Cold-rolled continuous annealing high-strength steel with excellent silanization performance and manufacturing method thereof

Abstract

The present invention relates to a cold-rolled continuously annealed high-strength steel with excellent silanization performance and a method for manufacturing the same, and belongs to the technical field of steel preparation. The present invention improves the surface quality of high-strength steel plates by adjusting the chemical composition and optimizing the production process, including hot rolling temperature and flue gas control, acid rolling reduction rate control, coordinated control of furnace zone atmosphere dew point and annealing temperature and steel-passing speed during continuous annealing, and control of flatness and roughness, thereby obtaining high-strength steel plates with excellent silanization performance. The present invention achieves a balance between high strength and excellent silanization performance of cold-rolled continuously annealed high-strength steel, and the final silane film weight of the steel plate after silanization is 30 to 100 mg / m 2 , and its corrosion resistance and adhesion meet the high surface quality control requirements of most OEMs.

Description

Technical Field

[0001] The invention belongs to the technical field of steel preparation, and specifically relates to a cold-rolled continuously annealed high-strength steel with excellent silanization performance and a manufacturing method thereof. Background Art

[0002] In recent years, with the increasing requirements of environmental protection and collision regulations, high-strength cold-rolled steel plates have begun to be used in large quantities in automobiles to replace traditional automotive steel, so as to achieve the purpose of energy saving and weight reduction, improve safety and reduce manufacturing costs. Ultra-high-strength automotive steel with a strength of more than 780MPa is becoming more and more widely used.

[0003] The silanization treatment technology for steel surface is an environmentally friendly and effective new metal surface treatment technology. The silane film not only plays a certain role in corrosion prevention, but also serves as a bridge between the steel substrate and the coating, realizing a stable film structure formed by chemical bonds between the substrate, silane and the coating. In addition, the film-forming reaction process of silane does not produce toxic substances and will not harm the environment and human health. This is also the reason why silane pretreatment will replace coating phosphating and chromium treatment passivation in the future.

[0004] In order to improve the strength of steel plates, it is inevitable to add alloy elements such as Si, Mn, Nb, Ti and Al. However, steel plates designed with high alloy components will form different types of oxide particles during the continuous annealing process, which affects the effect of the silanization process, causes rust on the steel plates during the silanization process, and causes problems such as poor adhesion of the silane film layer and poor corrosion resistance, which seriously limits the application of ultra-high-strength steel plates in the green silanization production line of automobile factories. The high content of high-strength steel alloy components makes it difficult to control the surface quality of the steel plates, and the surface quality of the steel plates will have a significant impact on the silanization process. Therefore, how to control the good surface quality of ultra-high-strength steel plates and obtain good silanization quality also directly determines the quality of green silanization coating and the corrosion resistance of the automobile, which in turn affects the application of ultra-high-strength steel plates in automobiles.

[0005] Therefore, how to prepare a cold-rolled and continuously annealed ultra-high strength steel with excellent silanization performance has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The present invention provides a cold-rolled continuously annealed ultra-high strength steel with excellent silanization performance and a manufacturing method thereof, which achieves a balance among ultra-high strength, good surface quality and excellent silanization performance of the cold-rolled continuously annealed high-strength steel, and meets the green silanization surface quality control requirements of most OEMs.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a cold-rolled continuously annealed high-strength steel with excellent silanization performance, the chemical composition and mass fraction of the cold-rolled continuously annealed high-strength steel are: C: 0.07-0.30%; Si≤0.1%; Mn: 1.00-3.00%; P≤0.020%; Al: 0.6-0.9%, and the remainder is Fe and unavoidable impurities.

[0008] The chemical composition of the cold-rolled and continuously annealed high-strength steel of the present invention further includes any one or more of Ti, Nb, V and Mo, with a mass percentage of ≥0.01%.

[0009] The thickness specification of the cold-rolled continuously annealed high-strength steel of the present invention is 0.8-2.0 mm.

