Iron-based alloy powder for laser selective melting forming high-performance aluminum profile extrusion die

Abstract

The application discloses a kind of iron-based alloy powder of laser selective melting forming high-performance aluminum profile extrusion die, the characteristics of the iron-based alloy powder are as follows: the particle size of iron-based alloy powder is 15-40 μm, and its chemical composition is as follows: C≤0.3wt.%; Si 0.5-1.5wt.%; Ni 2.0-3.2wt.%; Mn 0.5-0.8wt.%; Cr 4.5-6.5wt.%; V 0.5-1.5wt.%; Mo 2.0-3.5wt.%; Cu 5.0-8.0wt.%; Al 0.5-3.5wt.%; carbon nanotube 0.2-2.5wt.%; the balance is Fe.The application has the advantages that the iron-based alloy powder is suitable for the process characteristics of laser selective melting forming ultra-high cooling speed.Meanwhile, by using Cu-Fe liquid phase separation characteristics, laser selective melting forming shape complex, structure size, copper-rich particles dispersedly distributed in iron-rich matrix, with self-lubricating performance extrusion die under high efficiency conditions, has broad application prospect in the field of aluminum profile, automobile manufacturing and the like.

Description

Technical Field

[0001] This invention belongs to the field of laser additive manufacturing (3D printing) technology, and specifically relates to an iron-based alloy powder for laser selective melting forming of high-performance aluminum profile extrusion dies. Background Technology

[0002] Aluminum profiles possess advantages such as low density, high specific strength, good electrical and thermal conductivity, corrosion resistance, aesthetic appeal, and ease of processing and forming, making them widely used in aerospace, aviation, construction, transportation, machinery manufacturing, petroleum, and chemical industries. However, the working environment of aluminum profile extrusion dies is harsh. Under the triple effects of high temperature (520–550℃), high pressure (hundreds of megapascals), and abrasive wear (hard phase inclusions of Al2O3), the service life of aluminum profile extrusion dies is significantly shortened. This not only affects the stability of aluminum profile product quality but also increases production costs and reduces economic efficiency for enterprises. Generally speaking, aluminum profile extrusion dies need to be repaired after extruding 2–5 tons, and the cost of repairing a die is approximately 30–50% of the cost of a new die. Therefore, improving the quality and service life of extrusion dies has always been a pressing issue for the aluminum processing industry.

[0003] Selective laser melting (SLM) is a novel additive manufacturing or 3D printing technology that utilizes the thermal effect of a laser beam to completely melt metal powder, followed by cooling and solidification to form a shape. This technology features rapid heating, high processing efficiency, and rapid cooling, enabling the direct formation of near-perfectly dense metal parts with excellent mechanical properties. Furthermore, leveraging the immiscibility of the Cu-Fe liquid phases, the cooling rate using SLM can reach 10⁻⁶. 5-8 The K / s ratio can significantly shorten the Stokes settling and Marangoni migration times, resulting in high-performance aluminum profile extrusion dies made from in-situ self-assembled copper-rich particle dispersion-strengthened iron-based alloys. Currently, there are no iron-based alloy powders that are fully suitable for the characteristics of laser selective melting forming and can be successfully used to prepare large-size, high-performance aluminum profile extrusion dies. Summary of the Invention

[0004] Under high-efficiency conditions, laser selective melting forming technology is used to prepare large-size, high-performance aluminum profile extrusion dies, thereby achieving rapid manufacturing of the "heart" of aluminum profiles—the extrusion die. Therefore, it is necessary to develop specialized alloy powders tailored to the process characteristics of laser selective melting forming and the performance requirements of aluminum profile extrusion dies. Thus, the purpose of this invention is to provide an iron-based alloy powder for high-performance aluminum profile extrusion dies produced by laser selective melting forming. The chemical composition of the iron-based alloy powder is: C ≤ 0.3 wt.%; Si 0.5–1.5 wt.%; Ni 2.0–3.2 wt.%; Mn 0.5–0.8 wt.%; Cr 4.5–6.5 wt.%; V 0.5–1.5 wt.%; Mo 2.0–3.5 wt.%; Cu 5.0–8.0 wt.%; Al 0.5–3.5 wt.%; carbon nanotubes 0.2–2.5 wt.%; balance Fe.

[0005] The iron-based alloy powder of the present invention is prepared by the following three steps: (1) vacuum high-frequency induction melting, atomization, screening, activation, water washing and drying are carried out according to the chemical composition ratio (C 0.3wt.%; Si 1.2wt.%; Ni 2.5wt.%; Mn 0.7wt.%; Cr 5.5wt.%; V 0.8wt.%; Mo 2.8wt.%; Cu 7.5wt.%; Al 1.5wt.%; balance Fe) to prepare alloy powder; (2) carbon nanotubes are degummed, roughened, sensitized, activated, electroless nickel plating, water washing and drying to prepare nickel-plated carbon nanotubes with core-shell structure; (3) the alloy powder and nickel-plated carbon nanotubes are loaded into a high-energy ball mill and mixed evenly according to the mass ratio to prepare iron-based alloy powder, wherein the carbon nanotube content is 1.5wt.% and the particle size of the iron-based alloy powder is 15-40μm.

