WO2023098125A1 - Zinc-aluminum-magnesium alloy coated steel containing v and b and preparation method therefor - Google Patents

Abstract

The present invention relates to the technical field of ferrous metallurgy production, and to a zinc-aluminum-magnesium alloy coated steel containing V and B and a preparation method therefor. The present invention provides the zinc-aluminum-magnesium alloy coated steel containing V and B. A coating comprises the following chemical components in mass percentage: 0.4%-2.8% of aluminum, 0.5%-3.0% of magnesium, 0.005%-0.8% of vanadium, and 0.001%-0.20% of boron, with the balance being zinc and inevitable impurities, wherein Al/Mg is 0.8-1.5, and the total amount of vanadium and boron is 0.01-0.50%. The zinc-aluminum-magnesium alloy coated steel provided by the present invention can satisfy the requirements of a user for the corrosion resistance and formability of a steel, is particularly suitable for the fields of household appliances and automobiles, and has a good popularization and application prospect.

Description

Zinc-aluminum-magnesium alloy coated steel containing V and B and preparation method thereof technical field

The invention relates to zinc-aluminum-magnesium alloy coated steel containing V and B and a preparation method thereof, belonging to the technical field of iron and steel metallurgy production.

Background technique

Zn-Al-Mg alloy coating attracted widespread attention abroad in the 1980s, and became the focus of research in the professional field of hot-dip galvanizing and zinc alloy coating. According to the research results of domestic and foreign counterparts, under the same level of coating Zn and Al content, the hot-dip Zn-Al-Mg alloy coated steel plate with Mg addition has better corrosion resistance, and the processing and application performance of the material ( Formability, weldability and coating performance) are excellent, and can replace the current corresponding hot-dip galvanized or zinc alloy coated steel sheets, and the market demand prospect is very broad.

Hot-dip Zn-Al-Mg alloy-coated steel sheets have been industrialized and applied in steel companies such as Nippon Steel, Nisshin Steel, and ThyssenKrupp in the early 21st century. At present, the main application fields are in the construction industry, and are gradually It is popularized and applied in industries such as home appliances and automobile manufacturing. my country's research on Zn-Al-Mg alloy coating is relatively late. At present, only Baosteel, Shougang, Jiugang, Panzhihua Iron and Steel and other enterprises have launched hot-dip Zn-Al-Mg alloy coated steel sheets.

Existing hot-dip Zn-Al-Mg alloy coated steel sheet can be divided into "low aluminum" (WAl＜5%), "medium aluminum" (5%≤WAl＜13%) and "high aluminum" (47%≤WAl ≤57%) three types. For different types of Zn-Al-Mg alloy coated steel sheets, the content of Al and Mg in the coating is different, and the structure and quality of the coating are different, so the application fields are also different. CN105063532A discloses a highly corrosion-resistant single-plated zinc-aluminum-magnesium rare-earth protective coating and a preparation process thereof. The single-plated zinc-aluminum-magnesium rare-earth protective coating process uses a single hot-dipping method to obtain a zinc-aluminum-magnesium alloy coating on a metal surface. The coating and the metal substrate each maintain their original performance, but have more than 99.9% of the metallurgical bonding interface. At the same time, the coating has a dense structure, stable composition, no missing plating, excellent corrosion resistance, and salt spray corrosion up to 2060h. The corrosion resistance of the alloy coating is better than that of ordinary hot-dip pure zinc coating, which improves the service life. The single-plating process can be reused and industrialized, and overcomes the difficulties of metal and zinc-aluminum-magnesium alloy liquid plating, the difficulty of forming an excellent bonding interface between the two, and the lack of easy to produce missing plating. It can be widely used in the preparation of metal surfaces. 5%-12% Al, 1%-6% Mg content of zinc-aluminum-magnesium alloy plating solution, the prepared co-infiltrated layer forms Zn/Al/MgZn2 ternary eutectic and various types of binary eutectics, which is eutectic The main reason for the high corrosion resistance of the seepage layer. The above-mentioned high-corrosion-resistant single-plated zinc-aluminum-magnesium rare earth protective coating adopts a medium-aluminum component system.

