A molten steel rare earth / magnesium composite treatment method based on in-situ reduction of slag-gold

Abstract

The present application belongs to the field of rare earth / magnesium composite treatment, and discloses a molten steel rare earth / magnesium composite treatment method based on slag-gold in-situ reduction. The method uses selected slag to smelt different steels, and performs rare earth / magnesium composite treatment on the ingot by continuously adding magnesium alloy to the molten slag during smelting. The method provided by the embodiment of the present application adds magnesium alloy to the molten slag after the slag material is melted during smelting, the magnesium alloy reacts with rare earth oxides in the slag, and the rare earth metal and the magnesium alloy liquid enter the molten steel together. By adjusting the composition of the molten slag and the amount of added magnesium alloy, the content of rare earth and magnesium in the molten steel can be effectively controlled. The added magnesium alloy can also reduce the oxygen potential of the molten slag, thereby reducing the secondary oxidation of the molten steel and the burning loss of rare earth and magnesium elements, and more stably and controllably improving the cleanliness of the molten steel.

Description

Technical Field

[0001] This invention belongs to, but is not limited to, the field of rare earth / magnesium composite treatment, and particularly relates to a method for rare earth / magnesium composite treatment of molten steel based on slag-gold in-situ reduction. Background Technology

[0002] The presence of inclusions disrupts the continuity of the steel matrix, easily inducing the initiation and propagation of cracks, leading to cracking and further degrading the mechanical properties of the steel. To reduce the adverse effects of inclusions on steel properties, a two-pronged approach is typically adopted: first, reducing the total oxygen content in the steel to decrease the number of oxide inclusions; second, controlling the size and distribution of inclusions to refine them as much as possible and disperse them, thereby achieving the harmlessness of inclusions. Rare earth elements have a strong binding ability with oxygen and sulfur elements in steel, achieving deep deoxidation and desulfurization effects. Appropriate rare earth / magnesium composite treatment in steel can not only achieve deep deoxidation and desulfurization but also effectively refine inclusions. The linear expansion coefficient of rare earth inclusions is close to that of the steel matrix, which can effectively reduce stress concentration at the interface between inclusions and the steel matrix. At the same time, rare earth inclusions have high pitting corrosion sensitivity, thus effectively improving the corrosion resistance of steel. Because magnesium treatment can disperse the distribution of inclusions, these dispersed fine inclusions can act as nucleation sites for the crystal phase in the early stage of solidification, promoting the refinement of the solidification structure of the ingot and thus improving the overall performance of the steel.

[0003] However, current conventional rare earth / magnesium composite processing techniques for molten steel mostly involve directly adding rare earth elements and magnesium alloys. Because magnesium and rare earth elements have high vapor pressures and are easily burned off, they readily volatilize in high-temperature molten steel, exacerbating the slag-steel reaction. This results in low and fluctuating yields of rare earth and magnesium in the steel, and can even cause severe secondary oxidation of the molten steel, thus worsening its properties. This not only wastes rare earth and magnesium alloys but also makes it difficult to guarantee the stability of product quality.

[0004] Therefore, there is an urgent need for a method for treating high-quality steel with trace amounts of rare earth / magnesium to make the rare earth / magnesium composite treatment more stable and thus ensure the consistency of its effects. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing steel based on in-situ magnesia-reduction of rare earth / magnesium composite treatment in molten slag. From a thermodynamic perspective, metallic magnesium is used to reduce rare earth oxides in the molten slag to form an appropriate amount of rare earth metal, which, together with magnesium, is infiltrated into the molten steel for rare earth / magnesium composite treatment. The added magnesium alloy can also reduce the oxygen potential of the molten slag, thus reducing the burn-off of rare earth and magnesium in the steel and secondary oxidation of the steel. Furthermore, the content of rare earth and magnesium reduced and introduced into the molten steel can be controlled by adjusting the amount of magnesium alloy added and the content of rare earth oxides in the slag. This method has the advantages of being simple and controllable, reducing the burn-off of alloying elements, and having strong reproducibility.

[0006] This invention is implemented as follows: a method for rare earth / magnesium composite treatment of molten steel based on slag-gold in-situ reduction, the method comprising:

[0007] For steel, a selected slag system is used for smelting, and rare earth / magnesium composite treatment of steel is carried out by continuously adding magnesium alloy to the slag during the smelting process.

