Control method for selective oxidation of alloy elements of hot-dip galvanized high-strength steel

Abstract

The invention discloses a control method for selective oxidation of alloy elements of hot-dip galvanized high-strength steel, which relates to the technical field of hot-dip galvanized high-strength steel, and comprises the following steps: S1, carrying out hot rolling on a continuous casting billet to obtain a hot rolled steel coil; the hot rolling process comprises heating, rough rolling, finish rolling and coiling; s2, the hot rolled steel coil is subjected to acid pickling and cold rolling to obtain a cold-rolled steel sheet; s3, the cold-rolled steel plate is subjected to galvanization annealing treatment and hot galvanizing, and hot-galvanized high-strength steel is obtained; the galvanizing annealing treatment comprises preheating, pre-oxidation, heating and cooling, and the cooling process comprises slow cooling and rapid cooling. According to the method, the surface defect occurrence rate of the hot-dip galvanized high-strength steel is controlled by controlling the selective oxidation process.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-dip galvanized high-strength steel, and in particular is a control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel. Background Art

[0002] With the advancement of automobile lightweight technology, the application of high-strength steel in automobile manufacturing is increasing, and the demand for its strength grade is also increasing. For example, DP590 grade products have been used to manufacture key components such as door panels. However, in the hot-dip galvanizing process, due to the limitation of the zinc pot, many high-grade high-strength steels cannot be directly produced only through the cooling process. Therefore, it is necessary to add alloy elements according to the specific situation and combine annealing process to produce these high-strength materials.

[0003] Due to the production process limitations of the hot-dip galvanizing unit, it is not possible to achieve phase change of the material by rapid cooling using a continuous annealing unit to achieve the required strength level. In the production process of hot-dip galvanized high-strength steel, the addition of alloying elements easily leads to the precipitation and oxidation of alloying elements (such as manganese, silicon, and chromium), thus forming point defects such as missed plating and precipitation on the surface of the product.

[0004] Selective oxidation is divided into internal oxidation and external oxidation. Selective oxidation that occurs below the surface of the steel plate is called internal oxidation; selective oxidation that occurs on the surface of the steel plate is called external oxidation. External oxidation will cause the adhesion of the galvanized layer to decrease and dezincification, while internal oxidation can effectively ensure the cleanliness of the strip surface during the galvanizing process. In order to control the surface quality of hot-dip galvanized high-strength steel products, the existing technology usually controls the atmosphere during the production process to achieve selective internal oxidation in the furnace to inhibit the precipitation of alloy elements. Summary of the invention

[0005] In order to overcome the above technical problems, the present invention provides a control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel. The present invention realizes internal oxidation of hot-dip galvanized high-strength steel by controlling the oxidation process, thereby controlling the occurrence rate of apparent defects.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] A control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel comprises the following steps:

[0008] S1. hot rolling the continuous casting billet to obtain a hot rolled steel coil;

[0009] The hot rolling process includes heating, rough rolling, finish rolling and coiling;

[0010] S2. The hot-rolled steel coil is pickled and cold-rolled to obtain a cold-rolled steel sheet;

[0011] S3. The cold-rolled steel sheet is subjected to galvanizing annealing and hot-dip galvanizing to obtain hot-dip galvanized high-strength steel;

[0012] The galvannealing treatment includes preheating, preoxidation, heating and cooling, wherein the cooling process includes slow cooling and fast cooling.

[0013] In S1, the thickness of the continuous casting billet is 180-270 mm, for example, 230 mm.

[0014] In S1, the heating temperature is 1200-1280°C.

[0015] In S1, the heating time is 150 to 350 minutes; preferably, the heating time is 190 to 270 minutes.

[0016] In S1, the final rolling temperature of the finish rolling is 880-920°C.

[0017] In S1, the rough rolling is performed 5 to 8 times, for example, 7 times.

[0018] In S1, the coiling adopts a U-type coiling process, the coiling temperature of the head and tail of the U-type coiling process is 590-620° C., and the coiling temperature of the middle part is 540-580° C.;

[0019] The head range refers to the range within 20m of the strip head, the tail range refers to the range within 20m of the strip tail, and the rest of the strip is the middle part.