[0006] Compared with existing technologies, the iron-based alloy powder for high-performance aluminum profile extrusion dies produced by laser selective melting forming provided by this invention has the following advantages: Aluminum profile extrusion dies prepared by conventional casting and powder metallurgy processes suffer from porosity or air bubbles due to slow cooling rates (approximately 20 K / s), lack self-lubricating properties, and have high-temperature fatigue performance that needs further improvement. Furthermore, due to inherent limitations of the process, conventional processes struggle to achieve one-step fabrication of aluminum profile extrusion dies with complex shapes and large structural dimensions. Based on the laser selective melting forming process, high-performance aluminum profile extrusion dies can achieve up to 10... 5-8With a cooling rate of K / s, alloy powders suitable for near-equilibrium solidification, such as those used in casting and powder metallurgy, can no longer be used. It is necessary to combine the self-assembly characteristics of liquid phase separation with the concept of layered additive manufacturing to develop iron-based alloy powders suitable for ultra-fast cooling rates in laser selective melting forming processes. This will greatly reduce the time for droplet collision, solidification, and coarsening, shorten the droplet migration distance so that the Stokes motion of the droplets can be ignored. This will result in high-performance aluminum profile extrusion dies with uniform distribution of second-phase copper-rich particles and carbon nanotubes in the iron-rich matrix, and complex shapes and large structural dimensions. Due to the self-assembled copper-rich particles and the incorporated carbon nanotubes, the extrusion die has self-lubricating properties: compared with H13 steel, the coefficient of friction is reduced by 50-70%, and the wear resistance is improved by 1-2 times. Detailed Implementation

[0007] The chemical composition of the iron-based alloy powder of the present invention is as follows: C 0.3 wt.%; Si 1.2 wt.%; Ni 2.5 wt.%; Mn 0.7 wt.%; Cr 5.5 wt.%; V 0.8 wt.%; Mo 2.8 wt.%; Cu 7.5 wt.%; Al 1.5 wt.%; carbon nanotubes 2.2 wt.%; balance Fe.

[0008] The preparation process of this invention is as follows: (1) According to the chemical composition ratio (C 0.3wt.%), vacuum high-frequency induction melting, atomization, screening, activation, water washing and drying are carried out to prepare alloy powder; (2) Carbon nanotubes are degummed, roughened, sensitized, activated, electroless nickel plating, water washing and drying are carried out to prepare nickel-plated carbon nanotubes with core-shell structure; (3) The alloy powder and nickel-plated carbon nanotubes are loaded into a high-energy ball mill and mixed evenly according to the mass ratio to prepare iron-based alloy powder, wherein the carbon nanotube content is 2.2wt.% and the particle size of the iron-based alloy powder is 15-40μm.

[0009] The iron-based alloy powder of this invention uses the following laser selective melting forming process parameters: the power of the Yb:YAG fiber laser is 0.4kW, the spot diameter is 60μm, the laser scanning speed is 2500mm / s, the layer thickness is 30μm, and the overlap distance is 40μm. The main performance indicators of the obtained high-performance aluminum profile extrusion die are: compared with H13 steel, the coefficient of friction is reduced by 50-70%, and the wear resistance is improved by 1-2 times.

Claims

1. A powder of a ferrous alloy for selective laser melting forming of high performance aluminium extrusion dies, characterized in that: The chemical composition of the iron-based alloy powder is: C ≤ 0.3wt.%; Si 0.5~1.5 wt.%; Ni 2.0~3.2wt.%; Mn 0.5~0.8wt.%; Cr 4.5~6.5 wt.%; V 0.5~1.5 wt.%; Mo 2.0~3.5 wt.%; Cu 5.0~8.0 wt.%; Al 0.5~3.5wt.%; carbon nanotubes 0.2~2.5 wt.%; and the balance is Fe; The Ni in the iron-based alloy powder is coated on the outer surface of the carbon nanotubes in a chemical plating Ni treatment mode.

2. The iron-based alloy powder for laser beam melting forming high-performance aluminum profile extrusion dies as claimed in claim 1, characterized in that: The chemical composition of the iron-based alloy powder is: C 0.3wt.%; Si 1.2 wt.%; Ni 2.5wt.%; Mn 0.7wt.%; Cr 5.5 wt.%; V 0.8 wt.%; Mo 2.8 wt.%; Cu 7.5 wt.%; Al 1.5 wt.%; carbon nanotubes 2.2 wt.%; and the balance is Fe.

3. The iron-based alloy powder for laser beam melting forming high-performance aluminum profile extrusion dies as claimed in claim 1, characterized in that: The particle size of the iron-based alloy powder is 15~40μm.