阅读说明：本技术 一种锌铝镁镀层板的制备方法及其焊接方法 (Preparation method and welding method of zinc-aluminum-magnesium plating plate ) 是由 周磊磊 郭太雄 董学强 余腾义 王敏莉 宋裕 于 2021-07-28 设计创作，主要内容包括：本发明涉及一种锌铝镁镀层板的制备方法及其焊接方法。制备方法包括基板脱脂清洗、连续退火、热浸镀、气刀吹扫、冷却、表面处理、卷取步骤；所述脱脂清洗工序包括在碱液槽脱脂处理,碱液槽的组分质量百分比为5≤NaOH+Na-(2)SiO-(3)≤30％,表面活性剂≤10％,其余为水。焊接方法,包括步骤a、制备母材；b、下料；c、焊前准备,清理焊接面,并在焊接试板中间涂覆粉末状金属；d、采用点焊焊接成型。本方法能够制备具有优异焊接性能的锌铝镁镀层板,能够指导用户科学使用镀层板,点焊接头能够良好融合,具有优秀的力学性能。解决现有锌铝镁镀层板焊接性能差,锌铝镁镀层板之间的焊缝质量差的问题。(The invention relates to a preparation method and a welding method of a zinc-aluminum-magnesium plating plate. The preparation method comprises degreasing, cleaning and continuous annealing of the substrateHot dipping, air knife blowing, cooling, surface treatment and coiling; the degreasing and cleaning process comprises degreasing treatment in an alkali liquor tank, wherein the alkali liquor tank comprises the components of NaOH and Na with the mass percentage of 5-5 2 SiO 3 Less than or equal to 30 percent, less than or equal to 10 percent of surfactant and the balance of water. The welding method comprises the steps of a, preparing a base material; b. blanking; c. preparing before welding, cleaning a welding surface, and coating powdered metal in the middle of a welding test plate; d. and spot welding is adopted for forming. The method can prepare the zinc-aluminum-magnesium plating plate with excellent welding performance, can guide a user to scientifically use the plating plate, and the spot-welded joint can be well fused and has excellent mechanical performance. The problems of poor welding performance of the existing zinc-aluminum-magnesium plating plates and poor quality of welding seams among the zinc-aluminum-magnesium plating plates are solved.)

1. The preparation method of the zinc-aluminum-magnesium plating plate comprises a substrate degreasing and cleaning process, and is characterized in that: the degreasing and cleaning process comprises degreasing treatment in an alkali liquor tank, wherein the alkali liquor tank comprises N with the mass percentage of 5-5aOH+Na₂SiO₃Less than or equal to 30 percent, less than or equal to 10 percent of surfactant and the balance of water.

2. The method for preparing a zinc-aluminum-magnesium plating plate according to claim 1, wherein the method comprises the following steps: the substrate is a cold-rolled steel plate, and the mass percentages of chemical elements of the cold-rolled steel plate are that C is less than or equal to 0.10%, Si is less than or equal to 0.04%, Mn is less than or equal to 0.25%, P is less than or equal to 0.03%, S is less than or equal to 0.03%, Als is less than or equal to 0.10%, Ti is less than or equal to 0.10%, Nb is less than or equal to 0.10%, and the balance of Fe and unavoidable impurity elements.

3. The method for preparing a zinc-aluminum-magnesium plating plate according to claim 2, wherein the method comprises the following steps: the substrate is ultra-low carbon steel, the chemical elements of the substrate comprise, by mass, not less than 0.003% of C, not less than 0.15% of Si, not less than 0.0.25%, not less than 0.12% of Mn, not less than 0.14% of Mn, not less than 0.008% of P, not less than 0.010% of S, not less than 0.008% of S, not less than 0.05% of Als, not more than 0.0.07% of Als, and the balance of Fe and unavoidable impurity elements.

