阅读说明：本技术 一种镁合金熔炼的中碳钢坩埚表面除铁工艺 (Iron removing process for surface of medium carbon steel crucible for smelting magnesium alloy ) 是由 戴甲洪 蒋斌 杨青山 谢红梅 徐向俊 赵炎春 朱云虎 向超 彭程 于 2019-11-19 设计创作，主要内容包括：本发明公开了一种镁合金熔炼的中碳钢坩埚表面除铁工艺,包括以下步骤：S1：表面清理,取两个品质相同的中碳钢坩埚,并记为中碳钢坩埚A和中碳钢坩埚B,用200目砂纸分别将中碳钢坩埚A和中碳钢坩埚B的内表面的氧化皮打磨掉,然后用酒精清洗表面；S2：热镀,将中碳钢坩埚A放入电阻炉中,然后倒入预先熔化好的Mg-4wt.％Mn的镁合金,通过气体保护,在800℃下保温20min,在中碳钢坩埚A的内壁热镀上厚度20μm的Mn层,然后将镁熔体倒出；S3：熔炼,向中碳钢坩埚A和中碳钢坩埚B中分别将纯镁在700℃下熔化,保温60min后熔体在坩埚中自然冷却。本发明中热镀Mn层后铁含量大大降低了,可以有效的阻碍了铁坩埚中的杂质元素Fe向镁熔体中扩散,提高了镁合金的纯度。(The invention discloses a medium carbon steel crucible surface iron removal process for magnesium alloy smelting, which comprises the following steps: s1: cleaning the surface, namely taking two medium carbon steel crucibles with the same quality, marking as a medium carbon steel crucible A and a medium carbon steel crucible B, respectively polishing away oxide skins on the inner surfaces of the medium carbon steel crucible A and the medium carbon steel crucible B by 200-mesh abrasive paper, and then cleaning the surface by using alcohol; s2: hot-dip, putting the medium carbon steel crucible A into a resistance furnace, then pouring the magnesium alloy of Mg-4 wt.% Mn which is melted in advance, preserving the heat for 20min at 800 ℃ under the protection of gas, hot-dip coating a Mn layer with the thickness of 20 mu m on the inner wall of the medium carbon steel crucible A, and then pouring out the magnesium melt; s3: smelting, namely respectively melting pure magnesium in a medium carbon steel crucible A and a medium carbon steel crucible B at 700 ℃, preserving heat for 60min, and naturally cooling the melt in the crucibles. The content of iron is greatly reduced after the Mn layer is hot-dipped in the invention, which can effectively prevent the impurity element Fe in the iron crucible from diffusing into the magnesium melt and improve the purity of the magnesium alloy.)

1. A process for removing iron on the surface of a medium carbon steel crucible for smelting magnesium alloy is characterized by comprising the following steps:

s1: cleaning the surface, namely taking two medium carbon steel crucibles with the same quality, marking as a medium carbon steel crucible A and a medium carbon steel crucible B, respectively polishing away oxide skins on the inner surfaces of the medium carbon steel crucible A and the medium carbon steel crucible B by 200-mesh abrasive paper, and then cleaning the surface by using alcohol;

s2: hot-dip, putting the medium carbon steel crucible A into a resistance furnace, then pouring the magnesium alloy of Mg-4 wt.% Mn which is melted in advance, preserving the heat for 20min at 800 ℃ under the protection of gas, hot-dip coating a Mn layer with the thickness of 20 mu m on the inner wall of the medium carbon steel crucible A, and then pouring out the magnesium melt;

s3: smelting, namely respectively melting pure magnesium in a medium carbon steel crucible A and a medium carbon steel crucible B at 700 ℃, and naturally cooling the melt in the crucibles after heat preservation for 60 min;

s4: and (3) measuring Fe, namely sampling at the edge and the center of the pure magnesium ingot respectively, and measuring the Fe content in the sample by using an atomic emission spectrometer.

2. The process for removing iron from the surface of a medium carbon steel crucible for smelting magnesium alloy as claimed in claim 1, wherein the protective gas in the step S2 is CO2+ SF 6.

Technical Field

The invention relates to the technical field of magnesium alloy smelting, in particular to a process for removing iron on the surface of a medium carbon steel crucible for magnesium alloy smelting.

Background

The magnesium alloy is used as the lightest engineering metal structure material in the current industrial application, has the advantages of small density, high specific strength and specific stiffness, strong damping and vibration reduction capability, superior casting performance, good cutting and processing performance, capability of shielding electromagnetic radiation, easiness in recycling and the like, and has important application value and wide application prospect in the fields of automobiles, railway vehicles, 3C products, aerospace, national defense and military industry and the like.