CN109402547A provides a kind of hot-dip coated steel plate with excellent corrosion resistance and its manufacturing method. The hot-dip coated steel plate includes a substrate and an Al-Zn-Si-Mg coating coated on the substrate. The chemical composition quality of the coating is The percentages are: Al: 45%~65%, Si: 0.1%~3%, Mg: 0.2%~5%, Zr: 0.001%~0.15%, Cr: 0.001%~0.5%, the balance is Zn and unavoidable of impurities. The manufacturing method comprises steps: (1) pretreatment of the steel plate; (2) dipping the steel plate into a bath for hot-dip plating, and the temperature of the bath is 560-595° C.; (3) taking the steel plate out of the bath, and performing Sectional cooling. The hot-dip-coated steel sheet has excellent corrosion resistance, and has a remarkable inhibitory effect on the occurrence of white rust, the development of red rust, and the propagation of failure of the treatment film originating from the cut. The above-mentioned hot-dip coated steel sheet with excellent corrosion resistance adopts a high-aluminum composition system coating.

It can be seen that the zinc-aluminum-magnesium steel sheet with high corrosion resistance is mainly the zinc-aluminum-magnesium steel sheet with a medium-high aluminum composition system. With the increase of Al and Mg content, the corrosion resistance of the coating increases, but at the same time, the formability and weldability of the coating increase. Performance drops. In the fields of home appliances and automobiles, in order to ensure that the Zn-Al-Mg alloy coated steel sheet meets the user's stamping forming requirements, it must have good formability. At present, the Zn-Al-Mg alloy coated steel sheet with a medium and high aluminum composition system cannot meet the user's requirements. .

Contents of the invention

The technical problem to be solved by the present invention is to provide a zinc-aluminum-magnesium alloy coated steel material containing V and B with high formability and corrosion resistance and a preparation method thereof.

The technical scheme adopted by the present invention for solving the above-mentioned technical problems is: firstly, a zinc-aluminum-magnesium alloy coated steel material containing V and B is provided, and the chemical composition of the coating is calculated by mass percentage: 0.4% to 2.8% of aluminum and 0.5% of magnesium ~3.0%, vanadium 0.005%~0.50%, boron 0.001%~0.20%, the rest is zinc and unavoidable impurities; among them, Al/Mg is 0.8~1.5, and the total amount of vanadium + boron is 0.01%~0.50%.

Further, the chemical composition of the coating satisfies at least one of the following: the coating contains 1.0% to 2.5% of aluminum, 1.0% to 2.0% of magnesium, 0.02% to 0.30% of vanadium, and 0.03% to 0.20% of boron;

Al/Mg is 0.75～1.25;

The total amount of vanadium + boron is 0.05% to 0.20%.

Further, the sum of the inevitable impurities is ≤0.010%, among which lead≤0.003%, antimony≤0.002%, tin≤0.002%, arsenic≤0.001%, tellurium≤0.001%, cadmium≤0.002%.

Further, the weight of the coating is 20-600g/m2, calculated on both sides; preferably, the weight of the coating is 40-400g/m2, calculated on both sides.

Further, the steel base of the steel is selected from at least one of IF steel, bake-hardening steel, SPCC, SEDDQ, QP steel, DP steel, and TRIP steel; preferably, the IF steel is high-strength IF steel containing P steel.

Further, it includes the following steps: steel base degreasing cleaning, continuous annealing, hot-dip plating, and air knife purging.

Further, the continuous annealing process controls the hydrogen in the furnace to be ≥ 4.0% by volume percentage; preferably, the continuous annealing process controls the hydrogen in the furnace to be 4.0% to 6.0% by volume.

Further, the temperature of the steel-based galvanizing pot is controlled at 400°C to 520°C, the temperature of the bath during hot-dip plating is 390°C to 500°C, and the temperature difference between the zinc pot temperature and the bath temperature is controlled at ±20°C.

Further, after rapid cooling after plating, the temperature of the steel strip reaching the top turning roll is controlled to be ≤280°C; preferably, the temperature of the strip steel reaching the top turning roll is controlled to be 240°C to 260°C during rapid cooling after plating.

The beneficial effects of the present invention are: the zinc-aluminum-magnesium alloy coated steel provided by the present invention adopts a low-aluminum component system, and the Zn-Al-Mg alloy coated steel plate with high corrosion resistance and formability can be produced by controlling the components of the coating. After testing, the zinc-aluminum-magnesium alloy coated steel of the present invention can appear red rust for as long as 400 hours or even more than 4500 hours under the neutral salt spray test conditions. Under certain conditions, the time for red rust to appear is more than 300h or even 4000h, and the adhesion of the sprayed coating after spraying is excellent. The zinc-aluminum-magnesium alloy coated steel is especially suitable for the fields of home appliances and automobiles, and has good prospects for popularization and application.

