A hot-dip galvanized coating for iron casting materials and the hot-dip galvanizing method thereof

Abstract

A hot-dip galvanized coating for iron casting materials and its hot-dip galvanizing method are disclosed. The coating comprises the following raw materials in parts by weight: Mg: 4-6 parts; Al: 3-5 parts; Pb: 6-8 parts; Zn: 90-95 parts; copper selenide: 0.5-1 parts. This application utilizes a typical Mg-Al-Zn system, adding Pb and copper selenide to improve the fluidity of various materials in the galvanizing bath, adapting to the uneven surface of the iron casting material, thereby ensuring its corrosion resistance.

Description

Technical Field

[0001] This application relates to a hot-dip galvanized coating for iron casting materials and a hot-dip galvanizing method thereof. Background Technology

[0002] Casting involves pouring molten metal into a mold, allowing it to cool and solidify, and then removing the mold to obtain a component with the same internal cavity as the mold. Because casting is inexpensive, requires relatively simple conditions, and can produce components with complex shapes, it has been widely used since ancient times. Its main disadvantages are external defects and issues with the internal crystal structure.

[0003] Iron castings inherently lack good corrosion resistance, and currently, external coatings are often used to prevent corrosion. However, external defects in castings, such as pinholes and unevenness, have a significant impact, affecting both surface smoothness and the stability of the coating itself. Summary of the Invention

[0004] To address the aforementioned problems, this application proposes a hot-dip galvanizing coating for iron casting materials. The coating comprises the following raw materials in parts by weight: Mg: 4-6 parts; Al: 3-5 parts; Pb: 6-8 parts; Zn: 90-95 parts; and copper selenide: 0.5-1 parts. This application utilizes a typical Mg-Al-Zn system, adding Pb and copper selenide to improve the fluidity of various materials in the galvanizing bath. This allows the coating to adapt to the uneven surface of the iron casting material, ensuring its corrosion resistance.

[0005] Preferably, the raw material also includes the following quantities: boron oxide: 2-4 parts.

[0006] Preferably, the material also includes the following raw material by weight: SnCl2: 0.5-1 parts. This application, by adding boron oxide and SnCl2 to the original zinc plating material, can improve the strength of the external hot-dip galvanized layer to a certain extent, presumably because it strengthens the connection with the iron casting material, thereby improving the stability of the coating.

[0007] This application also discloses a hot-dip galvanizing method, comprising the following steps:

[0008] Pre-treated iron casting materials are used to obtain pre-treated parts;

[0009] Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide are mixed and heated in a zinc plating bath.

[0010] The pre-treated parts are immersed in the galvanizing bath to obtain pre-impregnated parts;

[0011] The pre-impregnated parts are placed in an environment of 120-150℃ to cool down to ambient temperature, and then taken outside for further cooling to complete the hot-dip galvanizing. This application adopts a step-by-step cooling method, which allows for relatively stable cooling of both the external coating and the internal structure, avoiding the impact on the structural stability of the coating due to inconsistent shrinkage between the internal and external parts caused by a sudden drop in temperature.

[0012] Preferably, the pretreatment is carried out in the following manner: the iron casting material is subjected to surface cleaning treatment;

[0013] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material and then dried.

[0014] Preferably, the concentration of the stannous chloride aqueous solution is 1-2 wt%.

[0015] Preferably, the amount of stannous chloride used is 1-2 g / m³. 2 .

[0016] Preferably, the temperature of the galvanizing bath is 700-800℃.

[0017] Preferably, the time for the pre-treated part to be immersed in the galvanizing bath is not less than 30 seconds.

[0018] Preferably, the surface cleaning treatment is a shot blasting rust removal method, wherein the shot blasting is a sphere with a diameter of 2-3 mm.

[0019] This application can bring the following beneficial effects:

[0020] 1. This application adopts the addition of Pb and copper selenide to a typical Mg-Al-Zn system, which improves the fluidity of various materials in the galvanizing bath, can adapt to the uneven surface of iron casting materials, and ensures the corrosion resistance of iron casting materials.

[0021] 2. This application improves the strength of the external hot-dip galvanized layer to a certain extent by adding boron oxide and SnCl2 to the original galvanized material. It is speculated that this is because it strengthens the connection with the iron casting material, thereby improving the stability of the coating.

[0022] 3. This application adopts a step-by-step cooling method, which can make the external coating and the internal structure cool down relatively stably, avoiding the impact on the structural stability of the coating due to inconsistent shrinkage between the inside and outside caused by a sudden drop in temperature. Detailed Implementation

[0023] To clearly illustrate the technical features of this solution, the following detailed description of specific implementation methods will be provided.

[0024] This application is essentially a hot-dip galvanizing method for iron casting materials, which mainly includes the following steps:

[0025] S1 involves pre-treating iron casting materials to obtain pre-treated parts;

[0026] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0027] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material and then dried.

[0028] The concentration of the stannous chloride aqueous solution is 1-2 wt%.

[0029] The amount of stannous chloride used is 1-2 g / m³. 2 .

[0030] S2 involves mixing and heating Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide in a zinc plating bath.

