阅读说明：本技术 一种低冷速敏感性的铝硅合金用细化剂、其制备方法、铝硅合金及其细化方法 (Low-cooling-rate-sensitivity refiner for aluminum-silicon alloy, preparation method of refiner, aluminum-silicon alloy and refining method of aluminum-silicon alloy ) 是由 吴大勇 李松 王立生 李天� 王巍 刘春海 刘海峰 于 2021-07-23 设计创作，主要内容包括：本发明涉及合金加工技术领域,具体公开一种低冷速敏感性的铝硅合金用细化剂、其制备方法、铝硅合金及其细化方法。所述细化剂的化学成分为：Al-xV-yB-zRE,1wt％≤x+y≤6wt％,0.1wt％≤z≤0.5wt％,余量为铝和不可避免的杂质元素；其中,V和B的摩尔比为1:1-6。本发明提供的铸造铝硅合金用Al-V-B-RE细化剂,对冷却速度的敏感性低,还具有较高的形核能力,可将铸造铝硅合金的晶粒尺寸细化至220μm以下,且比Al-3V-1B有更低的冷却速度敏感性,抗Si中毒效果明显,有利于铸造铝合金零部件综合性能的提高,且细化剂的成本较低,具有广阔的应用前景。(The invention relates to the technical field of alloy processing, and particularly discloses a refiner for low-cooling-rate sensitive aluminum-silicon alloy, a preparation method thereof, the aluminum-silicon alloy and a refining method thereof. The chemical components of the refiner are as follows: Al-xV-yB-zRE, x + y is more than or equal to 1 wt% and less than or equal to 6 wt%, z is more than or equal to 0.1 wt% and less than or equal to 0.5 wt%, and the balance is aluminum and inevitable impurity elements; wherein the molar ratio of V to B is 1: 1-6. The Al-V-B-RE refiner for casting aluminum-silicon alloy provided by the invention has low sensitivity to cooling speed, has higher nucleation capability, can refine the grain size of the cast aluminum-silicon alloy to be below 220 mu m, has lower cooling speed sensitivity than Al-3V-1B, has obvious Si poisoning resistance effect, is beneficial to improving the comprehensive performance of cast aluminum alloy parts, has lower cost and has wide application prospect.)

1. A refiner for low-cooling-rate-sensitivity aluminum-silicon alloy is characterized by comprising the following chemical components: Al-xV-yB-zRE, x + y is more than or equal to 1 wt% and less than or equal to 6 wt%, z is more than or equal to 0.1 wt% and less than or equal to 0.5 wt%, and the balance is aluminum and inevitable impurity elements; wherein the molar ratio of V to B is 1: 1-6.

2. A refiner for low cold-rate sensitive Al-Si alloys according to claim 1, wherein RE is at least one of La, Ce, Nd, Er, Gd, Y, Yb and Sc.

3. A refiner for low cold-rate sensitive Al-Si alloys according to claim 2, wherein the chemical composition of the refiner is: Al-3V-1B-0.5 Ce.

4. A refiner for aluminum-silicon alloys with low cold sensitivity according to claim 1, wherein the impurity elements are: fe is less than or equal to 0.2 wt%, Cu is less than or equal to 0.1 wt%, Mn is less than or equal to 0.1 wt%, Zn is less than or equal to 0.1 wt%, Ga is less than or equal to 0.05 wt%, and S is less than or equal to 0.05 wt%.

5. A preparation method of a refiner for low-cooling-rate sensitive aluminum-silicon alloy is characterized by comprising the following steps:

step one, weighing raw materials according to the proportion of any one of claims 1 to 4;

melting the weighed aluminum raw materials to obtain an aluminum melt, adding a covering agent to the surface of the aluminum melt, heating to 750-850 ℃, adding a B raw material and a V raw material, keeping the temperature, stirring and mixing uniformly, adding an RE raw material, keeping the temperature, stirring and mixing uniformly to obtain an Al-V-B-RE melt;

and step three, adding a refining agent to the bottom of the Al-V-B-RE melt, stirring and mixing uniformly, standing, removing floating slag, casting, and demolding to obtain the refiner for the low-cooling-rate sensitive aluminum-silicon alloy.

