Antimony bronze-steel bimetallic composite material and preparation method thereof

Abstract

The application discloses a kind of antimony bronze-steel bimetallic composite and preparation method thereof, including copper alloy layer and steel matrix, wherein the copper alloy layer is composed of the following components by weight percentage: Pb 10%~20%, Sb 4%~6%, Mn 4%~6%, Ni2%~5%, Zn 1%~3%, and the balance of copper, total amount of impurities is not more than 2%.The antimony bronze-steel bimetallic composite prepared by the application uses antimony bronze instead of commonly used tin bronze in the copper alloy layer, which reduces the manufacturing cost of the bimetallic composite, and through reasonable design of the antimony bronze formula, the strength and hardness of the antimony bronze are increased, and the bimetallic copper layer has good lubrication and friction reduction effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bimetallic composite materials, and particularly relates to a bismuth bronze-steel bimetallic composite material and a preparation method thereof. BACKGROUND

[0002] The copper-steel bimetallic composite material is widely used in the fields of gear pumps, plunger pumps and the like, and is composed of a copper alloy layer and a steel matrix. The copper alloy layer as a working layer of a friction pair component has the characteristics of friction reduction, wear resistance, corrosion resistance, heat resistance, thermal conductivity and fatigue resistance, and has excellent friction reduction and anti-sticking performance due to the combination of soft and hard phase structures. The steel matrix plays a role of bearing and impact resistance, and makes up for the low mechanical performance of the copper alloy. Therefore, the copper-steel bimetallic composite material has excellent performance of both materials.

[0003] At present, the most widely used copper-steel bimetallic composite material adopts tin bronze material for the copper layer. For example, Chinese patent CN116124820A discloses a copper-steel bimetallic casting experiment method, and the copper layer adopts tin bronze alloy (Sn7.25-7.85%, Pb 14.1-17.26%, Ni 1.24-1.86%, Zn 0.01-0.05%, P 0.1% or less, and the balance of Cu); Chinese patent CN104259434B discloses a preparation method of a tin bronze-stainless steel bimetallic wear-resistant part, and the copper alloy used in the examples is QSn7-0.2, QSn4-3 and ZQSn5Pb5Zn5 tin bronze alloy. However, the price of Sn element in tin bronze is relatively high, so the cost of preparing the copper-steel bimetallic composite material by using tin bronze is relatively high. Bismuth bronze has high resistance to fuel oil corrosion and excellent tribological performance under high-speed sliding, and the preparation of bismuth bronze-steel bimetallic composite material with excellent performance has great economic and social benefits. However, relevant literature (Note: Zhang Chunyou. Development of a copper-based friction-reducing material with added antimony and reduced tin [J]. Hunan Nonferrous Metals, 1997 (06): 31-33+46) points out that antimony will be precipitated in large quantities below 488℃, causing composition and structure segregation. In addition, antimony is a brittle element, which can easily cause insufficient interface bonding strength of the copper-steel bimetallic composite material. SUMMARY

[0004] In view of the above problems of composition and structure segregation of bismuth bronze and insufficient interface bonding strength of the copper-steel bimetallic composite material, the application provides a bismuth bronze-steel bimetallic composite material with uniform composition and structure distribution and good interface bonding. The composite material can be used as a substitute material for commonly used tin bronze-steel bimetallic composite materials, and can be applied to the fields of part of gear pumps, plunger pumps and the like.

[0005] To achieve the above object, the technical scheme adopted by the present application is:

[0006] An antimony bronze-steel bimetallic composite material, comprising a copper alloy layer and a steel matrix, the copper alloy layer is composed of the following components in percentage by weight: Pb 10%~20%, Sb 4%~6%, Mn 4%~6%, Ni 2%~5%, Zn 1%~3%, and the balance of copper, and the total amount of impurities is not more than 2%. The steel matrix is mainly medium carbon alloy steel.

[0007] Further scheme, the composition and organization of the copper alloy layer are uniformly distributed, and the microstructure is mainly composed of α-Cu phase, elemental Pb phase, a small amount of δ phase (molecular formula is Cu 4.5 Sb) and Cu2MnSb ternary intermetallic compound.

