Quick zero-defect degreasing method for large-size extrusion forming blank

An extrusion forming, large-scale technology, applied in the field of powder metallurgy, can solve the problems of high cost and product surface pollution, and achieve the effect of improving shape retention, improving degreasing efficiency, and convenient, rapid and defect-free degreasing.

Inactive Publication Date: 2011-11-23
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in this degreasing method, the surface of the green body and the siphon powder are bonded to each other to...

Method used

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  • Quick zero-defect degreasing method for large-size extrusion forming blank
  • Quick zero-defect degreasing method for large-size extrusion forming blank
  • Quick zero-defect degreasing method for large-size extrusion forming blank

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1. Using powder plasticized extrusion molding technology, a tungsten-based alloy billet with a large aspect ratio of Φ24mm is prepared, and the binder used is a paraffin-based composite binder.

[0029] 2. Put the extruded billet into the solvent degreasing tank, add a certain amount of n-heptane at the same time, and the liquid-solid ratio is 8:1 (volume ratio).

[0030] 2. Use a constant temperature water bath to control the temperature of the degreasing solvent, and degrease at 40°C for 8 hours.

[0031] 3. Take out the degreased base and place it in a constant temperature drying oven, and keep it warm at 35°C for 0.5h.

[0032] 4. Replace the degreasing solvent, then immerse the degreasing base in n-heptane, the degreasing temperature is 40°C, and the degreasing time is 4h.

[0033] 5. Take out the degreased base and place it in a constant temperature drying oven to dry. Repeat this process. After 2 times of solvent immersion to degrease and dry, the weight loss of...

Embodiment 2

[0037] 1. Using powder plasticized extrusion molding technology, a tungsten-based alloy billet with a large aspect ratio of Φ38mm is prepared, and the binder used is a paraffin-based composite binder.

[0038] 2. Put the extruded billet into the solvent degreasing tank, add a certain amount of n-heptane at the same time, and the liquid-solid ratio is 12:1 (volume ratio).

[0039] 2. Use a constant temperature water bath to control the temperature of the degreasing solvent, and degrease at 45°C for 10 hours.

[0040] 3. Take out the degreased base and place it in a constant temperature drying oven, and keep it warm at 40°C for 1 hour.

[0041] 4. Replace the degreasing solvent, then immerse the degreasing base in n-heptane, the degreasing temperature is 45°C, and the degreasing time is 6h.

[0042] 5. Take out the degreased base again and place it in a constant temperature drying oven to dry. After soaking in solvent twice to degrease and dry, the weight loss of the binder is ...

Embodiment 3

[0046] Contrast using the traditional degreasing method and the degreasing method of the present invention.

[0047] The traditional degreasing method is: thermal degreasing or simple solvent degreasing + thermal degreasing two-step degreasing process.

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PUM

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Abstract

The invention discloses a quick zero-defect degreasing method for a large-size extrusion forming blank, comprising the following steps of: feeding a formed blank into a solvent degreasing tank and adding a degreasing solvent at the same time, wherein the ratio of a liquid to a solid is 7:1-15:1; degreasing under the condition of constant temperature of 30-60 DEG C for 6-12h; taking out the degreased blank and drying the greased blank at the constant temperature of 30-50 DEG C for 0.5-1h; replacing the degreasing solvent and drying; repeating 2-3 times until the mass loss of a binding agent reaches 60-75 percent; and feeding a solvent greasing blank in a high-temperature degreasing furnace and raising the temperature to 600-850 DEG C in the atmosphere of vacuum or negative pressure to obtain the zero-defect large-size degreasing blank. According to the quick zero-defect degreasing method disclosed by the invention, the defects of long degreasing time of the large-size forming blank, poor degreasing shape retention and more greasing defects are overcome; in addition, two adopted degreasing processes are simple, easy to control and are widely applied in actual production.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, and relates to a degreasing technology of powder near-net shape. Background technique [0002] Powder Injection Molding (PIM) and Powder Extrusion Molding (PEM) are two new powder metallurgy near-net forming technologies that have developed rapidly in recent years. They are suitable for processing and forming various metals, alloys, ceramic powders and other materials, especially for forming such Cemented carbide, copper, steel, tungsten, high melting point intermetallic compounds, ceramics and other materials that are difficult to prepare by conventional processing and forming methods can use these two technologies, which provide new technologies for the research and development of new materials and their products method. [0003] The basic process of PIM and PEM is: [0004] Powder + binder→mixing→injection or extrusion molding→remove binder→sintering [0005] Among them, the desig...

Claims

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Application Information

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IPC IPC(8): B22F3/24B22F3/20B22F3/22
Inventor 马运柱刘文胜蔡青山
Owner CENT SOUTH UNIV
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