Secondary continuous extrusion processing method of magnesium alloy and die plate insert for secondary continuous extrusion processing method

A die insert, extrusion processing technology, applied in metal extrusion dies, metal extrusion, metal processing equipment and other directions, can solve the problems of increasing human and material consumption, product cracks, material performance improvement, etc., to improve industrial production. Efficiency, excellent mechanical properties, the effect of reducing production costs

Inactive Publication Date: 2012-08-15
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

When the extrusion speed is constant, the larger the extrusion ratio, the higher the extrusion temperature. Otherwise, the forming effect of the magnesium alloy will be affected, resulting in crack defects in the extruded product.
However, the previous research found that the extrusion process has a significant impact on the structure and performance of the extruded product, mainly as follows: the lower the extrusion temperature, the less obvious the recrystallization grain growth of the extruded material, and the microstructure is obtained. Thinning, the performance of the material is improved; the larger the extrusion ratio, the more uniform the structure after extrusion, the greater the elongation of the material, and the strength may also increase, and the texture may also be weakened
In order to realize the large deformation of the alloy at low temperature, obtain a refined and homogeneous structure, and obtain a product with excellent performance, the billet can be extruded multiple times at a small extrusion ratio at low temperature, but the increase in the number of processing passes affects on the one hand. Production efficiency, on the other hand, increases the consumption of manpower and material resources, which makes the production cost rise significantly

Method used

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  • Secondary continuous extrusion processing method of magnesium alloy and die plate insert for secondary continuous extrusion processing method
  • Secondary continuous extrusion processing method of magnesium alloy and die plate insert for secondary continuous extrusion processing method
  • Secondary continuous extrusion processing method of magnesium alloy and die plate insert for secondary continuous extrusion processing method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Mg 98 Zn 1.92 Gd 0.08 (at. %, Alloy 1) and Mg 96.83 Zn 2.7 Gd 0.47 (at. %, Alloy 2)

[0029] Alloy 1 and Alloy 2 were homogenized at 400°C for 8 hours and then cooled by water quenching. Preheat the two alloys to 100°C, preheat the mold to 80°C, carry out traditional extrusion and secondary continuous extrusion, put the heated magnesium or magnesium alloy billet into the extrusion cavity of the heated mold, extrude The punching head extruded the billet at a speed of 0.1m / min, and the extrusion ratio was 4:1. It was found that the two alloys could not realize the traditional extrusion at this temperature, but they could realize the secondary continuous extrusion and the shape was perfect. Image 6 is the microstructure photo of Alloy 1 (a) and Alloy 2 (b) after two consecutive extrusions (the arrows indicate the direction of extrusion), Figure 7 It is the room temperature mechanical properties diagram of alloy 1 and alloy 2 after secondary continuous extrusion....

Embodiment 2

[0031] Mg 98.25 Zn 1.5 Gd 0.25 (at. %, Alloy 3) conventional extrusion with Mg 98.25 Zn 1.5 Gd 0.25 (at. %, Alloy 3) Comparison of two consecutive extrusions

[0032]Alloy 3 was directly subjected to conventional extrusion (diameter 37mm to 12mm) and secondary continuous extrusion (diameter 37mm to 15mm, then extrusion to 12mm) in the cast state. The billet preheating temperature is 100°C, the mold preheating temperature is 100°C, the extrusion ratio is 9:1, and the extrusion punch speed is 0.12mm / min. Figure 8 a is the microstructure photo of Alloy 3 after conventional extrusion, Figure 8 b is the microstructure photo of alloy 3 after secondary continuous extrusion. Due to the low extrusion temperature, the recrystallization of the material is incomplete, and the recrystallization grains are very small. Figure 9 It is the room temperature mechanical properties diagram of alloy 3 after traditional extrusion and secondary continuous extrusion. As can be seen from th...

Embodiment 3

[0034] Mg 98.25 Zn 1.5 Gd 0.25 (at. %, Alloy 3)

[0035] Alloy 3 was homogenized at 400°C for 8 hours and then subjected to traditional extrusion. The billet preheating temperature was 400°C, the mold preheating temperature was 370°C, the extrusion ratio was 25:1, and the extrusion punch speed was 2mm / min. Yield strength 170MPa, elongation 19%. The alloy was subjected to secondary continuous extrusion (diameter 60mm extruded to 15mm, and then extruded to 12mm). The billet preheating temperature is 400°C, the mold preheating temperature is 370°C, the extrusion ratio is 25:1, and the extrusion punch speed is 2mm / min. After secondary extrusion, the yield strength of Alloy 3 is 180MPa. Compared with the traditional extrusion, the yield strength increases by about 6%, while the elongation is 22%, and the elongation increases by about 16%.

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Abstract

The invention discloses a secondary continuous extrusion processing method of magnesium alloy and a die plate insert for the secondary continuous extrusion processing method. The secondary continuous extrusion processing method comprises the steps of replacing a conventional extrusion die plate insert with a secondary continuous extrusion die plate insert, preheating magnesium or magnesium alloy blank to a temperature lower than an extrusion temperature by 0 to 30 DEG C, and performing unidirectional and uniform extrusion on the blank with the extrusion speed being 0.1m/min to 4m/min and the extrusion ratio being 4: 1 to 40: 1. The designed and manufactured secondary continuous extrusion die plate insert comprises an upper cylinder with a small diameter and a lower cylinder with a large diameter, which are connected with each other, wherein center through holes are formed in the insert and comprise a first extrusion forming work tape hole, an inverted cone hole, a secondary extrusion forming work tape hole and a molding product channel hole. The secondary continuous extrusion processing method has the characteristics of being simple in technology, easy to operate, low in extrusion cost and wide in application range; and compared with the conventional extrusion product, the magnesium alloy prepared by the secondary continuous extrusion processing method has more tiny structures and better performance.

Description

technical field [0001] The invention relates to the field of extrusion deformation of magnesium alloys, in particular to a magnesium alloy secondary continuous extrusion processing method and a die insert thereof. Background technique [0002] Magnesium alloy is the lightest metal structure material in practical application, and is known as "green engineering material in the 21st century". With the development of light weight in industries such as automobiles, aerospace, and transportation, the application of magnesium alloys is becoming more and more extensive. Magnesium alloys can be divided into cast magnesium alloys and deformed magnesium alloys. Deformed magnesium alloys are mainly refined through thermomechanical deformation, such as extrusion, rolling, forging, etc., to improve the properties of the alloy. Compared with cast magnesium alloys, wrought magnesium alloys have higher strength, better elongation and more diverse mechanical properties, which can meet the re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21C23/02B21C25/02B21C31/00
Inventor 袁广银黄华
Owner SHANGHAI JIAO TONG UNIV
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