[0010] The mechanical properties of the cold-rolled continuous annealing high-strength steel of the present invention are as follows: tensile strength ≥ 780MPa, yield strength ≥ 420MPa, elongation after fracture A 50mm ≥10%.

[0011] The internal microstructure of the cold-rolled and continuously annealed high-strength steel of the present invention is as follows: ferrite is 20-50%, martensite is 30-60%, and bainite is 0-20% by volume percentage.

[0012] The present invention also provides a method for manufacturing the above-mentioned cold-rolled continuously annealed high-strength steel with excellent silanization performance, the manufacturing method comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0013] 1) Hot rolling process: slab furnace temperature 1230 ~ 1350 ℃, furnace dwelling time 120 ~ 200min, residual oxygen content of flue gas in the furnace ≤ 4%; finishing rolling inlet temperature 1050 ~ 1120 ℃, final rolling temperature 850 ~ 890 ℃, coiling temperature 590 ~ 660 ℃;

[0014] 2) Pickling process: total reduction rate ≥ 40%;

[0015] 3) Continuous annealing process: soaking section temperature 750 ~ 840 ℃, soaking time 100 ~ 150s; slow cooling section temperature 630 ~ 680 ℃, slow cooling section cooling rate 5 ~ 15 ℃ / s; rapid cooling section temperature 260 ~ 310 ℃, rapid cooling section cooling rate 25 ~ 50 ℃ / s; over-aging section temperature 230 ~ 290 ℃.

[0016] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.6~1.0μm, and the roughness peak count R pc The value is controlled at ≥85.

[0017] In the continuous annealing process of the present invention, the strip speed is 100-200 m / min, the volume content of hydrogen in the furnace is 1.8-6.0%, the oxygen content in each section of the furnace is 0-30 ppm, and the dew point value is -20°C to +20°C.

[0018] The precipitation of Mn, Si and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel of the present invention is detected by glow spectrum analysis, and the maximum mass percentage content is ≤2% (the detection depth is 0.1 μm).

[0019] The cold-rolled continuous annealed high-strength steel of the present invention has a silane film weight of 30 to 100 mg / m after silanization. 2 , the weight difference of silane film on the same plate is ≤10mg / m 2 .

[0020] The cold-rolled continuously annealed high-strength steel of the present invention is subjected to a hundred-grid test after silanization, and the residual silane film is 100%.

[0021] The cold-rolled continuously annealed high-strength steel of the present invention is subjected to a 1000-hour salt spray corrosion test (referenced to GB / T1771) after silanization and electrophoresis, and the single-side corrosion expansion width at the scribe line is ≤2 mm.

[0022] The design concept of the present invention is as follows: the present invention adopts medium-low carbon, low silicon and high aluminum in chemical composition, and simultaneously adds a method of adding an appropriate amount of microalloying elements. When the silicon content is high, stable oxides such as olivine that are difficult to pickle will be produced during the hot rolling process, thereby reducing the surface quality of hot-rolled and cold-rolled steel sheets. Like silicon, aluminum can also inhibit the precipitation of carbides. More importantly, aluminum is not prone to surface segregation during the recrystallization annealing process of the steel sheet, and is more prone to internal oxidation and is not prone to producing surface oxides. Therefore, the low silicon and high aluminum component design is more conducive to obtaining good surface quality, and thus is conducive to obtaining surface quality after silanization.

[0023] The hot rolling process of the present invention adopts relatively low temperature heating and rolling, reduces the furnace time, controls the residual oxygen content of the flue gas, and adopts a suitable coiling temperature. These process means are conducive to obtaining a Fuhrsteine ​​structure and a relatively thin oxide scale thickness in the oxide scale that is easily washed off by subsequent pickling on the basis of ensuring the mechanical properties of the product, avoids the rolling and pressing of the oxide scale, and is conducive to obtaining good surface quality of the hot-rolled and pickled plates.

[0024] The pickling process uses a large total reduction rate to fully break up the hot-rolled structure, creating conditions for reserving energy for subsequent recrystallization annealing, obtaining uniform structure, and ensuring uniform performance.