[0020] In S2, the temperature of the pickling acid solution is ≥82°C, preferably 82-87°C.

[0021] In S2, the concentration of the pickling acid solution is ≥100 g / L, preferably 120-170 g / L.

[0022] In S2, the pickling speed of the pickling is ≤220m / min, preferably the pickling speed is ≤180m / min.

[0023] In S2, the total reduction ratio of the cold rolling is 52 to 70%.

[0024] In S3, the pulling speed during the galvanizing annealing treatment is ≥ 60 m / min.

[0025] In S3, the preheating temperature rise rate is 8-12°C / s.

[0026] In S3, the preheating temperature is 560-660°C.

[0027] In S3, the pre-oxidation temperature is 580-680° C., and the pre-oxidation time is 10-20 seconds.

[0028] In S3, the dew point temperature in the oxidation chamber of the pre-oxidation is -25°C to -10°C, for example, -10°C, -15°C, -20°C and -25°C, preferably -10 to -15°C.

[0029] Further in S3, when the model of the hot-dip galvanized high-strength steel is DP590, the dew point temperature in the pre-oxidation oxidation chamber is -15°C.

[0030] Further in S3, when the model of the hot-dip galvanized high-strength steel is DP780, the dew point temperature in the pre-oxidation oxidation chamber is -10°C.

[0031] In S3, the oxidizing gas used for pre-oxidation includes oxygen. Preferably, the volume percentage of oxygen in the oxidizing gas used for pre-oxidation is 0.2-2%, and the balance is nitrogen. Wherein, if the oxygen content is too low, external oxidation of alloy elements will occur, and galvanized products will suffer from plating leakage. If the oxygen content is too high, overoxidation will occur, and defects such as pitting will appear on the galvanized products.

[0032] In S3, the heating temperature is 760-780° C., and the heating insulation time is 60-100 s.

[0033] In S3, the reducing gas used for heating contains hydrogen; preferably, the volume percentage of hydrogen in the reducing gas used for heating is 4-5%, and the remainder is nitrogen.

[0034] In S3, the cooling rate is -10 to -50°C / s, preferably -25 to -40°C / s.

[0035] In S3, the slow cooling temperature is 680-720° C., and the slow cooling insulation time is 20-40 seconds.

[0036] In S3, the temperature of the rapid cooling is 450-470° C., and the insulation time of the rapid cooling is 50-80 seconds.

[0037] In S3, a pretreatment is required before hot-dip galvanizing. The process of the pretreatment is conventional in the art. Preferably, the pretreatment includes the steps of pickling, alkali washing, plating assistance and drying.

[0038] In S3, the temperature of the hot-dip galvanizing zinc bath is 450-500°C, preferably 450-470°C.

[0039] In S3, the hot-dip galvanizing zinc bath time is 80 to 150 seconds, preferably 110 to 120 seconds.

[0040] In S3, the galvanizing process also includes skin pass and straightening.

[0041] Further in S3, the rolling force of the skin pass is ≥ 200t.

[0042] In S3, the elongation of the polishing is 0.3-0.5%.

[0043] Further in S3, the elongation of the tension straightening is 0.05-0.15%.

[0044] In the present invention, the model of the hot-dip galvanized high-strength steel is DP590 or DP780.

[0045] In the present invention, the thickness of the hot-dip galvanized high-strength steel is 0.7-2.3 mm.

[0046] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The present invention adopts a U-shaped low-temperature coiling process, which effectively reduces the generation of surface iron oxide scale, thereby reducing the amount of acid and time required in the pickling process, and reducing the difficulty of pickling. At the same time, due to the reduction of iron oxide scale, the surface quality of the galvanized product is significantly improved, and the stability of the coiling performance is also guaranteed, which is crucial for subsequent processing and use.

[0049] 2. The present invention adopts a pre-oxidation process, and realizes the transformation of alloy elements from external oxidation to internal oxidation by precisely controlling the oxidation amount in the pre-oxidation stage. This transformation effectively reduces the occurrence of missed plating and point-shaped or pinhole-shaped dezincification black spot defects, thereby significantly improving the surface quality of hot-dip galvanized high-strength steel products and ensuring the uniformity and integrity of the galvanized layer.