[0008] Furthermore, the size of the magnesium alloy particles is approximately 1-4 mm, and they contain Mg ≥ 50 wt% and Al ≥ 5 wt%.

[0009] Furthermore, the steel composition by mass percentage is as follows: C 0.06~1.00%, Si 0.15~1.20%, Cr 0.06~6.00%, Mn 0~1%, P≤0.02%, Mo≤2%, Ni≤0.20%, S≤0.004%, O≤0.002%, Al≤5.00wt%.

[0010] Furthermore, the mass percentage of the selected slag components is as follows: (CaF2 + Na3AlF6) 40~70%, CaO 10~30%, La2O3 20~30%, after being pre-melted at high temperature and then crushed into powder.

[0011] Furthermore, the smelting equipment can operate at temperatures up to 1700℃.

[0012] Furthermore, the slag system can be adapted to various common alloy smelting methods.

[0013] Furthermore, the La and Mg contents of the treated molten steel are: La: 0~0.013%, Mg: 0~0.03%.

[0014] This invention also provides an alloy smelting process for high-quality steel rare earth / magnesium composite treatment, wherein a slag layer containing rare earth oxides is established during the smelting process and alloy smelting is carried out; magnesium alloy particles are continuously added to the slag during the smelting process; rare earth elements migrate to the molten steel through the slag during the smelting process, while magnesium elements diffuse to the molten steel, forming a rare earth / magnesium composite purification mechanism.

[0015] Furthermore, the mass percentage of the slag components is as follows:

[0016] The total content of calcium fluoride and cryolite is 40-70%.

[0017] Calcium oxide 10~30%

[0018] Lanthanum oxide 20-30%.

[0019] Furthermore, the slag is pre-melted at high temperature and cooled and crushed into powder before use.

[0020] Furthermore, the working temperature of the smelting process is 1600~1700℃.

[0021] Furthermore, it is compatible with various alloy smelting methods.

[0022] In combination with the above technical solutions and the technical problems solved, the significant advancements and unexpected technical effects of the technical solution to be protected by this invention are as follows:

[0023] The present invention provides a method for in-situ reduction of rare earth / magnesium composite steel based on slag-gold composite treatment.

[0024] During the smelting process, after the slag melts, a magnesium alloy is added to the slag. The magnesium alloy reacts with rare earth oxides in the slag to form rare earth metals, which, along with the magnesium alloy liquid, enter the molten steel. By adjusting the slag composition and the amount of magnesium alloy added, the rare earth and magnesium content in the molten steel can be effectively controlled. Because the magnesium alloy in the slag can reduce the oxygen potential and act as a diffusion deoxidizer, it can reduce the secondary oxidation of the molten steel after rare earth / magnesium treatment and the loss of rare earth and magnesium elements, thus more stably and controllably improving the cleanliness of the molten steel.

[0025] This invention addresses the technical problems of high magnesium vapor pressure and easy burn-off volatilization during rare earth / magnesium composite treatment of molten steel, the tendency for local enrichment, oxidation loss, and unstable yield when rare earth elements are directly added, and the difficulty of achieving synergistic, controllable, and uniform introduction of rare earth and magnesium into molten steel using traditional methods. To address these issues, a method based on slag-gold in-situ reduction for rare earth / magnesium composite treatment of molten steel is proposed. Instead of directly adding rare earth and magnesium metals to molten steel, this method pre-designs a CaF2-Na3AlF6-CaO-based slag system containing La2O3, and continuously adds magnesium alloy particles containing ≥50wt% Mg and ≥5wt% Al to the slag during the smelting process. This allows the magnesium alloy to participate in the slag-gold interface reaction in the high-temperature slag, achieving in-situ reduction of rare earth oxides and controlled transfer of magnesium into the molten steel. Because the slag system forms a reaction buffer layer and a mass transfer control layer on the surface of the molten steel, it can significantly mitigate the violent reaction when magnesium is directly added to the molten steel, reduce the risk of instantaneous volatilization, burn-off and splashing of magnesium, and avoid the problem of excessive local concentration and inclusion coarsening caused by the direct addition of rare earth elements, thus enabling La and Mg to enter the molten steel in a trace, uniform and adjustable manner.