Detailed ways

The invention provides a zinc-aluminum-magnesium alloy coated steel material containing V and B. The chemical composition of the coating is calculated by mass percentage: 0.4% to 2.8% of aluminum, 0.5% to 3.0% of magnesium, 0.005% to 0.50% of vanadium, and 0.001% of boron ~0.20%, the rest is zinc and unavoidable impurities; among them, Al/Mg is 0.8~1.5, and the total amount of vanadium + boron is 0.01%~0.50%.

In order to ensure the corrosion resistance of Zn-Al-Mg alloy-coated steel, the current field mainly adopts a medium-high aluminum composition system, but with the increase of Al and Mg content, the formability and welding performance of the steel decrease significantly, and it is difficult to meet the requirements of home appliances, automobiles, etc. Requirements for stamping performance in other fields. In view of the above problems, the present invention optimizes the addition of Mg, Al content and other alloying elements in the coating, V provides heterogeneous nucleation points in the coating formation process, refines and reduces the grain size of the coating, and improves the coating In the case of ductility, the corrosion resistance of the coating is improved, and B fills in the gap of the coating crystal, reducing the internal defects of the coating, solid solution strengthening enhances the strength of the coating, improves the hardness of the coating, and enhances the wear resistance of the coating. It can meet the user's requirements for high corrosion resistance and high formability.

In the coating preparation process, in order to ensure that the coating has good surface quality and performance, it is necessary to limit the process. Considering the ability of the air knife and the fluidity of the plating solution, the thickness of the coating should be controlled within a certain range. When the weight of the coating is too large and the pressure of the air knife is small, the surface quality and thickness of the coating are not easy to control; while the flow of the air knife is limited and the fluidity of the plating solution is constant, the thickness of the coating is too thin to be controllable. The wettability of the plating solution on the surface of different steel plates is different, and it can only form a coating with excellent adhesion on the steel plate with good wettability. The annealing atmosphere is to improve the reducibility of the steel base surface. Generally, the higher the H ₂ content, the better, but the higher the H ₂ content, the higher the risk of explosion. The bath temperature needs to ensure that the bath is in a molten state and has good fluidity. The addition of V increases the temperature range of the bath, but if the temperature is too high, zinc oxide slag will easily increase. In order to ensure that the coating is completely solidified, the temperature of the steel plate must be lowered below the freezing point before the first turning roll, and zinc, aluminum and magnesium are easy to oxidize, and rapid cooling can make the surface quality better.

The solutions of the present invention will be explained below in conjunction with examples. Those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be considered as limiting the scope of the present invention. If no specific technique or condition is indicated in the examples, it shall be carried out according to the technique or condition described in the literature in this field or according to the product specification. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products.

Example 1 Preparation of zinc-aluminum-magnesium alloy coated steel of the present invention

Coating weight 60g/ ^m2 (double-sided), the main components of the coating are: aluminum 2.8%, magnesium 2.0%, vanadium 0.10%, boron 0.02%, lead 0.002%, antimony 0.001%, chromium 0.001%, cadmium 0.001%, tin 0.001%, the rest is zinc; the steel base is TRIP steel.

The preparation method is: degreasing cleaning, continuous annealing, hot-dip plating, air knife purging, cooling, wherein the degreasing cleaning is to rinse the steel base after degreasing, and the continuous annealing process controls the hydrogen in the furnace to 6.0% by volume percentage. The temperature of the steel plate entering the zinc pot is 500°C, the temperature of the bath during the hot-dip plating process is 480°C, and it is cooled quickly after plating, and the temperature at which the strip steel reaches the top turning roll is 260°C.

Test Methods:

Corrosion resistance: neutral salt spray accelerated corrosion test is adopted. The test conditions and methods are carried out according to GB/T10125-2012 "Artificial Atmosphere Corrosion Test Salt Spray Test". The NaCl deionized aqueous solution with a value of 6.5 is the corrosive medium, and the test temperature is 35±2°C; the sample size is 75mm×150mm×0.8mm, and the edge is sealed with a size of 5mm with scotch tape to prevent the end corrosion from affecting the results; The sample is placed at an angle of 15° to 25° with the vertical direction. Observe the time when red rust occurs on the surface of the sample.