[0050] 3. The preheating and preoxidation process of the present invention successfully increases the thickness of the inner oxide layer. In some preferred embodiments, the thickness of the inner oxide layer can reach 1.2 to 2.2 μm. The thickening of the inner oxide layer effectively inhibits the diffusion of alloy elements to the surface of the steel plate, reduces the formation of surface oxides, and improves the wettability of the steel plate, which improves the adhesion of the coating and thus improves the overall surface quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is the appearance quality picture of the hot-dip galvanized high-strength steel prepared in Example 1. DETAILED DESCRIPTION

[0052] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0053] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0054] The "range" disclosed in the present invention is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60-120 and 80-110 is listed for a specific parameter, it is understood that the range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" represents that all real numbers between "0-5" have been fully listed herein, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0055] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0056] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0057] If not otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0058] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0059] If not specifically stated, in the present invention, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0060] Example 1

[0061] The hot-dip galvanized high-strength steel model in this embodiment is DP590.

[0062] The control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel of this embodiment comprises the following steps:

[0063] 1. Hot rolling:

[0064] The 230 mm thick continuous casting slab is hot rolled, and the hot rolling includes heating, rough rolling, finish rolling and coiling to obtain a hot rolled steel plate;

[0065] The heating temperature is 1241℃, the heating time is 211min; the number of rough rolling passes is 7 times; the final rolling temperature of the finishing rolling is 910℃;

[0066] The coiling adopts U-type coiling process; the coiling temperature of the head and tail of the strip is 612℃, and the coiling temperature of the middle part is 549℃; the head range refers to the range within 20m of the strip head, the tail range refers to the range within 20m of the strip tail, and the rest of the strip is the middle part.

[0067] 2. Pickling and cold rolling:

[0068] The hot-rolled steel sheet is acid (HCl) washed and cold rolled to obtain a cold-rolled steel sheet;

[0069] The acid temperature of pickling is 82°C; the acid concentration of pickling is 140g / L; the pickling speed is 220m / min;

[0070] The cold rolling is carried out through 5 stands, and the total cold rolling reduction rate is 70%.

[0071] 3. Galvanizing annealing treatment:

[0072] The pulling speed during galvanizing annealing is 68m / min;

[0073] The cold-rolled steel sheet is subjected to galvanizing and hot-dip galvanizing to obtain high-strength steel; the annealing process of the galvanizing treatment includes preheating, preoxidation, heating and cooling, wherein the cooling process includes slow cooling and fast cooling;

[0074] The preheating temperature is 634°C, and the preheating rate is 10°C / s;

[0075] The pre-oxidation temperature is 656°C, the pre-oxidation time is 15s, the dew point in the oxidation chamber of the pre-oxidation is -15°C, and the volume percentage of oxygen in the oxidizing gas used for pre-oxidation is 0.1%, and the balance is nitrogen;

[0076] The heating temperature is 775°C, the heating time is 80 seconds, and the volume percentage of hydrogen in the reducing gas used for heating is 4%, and the balance is nitrogen;

[0077] Cooling needs to be slow cooling first and then fast cooling: the cooling speed is -30℃ / s; the slow cooling temperature is 699℃, and it is kept at this slow cooling temperature for 30s; the fast cooling temperature is 468℃, and it is kept at this fast cooling temperature for 70s.

[0078] 4. Hot dip galvanizing:

[0079] Hot-dip galvanizing requires pre-treatment, and the pre-treatment steps are pickling, alkali washing, zinc addition and drying;

[0080] The zinc-adding solution includes 130 g / L NH4Cl and 150 g / L ZnCl2; the zinc-adding temperature is 70°C, and the zinc-adding time is 4 minutes;

[0081] The zinc bath time for hot-dip galvanizing is 460°C, and the zinc bath time for hot-dip galvanizing is 90s.