4. The method for preparing a zinc-aluminum-magnesium plating plate according to claim 1, wherein the method comprises the following steps: the thickness of the substrate is 0.4-2.0mm, and the weight of the zinc-aluminum-magnesium coating is 20-250g/m²。

5. The method for preparing a zinc-aluminum-magnesium plating plate according to claim 4, wherein the method comprises the following steps: the thickness of the substrate is 0.6-0.8mm, and the weight of the zinc-aluminum-magnesium coating is 20-100g/m²。

6. The method for preparing a zinc-aluminum-magnesium plating plate according to claim 1, wherein the method comprises the following steps: the zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 10-25%, Mg: 2.0-5%, 0.03-0.50% of lanthanum and cerium, and the balance of zinc and inevitable impurities.

7. The method for preparing a zinc-aluminum-magnesium plating plate according to claim 6, wherein the method comprises the following steps: the zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 15-20%, Mg: 2.0 to 2.5 percent of lanthanum and 0.35 to 0.50 percent of cerium, and the balance of zinc and inevitable impurities.

8. A welding method of a zinc-aluminum-magnesium plating plate is characterized by comprising the following steps:

a. preparing a base material, and selecting the zinc-aluminum-magnesium plating plate prepared by the method in any one of claims 1 to 7;

b. blanking, cutting out a welding test plate;

c. preparing before welding, cleaning a welding surface of a welding test plate, and coating powdered metal in the middle of the welding test plate, wherein the chemical components of the powdered metal in percentage by mass are that Ti is more than or equal to 3 and less than or equal to 8 percent, Mn is more than or equal to 2 and less than or equal to 5 percent, Cr is more than or equal to 4 and less than or equal to 4 percent, and the balance is Fe and inevitable impurities;

d. and welding, namely adopting spot welding for forming.

9. The method for welding a zinc-aluminum-magnesium plated plate according to claim 8, wherein: the warping degree of the welding test plate in the step b is less than or equal to 8 degrees, and the thickness of the powder metal in the step c is 0.1-0.3 mm.

10. The method for welding a zinc-aluminum-magnesium plated plate according to claim 8, wherein: in the step d, the welding current is 5.0-12.0kA, the welding time is 0.2-1s, and the electrode pressure is 3-5 kN.

Technical Field

The invention relates to a preparation method and a welding method of a zinc-aluminum-magnesium plating plate, belonging to the technical field of metallurgical welding.

Background

Hot dip Galvanized (GI) and hot dip 55% Al — Zn alloy coated (GL) steel sheets, which are currently widely used in construction, automobile, home appliance manufacturing and other industries in various countries around the world, are "traditional" coated steel sheets, and users expect to develop coated steel sheets with better performance. The hot dip coating Zn-Al-Mg alloy coating steel plate is a novel coating steel plate produced by the method. The Zn-Al-Mg alloy coating has attracted wide attention abroad in the 80 s of the 20 th century, and becomes a research focus in the professional field of hot dip galvanizing and zinc alloy coating. From the research results of the same lines at home and abroad, the hot-dip galvanized Zn-Al-Mg alloy coated steel plate added with Mg has better corrosion resistance under the condition that the contents of Zn and Al of the coatings are at the same level, and the processing application performance (formability, weldability and paintability) of the material is excellent, so that the trend of replacing the existing corresponding hot-dip galvanized or zinc alloy coated steel plate is gradually obvious, and the market demand prospect is very wide. When the zinc-aluminum-magnesium alloy coated steel plate is used by users of electric appliances, automobiles and the like, different parts are prepared and need to be welded.

Resistance spot welding is a connection technology widely applied to manufacturing industry, has the advantages of high efficiency, low cost, high automation degree and the like, and is widely applied to the household appliance industry. In particular, in the case of thin-plate joining, the advantage of resistance spot welding is more pronounced.

