Preparation method of instant-adding instant-melting zinc-aluminum-titanium-boron intermediate alloy, intermediate alloy and application

Abstract

The invention provides a preparation method of an instant-melting zinc-aluminum-titanium-boron intermediate alloy, the intermediate alloy and application. The invention relates to a preparation method of an instant-adding instant-melting zinc-aluminum-titanium-boron intermediate alloy, which comprises the following steps: weighing raw materials Zn, Al-10Ti alloy and Al-3B alloy, melting the dried Zn, stirring after completely melting, and preserving heat for 4-5 minutes; adding an Al-10Ti alloy at 740-750 DEG C, pressing the Al-10Ti alloy to the bottom of a smelting furnace for melting, scraping slag, stirring, and preserving heat for 4-5 minutes; the Al-3B alloy is pressed to the bottom of the smelting furnace to be smelted, stirring is conducted after slag scraping, heat preservation is conducted for 4-5 min, and zinc-aluminum-titanium-boron alloy liquid is obtained; and cooling to 680-700 DEG C, keeping the temperature for 9-10 minutes, and casting to obtain the zinc-aluminum-titanium-boron intermediate alloy with the required size. The melting point of the zinc-aluminum-titanium-boron intermediate alloy is lower than that of Zn-6Al-3Mg for hot dipping.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hot-dip galvanizing, and particularly relates to a preparation method of a zinc-aluminum-titanium-boron intermediate alloy that can be added and melted at the same time, the intermediate alloy and application. BACKGROUND

[0002] Hot-dip galvanizing is a process for effectively improving the corrosion resistance of metal materials, and is widely used due to its low cost, simple process and good coating quality. The zinc-containing coating is not easy to corrode in the atmosphere and has electrochemical protection characteristics, and has stronger electronegativity compared with common metals such as iron, copper and nickel. When the surface of the metal substrate forms an electrochemical corrosion of the Zn-containing coating, the metal Zn in the coating will sacrifice itself first, thereby achieving the purpose of protecting the metal substrate. Zinc-aluminum-magnesium alloy appeared in the environment of rapid development of hot-dip galvanizing technology. Common zinc-aluminum-magnesium alloy coating products include Superzinc (Zn-4.5Al-0.1Mg), Super Dyma (Zn-11Al-3Mg-0.2Si) and ZAM (Zn-6Al-3Mg). Among them, the performance of the ZAM alloy coating is the best, and the surface quality of the coating is better, and the corrosion resistance is 5-10 times higher than that of the conventional zinc-aluminum-magnesium alloy coating. The use rate of ZAM coating ranks first in the same industry, covering most industries such as machinery, household appliances and construction.

[0003] Hot-dip galvanizing alloy includes pure zinc, zinc-aluminum alloy and zinc-aluminum-magnesium alloy, and a small amount of Ti, Zr, B, Ca, Sr, RE and other alloy elements are usually added to the zinc pool to improve the coating organization and improve the corrosion resistance and processing formability of the coating. At present, most manufacturers use Al-5Ti-B to micro-alloy various galvanized alloys. Due to the high melting point of the Al-5Ti-B intermediate alloy, and the specific gravity is also significantly lower than the specific gravity of the galvanized alloy, the intermediate alloy is prone to floating and difficult to completely melt in actual production, which causes the quality of the zinc-aluminum-magnesium alloy to be difficult to achieve the expected target. Therefore, it is urgent to develop a zinc-aluminum-magnesium alloy micro-alloying zinc-aluminum-titanium-boron intermediate alloy that can be added and melted at the same time. The invention can meet the production needs of zinc-aluminum-magnesium alloy. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to provide a preparation method of a zinc-aluminum-titanium-boron intermediate alloy that can be added and melted at the same time, the intermediate alloy and application, which solves the problem that the melting point and specific gravity of the traditional Al-Me (Ti, Zr, B, Ca, Sr, RE) intermediate alloy are high, and the intermediate alloy is prone to floating and difficult to completely melt in the actual production process of the zinc-aluminum-magnesium alloy ingot, which causes the quality of the zinc-aluminum-magnesium alloy ingot to be difficult to achieve the expected target.