[0082] 5. Finishing and straightening:

[0083] After galvanizing, the process also includes skin straightening and straightening;

[0084] The elongation of skin finishing is 0.4%;

[0085] The rolling force for skin-pass is 225t;

[0086] The elongation of tension leveling is 0.1%.

[0087] The other steps and parameters of other steps are the same as those in Example 1.

[0088] Finally, the thickness of the hot-dip galvanized high-strength steel is 1.3mm and the width is 1000mm. Figure 1 .

[0089] Example 2

[0090] The difference between this embodiment and embodiment 1 is that:

[0091] 1. Hot rolling:

[0092] The heating temperature is 1232°C;

[0093] The final rolling temperature of the finishing rolling is 906℃;

[0094] The coiling temperature at the head and tail of the strip is 605℃, and the coiling temperature in the middle is 551℃.

[0095] 2. Pickling and cold rolling:

[0096] The acid temperature of pickling is 83°C; the acid concentration of pickling is 144g / L;

[0097] The total cold rolling reduction was 66%.

[0098] 3. Galvanizing annealing treatment:

[0099] The preheating temperature is 639°C;

[0100] The volume percentage of oxygen in the oxidizing gas is 0.2%, and the balance is nitrogen;

[0101] The heating temperature is 775°C;

[0102] Cooling is slow cooling and fast cooling: the temperature of slow cooling is 699℃, and the temperature of fast cooling is 468℃4. Hot dip galvanizing:

[0103] The zinc bath time for hot-dip galvanizing is 450°C, and the zinc bath time for hot-dip galvanizing is 120s.

[0104] Finally, the thickness of the hot-dip galvanized high-strength steel obtained is 1.5 mm.

[0105] The other steps and parameters of other steps are the same as those in Example 1.

[0106] Example 3

[0107] The difference between this embodiment and embodiment 1 is that:

[0108] 1. Hot rolling:

[0109] The heating temperature is 1233°C and the heating time is 223 min;

[0110] The final rolling temperature of the finishing rolling is 912℃;

[0111] The coiling temperature at the head and tail of the strip is 606℃, and the coiling temperature in the middle is 547℃.

[0112] 2. Pickling and cold rolling:

[0113] The acid temperature of pickling is 83°C; the acid concentration of pickling is 157g / L; the pickling speed is 215m / min;

[0114] The total cold rolling reduction was 57%.

[0115] 3. Galvanizing treatment:

[0116] The preheating temperature is 625°C;

[0117] The pre-oxidation temperature is 640°C;

[0118] The heating temperature is 778°C;

[0119] The cooling is slow cooling and fast cooling: the slow cooling temperature is 710℃, and the fast cooling temperature is 469℃

[0120] 5. Finishing and straightening:

[0121] The rolling force for skin pass is 219t.

[0122] Finally, the thickness of the hot-dip galvanized high-strength steel obtained is 1.4 mm.

[0123] The other steps and parameters of other steps are the same as those in Example 1.

[0124] Example 4

[0125] The difference between this embodiment and embodiment 1 is that:

[0126] 1. Hot rolling:

[0127] The heating temperature is 1240°C and the heating time is 226 min;

[0128] The final rolling temperature of the finishing rolling is 911°C;

[0129] The coiling temperature at the head and tail of the strip is 609℃, and the coiling temperature in the middle is 555℃.

[0130] 2. Pickling and cold rolling:

[0131] The pickling acid concentration is 156g / L; the pickling speed is 180m / min;

[0132] The total cold rolling reduction was 54%.

[0133] 3. Galvanizing treatment:

[0134] The preheating temperature is 628°C;

[0135] The pre-oxidation temperature is 641°C, the volume percentage of oxygen in the oxidizing gas is 0.6%, and the balance is nitrogen;

[0136] The heating temperature is 770°C;

[0137] The cooling is slow cooling and fast cooling respectively: the temperature of slow cooling is 706℃, and the temperature of fast cooling is 457℃.

[0138] 4. Hot dip galvanizing:

[0139] The zinc bath time for hot-dip galvanizing is 450°C, and the zinc bath time for hot-dip galvanizing is 90s.