Publication No. CN111304573A discloses a zinc-aluminum-magnesium alloy plated steel sheet with excellent corrosion resistance and a preparation method thereof, relates to a zinc-aluminum-magnesium alloy plated steel sheet with excellent corrosion resistance and a preparation method thereof, and belongs to the technical field of hot dip plating. The chemical components of the coating are 6.5-14.9% of aluminum, 2.3-4.5% of magnesium, 0.05-0.32% of silicon, 0.02-0.20% of lanthanum, 0.02-0.20% of cerium, 0.05-0.30% of lanthanum and cerium, and the balance of zinc and inevitable impurities.

Publication No. CN110548976A discloses a resistance spot welding process for 1800 MPa-level ultrahigh-strength thermoformed steel plates, and relates to a high-strength steel plate spot welding process. The invention provides a manufacturing and processing technology capable of perfecting the ultrahigh-strength hot-formed steel plates, which can enable the ultrahigh-strength hot-formed steel plates to be favorably combined together in production and manufacturing, thereby obviously improving the comprehensive performance of products.

In summary, the prior art only focuses on the plating composition and production of the zinc-aluminum-magnesium plating plate and the welding technology of spot welding to respectively improve the welding quality, most of the patents related to spot welding are made of dual-phase steel or high-strength steel, and most of the patents related to zinc-aluminum-magnesium plating plate focus on the plating composition and production of the plating, and do not relate to the welding process parameters to reduce the cost.

Disclosure of Invention

The invention aims to solve the technical problems that the existing zinc-aluminum-magnesium plating plates have poor welding performance and the quality of welding seams among the zinc-aluminum-magnesium plating plates is poor.

The technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method of the zinc-aluminum-magnesium coating plate comprises a substrate degreasing and cleaning step, wherein the degreasing and cleaning step comprises degreasing treatment in an alkaline solution tank, and the alkaline solution tank comprises the following components of NaOH and Na with the mass percentage of 5-5₂SiO₃Less than or equal to 30 percent, less than or equal to 10 percent of surfactant and the balance of water.

The substrate in the preparation method is a cold-rolled steel plate, and the mass percentages of chemical elements of the cold-rolled steel plate are that C is less than or equal to 0.10%, Si is less than or equal to 0.04%, Mn is less than or equal to 0.25%, P is less than or equal to 0.03%, S is less than or equal to 0.03%, Als is less than or equal to 0.10%, Ti is less than or equal to 0.10%, Nb is less than or equal to 0.10%, and the balance of Fe and inevitable impurity elements.

The substrate in the preparation method is ultra-low carbon steel, the chemical elements of the substrate comprise, by mass, not less than 0.003% of C, not less than 0.15% of Si, not less than 0.0.25% of Si, not less than 0.12% of Mn, not less than 0.14% of P, not less than 0.008% of P, not less than 0.010% of S, not less than 0.008% of Als, not less than 0.05% of Als, not less than 0.0.07% of Als, and the balance Fe and unavoidable impurity elements.

Wherein, the thickness of the substrate in the preparation method is 0.4-2.0mm, and the weight of the zinc-aluminum-magnesium coating is 20-250g/m²。

Wherein, the thickness of the substrate in the preparation method is 0.6-0.8mm, and the weight of the zinc-aluminum-magnesium coating is 20-100g/m²。

The zinc-aluminum-magnesium coating in the preparation method comprises the following chemical components in percentage by mass: 10-25%, Mg: 2.0-5%, 0.03-0.50% of lanthanum and cerium, and the balance of zinc and inevitable impurities.

The zinc-aluminum-magnesium coating in the preparation method comprises the following chemical components in percentage by mass: 15-20%, Mg: 2.0 to 2.5 percent of lanthanum and 0.35 to 0.50 percent of cerium, and the balance of zinc and inevitable impurities.

A welding method of a zinc-aluminum-magnesium plating plate comprises the following steps:

a. preparing a base material, and selecting the zinc-aluminum-magnesium plating plate prepared by the method in any one of claims 1 to 7;

b. blanking, cutting out a welding test plate;

c. preparing before welding, cleaning a welding surface of a welding test plate, and coating powdered metal in the middle of the welding test plate, wherein the chemical components of the powdered metal in percentage by mass are that Ti is more than or equal to 3 and less than or equal to 8 percent, Mn is more than or equal to 2 and less than or equal to 5 percent, Cr is more than or equal to 4 and less than or equal to 4 percent, and the balance is Fe and inevitable impurities;

d. and welding, namely adopting spot welding for forming.