However, the magnesium alloy has the problems of low absolute strength, difficult processing and forming, poor corrosion resistance and the like, and the application of magnesium alloy products in practical engineering is limited to a great extent. In order to solve the above problems, a great deal of research and development has been made in recent years on alloying, heat treatment, grain refinement, deformation processes, and the like, and significant progress has been made. In addition, the purity of the magnesium alloy is one of the most important factors influencing the corrosion resistance of the magnesium alloy, and particularly the content of harmful impurity elements such as Fe, Si, Ni, Cu and the like in the magnesium alloy. Researches show that the quality of magnesium alloy ingots is greatly reduced by the existence of harmful impurity elements, the texture state, the corrosion resistance, the mechanical property and the processing forming property of magnesium alloy materials are seriously influenced, and Fe is an impurity element which is most harmful in the metal impurities of magnesium alloys. Because the impurity element Fe is easily brought into the magnesium melt through raw materials, a fusing agent, a smelting tool and the like, the pure magnesium melt is the basic premise for obtaining a high-quality magnesium alloy material with good comprehensive performance. The purification technology of the magnesium alloy melt is researched and developed, and the content of impurity element Fe in the magnesium alloy casting blank is effectively reduced. Nowadays, elemental substances or compounds of elements such as B, Ti, Zr, Be, Mn and the like are generally adopted as a flux in magnesium alloy smelting to achieve the purpose of removing Fe. However, these fluxes introduce new impurities or inclusions while removing Fe, which adversely affect the purity of the melt and the overall properties of the magnesium alloy material. In view of the above, it is very necessary to develop a process for removing iron from the surface of a medium carbon steel crucible for smelting magnesium alloy, which is of great significance for improving the quality of magnesium alloy and expanding the engineering application of magnesium alloy materials.

Disclosure of Invention

The invention aims to solve the defects in the prior art, and provides a process for removing iron on the surface of a medium carbon steel crucible for smelting magnesium alloy.

In order to achieve the purpose, the invention adopts the following technical scheme:

a process for removing iron on the surface of a medium carbon steel crucible for smelting magnesium alloy comprises the following steps:

s1: cleaning the surface, namely taking two medium carbon steel crucibles with the same quality, marking as a medium carbon steel crucible A and a medium carbon steel crucible B, respectively polishing away oxide skins on the inner surfaces of the medium carbon steel crucible A and the medium carbon steel crucible B by 200-mesh abrasive paper, and then cleaning the surface by using alcohol;

s2: hot-dip, putting the medium carbon steel crucible A into a resistance furnace, then pouring the magnesium alloy of Mg-4 wt.% Mn which is melted in advance, preserving the heat for 20min at 800 ℃ under the protection of gas, hot-dip coating a Mn layer with the thickness of 20 mu m on the inner wall of the medium carbon steel crucible A, and then pouring out the magnesium melt;

s3: smelting, namely respectively melting pure magnesium in a medium carbon steel crucible A and a medium carbon steel crucible B at 700 ℃, and naturally cooling the melt in the crucibles after heat preservation for 60 min;

s4: and (3) measuring Fe, namely sampling at the edge and the center of the pure magnesium ingot respectively, and measuring the Fe content in the sample by using an atomic emission spectrometer.

Preferably, the shielding gas in step S2 is CO2+ SF 6.

Compared with the prior art, the invention has the beneficial effects that:

the content of iron is greatly reduced after the Mn layer is hot-dipped in the invention, which can effectively prevent the impurity element Fe in the iron crucible from diffusing into the magnesium melt and improve the purity of the magnesium alloy.

Drawings

FIG. 1 is a table showing the measurement results of the iron removal process from the surface of a medium carbon steel crucible for magnesium alloy melting according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1, a process for removing iron on the surface of a medium carbon steel crucible for smelting magnesium alloy comprises the following steps:

s1: cleaning the surface, namely taking two medium carbon steel crucibles with the same quality, marking as a medium carbon steel crucible A and a medium carbon steel crucible B, respectively polishing away oxide skins on the inner surfaces of the medium carbon steel crucible A and the medium carbon steel crucible B by 200-mesh abrasive paper, and then cleaning the surface by using alcohol;

s2: hot-dip, putting the medium carbon steel crucible A into a resistance furnace, then pouring the magnesium alloy of Mg-4 wt.% Mn which is melted in advance, preserving the heat for 20min at 800 ℃ under the protection of gas, hot-dip coating a Mn layer with the thickness of 20 mu m on the inner wall of the medium carbon steel crucible A, and then pouring out the magnesium melt;

s3: smelting, namely respectively melting pure magnesium in a medium carbon steel crucible A and a medium carbon steel crucible B at 700 ℃, and naturally cooling the melt in the crucibles after heat preservation for 60 min;

s4: and (3) measuring Fe, namely sampling at the edge and the center of the pure magnesium ingot respectively, and measuring the Fe content in the sample by using an atomic emission spectrometer.

Wherein, the shielding gas in step S2 is CO2+ SF 6.

From the measurement results of FIG. 1, in the present invention, the Fe content/ppm at the edge of the ingot in the medium carbon steel crucible B without the hot-dip Mn coating was 329, and the Fe content/ppm at the center of the ingot was 159; the Fe content/ppm of the edge of the ingot in the medium carbon steel crucible B hot-dip coated with the Mn layer is 40, and the Fe content/ppm of the center of the ingot is 38. Obviously, the content of iron is greatly reduced after the Mn layer is hot-dipped, the impurity element Fe in the iron crucible can be effectively prevented from diffusing into the magnesium melt, and the purity of the magnesium alloy is improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.