[0140] 5. Finishing and straightening:

[0141] The rolling force of skin-pass is 239t;

[0142] Finally, the thickness of the hot-dip galvanized high-strength steel obtained is 1.3 mm.

[0143] The other steps and other parameters of the other steps are the same as those in Example 1.

[0144] Example 5

[0145] The model of the hot-dip galvanized high-strength steel in this embodiment is DP780.

[0146] The difference between this embodiment and embodiment 1 is that:

[0147] 1. Hot rolling:

[0148] The heating temperature is 1243°C and the heating time is 215 min;

[0149] The final rolling temperature of the finishing rolling is 906℃;

[0150] The coiling temperature at the head and tail of the strip is 613℃, and the coiling temperature in the middle is 556℃.

[0151] 2. Pickling and cold rolling:

[0152] The pickling acid concentration is 167g / L; the pickling speed is 174m / min;

[0153] The total reduction ratio of cold rolling was 53%.

[0154] 3. Galvanizing treatment:

[0155] The preheating temperature is 622°C;

[0156] The pre-oxidation temperature is 639°C, the volume percentage of oxygen in the oxidizing gas is 0.6%, and the balance is nitrogen;

[0157] The heating temperature is 772°C;

[0158] The cooling is slow cooling and fast cooling: the temperature of slow cooling is 709℃, and the temperature of fast cooling is 460℃

[0159] 4. Hot dip galvanizing:

[0160] The zinc bath time for hot-dip galvanizing is 460°C, and the zinc bath time for hot-dip galvanizing is 90s.

[0161] 5. Finishing and straightening:

[0162] The rolling force of skin-pass is 234t;

[0163] Finally, the thickness of the hot-dip galvanized high-strength steel obtained is 1.0 mm.

[0164] The other steps and parameters of other steps are the same as those in Example 1.

[0165] Example 6

[0166] The model of the hot-dip galvanized high-strength steel in this embodiment is DP780.

[0167] The difference between this embodiment and embodiment 1 is that:

[0168] 1. Hot rolling:

[0169] The 200 mm thick continuous casting slab is hot rolled;

[0170] The heating temperature was 1237°C and the heating time was 267 min;

[0171] The final rolling temperature of the finishing rolling is 908℃;

[0172] The coiling temperature at the head and tail of the strip is 606℃, and the coiling temperature in the middle is 544℃.

[0173] 2. Pickling and cold rolling:

[0174] The acid temperature of pickling is 83°C; the acid concentration of pickling is 170g / L; the pickling speed is 157m / min;

[0175] The total cold rolling reduction was 52%.

[0176] 3. Galvanizing treatment:

[0177] The preheating temperature is 618°C;

[0178] The pre-oxidation temperature is 645°C, the volume percentage of oxygen in the oxidizing gas is 0.8%, and the balance is nitrogen;

[0179] The heating temperature is 769°C;

[0180] The cooling is slow cooling and fast cooling: the temperature of slow cooling is 711℃, and the temperature of fast cooling is 455℃

[0181] 4. Hot dip galvanizing:

[0182] The zinc bath time for hot-dip galvanizing is 460°C, and the zinc bath time for hot-dip galvanizing is 90s.

[0183] 5. Finishing and straightening:

[0184] The rolling force for skin finishing is 257t.

[0185] Finally, the thickness of the hot-dip galvanized high-strength steel obtained is 0.9 mm.

[0186] The other steps and parameters of other steps are the same as those in Example 1.

[0187] Comparative Example 1

[0188] The difference between this comparative example and Example 1 is:

[0189] This comparative example does not undergo a preheating process.

[0190] The other steps and parameters of other steps are the same as those in Example 1.

[0191] Comparative Example 2

[0192] The difference between this comparative example and Example 1 is:

[0193] The pre-oxidation temperature of this comparative example is 520°C.

[0194] The other steps and parameters of other steps are the same as those in Example 1.

[0195] Test Case

[0196] The apparent defect incidence and inner oxide layer thickness of the hot-dip galvanized high-strength steel obtained in the above examples and comparative examples are shown in Table 1.