[0026] The significant advancement of this invention lies in integrating the design of rare earth oxide-containing slag, continuous addition of magnesium alloys, in-situ reduction at the slag-metal interface, and trace composite treatment of molten steel into a cohesive whole. This transforms the addition method of rare earths and magnesium from traditional direct alloying to a composite treatment controlled by interface reaction. After treatment, the La content in the molten steel can be controlled at 0~0.013%, and the Mg content at 0~0.03%, demonstrating that this method can achieve stable introduction of rare earths / magnesium within extremely low content ranges, meeting the requirements for trace active elements in the refinement, modification, and purification of inclusions in steel. In particular, magnesium and rare earths are both strong deoxidizing, strong sulfur-affinity, and strong inclusion-regulating elements. If they are directly added to molten steel, they often fail to exert a stable composite effect due to excessively strong reactions. However, this invention, through the participation of slag in the reaction, transforms the high activity of magnesium into an effective driving force for the in-situ reduction of La2O3 and the regulation of inclusions in molten steel, improving the controllability of the composite treatment while reducing element loss.

[0027] The unexpected technical effect achieved by this invention lies in the fact that, even under high-temperature smelting conditions of approximately 1600-1700℃, the synergistic existence of La and Mg in molten steel can still be achieved through a specific slag system and a continuous addition method of magnesium alloy particles, rather than the result of difficulty in simultaneously and stably entering the molten steel. This effect cannot be obtained simply by changing the charging sequence or conventionally adding magnesium alloy, but rather depends on the synergistic matching of La2O3-containing slag, the CaF2+Na3AlF6 fluxing system, the basic component of CaO, and the reactivity of magnesium-aluminum alloy particles. Therefore, this invention can improve the stability, adaptability, and industrial operability of rare earth / magnesium composite treatment in molten steel, providing a new process route for the fine control of inclusions in low-oxygen, low-sulfur steel, chromium-containing steel, and various alloy steels, exhibiting outstanding substantive features and significant progress.

[0028] (1) The expected benefits and commercial value of the technical solution of this invention after transformation are as follows:

[0029] This invention, once transformed, possesses significant economic benefits and commercial value. By relying on slag-gold in-situ reduction to replace the direct addition of rare earth / magnesium alloys, it significantly reduces the burn-off of rare earth and magnesium alloys, improves element recovery rate, and reduces raw material waste. The process can precisely and stably control the rare earth and magnesium content in steel, refine the inclusions in the steel, and significantly improve the cleanliness, mechanical properties, and corrosion resistance of the steel. It can mass-produce high-end mold steel, saw blade steel, and other high-value-added special steels, achieving product premium in the fields of precision equipment and new energy. At the same time, it aligns with the development trend of domestic substitution of high-end special steels, which can be used internally to improve product gross profit margins and can also be exported as a complete process to realize technology monetization, with strong production stability.

[0030] (2) The technical solution of the present invention provides a new technical route for the clean smelting of high-quality steel:

[0031] Currently, the rare earth modification process at home and abroad generally adopts a single treatment mode of directly adding rare earth alloys to molten steel. There is a lack of mature technical solutions for the synergistic regulation of rare earth and magnesium. Magnesium and rare earth have high vapor pressure and are easily burned off. The composition stability is poor and the modification effect of inclusions is difficult to control stably. The industry has long suffered from the technical shortcomings of stable and controllable composite treatment of rare earth / magnesium. Based on this, this invention pioneers a new path for in-situ rare earth / magnesium composite treatment using slag-gold in-situ reduction. Using pre-melted slag containing rare earth oxides as the rare earth source, in-situ reduction of rare earth oxides in the slag is achieved by adding magnesium alloys to the slag. This synergistically supplies rare earth and magnesium elements to the molten steel, creating a new technical route for the synergistic effect of rare earth and magnesium, breaking through the limitations of traditional single rare earth addition processes. By bidirectionally controlling the rare earth and magnesium content in the steel through slag composition and magnesium alloy addition, integrated control of deoxidation, desulfurization, and inclusion refinement is achieved. This method is suitable for multiple series of steels, including H13 mold steel and 75Cr1 saw blade steel, filling the gap in the industry for low-cost, high-stability simultaneous rare earth / magnesium modification smelting technology, and providing a new technical route for the clean smelting of high-quality steel.