6. The method for preparing the refiner for aluminum-silicon alloy with low cold rate sensitivity according to claim 5, wherein in the second step, the addition amount of the covering agent is 0.15-0.20% of the mass of the aluminum melt; and/or

In the second step, the heat preservation and stirring time is 15min-30 min.

7. The method for preparing the refiner for low-cooling-rate-sensitivity aluminum-silicon alloy according to claim 5, wherein in the third step, the addition amount of the refining agent is 0.4-0.8% of the mass of the Al-V-B-RE melt.

8. The method of claim 7, wherein in step three, the refining agent is C in a mass ratio of 1:0.8-1.2₂Cl₆And Na₂SiF₆。

9. A method for refining an aluminum-silicon alloy is characterized by comprising the following steps:

melting an aluminum-silicon alloy raw material to obtain an aluminum-silicon alloy liquid;

adding the refiner of any one of claims 1-4 into the aluminum-silicon alloy liquid, and uniformly mixing to obtain molten metal; the addition amount of the refiner is 0.1 to 0.2 percent of the mass of the aluminum-silicon alloy liquid;

and adding a slag removing agent into the molten metal, introducing nitrogen into the molten metal, degassing for 10-20min, skimming, cooling to 710-730 ℃, and performing solidification molding treatment to obtain the refined aluminum-silicon alloy.

10. An aluminum-silicon alloy produced by the method for refining an aluminum-silicon alloy according to claim 9.

Technical Field

The invention relates to the technical field of alloy processing, in particular to a refiner for low-cooling-rate sensitive aluminum-silicon alloy, a preparation method thereof, the aluminum-silicon alloy and a refining method thereof.

Background

The cast aluminum alloy has the advantages of light weight, high strength, high expansion and contraction rate, good elasticity and the like, and is widely applied to the manufacturing industries of automobiles, aerospace and the like. The cast structure formed in the aluminum alloy solidification process can directly influence the performance indexes of the subsequent processing process, the quality of the final product, the service life and the like. Therefore, controlling the solidification structure of the aluminum alloy is an important way to control the material performance. By adding the refiner to treat the aluminum alloy melt, uniform and fine alpha-Al grains can be obtained, the defects of shrinkage porosity, shrinkage cavity and the like are reduced, the hot cracking and segregation tendency of a casting can be effectively reduced, the compactness of the structure is increased, and the mechanical property of the alloy are improved.

Currently, the grain size of aluminum alloys is improved mainly by adding Al-Ti-B refiners in industrial production. However, Al-Ti-B refiners are not effective in refining high Si content Al-Si alloys. Especially when the Si content is more than 4 wt%, Ti reacts with Si to form Ti₅Si₂This reaction will consume the Ti melt and hinder the grain refinement of the alloy. Meanwhile, the cooling speed also has great influence on the grain size, and the lower the cooling speed sensitivity of the common refiner is, the better the refining effect of the grains is. However, the existing refiner has high sensitivity to cooling speed and large difference of refining effect at different cooling speeds, so that when the same refiner is applied to cast aluminum alloy parts with different wall thicknesses, the difference of refining effect is large, and the improvement of the whole mechanical property of the aluminum alloy parts is not facilitated.

With the progress of weight reduction of automobiles, the amount of cast aluminum alloys used has been increasing, and the sizes and shapes of required parts have become larger and more complicated. Therefore, in order to improve the comprehensive performance of the cast aluminum alloy parts, the development of a refiner having low cold rate sensitivity and Si poisoning resistance is urgently required.

Disclosure of Invention

Aiming at the problems that the existing refiner has low Si poisoning resistance and high cooling rate sensitivity, so that the comprehensive performance of the prepared parts is poor, the invention provides the refiner for the low-cooling rate sensitivity aluminum-silicon alloy, the preparation method thereof, the aluminum-silicon alloy and the refining method thereof.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a refiner for low cold-rate sensitivity aluminum-silicon alloy comprises the following chemical components: Al-xV-yB-zRE, x + y is more than or equal to 1 wt% and less than or equal to 6 wt%, z is more than or equal to 0.1 wt% and less than or equal to 0.5 wt%, and the balance is aluminum and inevitable impurity elements; wherein the molar ratio of V to B is 1: 1-6.