[0031] The composition includes: Mg: 4-6 parts; Al: 3-5 parts; Pb: 6-8 parts; Zn: 90-95 parts; copper selenide: 0.5-1 parts; boron oxide: 2-4 parts; SnCl2: 0.5-1 parts.

[0032] The temperature of the galvanizing bath is 700-800℃.

[0033] S3 involves immersing the pre-treated parts into a galvanizing bath to obtain pre-impregnated parts;

[0034] The pre-treated parts shall be immersed in the galvanizing bath for no less than 30 seconds.

[0035] S4 places the pre-impregnated parts into an environment of 120-150℃ to cool them down to ambient temperature, and then takes them outside to cool completely to complete the hot-dip galvanizing.

[0036] Following the above method, the following example is executed:

[0037] Example 1:

[0038] S101 pre-treats a 5cm*5cm*0.1cm iron casting material to obtain a pre-treated part;

[0039] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0040] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material and then dried.

[0041] The concentration of the stannous chloride aqueous solution is 1 wt%.

[0042] The amount of stannous chloride used is 1 g / m³. 2 .

[0043] S102 involves mixing and heating Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide in a zinc plating bath.

[0044] The composition includes: Mg: 4 kg; Al: 3 kg; Pb: 6 kg; Zn: 90 kg; copper selenide: 0.5 kg; boron oxide: 2 kg; SnCl2: 0.5 kg.

[0045] The temperature of the galvanizing bath is 700℃.

[0046] S103 Immersing the pre-treated parts in the galvanizing bath to obtain pre-impregnated parts;

[0047] The pre-treated parts are immersed in the galvanizing bath for 30 seconds.

[0048] S104 involves placing the pre-impregnated part in an environment of 120°C to cool it down to ambient temperature, and then taking it outside for further cooling to complete the hot-dip galvanizing.

[0049] The surface of the casting material is smooth, without any graininess or cracks. It was tested according to the method of GB / T10125-1997 and tested and observed according to the conditions of CN102477522B. The time for the first appearance of rust was 8.5 days.

[0050] Example 2:

[0051] S201 involves pre-treating a 5cm*5cm*0.1cm iron casting material to obtain a pre-treated part;

[0052] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0053] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material, followed by drying.

[0054] The concentration of the stannous chloride aqueous solution is 2 wt%.

[0055] The amount of stannous chloride used is 2 g / m. 2 .

[0056] S202 involves mixing and heating Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide in a zinc plating bath.

[0057] The composition includes: Mg: 6 kg; Al: 5 kg; Pb: 8 kg; Zn: 95 kg; copper selenide: 1 kg; boron oxide: 4 kg; SnCl2: 1 kg.

[0058] The temperature of the galvanizing bath is 800℃.

[0059] S203 involves immersing the pre-treated parts in a galvanizing bath to obtain pre-impregnated parts;

[0060] The pre-treated parts are immersed in the galvanizing bath for 30 seconds.

[0061] S204 involves placing the pre-impregnated parts in an environment of 150°C to cool them down to ambient temperature, and then taking them outside for further cooling to complete the hot-dip galvanizing.

[0062] The surface of the casting material is smooth, without any graininess or cracks. It was tested according to the method of GB / T10125-1997 and tested and observed according to the conditions of CN102477522B. The first appearance of rust was 9 days.

[0063] Example 3:

[0064] S301 pre-treats a 5cm*5cm*0.1cm iron casting material to obtain a pre-treated part;

[0065] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0066] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material, followed by drying.

[0067] The concentration of the stannous chloride aqueous solution is 1.5 wt%.

[0068] The amount of stannous chloride used is 1.5 g / m³. 2 .

[0069] S302 involves mixing and heating Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide in a zinc plating bath.

[0070] The composition includes: Mg: 5 kg; Al: 4 kg; Pb: 7 kg; Zn: 92 kg; copper selenide: 0.8 kg; boron oxide: 3 kg; SnCl2: 0.8 kg.

[0071] The temperature of the galvanizing bath is 750℃.

[0072] S303 involves immersing the pre-treated parts in a galvanizing bath to obtain pre-impregnated parts;

[0073] The pre-treated parts are immersed in the galvanizing bath for 30 seconds.

[0074] S304 involves placing the pre-impregnated parts in an environment of 130°C to cool them down to ambient temperature, and then taking them outside for further cooling to complete the hot-dip galvanizing process.

[0075] The surface of the casting material is smooth and without a grainy texture. It was tested according to the method of GB / T10125-1997 and tested and observed according to the conditions of CN102477522B. The first rust appeared in 9 days.

[0076] Example 4:

[0077] S401 pre-treats a 5cm*5cm*0.1cm iron casting material to obtain a pre-treated part;

[0078] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0079] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material, followed by drying.

[0080] The concentration of the stannous chloride aqueous solution is 1 wt%.

[0081] The amount of stannous chloride used is 1 g / m2.

[0082] S402 involves mixing and heating Mg, Al, Pb, Zn, and copper selenide in a zinc plating bath.

[0083] The composition includes: Mg: 4 kg; Al: 3 kg; Pb: 6 kg; Zn: 90 kg; copper selenide: 0.5 kg; boron oxide: 2 kg; SnCl2: 0.5 kg.