Wherein, the warping degree of the welding test plate in the step b is less than or equal to 8 degrees in the welding method, and the thickness of the powder metal in the step c is 0.1-0.3 mm.

Wherein, in the step d of the welding method, the welding current is 5.0-12.0kA, the welding time is 0.2-1s, and the electrode pressure is 3-5 kN.

The invention has the beneficial effects that: the invention can prepare the zinc-aluminum-magnesium plating plate with excellent welding performance, can guide a user to scientifically use the plating plate, can well fuse spot-welded joints, has excellent mechanical property, and has larger popularization and application value in the household appliance industry. The zinc-aluminum-magnesium alloy coating steel plate has good surface quality, excellent corrosion resistance, formability, notch protection and coating property, and is used in the fields of construction, transportation, agriculture, animal husbandry, electric control cabinet manufacturing industry and the like. The size of a nugget of the spot welding joint produced by the spot welding process meets standard requirements, the diameter of the nugget is 4.3-7.2mm, the spot welding joint has good shearing resistance, the shearing force is 3.2-7.4kN, and the failure modes of the spot welding joint are nugget stripping.

Drawings

FIG. 1 is a nugget profile of example 1 of the present invention;

FIG. 2 is a nugget profile of example 2 of the present invention;

FIG. 3 is a nugget morphology map of a comparative example of the invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

As shown in figures 1 to 3, the preparation method of the zinc-aluminum-magnesium plating plate of the inventionThe method comprises a substrate degreasing and cleaning step, wherein the degreasing and cleaning step comprises degreasing treatment in an alkaline solution tank, and the alkaline solution tank comprises the following components of NaOH and Na in mass percentage of more than or equal to 5₂SiO₃Less than or equal to 30 percent, less than or equal to 10 percent of surfactant and the balance of water. As can be appreciated by those skilled in the art, the method ensures the subsequent processes by defining the composition of the lye tank to ensure the cleaning quality of the substrate. In particular to a lye tank which comprises 5-Na NaOH and Na₂SiO₃Less than or equal to 30 percent, less than or equal to 10 percent of surfactant and the balance of water.

Preferably, the substrate in the preparation method is a cold-rolled steel plate, and the chemical elements in percentage by mass of the substrate are C less than or equal to 0.10%, Si less than or equal to 0.04%, Mn less than or equal to 0.25%, P less than or equal to 0.03%, S less than or equal to 0.03%, Als less than or equal to 0.10%, Ti less than or equal to 0.10%, Nb less than or equal to 0.10%, and the balance of Fe and inevitable impurity elements. As can be understood by those skilled in the art, in order to ensure the close adhesion of the coating and the substrate, the method actually prefers that the substrate is a cold-rolled steel plate, and further defines the chemical elements of the substrate in percentage by mass as C being less than or equal to 0.10%, Si being less than or equal to 0.04%, Mn being less than or equal to 0.25%, P being less than or equal to 0.03%, S being less than or equal to 0.03%, Als being less than or equal to 0.10%, Ti being less than or equal to 0.10%, Nb being less than or equal to 0.10%, and the balance being Fe and unavoidable impurity elements.