[0005] The present application provides a preparation method of a zinc-aluminum-titanium-boron intermediate alloy that can be added and melted at the same time, comprising the following steps:

[0006] The raw materials Zn, Al-10Ti alloy and Al-3B alloy are weighed, the Zn is melted after drying, stirred after complete melting, and kept for 4-5 min;

[0007] The Al-10Ti alloy is added at 740-750℃, and the Al-10Ti alloy is pressed to the bottom of the furnace to melt, stirred after slagging, and kept for 4-5 min; and the Al-3B alloy is pressed to the bottom of the furnace to melt, stirred after slagging, and kept for 4-5 min, to obtain a zinc-aluminum-titanium-boron master alloy liquid;

[0008] The temperature is lowered to 680-700℃, kept for 9-10 min, and the zinc-aluminum-titanium-boron master alloy of the required size is obtained by casting.

[0009] Preferably, the zinc-aluminum-titanium-boron master alloy comprises 15-20 wt.% Al, 0.8-1.2 wt.% Ti, 0.1-0.5 wt.% B, and the balance Zn, in terms of mass percentage.

[0010] Preferably, the temperature of the Zn melting is 460±1℃.

[0011] Preferably, the Zn is melted in a medium-frequency furnace.

[0012] Preferably, the Al-10Ti alloy is added at 740℃.

[0013] Preferably, the Al-10Ti alloy is melted, stirred after slagging for 1-2 min.

[0014] Preferably, the Al-3B alloy is melted, stirred after slagging for 1-2 min.

[0015] Preferably, the casting temperature is 690℃.

[0016] A zinc-aluminum-titanium-boron master alloy obtained by the preparation method of the instant melt zinc-aluminum-titanium-boron master alloy according to any of the above.

[0017] The preparation method of the instant melt zinc-aluminum-titanium-boron master alloy according to any of the above, or the zinc-aluminum-titanium-boron master alloy, is used in the micro-alloying treatment of a zinc-plated alloy.

[0018] The melting point of the zinc-aluminum-titanium-boron master alloy of the present application is 475-480℃, which is lower than the melting point of Zn-6Al-3Mg for hot-dip plating.

[0019] The average size of Al3Ti phase in the existing intermediate alloy, such as Al-3Ti-1B, is about 50 microns, and the Al3Ti phase can only play a refining role on the alloy by being dissolved into smaller particles, so that the larger Al3Ti phase in the intermediate alloy is not conducive to the subsequent micro-alloying effect. The preparation method of the present application makes the Al3Ti phase in the microstructure uniformly dispersed, and the average size is <20 microns. At the same time, the preparation method of the present application makes the average size of T phase (a ternary phase of Al3Ti phase and Zn) in the microstructure <20 microns, and the improvement effect on the alloy is significant.

[0020] After the Zn-6Al-3Mg alloy is micro-alloyed by the instant-melted zinc-aluminum-titanium-boron intermediate alloy, not only the absorption rate of titanium element is improved, but also the solidification structure of the zinc-aluminum-magnesium alloy is refined significantly. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Example 1 of the present application;

[0022] Figure 2 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Example 2 of the present application;

[0023] Figure 3 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Example 3 of the present application;

[0024] Figure 4 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Example 4 of the present application;

[0025] Figure 5 The microstructure photograph of the Zn-6Al-3Mg alloy after micro-alloying of the zinc-aluminum-titanium-boron intermediate alloy prepared in Example 3 of the present application;

[0026] Figure 6 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Comparative Example 1 of the present application;

[0027] Figure 7 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Comparative Example 2 of the present application;

[0028] Figure 8 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Comparative Example 3 of the present application;

[0029] Figure 9 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Comparative Example 4 of the present application;

[0030] Figure 10 The microstructure photograph of the zinc-aluminum-titanium-boron intermediate alloy prepared in Comparative Example 5 of the present application. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. If the specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are used if not otherwise specified.

[0032] A preparation method of a ready-to-melt zinc-aluminum-titanium-boron intermediate alloy, comprising the following steps:

[0033] (1) The raw materials Zn block, Al-10Ti alloy block and Al-3B alloy block are weighed, the dried Zn block is placed in a medium-frequency furnace and melted at 460±1℃, and after complete melting, stirring is performed and the temperature is maintained for 4-5 min.