The refining agent is composed of an alpha-Al solid solution and particle particles playing a refining role, the particle particles are uniformly distributed in the alpha-Al solid solution, and the phase of the particle particles simultaneously contains V₃RE phase, VB₂Phase sum V₂Al₂₀Multiple phases of the RE phase.

Compared with the prior art, the Al-V-B-RE refiner for the aluminum-silicon alloy has low sensitivity to the cooling speed, and when the refiner is applied to aluminum-silicon alloy parts with larger sizes and complex shapes, the refining effect is basically the same at different parts with larger difference of the cooling speed; meanwhile, the Al-V-B-RE refiner provided by the invention also has higher nucleation capability, and the Al-Si alloy is refined by adopting the refiner, so that the refining effect is more excellent than that of the Al-5Ti-1B, Al-3V-1B refiner used in the prior art, the grain size of the Al-Si alloy can be refined to be less than 220 mu m, and the Al-V-B refiner has lower cooling speed sensitivity than that of Al-3V-1B; in addition, the Al-V-B-RE refiner provided by the invention can improve the deterioration effect of eutectic silicon in the aluminum-silicon alloy, has an obvious Si poisoning resistance effect, is beneficial to improving the comprehensive performance of cast aluminum alloy parts, has low cost and has wide application prospect.

Preferably, RE is at least one of La, Ce, Nd, Er, Gd, Y, Yb or Sc.

Preferably, the chemical components of the refiner are as follows: Al-3V-1B-0.5 Ce.

Preferably, the impurity elements are: fe is less than or equal to 0.2 wt%, Cu is less than or equal to 0.1 wt%, Mn is less than or equal to 0.1 wt%, Zn is less than or equal to 0.1 wt%, Ga is less than or equal to 0.05 wt%, and S is less than or equal to 0.05 wt%.

Preferably, the Al-V-B-RE refiner is added into the cast aluminum-silicon alloy with the Si content of not less than 10 wt% by mass, so that the grain size of alpha-Al in the cast aluminum-silicon alloy is refined to be less than 220 mu m.

The invention also provides a preparation method of the refiner for the low-cooling-rate sensitive aluminum-silicon alloy, which comprises the following steps:

step one, weighing all the raw materials according to the proportion of any one of the raw materials;

melting the weighed aluminum raw materials to obtain an aluminum melt, adding a covering agent to the surface of the aluminum melt, heating to 750-850 ℃, adding a B raw material and a V raw material, keeping the temperature, stirring and mixing uniformly, adding an RE raw material, keeping the temperature, stirring and mixing uniformly to obtain an Al-V-B-RE melt;

and step three, adding a refining agent to the bottom of the Al-V-B-RE melt, stirring and mixing uniformly, standing, removing floating slag, casting, and demolding to obtain the refiner for the low-cooling-rate sensitive aluminum-silicon alloy.

The preparation method of the refiner for the low-cooling-rate sensitive aluminum-silicon alloy is simple to operate, low in product preparation cost and capable of realizing batch industrial production.

Preferably, in the second step, the adding amount of the covering agent is 0.15-0.20% of the mass of the aluminum melt.

Preferably, the covering agent consists of sodium chloride and potassium chloride in a mass ratio of 1: 0.8-1.2.

The addition of the preferred covering agent prevents the aluminum melt from being oxidized.

Preferably, in the second step, the heat preservation and stirring time is 15min-30 min.

Stirring once every 10min during the heat preservation period, and adding a covering agent after each stirring to prevent the aluminum melt from being oxidized.

Preferably, in the third step, the addition amount of the refining agent is 0.4-0.8% of the mass of the Al-V-B-RE melt.

Preferably, in the third step, the refining agent is C with the mass ratio of 1:0.8-1.2₂Cl₆And Na₂SiF₆。

The optimized refining agent has good refining effect and strong degassing capability, and does not generate harmful gas in the production process.

Alternatively, V, B and RE can be in the form of a variety of different materials, such as B in the form of potassium fluoroborate (KBF)₄) Or Al-B master alloy, wherein RE is in the form of RE block or Al-RE master alloy; v can be added in the form of Al-10V or V powder.