Preferably, the substrate in the preparation method is ultra-low carbon steel, the chemical elements of the substrate comprise, by mass, not less than 0.003% of C, not less than 0.15% of Si, not less than 0.0.25% of Si, not less than 0.12% of Mn, not less than 0.14% of P, not less than 0.008% of P, not less than 0.010% of S, not less than 0.008% of S, not less than 0.010% of Als, not less than 0.05% of Als, not less than 0.0.07 and the balance of Fe and unavoidable impurity elements. As can be understood by those skilled in the art, the method is only to further preferably select the substrate to be ultra-low carbon steel and further define the substrate to have the chemical elements with the mass percentages of C less than or equal to 0.003 percent, Si less than or equal to 0.15 percent and less than or equal to 0.0.25 percent, Mn less than or equal to 0.12 percent and less than or equal to 0.14 percent, P less than or equal to 0.008 percent and less than or equal to 0.010 percent, S less than or equal to 0.008 percent and less than or equal to 0.010 percent, Als less than or equal to 0.05 percent and less than or equal to 0.0.07 percent, and the balance of Fe and inevitable impurity elements to ensure the quality of the plating plate

Preferably, in the preparation method, the thickness of the substrate is 0.4-2.0mm, and the weight of the zinc-aluminum-magnesium coating is 20-250g/m². It will be appreciated by those skilled in the art that the process is further preferred for the thickness of the substrate and the weight of the zinc-aluminum-magnesium coatingThe amount is respectively 0.4-2.0mm of the thickness of the substrate and 20-250g/m of the weight of the zinc-aluminum-magnesium coating²。

Preferably, in the preparation method, the thickness of the substrate is 0.6-0.8mm, and the weight of the zinc-aluminum-magnesium coating is 20-100g/m². As will be understood by those skilled in the art, the method further preferably has a substrate thickness and a zinc-aluminum-magnesium coating weight of 0.6-0.8mm and a zinc-aluminum-magnesium coating weight of 20-100g/m²。

Preferably, in the preparation method, the zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 10-25%, Mg: 2.0-5%, 0.03-0.50% of lanthanum and cerium, and the balance of zinc and inevitable impurities. As can be understood by those skilled in the art, the zinc-aluminum-magnesium plating plate has different coating textures and quality properties due to different Al and Mg contents in the coating, so that the application fields are different. As the content of Al and Mg increases, the corrosion resistance of the plating layer increases, but the formability and weldability decrease. Therefore, in order to meet the requirement of later-stage welding, the method preferably selects the chemical components of the zinc-aluminum-magnesium coating in percentage by mass as Al: 10-25%, Mg: 2.0-5%, 0.03-0.50% of lanthanum and cerium, and the balance of zinc and inevitable impurities.

Preferably, in the preparation method, the zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 15-20%, Mg: 2.0 to 2.5 percent of lanthanum and 0.35 to 0.50 percent of cerium, and the balance of zinc and inevitable impurities. The technical personnel in the field can understand that the method further defines the chemical components of the zinc-aluminum-magnesium coating, and particularly the chemical components of the zinc-aluminum-magnesium coating in percentage by mass are Al: 15-20%, Mg: 2.0 to 2.5 percent of lanthanum and 0.35 to 0.50 percent of cerium, and the balance of zinc and inevitable impurities.

A welding method of a zinc-aluminum-magnesium plating plate comprises the following steps:

a. preparing a base material, and selecting the zinc-aluminum-magnesium plating plate prepared by any one method;

b. blanking, cutting out a welding test plate;

c. preparing before welding, cleaning a welding surface of a welding test plate, and coating powdered metal in the middle of the welding test plate, wherein the chemical components of the powdered metal in percentage by mass are that Ti is more than or equal to 3 and less than or equal to 8 percent, Mn is more than or equal to 2 and less than or equal to 5 percent, Cr is more than or equal to 4 and less than or equal to 4 percent, and the balance is Fe and inevitable impurities;