[0025] The continuous annealing process adopts appropriate temperature and cooling rate to obtain high-strength steel with different properties. The atmosphere and dew point control create conditions for the internal oxidation of Mn, Si and Al elements, avoiding the aggregation and precipitation of Mn, Si and Al oxides on the surface of the steel plate. According to the glow spectrum analysis, the maximum mass percentage content of the precipitation of Mn, Si and Al elements on the surface is ≤2% (the detection depth is 0.1μm), which is beneficial to the bonding reaction between the metal substrate and silane during silanization, and improves the adhesion and uniformity of the silane film.

[0026] The flattening process uses a smaller R a Value control to ensure the coverage effect of the silane film layer and avoid a The value is large and the peak is poorly covered, resulting in defects that are easy to rust; while the higher R pc The value increases the silanized surface area of ​​the steel plate, which is beneficial to improving the adhesion of the silane film.

[0027] In summary, in terms of the preparation method, the surface quality of high-strength steel plates is improved by controlling the temperature and flue gas of hot rolling, controlling the reduction rate of pickling rolling, coordinating the dew point of the furnace atmosphere and the annealing temperature during continuous annealing, and controlling the steel-passing speed, and the flatness and roughness, and a high-strength steel plate with good silanization performance is obtained.

[0028] The beneficial effects of adopting the above technical solution are: 1. The present invention does not require equipment upgrades and renovations. By adjusting the chemical composition and optimizing the production process, including hot rolling temperature and flue gas control, acid rolling reduction rate control, coordinated control of furnace atmosphere dew point and annealing temperature during continuous annealing and steel-passing speed, and flatness and roughness control, the surface quality of high-strength steel plates is improved, and high-strength steel plates with good silanization performance are obtained. 2. The present invention achieves a balance between the high strength and excellent silanization performance of cold-rolled and continuously annealed high-strength steel. The final silane film weight of the steel plate after silanization is 30 to 100 mg / m 2 , and the corrosion resistance and adhesion meet the control requirements of the high surface quality of most OEMs. The improvement of silanization quality is conducive to improving the painting quality of the car body and improving the corrosion resistance of the car, thereby continuously expanding the application of high-strength steel plates in automobiles and promoting the industrialization of green painting and intelligent manufacturing. 3. The manufacturing method of the present invention is used to avoid the aggregation and precipitation of Mn, Si, and Al element oxides on the surface of the steel plate. According to the glow spectrum analysis, the maximum mass percentage content of the precipitation of Mn, Si, and Al elements on the surface is ≤2% (the detection depth is 0.1μm), which is beneficial to the bonding reaction effect between the silanized metal substrate and silane, and improves the adhesion and uniformity of the silane film. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Example 1: 100-grid test morphology of cold-rolled and continuously annealed high-strength steel after silanization;

[0030] Figure 2 Comparative Example 1: 100-grid test morphology of cold-rolled continuously annealed high-strength steel after silanization;

[0031] Figure 3 Example 1: Morphology of cold-rolled continuously annealed high-strength steel after silane electrophoresis and salt spray corrosion for 1000h;

[0032] Figure 4 Comparative Example 1: Morphology of cold-rolled continuously annealed high-strength steel after silane electrophoresis and salt spray corrosion for 1000h;

[0033] Figure 5 Example 1 Typical metallographic structure morphology of cold-rolled and continuously annealed high-strength steel 800Mpa grade (200×);

[0034] Figure 6 Example 2 Typical metallographic structure morphology of cold-rolled and continuously annealed high-strength steel 1000Mpa grade (200×). DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Example 1

[0037] A method for manufacturing cold-rolled continuously annealed high-strength steel with excellent silanization performance, comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0038] 1) Hot rolling process: slab out-of-furnace temperature 1230℃, furnace dwelling time 120min, residual oxygen content of flue gas in the furnace 4%. Finishing rolling inlet temperature 1050℃, final rolling temperature 850℃, coiling temperature 590℃;

[0039] 2) Pickling process: total reduction rate 40%;

[0040] 3) Continuous annealing process: soaking section temperature 750℃, soaking time 100s; slow cooling section temperature 630℃, slow cooling section cooling rate 5℃ / s; rapid cooling section temperature 260℃, rapid cooling section cooling rate 25℃ / s; over-aging section temperature 230℃. Strip speed 100m / min, hydrogen volume content in the furnace is 1.8%, oxygen content in each section of the furnace is 30ppm, and dew point value is +20℃;

[0041] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.6μm, R pc The value is controlled at 85.