The invention also provides a refining method of the aluminum-silicon alloy, which comprises the following steps:

melting an aluminum-silicon alloy raw material to obtain an aluminum-silicon alloy liquid;

adding the refiner into the aluminum-silicon alloy liquid, and uniformly mixing to obtain a metal liquid; the addition amount of the refiner is 0.1 to 0.2 percent of the mass of the aluminum-silicon alloy liquid;

and adding a slag removing agent into the molten metal, introducing nitrogen into the molten metal, degassing for 10-20min, skimming, cooling to 710-730 ℃, and performing solidification molding treatment to obtain the refined aluminum-silicon alloy.

The refining method of the aluminum-silicon alloy has simple refining process, is easy to control, and has important practical application value for controlling the structure performance of the aluminum-silicon alloy.

Preferably, the addition amount of the slag removing agent is 0.1-0.2% of the mass of the aluminum-silicon alloy liquid.

Preferably, the slag remover comprises the following chemical components: 15-30% of Na, 10-20% of K, 1-5% of Ca, 1-5% of Mg, 20-50% of Cl, 1-10% of Si, 5-20% of F, less than or equal to 5% of Al and less than or equal to 5% of C.

Preferably, the nitrogen flow is 1-1.5L/min.

The invention also provides an aluminum-silicon alloy which is prepared by the refining method of the aluminum-silicon alloy.

Preferably, the refined aluminum-silicon alloy has an average grain size of 220 μm or less.

The Al-xV-yB-zRE refiner prepared by the invention has simple operation in the smelting process, low impurity content of the obtained refiner and good refining effect. The cooling rate sensitivity of the refining effect on each part of the aluminum alloy casting with complex shape and different thickness is lower, the mechanical property of the refined alloy is obviously improved, especially the performance of the part (thick wall part) with lower cooling rate of the casting is obviously improved, the difference of the performance of each part with different cooling rates is obviously reduced, the comprehensive performance of the alloy part is favorably improved, and the popularization and application value is higher.

Drawings

FIG. 1 is an XRD pattern of Al-3V-1B-0.5Ce refiner prepared in example 1 of the present invention;

FIG. 2 is a grain size photograph of an Al-10Si-Mg alloy ingot prepared in example 5 of the present invention;

FIG. 3 is a grain size photograph of an Al-10Si-Mg alloy ingot prepared in comparative example 1 of the present invention;

FIG. 4 is a schematic structural diagram of a mold for casting in the embodiment of the present invention, in which the left drawing is a left side view of the mold and the right drawing is a front view of the mold;

FIG. 5 is a grain size photograph of an Al-10Si-Mg alloy ingot at a mold temperature of room temperature when the Al-10Si-Mg alloy ingot is refined using an Al-3V-1B-0.5Ce refiner;

FIG. 6 is a grain size photograph of an Al-10Si-Mg alloy ingot at a mold temperature of 100 ℃ when the Al-10Si-Mg alloy ingot is refined using an Al-3V-1B-0.5Ce refiner;

FIG. 7 is a grain size photograph of an Al-10Si-Mg alloy ingot at a mold temperature of 300 ℃ when the Al-10Si-Mg alloy ingot is refined using an Al-3V-1B-0.5Ce refiner;

FIG. 8 is a grain size photograph of an Al-10Si-Mg alloy ingot at a mold temperature of room temperature when the Al-10Si-Mg alloy ingot is refined using an Al-3V-1B refiner;

FIG. 9 is a grain size photograph of an Al-10Si-Mg alloy ingot at a mold temperature of 100 ℃ when the Al-10Si-Mg alloy ingot is refined using an Al-3V-1B refiner;

FIG. 10 is a grain size photograph of an Al-10Si-Mg alloy ingot at a mold temperature of 300 ℃ when the Al-10Si-Mg alloy ingot is refined using an Al-3V-1B refiner;

FIG. 11 is a graph comparing grain size curves at different die temperatures for Al-10Si-Mg alloy ingot samples with Al-3V-1B-0.5Ce refiner and Al-3V-1B refiner added.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In order to better illustrate the invention, the following examples are given by way of further illustration.