[0084] The temperature of the galvanizing bath is 700℃.

[0085] S403 involves immersing the pre-treated parts in a galvanizing bath to obtain pre-impregnated parts;

[0086] The pre-treated parts are immersed in the galvanizing bath for 30 seconds.

[0087] S404 involves placing the pre-impregnated parts in an environment of 120°C to cool them down to ambient temperature, and then taking them outside for further cooling to complete the hot-dip galvanizing process.

[0088] The surface of the casting material is smooth with slight cracks and no grainy texture. It was tested according to the method of GB / T10125-1997 and tested and observed according to the conditions of CN102477522B. The first rust appeared in 7 days.

[0089] Comparative Example 1:

[0090] S501 pre-treats a 5cm*5cm*0.1cm iron casting material to obtain a pre-treated part;

[0091] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0092] After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material, followed by drying.

[0093] The concentration of the stannous chloride aqueous solution is 1 wt%.

[0094] The amount of stannous chloride used is 1 g / m³. 2 .

[0095] S502 involves mixing and heating Mg, Al, and Zn in a galvanizing bath;

[0096] The composition includes: Mg: 4 kg; Al: 3 kg; Zn: 90 kg.

[0097] The temperature of the galvanizing bath is 700℃.

[0098] S503 involves immersing the pre-treated parts in a galvanizing bath to obtain pre-impregnated parts;

[0099] The pre-treated parts are immersed in the galvanizing bath for 30 seconds.

[0100] S504 involves placing the pre-impregnated parts in an environment of 120°C to cool them down to ambient temperature, and then taking them outside for further cooling to complete the hot-dip galvanizing process.

[0101] The surface of the casting material is smooth, with cracks and no grainy texture. It was tested according to the method of GB / T10125-1997 and tested and observed according to the conditions of CN102477522B. The first rust appeared in 4 days.

[0102] Comparative Example 2:

[0103] S601 pre-treats a 5cm*5cm*0.1cm iron casting material to obtain a pre-treated part;

[0104] The surface cleaning treatment method is shot blasting for rust removal, wherein the shot is a sphere with a diameter of 2-3 mm.

[0105] S602 involves mixing and heating Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide in a zinc plating bath.

[0106] The composition includes: Mg: 4 kg; Al: 3 kg; Pb: 6 kg; Zn: 90 kg; copper selenide: 0.5 kg; boron oxide: 2 kg; SnCl2: 0.5 kg.

[0107] The temperature of the galvanizing bath is 700℃.

[0108] S603 involves immersing the pre-treated parts in a galvanizing bath to obtain pre-impregnated parts;

[0109] The pre-treated parts are immersed in the galvanizing bath for 30 seconds.

[0110] S604 involves placing the pre-impregnated parts in an environment of 120°C to cool them down to ambient temperature, and then taking them outside for further cooling to complete the hot-dip galvanizing process.

[0111] The surface of the casting material is smooth with slight cracks and a slight grainy texture. It was tested according to the method of GB / T10125-1997 and tested and observed according to the conditions of CN102477522B. The time for the first appearance of rust was 3.5 days.

[0112] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A hot-dip galvanized coating for an iron casting material, characterized in that: The coating comprises the following parts by weight of raw materials composition: Mg: 4-6 parts; Al: 3-5 parts; Pb: 6-8 parts; Zn: 90-95 parts; Copper selenide: 0.5-1 part; Boron oxide: 2-4 parts; SnCl2: 0.5-1 part.

2. A hot-dip galvanizing method for preparing the hot-dip galvanized coating of claim 1, characterized in that: Includes the following steps: Pre-treated iron casting materials are used to obtain pre-treated parts; Mg, Al, Pb, Zn, SnCl2, copper selenide, and boron oxide are mixed and heated in a zinc plating bath. The pre-treated parts are immersed in the galvanizing bath to obtain pre-impregnated parts; The pre-impregnated parts are placed in an environment of 120-150℃ to cool down to the ambient temperature, and then taken outside to cool completely to complete the hot-dip galvanizing.

3. The hot-dip galvanizing method according to claim 2, characterized in that: The pretreatment is carried out in the following manner: the iron casting material is subjected to surface purification treatment; After purification, a stannous chloride aqueous solution is evenly sprayed onto the surface of the iron casting material, followed by drying.

4. The hot-dip galvanizing method according to claim 3, characterized in that: The concentration of the stannous chloride aqueous solution is 1-2 wt%.

5. The hot-dip galvanizing method according to claim 3, characterized in that: The amount of stannous chloride used is 1-2 g / m³. 2 .

6. The hot-dip galvanizing method according to claim 3, characterized in that: The temperature of the galvanizing bath is 700-800℃.

7. The hot-dip galvanizing method according to claim 3, characterized in that: The pre-treated parts shall be immersed in the galvanizing bath for no less than 30 seconds.

8. The hot-dip galvanizing method according to claim 3, characterized in that: The surface cleaning treatment method is shot blasting for rust removal, and the shot blasting is a sphere with a diameter of 2-3 mm.