[0032] (3) The technical solution of the present invention solves a technical problem that people have long wanted to solve but have never been able to solve successfully:

[0033] Traditional rare earth / magnesium composite treatment processes for molten steel directly add rare earth elements and magnesium alloys. Due to their high temperature and vapor pressure, these elements are prone to volatilization and burn-off, resulting in low rare earth and magnesium yields and drastic content fluctuations in the steel. This can also trigger secondary oxidation of the molten steel, leading to unstable inclusion control and difficulty in achieving stable batch control of steel cleanliness and mechanical properties – a major challenge for the rare earth / magnesium composite steel treatment industry. Previous research could only modify rare earth or magnesium separately, failing to simultaneously and precisely control the content of both elements. This hindered the stable achievement of synergistic effects in deep deoxidation and desulfurization, as well as inclusion refinement and dispersion. A low-cost, mass-producible simultaneous treatment solution has long been lacking. This invention relies on the slag-gold in-situ reduction approach, using rare earth oxides in the slag as a rare earth supply source. Through the reduction reaction of magnesium alloy, rare earth and magnesium are simultaneously introduced into the molten steel. The magnesium alloy reduces the oxygen potential of the slag, significantly alleviating element loss and secondary oxidation. At the same time, by adjusting the slag ratio and the amount of magnesium alloy added, the target range of rare earth and magnesium in the steel is precisely controlled, achieving multiple effects such as inclusion modification, microstructure refinement, and improved corrosion resistance of the steel. It is suitable for the industrial production of various types of steel and solves the technical problem of low rare earth / magnesium yield, difficult composition control, and unstable batch quality that has long been unresolved in the industry.

[0034] (4) The technical solution of the present invention overcomes technical bias:

[0035] Currently, there is a prevalent technical bias in the industry, believing that rare earth and magnesium can be directly added to molten steel in alloy form to modify inclusions. However, both are easily lost in large quantities at high temperatures, making simultaneous and stable quantity control impossible. This invention breaks with this preconceived notion, abandoning the traditional approach of directly adding rare earth / magnesium alloys. It innovatively utilizes slag containing rare earth oxides as a rare earth source, relying on the in-situ reduction of rare earth oxides in the slag by magnesium alloys to simultaneously deliver rare earth and magnesium to the molten steel. This demonstrates that slag can serve as a controllable rare earth supply medium, and that the addition of magnesium and rare earths can synergistically deoxidize, desulfurize, and refine inclusions. This scheme establishes a new approach to slag-gold in-situ reduction composite treatment, achieving precise control of rare earth / magnesium content and improving yield, thus opening up a completely new technical avenue for the clean steel rare earth / magnesium composite treatment. Attached Figure Description

[0036] Figure 1 This is a mechanism diagram provided in the embodiments of the present invention;

[0037] Figure 2 This is the control diagram provided in the embodiments of the present invention;

[0038] Figure 3 This invention provides the characteristics of rare earth inclusions (rare earth-magnesium composite inclusions) in 75Cr1 steel treated by slag-gold in-situ reduction of rare earth / magnesium composites.

[0039] Figure 4 This invention provides the characteristics of rare earth inclusions (rare earth-magnesium composite inclusions) in mold steel treated by slag-gold in situ reduction of rare earth / magnesium composites.

[0040] Figure 5 The variation of inclusion quantity density and average size in S1-S3 examples of slag-gold in-situ reduction rare earth / magnesium composite treatment mold steel provided in the embodiments of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0042] like Figure 1 , 2 As shown in Figures 3, 4, and 5, embodiments of the present invention provide a method for rare earth / magnesium composite treatment of molten steel based on slag-gold in-situ reduction. This method includes:

[0043] For steel, a selected slag system is used for smelting, and rare earth / magnesium composite treatment of ingots is carried out by continuously adding magnesium alloy to the slag.

[0044] The magnesium alloy particles are approximately 1-4 mm in size and contain Mg ≥ 50 wt% and Al ≥ 5 wt%.