Formability: Bend the sample at 0T (180°bending, the center radius is 0), observe with the naked eye whether there are cracks, and test the time for the appearance of red rust on the bent part under neutral salt spray test conditions, neutral Salt spray test conditions and methods are carried out according to GB/T10125-2012 "Artificial Atmosphere Corrosion Test Salt Spray Test".

Hardness: Use the INNOVATESTEurope BV universal hardness tester to select three positions to measure the surface hardness of the coating (HV0.01), and take the average value.

Paintability: After degreasing, cleaning, vitrification or phosphating, the coated steel plate after oiling is sprayed and dried, and then the degree of bonding between the sprayed coating and the steel plate is tested by the cross-hatch method. If there is no coating peeling off, it is Good adhesion.

After testing, the zinc-aluminum-magnesium alloy coated steel prepared in this example has good surface quality and excellent corrosion resistance, formability and coating properties. Under the neutral salt spray test conditions, the time for red rust to appear is more than 600h. After 0T bending, no obvious cracks are visible to the naked eye, and the time for the bent part to appear red rust under neutral salt spray test conditions is more than 500h. The hardness of the coating is 110, the adhesion of the sprayed coating after spraying is excellent, which meets the requirements of users.

Example 2 Preparation of zinc-aluminum-magnesium alloy coated steel of the present invention

The weight of the coating is 200g/m2 (double-sided). The main components of the coating are: aluminum 1.5%, magnesium 2.0%, vanadium 0.05%, boron 0.10%, lead 0.001%, antimony 0.002%, chromium 0.001%, cadmium 0.001%, tin 0.001 %, the rest is zinc; the steel base is SEDDQ steel.

The preparation method is: degreasing cleaning, continuous annealing, hot-dip plating, air knife purging, and cooling, wherein the degreasing cleaning is to rinse the steel base after degreasing, and the continuous annealing process controls the hydrogen in the furnace to 5.0% by volume percentage. The temperature of the steel plate entering the zinc pot is 450°C, the temperature of the bath during the hot-dip galvanizing process is 450°C, and it is cooled quickly after plating, and the temperature at which the strip steel reaches the top turning roll is 240°C.

Test method is the same as embodiment 1. After testing, the zinc-aluminum-magnesium alloy coated steel prepared in this example has good surface quality and excellent corrosion resistance, formability and coating properties. Under the neutral salt spray test conditions, the time for red rust to appear is more than 2000h, the hardness of the coating is 120, no obvious cracks are visible to the naked eye after 0T bending, and the time for the bent part to appear red rust under neutral salt spray test conditions is 1800h Above, the adhesion of the sprayed coating after spraying is excellent, which meets the requirements of users.

Example 3 Preparation of zinc-aluminum-magnesium alloy coated steel of the present invention

Coating weight 500g/ ^m2 (double-sided), the main components of the coating are: aluminum 1.0%, magnesium 1.0%, vanadium 0.20%, boron 0.15%, calcium 0.05%, lead 0.002%, antimony 0.001%, chromium 0.001%, cadmium 0.002%, tin 0.002%, the rest is zinc; the steel base is QP steel.

The preparation method is: degreasing cleaning, continuous annealing, hot-dip plating, air knife purging, cooling, wherein the degreasing cleaning is to rinse the steel base after degreasing, and the continuous annealing process controls the hydrogen in the furnace to 4.0% by volume percentage. The temperature of the steel plate entering the zinc pot is 440°C, the temperature of the plating solution during the hot-dip galvanizing process is 430°C, and the temperature is 260°C when the strip reaches the top turning roll after rapid cooling after plating.

Test method is the same as embodiment 1. After testing, the zinc-aluminum-magnesium alloy coated steel prepared in this example has good surface quality and excellent corrosion resistance, formability and coating properties. Under the neutral salt spray test conditions, the time for red rust to appear is more than 4500h, the hardness of the coating is 110, no obvious cracks are visible to the naked eye after 0T bending, and the time for the bent part to appear red rust under neutral salt spray test conditions is 4000h Above, the adhesion of the sprayed coating after spraying is excellent, which meets the requirements of users.

comparative example

Coating weight 180g/ ^m2 (double-sided), the main components of the coating are: aluminum 1.6%, magnesium 1.8%, lead 0.001%, antimony 0.001%, chromium 0.001%, cadmium 0.001%, tin 0.001%, the rest is zinc; steel The base is bake-hardened steel.

