel plate to 100°C;

(3) Then, the aluminum-tin alloy cored wire arc is added to the surface of the steel plate through the CMT digital inverter welding power supply. The welding wire is perpendicular to the substrate. The arc additive process parameters are: current 90A, voltage 100% avp, argon gas flow 20L/min, swing amplitude 8mm, additive speed 10cm/min, swing frequency 2.5Hz. The above-mentioned new aluminum-tin additive layer has average formability and a bonding strength of 43.6MPa.

Claims (2)

1. An aluminum steel composite material, includes steel layer and covers the aluminium tin alloy layer on the steel layer, its characterized in that: a Sn-containing layer is present at the bonding interface of the steel layer and the aluminum-tin alloy layer in addition to the Fe-Al phase, the aluminum-tin alloy layer comprising: al, sn, cu and Si, wherein the weight percentages of the components are as follows: 20 to 23wt.% of Sn,0.75 to 0.85wt.% of Cu,0.05 to 0.06wt.% of Si, and the balance of Al; the aluminum-tin alloy layer is an aluminum-tin alloy flux-cored wire prepared by mixing the components according to the proportion, and the aluminum-tin alloy flux-cored wire is subjected to arc material addition to the surface of the steel plate through a CMT digital inverter welding power supply;

the arc additive preparation method of the aluminum steel composite material comprises the following steps:

(1) Firstly, cleaning a steel back, polishing the surface to remove rust, wiping the surface with alcohol, airing, and preheating a steel plate to 90-120 ℃;

(2) Adopting a CMT digital inverter welding power supply, carrying out arc material adding on an aluminum-tin alloy flux-cored wire to the surface of a steel plate and obtaining an aluminum-steel composite material with Sn-containing layers distributed on an aluminum-steel bonding interface;

arc material adding process: spreading an aluminum-tin alloy flux-cored wire from one side to the other side of the surface of a steel plate, connecting the aluminum-tin alloy flux-cored wire with a positive electrode of a power supply, connecting the steel plate with a negative electrode of the power supply, generating an electric arc between the two electrodes after the steel plate is electrified, melting the wire under the action of electric arc heat to form molten drops, and spreading the molten drops on the steel plate to form an additive belt to obtain an aluminum-steel composite material with Sn-containing layers distributed on an aluminum-steel bonding interface;

the technological parameters of the arc material increase are as follows: the current 65A-95A, the voltage 100% avp, the argon flow rate 18-20L/min, the swing amplitude 8mm, the additive speed 7-10 cm/min and the swing frequency 1.0-4.0 Hz.

2. The aluminum steel composite material according to claim 1, wherein: the preparation process of the aluminum-tin alloy flux-cored wire comprises the following steps: the 4043 aluminum alloy is rolled into a U-shaped section shape, then 800-mesh high-purity Sn powder and 1000-mesh high-purity Cu powder which are prepared according to the dosage are filled into a U-shaped belt material, the materials are rolled by a rolling mill, and finally, a flux-cored wire with the components of 20-23wt.% Sn,0.75-0.85wt.% Cu,0.05-0.06wt.% Si and the balance Al and the diameter of 1.6mm is manufactured through drawing.