[0045] Furthermore, the steel composition by mass percentage is as follows: C 0.06~1.00%, Si 0.15~1.20%, Cr 0.06~6.00%, Mn 0~1%, P≤0.02%, Mo≤2%, Ni≤0.20%, S≤0.004%, O≤0.002%, Al≤5.00wt%.

[0046] The selected slag components are defined by the following mass percentages: (CaF2 + Na3AlF6) 40~70%, CaO 10~30%, La2O3 20~30%, after being pre-melted at high temperature and then crushed into powder.

[0047] Furthermore, the smelting equipment can operate at temperatures up to 1700℃.

[0048] The slag system is compatible with various common alloy smelting methods.

[0049] The La and Mg contents of the treated molten steel are: La: 0~0.013%, Mg: 0~0.03%.

[0050] Example 1

[0051] H13 steel and selected slag were smelted, and after melting, magnesium alloy was added to the slag to obtain rare earth / magnesium composite treated steel. The mass percentage of the steel composition was as follows: C 0.39%, Si 1.06%, Cr 4.93%, Mn 0.35%, P 0.02%, Mo 1.34%, Ni 0.19%, S 0.003%, and the balance Fe. The mass percentage of the slag composition was as follows: CaF2 50%, CaO 30%, La2O3 20%. The amount of metal used accounted for 0.15% of the slag. Rare earth / magnesium treated steel S1 was obtained.

[0052] Example 2

[0053] In this embodiment, the amount of magnesium alloy added in Example 1 is adjusted to 0.5% of the slag amount, and its technical characteristics are the same as those in Example 1, resulting in rare earth / magnesium composite treated steel S2.

[0054] Example 3

[0055] In this embodiment, the amount of magnesium alloy added in Example 1 is adjusted to 2.5% of the slag amount, and its technical characteristics are the same as those in Example 1, resulting in rare earth / magnesium composite treated steel S3.

[0056] This invention is applicable to all slag-based metallurgical systems that rely on slag for steel refining, not limited to electroslag remelting processes. It covers various smelting scenarios involving slag refining processes, including LF refining furnaces, vacuum induction furnaces, electroslag furnaces, and welding metallurgy. It is suitable for the production of various aluminum-killed steels, and applicable steel grades include high-end steels such as H13 mold steel and 75Cr1 steel. Downstream applications cover precision die-casting molds, engineering machinery, new energy equipment, and wear-resistant metallurgical components. In the mold industry, it can produce high-purity rare-earth / magnesium modified mold steel, improving the steel's fatigue resistance and corrosion resistance. In engineering machinery, high-quality alloy steel treated with this process has refined and dispersed internal inclusions, significantly reducing the probability of crack formation. The process only requires the design of appropriate slag composition and magnesium alloy addition, and is not limited by smelting equipment. It can produce steel ingots and billets of different specifications. The rare earth / magnesium composite treated clean steel billets produced can be used in die casting molds and other applications, meeting the mass production needs of high-end equipment localization, special clean metallurgy, and precision manufacturing industries for ultra-low oxygen and sulfur and refined inclusion steel.

[0057] Example 4

[0058] H13 steel was selected as the raw material for the experiment. The chemical composition of the steel (mass percentage) was: C 0.39%, Si 1.06%, Cr 4.93%, Mn 0.35%, P 0.02%, Mo 1.34%, Ni 0.19%, S 0.003%, and the balance Fe. The steel was smelted under a controlled atmosphere using a rare earth / magnesium composite treatment. The slag composition (mass percentage) was 50% calcium fluoride, 30% calcium oxide, and 20% lanthanum oxide. The slag was pre-melted at high temperature and then cooled and crushed into powder. During the smelting process, 0.15% magnesium alloy particles (2 mm in diameter) were continuously added to the slag, with a magnesium mass fraction of 50% and an aluminum mass fraction of 50%. After treatment, the lanthanum content in the steel was 0.0002%, and the magnesium content was 0.0082%. Metallographic observation revealed that the alumina inclusions were fine, dispersed composite inclusions with an average size of 1.71 μm and a number density of 215 inclusions / mm². 2 .