The preparation method is: degreasing cleaning, continuous annealing, hot-dip plating, air knife purging, cooling, wherein the degreasing cleaning is to rinse the steel base after degreasing, and the continuous annealing process controls the hydrogen in the furnace to 4.0% by volume percentage. The temperature of the steel plate entering the zinc pot is 460°C, the temperature of the bath during the hot-dip galvanizing process is 450°C, and it is cooled quickly after plating, and the temperature at which the strip steel reaches the top turning roll is 320°C.

Test method is the same as embodiment 1. After testing, the surface quality of the zinc-aluminum-magnesium alloy coated steel prepared in this comparative example is poor, there are horizontal line defects, and the corrosion resistance, formability and coating performance are slightly poor. Under the neutral salt spray test conditions, the time for red rust to appear is more than 1200h, the hardness of the coating is 90, and there are slight cracks to the naked eye after 0T bending, and the time for the bent part to appear red rust under neutral salt spray test conditions is more than 1100h. The adhesion of the spray coating after spraying is good.

It should be noted that the specific features, structures, materials or characteristics described in this specification may be combined in any one or more embodiments in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments and features of different embodiments described in this specification without conflicting with each other.

Claims (10)

1. The zinc-aluminum-magnesium alloy coated steel material containing V and B is characterized in that: the chemical composition of the coating is calculated by mass percentage: 0.4% to 2.8% of aluminum, 0.5% to 3.0% of magnesium, 0.005% to 0.50% of vanadium, and 0.001% of boron ~0.20%, the rest is zinc and unavoidable impurities; among them, Al/Mg is 0.8~1.5, and the total amount of vanadium + boron is 0.01%~0.50%.
2. The zinc-aluminum-magnesium alloy coated steel material containing V and B as claimed in claim 1, wherein the chemical composition of the coating satisfies at least one of the following:

   The coating contains 1.0% to 2.5% of aluminum, 1.0% to 2.0% of magnesium, 0.02% to 0.30% of vanadium, and 0.03% to 0.20% of boron;

   Al/Mg is 0.75～1.25;

   The total amount of vanadium + boron is 0.05% to 0.20%.
3. The zinc-aluminum-magnesium alloy coated steel material containing V and B as claimed in claim 1 is characterized in that: the sum of the inevitable impurities is ≤0.010%, wherein lead is ≤0.003%, antimony is ≤0.002%, tin is ≤0.002%, Arsenic ≤ 0.001%, Tellurium ≤ 0.001%, Cadmium ≤ 0.002%.
4. The zinc-aluminum-magnesium alloy coated steel material containing V and B as claimed in claim 1 is characterized in that: the weight of the coating is 20-600g/m ² , calculated on both sides; preferably, the weight of the coating is 40～400g/m ² , calculated on both sides.
5. The zinc-aluminum-magnesium alloy coated steel containing V and B as claimed in claim 1 is characterized in that: the steel base of the steel is selected from IF steel, bake hardening steel, SPCC, SEDDQ, QP steel, DP steel, TRIP At least one of the steels; preferably, the IF steel is a P-containing high-strength IF steel.
6. The method for preparing zinc-aluminum-magnesium alloy coated steel containing V and B according to any one of claims 1 to 5 is characterized in that it comprises the following steps: degreasing and cleaning the steel base, continuous annealing, hot dipping, and air knife purging.
7. The preparation method of zinc-aluminum-magnesium alloy coated steel containing V and B as claimed in claim 6 is characterized in that: the continuous annealing process controls the hydrogen in the furnace to be ≥ 4.0%, in terms of volume percentage; preferably, the continuous annealing process Control the hydrogen in the furnace to 4.0% to 6.0%, calculated by volume percentage.
8. The preparation method of zinc-aluminum-magnesium alloy coated steel containing V and B as claimed in claim 6 is characterized in that: the temperature of the steel-based zinc pot is controlled at 400°C-520°C, and the temperature of the bath during hot-dip plating is 390°C ~500°C, the temperature difference between the temperature of the zinc pot and the temperature of the plating solution is controlled within ±20°C.
9. The preparation method of zinc-aluminum-magnesium alloy coated steel containing V and B as claimed in claim 6 is characterized in that: fast cooling after plating, controlling the temperature at which the strip steel reaches the top turning roll ≤ 280 ° C; preferably, fast cooling after plating Cold, control the temperature at which the strip reaches the top turning roll to be 240°C to 260°C.
10. The zinc-aluminum-magnesium alloy coated steel containing V and B is characterized in that it is obtained according to the preparation method of the zinc-aluminum-magnesium alloy coated steel described in any one of claims 6-9.