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CN-122013053-A - Galvanized steel sheet and manufacturing method thereof

CN122013053ACN 122013053 ACN122013053 ACN 122013053ACN-122013053-A

Abstract

The invention belongs to the technical field of metal manufacturing, and particularly relates to a galvanized steel sheet and a manufacturing method thereof, wherein the galvanized steel sheet comprises a base steel sheet and an alloyed hot-dip galvanized layer, the alloyed hot-dip galvanized layer is plated on the surface of the base steel sheet, the base steel sheet comprises 0.35-0.45% of C, 0.10-0.55% of Si, 4.0-7.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.01% of S, less than or equal to 0.008% of N and the balance of Fe, the alloyed hot-dip galvanized layer has the average Fe content in the range of 8-11% and the balance of Zn, and the surface phase consists of columnar phases and polygonal phases, wherein the proportion of the columnar phases is not more than 30%, and the proportion R of the length and the width is 1< R <5. Compared with the prior art, the invention solves the problem that the galvanized steel sheet cannot be manufactured at low cost in the prior art. The galvanized steel sheet of this scheme is with low costs, high quality, and the coefficient of friction on cladding material surface is less, and has good anti peel performance.

Inventors

  • WANG BO
  • BI WENZHEN
  • WEI XICHENG

Assignees

  • 上海大学

Dates

Publication Date
20260512
Application Date
20260410

Claims (10)

  1. 1. The galvanized steel sheet is characterized by comprising a base steel sheet and an alloyed hot-dip galvanized layer, wherein the alloyed hot-dip galvanized layer is plated on the surface of the base steel sheet; The matrix steel plate comprises the following components in percentage by mass: 0.35-0.45% of C, 0.10-0.55% of Si, 4.0-7.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.01% of S, less than or equal to 0.008% of N, and the balance of Fe and unavoidable impurities; The alloyed hot-dip galvanized layer comprises, by mass, an average Fe content in a range of 8-11%, and the balance of Zn and unavoidable impurities; the surface phase of the alloyed hot-dip galvanized layer consists of two zinc-iron alloy phases, namely a columnar phase and a polygonal phase, wherein: the proportion of columnar phase is not more than 30%, and, The ratio R of the length and width of the columnar phase satisfies 1< R <5.
  2. 2. The galvanized steel sheet according to claim 1, characterized in that the base steel sheet further comprises, in mass percent: 0.1 to 1.0% of Al, 0.005 to 0.1% of Ti, 0.005 to 0.1% of Nb, 0.01 to 0.7% of Cr, 0.05 to 0.2% of Mo, 0.005 to 0.2% of V, and 0.0001 to 0.010% of B.
  3. 3. A galvanized steel sheet as set forth in claim 1, wherein said alloyed hot-dip galvanized layer further comprises, in mass percent: Al:0.01~1.0%。
  4. 4. The galvanized steel sheet according to claim 1, characterized in that the tensile strength of the galvanized steel sheet is not less than 1000MPa.
  5. 5. A method for producing a galvanized steel sheet as set forth in any one of claims 1 to 4, characterized by comprising the steps of: and sequentially carrying out the procedures of preheating, soaking, galvanization and alloying on the base steel plate to obtain the galvanized steel plate with the surface plated with the alloyed hot-dip galvanization layer.
  6. 6. The method of producing a galvanized steel sheet as set forth in claim 5, wherein the base steel sheet is obtained by the steps of smelting, hot rolling, pickling and cold rolling.
  7. 7. The method of manufacturing a galvanized steel sheet according to claim 5, characterized in that the preheating conditions are: The oxygen content in the preheated atmosphere is within the range of 0.01-0.1%; the preheating temperature is 600-850 ℃.
  8. 8. The method of manufacturing a galvanized steel sheet according to claim 5, characterized in that the soaking conditions are: The hydrogen volume concentration in the soaking atmosphere is 3-25%, the dew point DP is-50-0 ℃, and the balance is N 2 and unavoidable impurities; The soaking temperature is 700-900 ℃.
  9. 9. The method of manufacturing a galvanized steel sheet according to claim 5, characterized in that the galvanization is: And cooling the steel plate, and then, putting the steel plate into a zinc liquid at 450-465 ℃ for hot dip plating.
  10. 10. The method of manufacturing a galvanized steel sheet according to claim 5, characterized in that the alloying conditions are: the alloying temperature range is controlled to be 450-500 ℃; the alloying time range is controlled to be 10-30 s.

