Semi-solid billet fast preparation method based on texture control idea

A semi-solid and billet technology, which is applied in the field of magnesium alloy semi-solid billet preparation, can solve the problems of semi-solid billets such as low sphericity, large crystal grains, and large plastic deformation, so as to improve the effect of grain refinement and sphericity Higher, less likely effects

Inactive Publication Date: 2017-05-31
HARBIN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention solves the problem that in the preparation process of the existing semi-solid thixotropic blanks, a large amount of plastic deformation is required in advance, and in the semi-solid remelting process, the crystal grains that occur merge and grow to reduce the sphericity of the semi-solid blanks. , the problem of large grains provides a new perspective, that is, to control the growth mechanism of grains in the process of semi-solid remelting from the perspective of texture, and to prepare semi-solid billets with high sphericity and fine grains

Method used

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  • Semi-solid billet fast preparation method based on texture control idea
  • Semi-solid billet fast preparation method based on texture control idea
  • Semi-solid billet fast preparation method based on texture control idea

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Embodiment 1: Preparation of large-size semi-solid blank

[0034] Raw material: semi-continuous drawing and casting AZ91 magnesium alloy bar stock

[0035] Size: Φ60x150mm

[0036] Mold inner corner radius: r=3mm

[0037] The preparation method comprises the following steps:

[0038] (1) ECAP extrusion: Heat the AZ91 magnesium alloy bar to 210°C and keep it warm for 15 minutes. Also heat the ECAP mold (the angle between the two channels is 90°) to 210°C, and then put the bar into the entrance of the mold. Spray MoS2 lubricant on the contact surface between the bar and the entrance of the die, start the press, and slowly extrude the bar at an extrusion speed of 1.5mm / s until the bar can be taken out from the exit of the die;

[0039] (2) Semi-solid remelting: Put the rod taken out from ECAP into the resistance furnace, vacuumize, put argon gas as a protective atmosphere to prevent oxidation, keep the resistance furnace at 570°C for 15 minutes, then take out the billet...

Embodiment 2

[0040] Example 2: Preparation of smaller size semi-solid billets

[0041] Raw material: extruded AZ91 magnesium alloy bar

[0042] Size: Φ20x45mm

[0043] Mold inner corner radius: r=1mm

[0044] The preparation method comprises the following steps:

[0045] (3) ECAP extrusion: Heat the AZ91 magnesium alloy bar to 210°C and keep it warm for 10 minutes. Also heat the ECAP mold (the angle between the two channels is 90°) to 180°C, and then put the bar into the entrance of the mold. On the contact surface between the bar and the entrance of the die, spray graphite lubricant, start the press, and slowly extrude the bar at an extrusion speed of 0.5 mm / s until the bar can be taken out from the exit of the die. Then put the bar into the ECAP inlet again, extrude continuously for 4 passes according to the Bc path, and take it out from the outlet;

[0046] (4) Semi-solid remelting: put the AZ91 magnesium alloy bar that has been extruded by ECAP into a resistance furnace, vacuumize,...

Embodiment 3

[0047] Example 3: Preparation of smaller size semi-solid billets

[0048] Raw material: semi-continuous drawing and casting AZ91 magnesium alloy bar stock

[0049] Size: Φ10x45mm

[0050] Mold inner corner radius: r=0.5mm

[0051] The preparation method comprises the following steps:

[0052](5) ECAP extrusion: Heat the AZ91 magnesium alloy bar to 200°C and keep it warm for 8 minutes. Also heat the ECAP mold (the angle between the two channels is 90°) to 190°C, and then put the bar into the entrance of the mold. On the contact surface between the bar and the entrance of the die, spray graphite lubricant, start the press, and slowly extrude the bar at an extrusion speed of 0.5 mm / s until the bar can be taken out from the exit of the die. Then put the bar into the ECAP inlet again, extrude the second pass according to the C path, and take it out from the mold outlet;

[0053] (6) Semi-solid remelting: Put the AZ91 magnesium alloy bar that has been extruded by ECAP into a res...

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Abstract

The invention discloses a method for fast preparing a semi-solid thixoforming billet and belongs to the technical field of semi-solid billet preparation. The preparation method includes the following steps that an AZ91 magnesium alloy bar material prepared through a semi-continuous drawing cast method is heated to 215 DEG C, heat preservation is conducted for 15 minutes so as to keep the temperature uniform, a heated bar material is put in a 215-DEG C ECAP steel mold, the channel inner-angle transition radius of the mold is controlled to be within 1/15 of the diameter of the AZ91 bar material, after squeezing is conducted for one pass, a billet is taken out of the mold and put in an 560-DEG C resistance furnace, heat preservation is conducted for a certain time, water cooling is conducted till the temperature reaches the room temperature, and a semi-solid billet is obtained; or ECAP squeezing is conducted for multiple passes through a Bc path, squeezing is conducted for at most two passes through a C path, and squeezing is conducted for at most four passes through a Ba path; and then semi-solid remelting is conducted, and the semi-solid thixoforming billet is prepared. By means of the semi-solid billet fast preparation method based on the texture control idea, on the basis of existing technologies, control is conducted on aspects of the mold structure and the ECAP deformation, and therefore, it is possible that the semi-solid thixotropy billet which is small in grain size and high in sphericity degree is fast prepared.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloy semi-solid blank preparation, and relates to a rapid preparation method for semi-solid thixotropic blanks. On the basis of the prior art, it is considered from the perspective of mesoscale-texture of magnesium alloys , which can solve the problems of merging and growing grains and poor sphericity in the process of preparing semi-solid blanks in the prior art, and ensure that the initial plastic deformation strain is as small as possible to prepare semi-solid thixotropic deformation with excellent performance billet. Background technique [0002] Existing methods for preparing semi-solid thixotropic blanks all adopt the method of first performing large plastic deformation on the initial blank, and then keeping the semi-solid temperature range of the blank for a period of time to obtain a semi-solid thixotropic blank. According to this method, the finer the structure obtained by large plast...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22F1/06C22F1/02
CPCC22F1/06C22F1/02
Inventor 张晓华陈晓桐刘晓晶
Owner HARBIN UNIV OF SCI & TECH
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