Example 1

The embodiment provides an Al-3V-1B-0.5Ce refiner, and the preparation method comprises the following steps:

step one, selecting commercial pure Al ingot, Al-10V, Al-5B and Ce powder with the purity of 99% as raw materials, weighing 490g of Al ingot, 300g of Al-10V alloy, 200g of Al-5B alloy and 5g of metal cerium powder according to the mass percent of 95.5% of Al, 3% of V, 1% of B (V/B is 1:1.57) and 0.5% of Ce;

step two, adding the weighed Al ingot into a resistance furnace, and heating to 800 ℃ to melt the Al ingot to obtain an aluminum melt; adding a covering agent with the mass of 0.16 Wt% of the aluminum melt, heating to 800 ℃, adding the weighed Al-10V and Al-5B alloy, stirring for 20min under heat preservation, adding the weighed Ce powder, and continuously stirring for 20min under heat preservation to obtain an Al-V-B-RE melt; stirring once every 10min during melting, and adding the covering agent again after each stirring to prevent the aluminum melt from being oxidized;

and step three, adding a refining agent to the bottom of the Al-V-B-RE melt, wherein the adding amount of the refining agent is 0.6 wt% of the mass of the Al-V-B-RE melt, fully stirring for 15min, standing for 10min, removing floating slag, casting into ingots, and demolding to obtain the Al-3V-1B-0.5Ce refining agent.

The covering agent consists of sodium chloride and potassium chloride in a mass ratio of 1:1, and the refining agent consists of C in a mass ratio of 1:1₂Cl₆And Na₂SiF₆And (4) forming.

Example 2

The embodiment provides an Al-4.84V-1.03B-0.1Ce refiner, and the preparation method comprises the following steps:

firstly, selecting commercial pure Al ingot, Al-10V, Al-5B and Ce powder with the purity of 99% as raw materials, weighing 309.87g of Al ingot, 483.93g of Al-10V alloy, 205.2g of Al-5B alloy and 1g of metal cerium powder according to the mass percent of Al of 94.03%, V of 4.84%, B of 1.03% (V/B is 1:1) and Ce of 0.1%;

step two, adding the weighed Al ingot into a resistance furnace, and heating to 750 ℃ to melt the Al ingot to obtain an aluminum melt; adding a covering agent accounting for 0.20 Wt% of the mass of the aluminum melt, heating to 750 ℃, adding the weighed Al-10V and Al-5B alloy, stirring for 15min under heat preservation, adding the weighed Ce powder, and continuously stirring for 25min under heat preservation to obtain an Al-V-B-RE melt; stirring once every 10min during melting, and adding the covering agent again after each stirring to prevent the aluminum melt from being oxidized;

and step three, adding a refining agent to the bottom of the Al-V-B-RE melt, wherein the adding amount of the refining agent is 0.4 wt% of the mass of the Al-V-B-RE melt, fully stirring for 5min, standing for 15min, removing floating slag, casting into ingots, and demolding to obtain the Al-4.84V-1.03B-0.1Ce refiner.

The covering agent consists of sodium chloride and potassium chloride in a mass ratio of 1:1, and the refining agent consists of C in a mass ratio of 1:1₂Cl₆And Na₂SiF₆And (4) forming.

Example 3

The embodiment provides an Al-1.35V-1.72B-0.2Ce refiner, and the preparation method comprises the following steps:

step one, selecting commercial pure Al ingot, Al-10V, Al-5B and Ce powder with the purity of 99% as raw materials, weighing 520g of Al ingot, 135g of Al-10V alloy, 343g of Al-5B alloy and 2g of metal cerium powder according to the mass percent of 96.74% of Al, 1.35% of V, 1.72% of B (V/B is 1:6) and 0.2% of Ce;

step two, adding the weighed Al ingot into a resistance furnace, and heating to 850 ℃ to melt the Al ingot to obtain an aluminum melt; adding a covering agent accounting for 0.18 Wt% of the mass of the aluminum melt, heating to 850 ℃, adding the weighed Al-10V and Al-5B alloys, stirring for 30min under heat preservation, adding the weighed Ce powder, and continuously stirring for 15min under heat preservation to obtain an Al-V-B-RE melt; stirring once every 10min during melting, and adding the covering agent again after each stirring to prevent the aluminum melt from being oxidized;

and step three, adding a refining agent to the bottom of the Al-V-B-RE melt, wherein the adding amount of the refining agent is 0.85 wt% of the mass of the Al-V-B-RE melt, fully stirring for 20min, standing for 20min, removing floating slag, casting into ingots, and demolding to obtain the Al-1.35V-1.72B-0.2Ce refiner.