d. and welding, namely adopting spot welding for forming. As will be understood by those skilled in the art, the base material in step a is a zn-al-mg plated plate, and the structure includes a substrate and a zn-al-mg plated layer plated on the surface of the substrate. Preferably, the substrate is a thin plate. And step b, cutting out the base material according to the actually required plate size. And c, in order to ensure the quality of the welding seam, the welding surface needs to be processed before welding, and the welding surface is ensured to meet the welding requirement. The method further preferably adopts alcohol to wipe the surface to be welded, so as to ensure that the welding surface meets the welding requirement. In step c, preferably, powder metal is coated between the two plates to be welded, the chemical components of the powder metal in percentage by mass are that Ti is more than or equal to 1 and less than or equal to 3 percent, Mn is more than or equal to 5 and less than or equal to 10 percent, Cr is more than or equal to 2 and less than or equal to 4 percent, and the balance is Fe; the method improves the mechanical property of the spot welding joint by using an alloying method; the amount of molten metal inside the spot welding joint is increased, thereby enlarging the width of a spot welding process window. Step d further limits the welding mode, and spot welding is adopted for forming. And d, all failure modes of the welding head of the plated plate welded in the step d are nugget peeling. And the failure mode of the nugget peeling is qualified, which indicates that the joint forms a complete nugget and has certain strength. The failure mode of interfacial fracture is unacceptable, indicating that a complete nugget is not formed, or the nugget connection is in the form of a cold joint with internal defects in the joint.

Preferably, the warping degree of the welding test plate in the step b in the welding method is less than or equal to 8 degrees, and the thickness of the powder metal in the step c is 0.1-0.3 mm. As can be understood by those skilled in the art, in order to prevent welding deformation, the warping degree of the welding test panel cut in step b is preferably less than or equal to 3 degrees. The thickness of the powdered metal is further limited to be 0.1-0.3mm, and the requirements are met while the using amount of the powdered metal is reduced.

Preferably, in the welding method, the welding current in the step d is 5.0-12.0kA, the welding time is 0.2-1s, and the electrode pressure is 3-5 kN. As can be understood by those skilled in the art, in order to ensure the formation of the welding seam, the method only needs one-time current welding, does not need secondary current, does not generate larger flying sword, does not influence the surface quality of the plating plate, and can also reduce the equipment cost and improve the production efficiency. Therefore, the welding current is preferably 5.0-12.0kA, the welding time is 0.2-1s, and the electrode pressure is preferably 3-5 kN.

Example 1:

the weight of the zinc-aluminum-magnesium coating is 60g/m²The zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 15%, Mg: 2.1 percent, 0.32 percent of lanthanum and cerium, and the balance of zinc and inevitable impurities. NaOH + Na in the lye tank₂SiO₃20% of surfactant, 5% of surfactant and the balance of water. The warping degree of the test plate to be welded is 5 degrees. Welding current is 7.0kA, welding time is 0.4s, electrode pressure is 3.0kN, the diameter of an obtained nugget of the spot-welded joint is 4.8mm, shearing force is 5.6kN, and the failure mode of the spot-welded joint is nugget stripping.

Example 2:

the weight of the zinc-aluminum-magnesium coating is 80g/m²The zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 20%, Mg: 2.4 percent of lanthanum and cerium, and the balance of zinc and inevitable impurities. NaOH + Na in the lye tank₂SiO₃15% of surfactant, 8% of surfactant and the balance of water. The warping degree of the test plate to be welded is 6 degrees. The welding current is 11.0kA, the welding time is 0.6s, the electrode pressure is 5.0kN, the diameter of the obtained nugget of the spot-welded joint is 5.5mm, the shearing force is 7.1kN, and the failure mode of the spot-welded joint is nugget stripping.

Comparative example

The weight of the zinc-aluminum-magnesium coating is 120g/m2, and the zinc-aluminum-magnesium coating comprises the following chemical components in percentage by mass: 7%, Mg: 9 percent of lanthanum and cerium, 0.2 percent of lanthanum and cerium, and the balance of zinc and inevitable impurities. NaOH + Na in the lye tank₂SiO₃3% of surfactant, 12% of surfactant and the balance of water. The warping degree of the test plate to be welded is 8 degrees. Welding current is 4kA, welding time is 0.6s, electrode pressure is 2.5kN, the diameter of an obtained nugget of the spot-welded joint is 2.2mm, shearing force is 2.36kN, and a failure mode of the spot-welded joint is an interface.