[0042] The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel obtained in this embodiment are shown in Table 1, the thickness specifications, mechanical properties, and microstructure content are shown in Table 2, and the maximum mass percentage content of Mn, Si, and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel, the film weight of the silane film, the adhesion, and the corrosion resistance after silanization and electrophoresis (single-side corrosion expansion width) are shown in Table 3.

[0043] The cold-rolled continuously annealed high-strength steel of this embodiment was silanized and the adhesion of the silane film was tested by the hundred-grid test. Figure 1 As shown (the other embodiment drawings are similar and omitted). After silane and electrophoresis, the salt spray corrosion test was carried out for 1000 hours. The single-side corrosion width at the scribe line was 1.5mm, which meets the corrosion resistance requirements of automobile OEMs such as SAIC (the test standard refers to GB / T 1771, and the single-side corrosion width at the scribe line is required to be ≤2mm). Figure 3 As shown in the figure (other examples are similar and omitted). Figure 5 As shown (200 times) (the drawings of the other embodiments are similar and omitted).

[0044] Example 2

[0045] A method for manufacturing cold-rolled continuously annealed high-strength steel with excellent silanization performance, comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0046] 1) Hot rolling process: slab furnace temperature 1350℃, furnace dwell time 200min, flue gas residual oxygen content 3%. Finishing rolling inlet temperature 1120℃, final rolling temperature 890℃, coiling temperature 660℃;

[0047] 2) Pickling process: total reduction rate 50%;

[0048] 3) Continuous annealing process: soaking section temperature 840℃, soaking time 150s; slow cooling section temperature 680℃, slow cooling section cooling rate 15℃ / s; rapid cooling section temperature 310℃, rapid cooling section cooling rate 50℃ / s; over-aging section temperature 290℃. Strip speed 200m / min, hydrogen volume content in the furnace 6.0%, oxygen content in each section of the furnace 20ppm, dew point value -20℃;

[0049] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 1.0μm, R pc The value is controlled at 90.

[0050] The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel obtained in this embodiment are shown in Table 1, the thickness specifications, mechanical properties, and microstructure content are shown in Table 2, and the maximum mass percentage content of Mn, Si, and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel, the film weight of the silane film, the adhesion, and the corrosion resistance after silanization and electrophoresis (single-side corrosion expansion width) are shown in Table 3.

[0051] The cold-rolled continuously annealed high-strength steel in this embodiment has good adhesion after silanization in the 100-grid test. After silanization and electrophoresis, the salt spray corrosion test for 1000 hours meets the corrosion resistance requirements of automobile OEMs such as SAIC (the test standard refers to GB / T 1771, and the single-side corrosion width at the scribe line is required to be ≤2mm). Typical metallographic morphology is as follows Figure 6 As shown (200 times).

[0052] Example 3

[0053] A method for manufacturing cold-rolled continuously annealed high-strength steel with excellent silanization performance, comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0054] 1) Hot rolling process: slab furnace temperature 1300℃, furnace dwell time 150min, flue gas residual oxygen content 2%. Finishing rolling inlet temperature 1100℃, final rolling temperature 880℃, coiling temperature 620℃;

[0055] 2) Pickling process: total reduction rate 60%;

[0056] 3) Continuous annealing process: soaking section temperature 800℃, soaking time 120s; slow cooling section temperature 650℃, slow cooling section cooling rate 10℃ / s; rapid cooling section temperature 300℃, rapid cooling section cooling rate 28℃ / s; over-aging section temperature 260℃. Strip speed 150m / min, hydrogen volume content in the furnace 5.0%, oxygen content in each section of the furnace 10ppm, dew point value 0℃;

[0057] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.8μm, R pc The value is controlled at 110.