The covering agent consists of sodium chloride and potassium chloride in a mass ratio of 1:1, and the refining agent consists of C in a mass ratio of 1:1₂Cl₆And Na₂SiF₆And (4) forming.

Example 4

The embodiment provides an Al-0.65V-0.5B-0.35Ce refiner, and the preparation method comprises the following steps:

step one, selecting commercial pure Al ingot, Al-10V, Al-5B and Ce powder with the purity of 99% as raw materials, weighing 831.5g of Al ingot, 65g of Al-10V alloy, 100g of Al-5B alloy and 3.5g of metal cerium powder according to the mass percent of 98.5% of Al, 0.65% of V, 0.5% of B (V/B is 1:3.6) and 0.35% of Ce;

step two, adding the weighed Al ingot into a resistance furnace, and heating to 830 ℃ to melt the Al ingot to obtain an aluminum melt; adding a covering agent accounting for 0.15 Wt% of the mass of the aluminum melt, heating to 830 ℃, adding the weighed Al-10V and Al-5B alloy, stirring for 20min under heat preservation, adding the weighed Ce powder, and continuously stirring for 30min under heat preservation to obtain an Al-V-B-RE melt; stirring once every 10min during melting, and adding the covering agent again after each stirring to prevent the aluminum melt from being oxidized;

and step three, adding a refining agent to the bottom of the Al-V-B-RE melt, wherein the adding amount of the refining agent is 0.75 wt% of the mass of the Al-V-B-RE melt, fully stirring for 18min, standing for 10min, removing floating slag, casting into ingots, and demolding to obtain the Al-0.65V-0.5B-0.35Ce refiner.

The covering agent consists of sodium chloride and potassium chloride in a mass ratio of 1:1, and the refining agent consists of C in a mass ratio of 1:1₂Cl₆And Na₂SiF₆And (4) forming.

Example 5

The embodiment provides a refining method of an Al-10Si-Mg alloy, which comprises the following steps:

step one, melting a commercial Al-10Si-Mg alloy ingot in an aluminum melting furnace, keeping the temperature at 750 ℃, adding the Al-3V-1B-0.5Ce refiner prepared in the example 1, and stirring for 10min under heat preservation; the adding amount of the Al-3V-1B-0.5Ce refiner is 0.2 wt% of the mass of the Al-10Si-Mg alloy ingot;

and step two, adding a slag removing agent accounting for 0.2 wt% of the mass of the Al-10Si-Mg alloy ingot, introducing nitrogen gas for degassing for 10min at the same time, wherein the nitrogen flow is 1L/min, slagging off, then cooling to 720 ℃, casting the alloy liquid into a mold by adopting a TP-1 method, casting the alloy liquid into an ingot, and demolding to obtain the refined Al-10Si-Mg alloy ingot.

The slag remover comprises the following chemical components: 15-30% of Na, 10-20% of K, 1-5% of Ca, 1-5% of Mg, 20-50% of Cl, 1-10% of Si, 5-20% of F, less than or equal to 5% of Al and less than or equal to 5% of C.

Comparative example 1

This comparative example provides a refining method of an Al-10Si-Mg alloy, which has exactly the same procedure as in example 5 except that the refiner was replaced with 0.3 wt% Al-5 Ti-1B.

The XRD pattern of the Al-3V-1B-0.5Ce refiner prepared in example 1 is shown in FIG. 1, from which it can be seen that the Al-3V-1B-0.5Ce refiner comprises an alpha-Al matrix and a V₃Ce phase, VB₂Phase, V₂Al₂₀A Ce phase.