[0008] Further scheme, the friction coefficient (μ) of the copper alloy layer is 0.03~0.07.

[0009] Further scheme, the hardness of the copper alloy layer is not less than 70 HRF.

[0010] Further scheme, the bimetallic interface forms a metallurgical bond, and the bonding strength (P) is not less than 150 MPa.

[0011] Another object of the present application is to provide a preparation method of the above-mentioned antimony bronze-steel bimetallic composite material, comprising the following steps:

[0012] S1, preparation of antimony bronze material

[0013] (S11) according to the proportion, the copper powder, nickel powder, manganese powder, lead powder, antimony powder, zinc powder are weighed, and anhydrous borax is weighed as deoxidizer and covering agent;

[0014] (S12) first, the copper powder and anhydrous borax are placed in a power frequency electric furnace and heated to 1250℃, so that the copper powder is completely melted, then the nickel powder, manganese powder, antimony powder, zinc powder and lead powder are added in turn according to the melting point from high to low, and graphite rod is used for sufficient stirring;

[0015] (S13) after holding for 25~30 min, the molten liquid is poured into a water-cooled mold to form an antimony bronze ingot, and the borax floating on the surface is removed, thereby obtaining the antimony bronze material.

[0016] S2, material processing

[0017] (S21) the structure of the steel matrix is designed, and the medium carbon alloy steel material is processed according to the designed structure, so that the upper surface of the steel matrix forms a molten copper pool;

[0018] (S22) according to the weight requirement, the corresponding antimony bronze material is cut off, and the antimony bronze material only needs to meet the weight requirement, and there is no requirement for the shape.

[0019] S3, surface cleaning treatment of material

[0020] The surface of the steel base and antimony bronze material is cleaned to remove the contaminants on the metal surface.

[0021] S4, surface pretreatment of steel base copper melting pool

[0022] The steel base copper melting pool is sandblasted, and then a layer of anhydrous borax with a content of 99% or more is uniformly coated on the surface. Preferably, the sandblasting grade reaches Sa2.5, and the surface roughness reaches Rz 45-75 μm. The sandblasting can form a fine concave-convex structure on the surface of the steel base copper melting pool, and increase the contact area; the coating of anhydrous borax can further purify the surface of the copper melting pool. The combination of sandblasting and coating of anhydrous borax can effectively improve the interfacial bonding strength of the copper-steel bimetal.

[0023] S5, high-temperature melting and casting

[0024] The antimony bronze material is placed in the steel base copper melting pool, and a layer of insulation layer is added above the antimony bronze material, and the state of the material before entering the furnace is shown in Figure 1 (a); then the material is sent into a high-temperature melting and casting furnace, pure nitrogen with a purity of ≥99.99% is used as a protective atmosphere, the furnace temperature is raised to 1050-1150℃, and the temperature is maintained for 30-60 min. Preferably, the insulation layer can withstand a high temperature of 1150℃ or more, and has a thermal conductivity of ≤5 W / (m·K). Suitable insulation layer materials include high-temperature resistant cotton, graphite felt, and various types of refractory bricks, etc.

[0025] S6, cooling

[0026] After the insulation is completed, the material is taken out of the melting and casting furnace and immersed in a liquid cooling medium for cooling. Preferably, the liquid cooling medium is a water-based quenching liquid, and the volume concentration of the quenching liquid is 10-20%. Preferably, after the material is immersed in the liquid cooling medium, the liquid cooling medium submerges 1 / 3-1 / 2 of the height of the part below the steel base copper melting pool, and the cooling state is shown in Figure 1 (b). The use of the liquid cooling medium for cooling can realize rapid and directional solidification forming of the copper alloy layer, and ensure uniform distribution of the composition and structure of the copper alloy layer. Since the cooling speed is fast, the segregation of antimony does not occur, and the segregation problem of antimony is effectively solved.