[0058] The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel obtained in this embodiment are shown in Table 1, the thickness specifications, mechanical properties, and microstructure content are shown in Table 2, and the maximum mass percentage content of Mn, Si, and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel, the film weight of the silane film, the adhesion, and the corrosion resistance after silanization and electrophoresis (single-side corrosion expansion width) are shown in Table 3.

[0059] The cold-rolled continuously annealed high-strength steel of this embodiment has good adhesion after silanization in the 100-grid test. After silanization and electrophoresis, the salt spray corrosion test for 1000 hours meets the corrosion resistance requirements of automobile OEMs such as SAIC (the test standard refers to GB / T 1771, and the single-side corrosion expansion width at the scribe line is required to be ≤2mm).

[0060] Example 4

[0061] A method for manufacturing cold-rolled continuously annealed high-strength steel with excellent silanization performance, comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0062] 1) Hot rolling process: slab furnace temperature 1270℃, furnace dwelling time 130min, residual oxygen content of flue gas in the furnace 2.6%. Finishing rolling inlet temperature 1090℃, final rolling temperature 885℃, coiling temperature 645℃;

[0063] 2) Pickling process: total reduction rate 55%;

[0064] 3) Continuous annealing process: soaking section temperature 810℃, soaking time 140s; slow cooling section temperature 675℃, slow cooling section cooling rate 12℃ / s; rapid cooling section temperature 275℃, rapid cooling section cooling rate 32℃ / s; over-aging section temperature 247℃. Strip speed 175m / min, hydrogen volume content in the furnace is 4.7%, oxygen content in each section of the furnace is 10ppm, and dew point value is -15℃;

[0065] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.75μm, R pc The value is controlled at 109.

[0066] The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel obtained in this embodiment are shown in Table 1, the thickness specifications, mechanical properties, and microstructure content are shown in Table 2, and the maximum mass percentage content of Mn, Si, and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel, the film weight of the silane film, the adhesion, and the corrosion resistance after silanization and electrophoresis (single-side corrosion expansion width) are shown in Table 3.

[0067] The cold-rolled continuously annealed high-strength steel of this embodiment has good adhesion after silanization in the 100-grid test. After silanization and electrophoresis, the salt spray corrosion test for 1000 hours meets the corrosion resistance requirements of automobile OEMs such as SAIC (the test standard refers to GB / T 1771, and the single-side corrosion expansion width at the scribe line is required to be ≤2mm).

[0068] Example 5

[0069] A method for manufacturing cold-rolled continuously annealed high-strength steel with excellent silanization performance, comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0070] 1) Hot rolling process: slab out-of-furnace temperature 1290℃, furnace dwelling time 160min, residual oxygen content of flue gas in the furnace 3.5%. Finishing rolling inlet temperature 1105℃, final rolling temperature 865℃, coiling temperature 630℃;

[0071] 2) Pickling process: total reduction rate 45%;

[0072] 3) Continuous annealing process: soaking section temperature 790℃, soaking time 135s; slow cooling section temperature 660℃, slow cooling section cooling rate 9℃ / s; rapid cooling section temperature 295℃, rapid cooling section cooling rate 40℃ / s; over-aging section temperature 270℃; strip speed 130m / min, hydrogen volume content in the furnace 3.5%, oxygen content in each section of the furnace 15ppm, dew point value +10℃;

[0073] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.9μm, R pc The value is controlled at 100.

[0074] The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel obtained in this embodiment are shown in Table 1, the thickness specifications, mechanical properties, and microstructure content are shown in Table 2, and the maximum mass percentage content of Mn, Si, and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel, the film weight of the silane film, the adhesion, and the corrosion resistance after silanization and electrophoresis (single-side corrosion expansion width) are shown in Table 3.

