Reverse temperature field extrusion process for producing microcrystal magnesium alloy

An extrusion method and technology of magnesium alloys, applied in metal extrusion, metal extrusion control equipment, manufacturing tools, etc., can solve problems such as easy cracking, uneven plastic deformation, and insignificant grain refinement effect

Active Publication Date: 2005-09-28
HARBIN INST OF TECH
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve the shortcomings of significant uneven plastic deformation, insignificant grain refinement effect, and easy cracking during extrusion of magnesium alloys, the present invention provides a reverse temperature field extrusion method for manufacturing microcrystalline magnesium alloys. Magnesium alloys with a grain size below 10 μm can be produced by one-time extrusion, which is conducive to improving or enhancing the plasticity of magnesium alloys. It is suitable for extrusion forming to manufacture magnesium alloy rods, plates, profil

Method used

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specific Embodiment approach 1

[0009] Embodiment 1: This embodiment is processed according to the following steps: In order to reduce friction, the surface of the extrusion die is lubricated with traditional oil-based graphite or water-based graphite; preheat the extrusion die, and control the temperature of the extrusion die and the billet The surface temperature is the same or 30-50°C higher than the billet surface temperature. Put the billet into the mold to ensure that the billet surface temperature is significantly higher than the core temperature, and the temperature difference between the core and the surface is controlled within the range of 100-320°C. The core of the magnesium alloy billet The temperature with the surface can be adjusted in the range of 20-300°C or 20-200°C, and the large-size billet can be adjusted in the range of 80-400°C; then when the extrusion ratio is 2-64 and the extrusion die punch speed is 20- 30mm·S -1 extrusion under conditions. The extrusion ratio of this embodiment ca...

specific Embodiment approach 2

[0010] Specific implementation mode two: This implementation mode takes AZ31 magnesium alloy as an example for illustration, and the specific process conditions are as follows:

[0011] a. Billet size Φ40×60mm, extrusion ratio 6.25, extruded rod Φ16mm;

[0012] b. The temperature gradient of the reverse temperature field is controlled according to four schemes, and the temperature difference between the billet surface and the core is 150°C, 200°C, 250°C, and 300°C;

[0013] c. The inner surface of the extrusion die is lubricated with oil-based graphite, and the preheating temperature of the extrusion die is respectively carried out according to the temperature in b;

[0014] d. The movement speed of the extrusion punch is 22mm·S -1 ;

[0015] e. The extrusion forces of the four schemes are: 1000MPa, 800MPa, 600MPa, 500MPa;

[0016] f. The grain size of AZ31 magnesium alloy extruded in reverse temperature field with an extrusion ratio of 4 to 6 is below 10 μm. If the extrusi...

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Abstract

The reverse temperature field extrusion process as improved extrusion process for producing microcrystal magnesium alloy includes the following steps: preheating extrusion mold, setting magnesium alloy blank into the extrusion mold, controlling the mold temperature the same as or 30-50 deg.c higher than that of blank surface and the temperature difference between the core of the blank and the surface of the blank in 20-400 deg.c, and extrusion at extrusion ratio of 2-64 and extrusion ram speed of 20-30 mm/s. Extruding magnesium alloy in the said reverse temperature field and at extrusion ratio of 4-6 can fine the crystal particle to below 10 micron, or below 5 micron optimally. Meanwhile, the extruded magnesium alloy has obvious raised plasticity and unit extension over 20 %. The present invention may be used in producing magnesium alloy rod, plate, section bar and pipe.

Description

Technical field: [0001] The present invention is an improvement to the extrusion method. Background technique: [0002] Magnesium is the metal with the most abundant mineral resources on the surface of the earth's crust, and my country accounts for 1 / 3 of the world's magnesium ore resources. Magnesium is the lightest metal among metal structural materials, its density is only 1.74g / cm 3 , which is 2 / 3 of the density of aluminum. Magnesium alloy has the characteristics of high specific strength and specific stiffness, good impact resistance and shock resistance, and good electromagnetic shielding performance. It is expected to replace engineering plastics as shell materials. It is known as a clean material that can be recycled and does not pollute the environment in the 21st century. In aerospace, automobiles, trains, light rail trains, electronic communications, household appliances and other fields, it will be increasingly widely used. [0003] Magnesium alloy has a clos...

Claims

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Application Information

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IPC IPC(8): B21C23/02B21C31/00
Inventor 王尔德于洋王晓琳胡连喜刘祖岩孙宏飞
Owner HARBIN INST OF TECH
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