Description

Galvanized steel sheet and manufacturing method thereof Technical Field The invention belongs to the technical field of metal manufacturing, and particularly relates to a galvanized steel sheet and a manufacturing method thereof. Background In recent years, the demand of the ultra-high strength steel for the automobile is continuously increased, and the ultra-high strength steel has good mechanical property and service performance, is suitable for manufacturing automobile structural parts, and can effectively reduce the weight of the automobile in wide application. With the improvement of corrosion resistance requirements of automobiles, the alloyed hot dip plated steel plate is widely applied, and after hot dip plating, a plating layer is heated to an alloying temperature, so that Fe of a substrate is diffused into the plating layer to form different zinc-ferrum alloy phases, and compared with a pure zinc plating layer, the alloyed hot dip plated steel plate has better appearance and corrosion resistance. However, the performance of the alloyed coating is closely related to the phase structure of the alloyed coating, the poor alloying can cause the surface of the coating to form an excessively thick zeta phase and increase the friction coefficient, and the excessive alloying can cause the interface between the coating and the matrix to form an excessively thick gamma phase, so how to control and obtain a better phase structure composition through an alloying process is important to the performance influence of the hot dip plated steel plate. International patent WO2017102982A1 discloses a method for producing a high-strength hot-dip galvanized steel sheet. The typical components of the alloy are 0.19C-2.0Mn-0.6Si-0.45Al-0.12V-0.024B, ferrite, martensite, residual austenite and complex phase structure of a large amount of precipitated phases are obtained by controlling a hot rolling process and a continuous annealing process, continuous work hardening is provided by TRIP action in the nano precipitation strengthening and deforming process, the material has better plasticity, and the yield strength, tensile strength and elongation can reach 550MPa, 1080MPa and 15 percent respectively. The addition of large amounts of Al and V increases manufacturing difficulty and cost. The ultra-high strength steel with higher yield strength is invented by the U.S. patent No. 20180044750A1, the typical composition of which is 0.18C-2.0Mn-1.5Si-0.6Al-0.15Mo, and by adjusting coiling temperature and hot galvanizing process parameters, a small amount of ferrite, martensite and austenite structures are formed, so that the material can obtain 14% elongation at 980MPa level and 13% elongation at 1180MPa level. But the design of the components with high Si is not beneficial to improving the surface quality of the galvanized sheet, and meanwhile, the addition of a large amount of noble metal element Mo also greatly improves the alloy cost. Chinese patent CN108486501a discloses a 1000MPa grade cold-rolled hot-dip galvanized dual phase steel with enhanced plasticity and a manufacturing method thereof. The typical composition of the steel is 0.19-2.0 Mn-0.3Si-0.7Al-0.45Cr-0.02Ti, the ferrite, martensite, retained austenite and bainite complex phase structure can be obtained through the conventional DP steel manufacturing process (coiling temperature is up to 650 ℃), and the yield strength, tensile strength and elongation can respectively reach 700MPa, 980MPa and 14% through TRIP reinforcement plasticization in the deformation process. But the high Al content increases the smelting difficulty, and the high Cr content not only increases the alloy cost, but also is unfavorable for the surface quality of the galvanized sheet. In addition, the high coiling temperature also greatly increases the risk of surface defects. U.S. Pat. No. 3, 20180023155A1 discloses a 980MPa or higher grade ultra-high strength cold-rolled steel sheet excellent in elongation and hole expansion ratio and a method for producing the same. 0.1 to 0.5% of C, 0.8 to 4.0% of Si, 1.0 to 4.0% of Mn, less than 0.015% of P, less than 0.005% of S, 0 to 2% of Al, 0.02 to 0.15% of Ti, and other elements may be added. The final structure is required to contain ferrite phase, bainite phase and martensite phase, and 10 to 25% of retained austenite phase. The uniqueness of the alloy mainly depends on the addition of Si to obtain residual austenite, so that the alloy has better elongation and hole expansion rate, and the hole expansion rate 980MPa can only reach more than 30%. The analysis of the prior published patent shows that the prior steel plate mainly utilizes the composite addition of a large amount of Cr/Mo to improve the performance, and the residual austenite plasticized Gao Cheng section steel mainly depends on the addition of residual austenite in the structure to improve the plasticity of the hot dip galvanized dual-phase steel. However, the addition of a large amount