[0075] The cold-rolled continuously annealed high-strength steel of this embodiment has good adhesion after silanization in the 100-grid test. After silanization and electrophoresis, the salt spray corrosion test for 1000 hours meets the corrosion resistance requirements of automobile OEMs such as SAIC (the test standard refers to GB / T 1771, and the single-side corrosion expansion width at the scribe line is required to be ≤2mm).

[0076] Comparative Example 1

[0077] A method for manufacturing cold-rolled and continuously annealed high-strength steel, comprising hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows:

[0078] 1) Hot rolling process: slab out-of-furnace temperature 1275℃, furnace dwelling time 135min, residual oxygen content of flue gas in the furnace 2.7%. Finishing rolling inlet temperature 1095℃, final rolling temperature 875℃, coiling temperature 635℃;

[0079] 2) Pickling process: total reduction rate 50%;

[0080] 3) Continuous annealing process: soaking section temperature 815℃, soaking time 145s; slow cooling section temperature 670℃, slow cooling section cooling rate 11℃ / s; rapid cooling section temperature 270℃, rapid cooling section cooling rate 33℃ / s; over-aging section temperature 248℃. Strip speed 172m / min, hydrogen volume content in the furnace 4.9%, oxygen content in each section of the furnace 13ppm, dew point value -50℃;

[0081] 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.70μm, R pc The value is controlled at 111.

[0082] The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel obtained in this embodiment are shown in Table 1, the thickness specifications, mechanical properties, and microstructure content are shown in Table 2, and the maximum mass percentage content of Mn, Si, and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel, the film weight of the silane film, the adhesion, and the corrosion resistance after silanization and electrophoresis (single-side corrosion expansion width) are shown in Table 3.

[0083] The dew point of the continuous annealing process in this comparative example does not meet the requirements of the present invention, resulting in the precipitation content of the surface elements Mn, Si, and Al not meeting the requirements of the present invention. Although the film weight of the silane film after silanization of the cold-rolled continuous annealed high-strength steel in this comparative example meets the requirements, the adhesion of the silane film is poor after the 100-grid test, and the residual amount is about 85%. Figure 2 After silane and electrophoresis, the salt spray corrosion test for 1000h did not meet the corrosion resistance requirements of SAIC and other automobile OEMs (SAIC standard number: SMTC 5 200 010), and the single-side corrosion expansion width reached 3mm. Figure 4 shown.

[0084] Table 1 Chemical composition and mass percentage of cold-rolled and continuously annealed high-strength steel of Example 1-6

[0085]

[0086] Table 2 Specifications, mechanical properties, and microstructure content of cold-rolled and continuously annealed high-strength steel of Examples 1-6

[0087]

[0088] Table 3 Properties of cold-rolled and continuously annealed high-strength steel after surface silanization in Example 1-6

[0089]

[0090] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A cold-rolled and continuously annealed high-strength steel with excellent silanization performance, characterized in that: The chemical composition and mass fraction of the cold-rolled and continuously annealed high-strength steel are: C: 0.07-0.30%; Si≤0.1%; Mn: 1.00-3.00%; P≤0.020%; Al: 0.6-0.9%, the balance being Fe and unavoidable impurities; the chemical composition of the cold-rolled and continuously annealed high-strength steel also includes any one or more of Ti, Nb, V, and Mo, with a mass percentage of ≥0.01%; The precipitation of Mn, Si and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel is detected by glow spectrum analysis, and the maximum mass percentage content is ≤2%; The cold-rolled and continuously annealed high-strength steel was subjected to a hundred-grid test after silanization, and the residual silane film was 100%; the cold-rolled and continuously annealed high-strength steel was subjected to a salt spray corrosion test for 1000 hours, and the single-side corrosion expansion width at the scribe line was ≤2mm; The method for manufacturing cold-rolled continuously annealed high-strength steel includes hot rolling, acid rolling, continuous annealing, and leveling processes, and the specific control parameters are as follows: 1) Hot rolling process: slab furnace temperature 1230 ~ 1350 ℃, furnace dwelling time 120 ~ 200min, residual oxygen content of flue gas in the furnace ≤ 4%; finishing rolling inlet temperature 1050 ~ 1120 ℃, final rolling temperature 850 ~ 890 ℃, coiling temperature 590 ~ 660 ℃; 2) Pickling process: total reduction rate ≥ 40%; 3) Continuous annealing process: soaking section temperature 750-840℃, soaking time 100-150s; slow cooling section temperature 630-680℃, slow cooling section cooling rate 5-15℃ / s; fast cooling section temperature 260-310℃, fast cooling section cooling rate 25-50℃ / s; over-aging section temperature 230-290℃; 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.6~1.0μm, and the roughness peak count R pc The value is controlled at ≥85; In the continuous annealing process, the strip speed is 100-200 m / min, the volume content of hydrogen in the furnace is 1.8-6.0%, the oxygen content in each section of the furnace is 0-30 ppm, and the dew point value is -20°C to +20°C.