[0034] (2) At 740-750℃, preferably 740℃, the Al-10Ti alloy block is added and pressed to the bottom of the melting furnace to be melted, after slagging, stirring is performed for 1-2 min and the temperature is maintained for 4-5 min; then the Al-3B alloy block is pressed to the bottom of the melting furnace to be melted, after slagging, stirring is performed for 1-2 min and the temperature is maintained for 4-5 min, to obtain a zinc-aluminum-titanium-boron alloy liquid.

[0035] (3) The temperature is lowered to 680-700℃, the temperature is maintained for 9-10 min, and the zinc-aluminum-titanium-boron intermediate alloy with the required size is obtained by casting, and the casting temperature is preferably 690℃.

[0036] The zinc-aluminum-titanium-boron intermediate alloy comprises 15-20wt.% Al, 0.8-1.2wt.% Ti, 0.1-0.5wt.% B, and the balance is Zn. The zinc-aluminum-titanium-boron intermediate alloy is preferably Zn-18.7%Al-1%Ti-0.3%B. If the aluminum exceeds the corresponding content, the fluidity of the alloy will become poor when the temperature is maintained during cooling and waiting for casting, which will cause the Al3Ti phase to segregate and gather in the finished product, and it is difficult to be used in industrial use. If the B exceeds the corresponding content, there will be more black B-rich phases in the solidification structure of the alloy, causing waste.

[0037] The main component of Al-5Ti-1B is aluminum, and its melting point is close to 660℃. When Al-5Ti-1B is used for micro-alloying treatment, a higher molten pool temperature is set, and a large amount of energy is consumed in this process. Compared with the Al-5Ti-B intermediate alloy, the melting point of the zinc-aluminum-titanium-boron intermediate alloy of the present application is lower, and in the micro-alloying treatment of the galvanized alloy, the overall temperature does not need to be raised, the energy consumption is reduced, and the economic value is good.

[0038] The Zn block in the following embodiments of the present application is purchased from Shanghai Qichen Industry Co., Ltd., and the purity is 99.99%.

[0039] The Zn-6Al-3Mg alloy block in the following examples of the present application is purchased from Jiangsu Scientific Research Rare Metal Institute.

[0040] The Al-10Ti alloy block in the following examples of the present application is purchased from Shenyang Jiabei Business and Trade Co., Ltd., and the brand is AlTi10.

[0041] The Al-3B alloy block in the following examples of the present application is purchased from Shenyang Jiabei Business and Trade Co., Ltd., and the brand is Al-3B.

[0042] Example 1

[0043] A preparation method of a ready-to-add and ready-to-melt zinc-aluminum-titanium-boron intermediate alloy Zn-18.7%Al-1%Ti-0.3%B, comprising the following steps:

[0044] (1) The raw materials Zn block, Al-10Ti alloy block and Al-3B alloy block are weighed according to the proportion, the dried Zn block is placed in a 460℃ intermediate frequency furnace for melting, and after complete melting, stirring is performed, and the temperature is maintained for 5min.

[0045] (2) When the furnace temperature is raised to 740℃, the Al-10Ti alloy block is added, and the Al-10Ti alloy block is pressed to the bottom of the melting furnace for melting, after the alloy liquid is scraped slag, stirring is performed for 1min, and the temperature is maintained for 5min; then the Al-3B alloy block is pressed to the bottom of the melting furnace for melting, after the alloy liquid is scraped slag, stirring is performed for 1min, and the temperature is maintained for 5min, to obtain a zinc-aluminum-titanium-boron alloy liquid.

[0046] (3) The temperature is lowered to 680℃, and the temperature is maintained for 10min, and the zinc-aluminum-titanium-boron intermediate alloy with the required size is obtained through casting.

[0047] The scanning electron microscope image of the cross section of the zinc-aluminum-titanium-boron intermediate alloy of Example 1 is shown in Figure 1 . The scanning electron microscope result shows that the average size of Al3Ti in the alloy organization is less than 20μm. Due to the significant reduction of the size of Al3Ti, when this intermediate alloy is used for micro-alloying treatment of zinc-aluminum-magnesium alloy, the absorption rate of Ti element will be improved.

[0048] Example 2

[0049] A preparation method of a ready-to-add and ready-to-melt zinc-aluminum-titanium-boron intermediate alloy Zn-18.7%Al-1%Ti-0.3%B, comprising the following steps:

[0050] (1) The same as step (1) of Example 1.

[0051] (2) The furnace temperature is raised to 750℃, and the remaining process is the same as step (2) of Example 1.