[0027] S7, tempering

[0028] The antimony bronze-steel bimetallic composite material after cooling is subjected to a tempering treatment, and the tempering process parameters are: temperature 350-500℃, and holding time 2-3 h. The steel base after tempering is mainly tempered troostite.

[0029] Compared with the existing tin bronze-steel bimetallic composite material preparation technology, the present application has the beneficial effects of:

[0030] (1) The antimony bronze-steel bimetallic composite material prepared by the present application uses antimony bronze instead of commonly used tin bronze for the copper alloy layer: on the one hand, the price of antimony is lower than that of tin, reducing the manufacturing cost of the bimetallic composite material; on the other hand, through reasonable design of the antimony bronze formula, the Cu, Sb and Mn elements in the antimony bronze material can form Cu2MnSb ternary intermetallic compounds, increasing the strength and hardness of the antimony bronze, while avoiding the negative impact of the brittleness of the Sb element on the interfacial bonding strength of the copper-steel bimetallic material; in addition, Pb exists in the antimony bronze in the form of a single phase, which can make the bimetallic copper layer have good lubrication and friction reduction effect.

[0031] (2) The present application pretreats the surface of the steel substrate molten copper pool by sandblasting and coating anhydrous borax, and simultaneously adopts a reasonable bimetallic casting process, so that a good interfacial metallurgical bonding is formed between the antimony bronze and the steel substrate.

[0032] (3) The present application adds a heat-resistant and low-thermal-conductivity heat preservation layer above the bimetallic copper alloy layer, and simultaneously cools the steel substrate part after the bimetallic casting is completed using a liquid cooling medium, effectively realizing rapid and directional solidification forming of the copper alloy layer, ensuring uniform distribution of the composition and organization of the copper alloy layer. Since the cooling speed is fast, the antimony does not have time to segregate greatly before solidification, effectively solving the segregation problem of antimony.

[0033] (4) The present application performs tempering treatment on the bimetallic composite material, which not only eliminates the stress generated during the rapid cooling process of the bimetallic composite material, but also forms tempered troostite structure in the steel substrate, which not only has high hardness, but also has good plasticity and toughness. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The figure is a schematic diagram for preparing the antimony bronze-steel bimetallic composite material of the present application, wherein (a) is the state before the material is put into the furnace, and (b) is the state during the cooling process of the material.

[0035] Figure 2 The figure is a copper layer metallographic structure diagram (x100) of the bimetallic composite material in Example 3.

[0036] Figure 3 The figure is a copper-steel interface metallographic structure diagram (x200) of the bimetallic composite material in Example 3. DETAILED DESCRIPTION

[0037] The application will be described in further detail below with reference to the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the protection scope of the present application.

[0038] Table 1 is a comparison of specific embodiments of the present application and comparative examples.

[0039] Table 1

[0040]

[0041]

[0042] The test method of the copper layer friction coefficient (μ) of the materials prepared in the above examples and comparative examples is as follows: the ring block friction and wear test is adopted, the standard is GB / T 12444-2006 “Metallic Materials Wear Test Method Test Ring-Test Block Sliding Wear Test”, the loading force is 20 Kg, the rotating speed is 400 r / min, the oil is dripped for lubrication, the oil dripping amount is 10-12 drops per minute. The examples of the same group of the present application are tested for 6 times, each test lasts for 120 min, the value is recorded from 10 min, and is recorded every 10 min, the test result is taken as an average value, and the two effective digits are retained. The copper layer hardness detection adopts the standard GB / T 230.1-2018 “Metallic Materials Rockwell Hardness Test Part 1: Test Method”, 3 test samples are prepared for each example, 6 points are selected for detection for each test sample, the detection result is taken as an average value, and the three effective digits are retained; the interface bonding strength (P) between the copper alloy layer and the steel substrate is tested by the standard YS / T 485-2005 “Method for Determining Shear Strength of Sintered Bimetallic Material”, 6 test samples are prepared for each example, and the average value is taken after the test, and the three effective digits are retained. From the test results, compared with the comparative examples, the antimony bronze-steel bimetallic composite material prepared by the preparation method in the embodiments of the present application has excellent performance, the friction coefficient, hardness and interface bonding strength of the copper layer reach the performance indicators of commonly used tin bronze materials, and effectively solves the problems of antimony bronze composition, organization segregation and insufficient copper-steel bimetallic interface bonding strength.