2. The cold-rolled continuously annealed high-strength steel with excellent silanization performance according to claim 1, characterized in that: The thickness specification of the cold-rolled continuously annealed high-strength steel is 0.8 to 2.0 mm.

3. The cold-rolled continuously annealed high-strength steel with excellent silanization performance according to claim 1, characterized in that: The mechanical properties of the cold-rolled and continuously annealed high-strength steel are as follows: tensile strength ≥ 780 MPa, yield strength ≥ 420 MPa, elongation after fracture A 50mm ≥10%.

4. The cold-rolled continuously annealed high-strength steel with excellent silanization performance according to claim 1, characterized in that: The internal microstructure of the cold-rolled and continuously annealed high-strength steel is as follows: ferrite is 20-50%, martensite is 30-60%, and bainite is 0-20% by volume percentage.

5. A method for manufacturing a cold-rolled and continuously annealed high-strength steel with excellent silanization performance according to any one of claims 1 to 4, characterized in that: The manufacturing method includes hot rolling, pickling, annealing and leveling processes, and the specific control parameters are as follows: 1) Hot rolling process: slab furnace temperature 1230 ~ 1350 ℃, furnace dwelling time 120 ~ 200min, residual oxygen content of flue gas in the furnace ≤ 4%; finishing rolling inlet temperature 1050 ~ 1120 ℃, final rolling temperature 850 ~ 890 ℃, coiling temperature 590 ~ 660 ℃; 2) Pickling process: total reduction rate ≥ 40%; 3) Continuous annealing process: soaking section temperature 750-840℃, soaking time 100-150s; slow cooling section temperature 630-680℃, slow cooling section cooling rate 5-15℃ / s; fast cooling section temperature 260-310℃, fast cooling section cooling rate 25-50℃ / s; over-aging section temperature 230-290℃; 4) Leveling process: The surface roughness R of the steel strip after leveling a The value is controlled to be 0.6~1.0μm, and the roughness peak count R pc The value is controlled at ≥85; The precipitation of Mn, Si and Al elements on the surface of the cold-rolled and continuously annealed high-strength steel is detected by glow spectrum analysis, and the maximum mass percentage content is ≤2%; The cold-rolled and continuously annealed high-strength steel was subjected to a hundred-grid test after silanization, and the residual silane film was 100%; the cold-rolled and continuously annealed high-strength steel was subjected to a salt spray corrosion test for 1000 hours, and the single-side corrosion expansion width at the scribe line was ≤2mm.

6. The method for manufacturing cold-rolled and continuously annealed high-strength steel with excellent silanization performance according to claim 5, characterized in that: In the continuous annealing process, the strip speed is 100-200 m / min, the volume content of hydrogen in the furnace is 1.8-6.0%, the oxygen content in each section of the furnace is 0-30 ppm, and the dew point value is -20°C to +20°C.

7. The method for manufacturing a cold-rolled and continuously annealed high-strength steel with excellent silanization performance according to claim 5 or 6, characterized in that: The cold-rolled and continuously annealed high-strength steel has a silane film weight of 30 to 100 mg / m after silanization. 2 , the weight difference of silane film on the same plate is ≤10mg / m 2 .

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