[0059] Example 5

[0060] The H13 steel used in Example 1 was selected as the treatment material, and smelting was carried out under the same controlled atmosphere. The steel composition by mass percentage was: C 0.39%, Si 1.06%, Cr 4.93%, Mn 0.35%, P 0.02%, Mo 1.34%, Ni 0.19%, S 0.003%, and the balance Fe. The slag composition by mass percentage was: calcium fluoride 50%, calcium oxide 30%, and lanthanum oxide 20%. The slag was pre-melted and then crushed into powder. During the smelting process, magnesium alloy particles with a particle size of 2 mm and a slag weight of 0.5% were continuously added to the slag, with a magnesium mass fraction of 50% and an aluminum mass fraction of 50%. After smelting, the lanthanum content in the steel was 0.0008%, and the magnesium content was 0.013%. Microscopic analysis showed that the inclusions were uniformly distributed, with an average inclusion size of 1.74 μm and a number density of 136 inclusions / mm. 2 .

[0061] Example 6

[0062] The H13 steel used in Example 1 was selected as the treatment material, and smelting was carried out under the same controlled atmosphere. The steel composition by mass percentage was: C 0.39%, Si 1.06%, Cr 4.93%, Mn 0.35%, P 0.02%, Mo 1.34%, Ni 0.19%, S 0.003%, and the balance Fe. The slag composition by mass percentage was: calcium fluoride 50%, calcium oxide 30%, and lanthanum oxide 20%. The slag was pre-melted and then crushed into powder. During the smelting process, magnesium alloy particles with a particle size of 2 mm and a slag weight of 2.5% were continuously added to the slag, with a magnesium mass fraction of 50% and an aluminum mass fraction of 50%. After treatment, the lanthanum content in the steel was 0.0021%, and the magnesium content was 0.0199%. Statistical results of inclusions showed that the inclusions were small in size and highly uniform in distribution. The average size of the inclusions was 1.51 μm, and the number density was 137 inclusions / mm. 2 .

[0063] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for high-quality steel rare earth / magnesium composite treatment, characterized in that, Includes the following steps: For different steel grades, slag containing rare earth oxides is selected and alloy smelting is carried out; magnesium alloy particles are continuously added to the slag during the smelting process; magnesium dissolves in the slag and diffuses into the molten steel; rare earth elements migrate into the molten steel through the slag; under low oxygen partial pressure atmosphere conditions, a process of synergistic effect of rare earth and magnesium is formed to purify the molten steel and modify inclusions.

2. The method as described in claim 1, characterized in that, The magnesium alloy particles have a particle size of 1~4mm.

3. The method as described in claim 1, characterized in that, The magnesium alloy contains a magnesium mass fraction of not less than 50 wt% and an aluminum mass fraction of not less than 5 wt%.

4. The method as described in claim 1, characterized in that, The steel composition by mass percentage is: Carbon 0.06~1.00%; Silicon 0.15~1.20%; Chromium 0.06~6.00%; Manganese 0~1.00%; Phosphorus content is less than or equal to 0.02%; Molybdenum content is less than or equal to 2.00%; Nickel content is less than or equal to 0.20%; Sulfur content is less than or equal to 0.004%; Oxygen content is less than or equal to 0.002%; Aluminum content is less than or equal to 5.00%.

5. The method as described in claim 1, characterized in that, The mass fraction of lanthanum in the treated molten steel is 0~0.013%, and the mass fraction of magnesium is 0~0.03%.

6. An alloy smelting process for high-quality rare earth / magnesium composite treatment of steel, characterized in that, During the smelting process, a slag layer containing rare earth oxides is established and alloy smelting is carried out; magnesium alloy particles are continuously added to the slag during the smelting process; rare earth elements migrate to the molten steel through the slag during the smelting process, while magnesium elements diffuse to the molten steel, forming a rare earth / magnesium composite purification mechanism.

7. The alloy smelting process as described in claim 6, characterized in that, The mass percentage of the slag components is: The total content of calcium fluoride and cryolite is 40-70%; Calcium oxide 10-30%; Lanthanum oxide 20-30%.

8. The alloy smelting process as described in claim 6, characterized in that, The slag is pre-melted at high temperature and then cooled and crushed into powder before use.

9. The alloy smelting process as described in claim 6, characterized in that, The working temperature of the smelting process is 1600~1700℃.

10. The alloy smelting process as described in claim 6, characterized in that, It is compatible with various alloy smelting methods.

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