[0197] Table 1

[0198]

[0199]

[0200] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods. The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for selective oxidation of alloying elements in hot-dip galvanized high-strength steel, characterized in that: The following steps are involved: S1. hot rolling the continuous casting billet to obtain a hot rolled steel coil; The hot rolling process includes heating, rough rolling, finish rolling and coiling; S2. The hot-rolled steel coil is pickled and cold-rolled to obtain a cold-rolled steel sheet; S3. The cold-rolled steel sheet is subjected to galvanizing annealing and hot-dip galvanizing to obtain hot-dip galvanized high-strength steel; The galvannealing treatment includes preheating, preoxidation, heating and cooling, wherein the cooling process includes slow cooling and fast cooling.

2. The control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel according to claim 1, characterized in that: The continuous casting billet has a thickness of 180 to 270 mm; And / or, in S1, the heating temperature is 1200-1280° C.; And / or, in S1, the heating time is 150 to 350 minutes.

3. The control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel according to claim 1, characterized in that: The final rolling temperature of the finishing rolling is 880-920°C; And / or, the rough rolling is performed in 5 to 8 passes; And / or, the coiling adopts a U-shaped coiling process, the coiling temperature of the head and tail of the U-shaped coiling process is 590-620° C., and the coiling temperature of the middle part is 540-580° C.; The head range refers to the range within 20m of the strip head, the tail range refers to the range within 20m of the strip tail, and the rest of the strip is the middle part.

4. The control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel according to claim 1, characterized in that: The acid solution temperature of the pickling is ≥82°C; And / or, the acid concentration of the pickling acid is ≥100g / L; And / or, the pickling speed of the pickling is ≤220m / min; and / or, the total reduction ratio of the cold rolling is 52-70%; And / or, the pulling speed during the galvanizing annealing treatment is ≥60m / min.

5. The control method for selective oxidation of alloying elements in hot-dip galvanized high-strength steel according to claim 1, characterized in that: The preheating temperature rise rate is 8-12°C / s; And / or, the preheating temperature is 560-660°C; And / or, the pre-oxidation temperature is 580-680° C., and the pre-oxidation time is 10-20 s; And / or, the dew point temperature in the oxidation chamber of the pre-oxidation is -25°C to -10°C; And / or, the oxidizing gas used in the pre-oxidation includes oxygen.

6. The method for controlling the selective oxidation of alloying elements in hot-dip galvanized high-strength steel according to claim 5, characterized in that: When the model of the hot-dip galvanized high-strength steel is DP590, the dew point temperature in the pre-oxidation oxidation chamber is -15°C; And / or, when the model of the hot-dip galvanized high-strength steel is DP780, the dew point temperature in the pre-oxidation oxidation chamber is -10°C.

7. The control method for selective oxidation of alloy elements in hot-dip galvanized high-strength steel according to claim 1, characterized in that: In S3, the heating temperature is 760-780° C., and the heating holding time is 60-100 s; And / or, in S3, the reducing gas used for heating comprises hydrogen; And / or, the cooling rate is -10 to -50°C / s; And / or, the slow cooling temperature is 680-720° C., and the slow cooling holding time is 20-40 seconds; And / or, the temperature of the rapid cooling is 450-470° C., and the insulation time of the rapid cooling is 50-80 seconds.

8. The method for controlling the selective oxidation of alloying elements in hot-dip galvanized high-strength steel according to claim 1, characterized in that: The zinc bath temperature of the hot-dip galvanizing is 450-500°C; And / or, the hot-dip galvanizing zinc bath time is 80 to 150 seconds.

9. The method for controlling the selective oxidation of alloying elements in hot-dip galvanized high-strength steel according to claim 8, characterized in that: The galvanizing process also includes skin-passing and straightening. The rolling force of skin pass is ≥200t; The elongation of the finishing is 0.3-0.5%; The elongation of the tension-correction is 0.05-0.15%.

10. The method for controlling the selective oxidation of alloy elements in hot-dip galvanized high-strength steel according to any one of claims 1 to 9, characterized in that: The model of the hot-dip galvanized high-strength steel is DP590 or DP780.

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