[0043] The above description of the embodiments is for the convenience of the ordinary skilled person in the art to understand and apply the present application. Those skilled in the art can obviously make various modifications to the embodiments, and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present application is not limited to the embodiments herein, and the improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. An antimony bronze-steel bimetallic composite comprising a copper alloy layer and a steel substrate, characterized in that: The copper alloy layer is composed of the following components in percentage by weight: Pb 10%~20%, Sb 4%~6%, Mn 4%~6%, Ni 2%~5%, Zn 1%~3%, and the balance of copper, with the total amount of impurities being not more than 2%; the steel base is a medium-carbon alloy steel; The preparation method of the antimony bronze-steel bimetallic composite material comprises the following steps: S1, preparation of antimony bronze material (S11) according to the proportion, copper powder, nickel powder, manganese powder, lead powder, antimony powder, zinc powder are weighed, and anhydrous borax is weighed as a deoxidizer and a covering agent; (S12) first, the copper powder and anhydrous borax are placed in a power frequency electric furnace and heated to 1250℃, so that the copper powder is completely melted, then the nickel powder, manganese powder, antimony powder, zinc powder and lead powder are added in turn according to the melting point from high to low, and a graphite rod is used for sufficient stirring; (S13) after 25~30min of heat preservation, the molten liquid is poured into a water-cooled mold to form an antimony bronze ingot, and the borax floating on the surface is removed, thereby obtaining the antimony bronze material; S2, material processing (S21) the structure of the steel base is designed, and the steel base is processed according to the designed structure, so that a copper melting pool is formed on the upper surface of the steel base; (S22) the corresponding antimony bronze material is cut according to the weight requirement; S3, surface cleaning treatment of the material The surfaces of the steel base and the antimony bronze material are cleaned to remove the contaminants on the metal surfaces; S4, surface pretreatment of the steel base copper melting pool The steel base copper melting pool is sand blasted, and then a layer of anhydrous borax with a content of 99% or more is uniformly coated on the surface thereof; S5, high-temperature melting and casting The antimony bronze material is placed in the steel base copper melting pool, and a layer of insulation is added above the antimony bronze material, then the material is sent into a high-temperature melting and casting furnace, pure nitrogen with a purity of ≥99.99% is used as a protective atmosphere, the furnace temperature is raised to 1050~1150℃, and the material is heat preserved for 30~60min; S6, cooling After the heat preservation is completed, the material is taken out of the melting and casting furnace and immersed in a liquid cooling medium for cooling; the liquid cooling medium is a water-based quenching liquid, and the volume concentration of the quenching liquid is 10~20%; S7, tempering The antimony bronze-steel bimetallic composite material after cooling is subjected to tempering treatment, and the tempering process parameters are: temperature 350~500℃, and heat preservation time 2~3h.

2. The bimetallic composite of antimony bronze-steel according to claim 1, characterized in that: The microstructure of the copper alloy layer comprises an α-Cu phase, an elemental Pb phase, a ternary intermetallic compound of formula Cu 4.5 a δ phase of Sb and a Cu2MnSb ternary intermetallic compound.

3. The bimetallic composite of antimony bronze-steel according to claim 1 or 2, characterized in that: The friction coefficient μ of the copper alloy layer is 0.03~0.

07.

4. The bimetallic composite of antimony bronze-steel according to claim 1 or 2, characterized in that: The hardness of the copper alloy layer is not less than 70HRF.

5. The bimetallic composite of antimony bronze-steel according to claim 1 or 2, characterized in that: The bimetallic interface forms a metallurgical bond, and the bonding strength is not less than 150MPa.

6. The bimetallic composite of antimony bronze-steel according to claim 1, characterized by: In step S6, after the material is immersed in the liquid cooling medium, the liquid cooling medium submerges 1 / 3~1 / 2 of the height of the part below the steel base copper melting pool.

Images