The morphology of the crystal grains was observed by an ultra-depth-of-field digital microscope, and the grain size photograph of the Al-10Si-Mg alloy ingot prepared in example 5 is shown in fig. 2, and the grain size photograph of the Al-10Si-Mg alloy ingot prepared in comparative example 1 is shown in fig. 3. According to GB/T3246.2-2012, the average grain size of the Al-10Si-Mg alloy ingot prepared in example 5 was 213 μm, and the average grain size of the Al-10Si-Mg alloy ingot prepared in comparative example 1 was 4311 μm, as calculated by the average intercept method. Therefore, the Al-3V-1B-0.5Ce refiner provided by the invention has a refining effect obviously better than that of Al-5Ti-1B, and has an excellent Si poisoning resistance effect.

Al-10Si-Mg alloy ingots were refined by the refiner prepared in examples 2-4 in the same manner as in example 5, and the average grain size of the refined Al-10Si-Mg alloy ingots was in the range of 210-220 μm.

In order to test the sensitivity of the Al-V-B-RE refiner to the cooling rate, the Al-V-B-RE refiner provided by the invention is cast by adopting dies with different preheating temperatures, and the preheating temperatures of the dies are different, and the cooling rates of the cast alloy are also different. By analyzing the variation degree of the refining effect of the sample under different cooling speed conditions, the sensitivity degree of the refining effect of the refiner along with the variation of the cooling speed can be obtained.

The specific test method is as follows:

step one, melting a commercial Al-10Si-Mg alloy ingot in an aluminum melting furnace, keeping the temperature at 750 ℃, adding the Al-3V-1B-0.5Ce refiner prepared in the example 1, and stirring for 10min under heat preservation; the adding amount of the Al-3V-1B-0.5Ce refiner is 0.2 wt% of the mass of the Al-10Si-Mg alloy ingot;

and step two, adding a slag removing agent accounting for 0.2 wt% of the mass of the Al-10Si-Mg alloy ingot, introducing nitrogen gas for degassing for 10min at the same time, wherein the nitrogen flow is 1L/min, removing slag, cooling to 720 ℃, casting the alloy liquid into a die with the die temperature of 100 ℃ and 300 ℃ by adopting a TP-1 method, casting into ingots, and demolding to respectively obtain refined Al-10Si-Mg alloy ingots.

The schematic structure of the mold used in the test is shown in fig. 4.

The crystal grain morphology of the Al-10Si-Mg alloy ingot prepared at different die temperatures is observed by using an ultra-depth-of-field digital microscope, and as shown in FIGS. 5-7, the average sizes of the crystal grains of the Al-10Si-Mg alloy ingot in a die at room temperature, a die at 100 ℃ and a die at 300 ℃ are respectively 213 μm, 221 μm and 243 μm according to GB/T3246.2-2012 and calculation by an average intercept method.

The Al-3V-1B refiner was tested for cold rate sensitivity in exactly the same manner as above except that the Al-3V-1B refiner was added in an amount of 0.3 wt%.

The crystal grain morphology of the Al-10Si-Mg alloy ingots prepared at different die temperatures is observed by using an ultra-depth-of-field digital microscope, and as shown in FIGS. 8-10, the average sizes of the crystal grains of the Al-10Si-Mg alloy ingots in a room-temperature die, a 100 ℃ die and a 300 ℃ die are 327 μm, 703 μm and 1021 μm respectively according to GB/T3246.2-2012 and calculation by an average intercept method.

The grain size curves of the samples with Al-3V-1B-0.5Ce refiner and Al-3V-1B refiner added are shown in FIG. 11. As can be seen from the figure, the thinning effect is in a linear relation with the temperature, the slope represents the sensitivity of the thinning effect of the refiner to the cold speed, and the Al-3V-1B-0.5Ce refiner has lower sensitivity to the cold speed and more excellent thinning effect than the Al-3V-1B refiner, can be better applied to complex parts, and improves the comprehensive mechanical property of the complex parts.

The Al-V-B-Ce prepared in the embodiments 2 to 4 is used for refining the Al-10Si-Mg alloy ingot, and all the technical effects basically equivalent to those of the embodiment 1 can be achieved.

Other process parameters defined by the invention can also be adopted in the refining method of the embodiment 5, and all the technical effects basically equivalent to the embodiment 5 can be achieved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.