[0052] (3) The same as step (3) of Example 1.

[0053] The scanning electron microscope image of the cross section of the zinc aluminum titanium boron master alloy of Example 2 is shown in Fig. 2. The scanning electron microscope results show that the average size of Al3Ti in the alloy structure is less than 20 μm. Figure 2

[0054] Example 3

[0055] A method for preparing a ready-to-melt zinc aluminum titanium boron master alloy Zn-18.7%Al-1%Ti-0.3%B, comprising the following steps:

[0056] (1) The same as step (1) of Example 1.

[0057] (2) The same as step (2) of Example 1.

[0058] (3) Cooling to 690°C, and the rest of the process is the same as step (3) of Example 1.

[0059] The scanning electron microscope image of the cross section of the zinc aluminum titanium boron master alloy of Example 3 is shown in Fig. 3. The scanning electron microscope results show that the average size of Al3Ti in the alloy structure is less than 20 μm. Since the size of Al3Ti is significantly reduced, the absorption rate of Ti element will be significantly improved when this master alloy is used for micro-alloying treatment of zinc aluminum magnesium alloy. Figure 3

[0060] The solidification structure of Zn-6Al-3Mg alloy (referred to as ZAM) with different titanium contents treated by the zinc aluminum titanium boron master alloy prepared in Example 3 is shown in Fig. 4. Among them, a: 0wt.%Ti, b: 0.03wt.%Ti, c: 0.06wt.%Ti, d: 0.09wt.%Ti, e: 0.12wt.%Ti, f: 0.15wt.%Ti. It can be seen that with the increase of titanium content, the solidification structure of Zn-6Al-3Mg alloy is continuously refined. Figure 5

[0061] Example 4

[0062] A method for preparing a ready-to-melt zinc aluminum titanium boron master alloy Zn-18.7%Al-1%Ti-0.3%B, comprising the following steps:

[0063] (1) The same as step (1) of Example 1.

[0064] (2) The same as step (2) of Example 1.

[0065] (3) Cooling to 700°C, and the rest of the process is the same as step (3) of Example 1.

[0066] The scanning electron microscope image of the cross section of the zinc aluminum titanium boron master alloy of Example 4 is shown in Fig. 5. The scanning electron microscope results show that the average size of Al3Ti in the alloy structure is less than 20 μm. Figure 4 ​​​As shown in the figure. Scanning electron microscopy results show that the average size of Al3Ti in the alloy microstructure is less than 20 μm.

[0067] Comparative Example 1

[0068] A method for preparing an instant-melting zinc-aluminum-titanium-boron master alloy (Zn-18.7%Al-1%Ti-0.3%B) includes the following steps:

[0069] (1) Same as step (1) in Example 1.

[0070] (2) When the furnace temperature is raised to 720°C, the rest of the process is the same as step (2) in Example 1.

[0071] (3) Same as step (3) in Example 1.

[0072] Scanning electron microscope (SEM) image of the cross-section of the zinc-aluminum-titanium-boron master alloy of Comparative Example 1 is shown below. Figure 6 As shown in the figure. Scanning electron microscopy results show that the Al3Ti size in the alloy microstructure is significantly larger than 50 μm. Due to the large size of Al3Ti, the absorption rate of Ti element is low when using this intermediate alloy to perform microalloying treatment on zinc-aluminum-magnesium alloy.

[0073] Comparative Example 2

[0074] A method for preparing an instant-melting zinc-aluminum-titanium-boron master alloy (Zn-18.7%Al-1%Ti-0.3%B) includes the following steps:

[0075] (1) Same as step (1) in Example 1.

[0076] (2) Raise the furnace temperature to 730°C, and the rest of the process is the same as step (2) in Example 1.

[0077] (3) Same as step (3) in Example 1.

[0078] Scanning electron microscope (SEM) image of the cross-section of the zinc-aluminum-titanium-boron master alloy of Comparative Example 2 is shown below. Figure 7 As shown in the figure. Scanning electron microscopy results show that the Al3Ti particles in the alloy microstructure are relatively large, exceeding 20 μm. Due to the still large size of Al3Ti, the absorption rate of Ti element is low when using this intermediate alloy for microalloying of zinc-aluminum-magnesium alloys.

[0079] Comparative Example 3

[0080] A method for preparing an instant-melting zinc-aluminum-titanium-boron master alloy (Zn-18.7%Al-1%Ti-0.3%B) includes the following steps:

[0081] (1) Same as step (1) in Example 1.

[0082] (2) Same as step (2) in Example 1.

[0083] (3) Cool down to 650°C, and the rest of the process is the same as step (3) in Example 1.

[0084] Scanning electron microscope (SEM) image of the cross-section of the zinc-aluminum-titanium-boron master alloy of Comparative Example 3 is shown below. Figure 8 As shown in the figure, scanning electron microscopy results indicate that the size of Al3Ti in the alloy microstructure is much larger than 50 μm. Due to the large size of Al3Ti, the absorption rate of Ti element is low when using this master alloy for microalloying of zinc-aluminum-magnesium alloys.

[0085] Comparative Example 4

[0086] A method for preparing an instant-melting zinc-aluminum-titanium-boron master alloy (Zn-18.7%Al-1%Ti-0.3%B) includes the following steps:

[0087] (1) Same as step (1) in Example 1.

[0088] (2) Same as step (2) in Example 1.

[0089] (3) Cool down to 660°C, and the rest of the process is the same as step (3) in Example 1.

[0090] Scanning electron microscope (SEM) image of the cross-section of the zinc-aluminum-titanium-boron master alloy of Comparative Example 4 is shown below. Figure 9 As shown in the figure. Scanning electron microscopy results show that the size of some Al3Ti in the alloy microstructure has decreased, but some parts are still relatively large.

[0091] Comparative Example 5

[0092] A method for preparing an instant-melting zinc-aluminum-titanium-boron master alloy (Zn-18.7%Al-1%Ti-0.3%B) includes the following steps:

[0093] (1) Same as step (1) in Example 1.

[0094] (2) Same as step (2) in Example 1.

[0095] (3) Cool down to 670°C, and the rest of the process is the same as step (3) in Example 1.

[0096] Scanning electron microscope (SEM) image of the cross-section of the zinc-aluminum-titanium-boron master alloy of Comparative Example 5 is shown below. Figure 10 As shown in the figure. Scanning electron microscopy results show that the size of some Al3Ti in the alloy microstructure is less than 20 μm, but some parts are still relatively large.

[0097] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an instant-melting zinc-aluminum-titanium-boron master alloy, characterized in that, Includes the following steps: Weigh out raw materials Zn, Al-10Ti alloy and Al-3B alloy, melt the dried Zn, stir after complete melting, and keep warm for 4 to 5 minutes; At 740–750°C, the Al-10Ti alloy is added and pressed to the bottom of the furnace to melt. After slag is scraped off and stirring, the mixture is kept at the temperature for 4–5 minutes. Then, the Al-3B alloy is pressed to the bottom of the furnace to melt. After slag is scraped off and stirring, the mixture is kept at the temperature for 4–5 minutes to obtain a zinc-aluminum-titanium-boron alloy liquid. The temperature is lowered to 680-700℃ and held for 9-10 minutes. The zinc-aluminum-titanium-boron master alloy of the required size is then obtained by casting.

2. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The zinc-aluminum-titanium-boron master alloy comprises, by weight percentage, 15-20 wt.% Al, 0.8-1.2 wt.% Ti, 0.1-0.5 wt.% B, with the balance being Zn.

3. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The Zn melts at a temperature of 460±1℃.

4. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The Zn is melted in an intermediate frequency furnace.

5. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The Al-10Ti alloy was added at 740°C.

6. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The Al-10Ti alloy is melted, and after slag is scraped off, it is stirred for 1 to 2 minutes.

7. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The Al-3B alloy is melted, slag is scraped off, and then stirred for 1-2 minutes.

8. The method for preparing the instant-melting zinc-aluminum-titanium-boron master alloy according to claim 1, characterized in that, The casting temperature is 690℃.

9. A zinc-aluminum-titanium-boron master alloy, characterized in that, It is the zinc-aluminum-titanium-boron master alloy obtained by the preparation method of the instant-addition and instant-melting zinc-aluminum-titanium-boron master alloy according to any one of claims 1 to 8.

10. The preparation method of the instant-melting zinc-aluminum-titanium-boron master alloy according to any one of claims 1 to 8, or the application of the zinc-aluminum-titanium-boron master alloy according to claim 9 in the microalloying treatment of zinc-plated alloys.

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