Search

CN-121976109-A - Manufacturing method of fingerprint-resistant galvanized steel sheet with high scrap ratio and steel sheet

CN121976109ACN 121976109 ACN121976109 ACN 121976109ACN-121976109-A

Abstract

The invention provides a manufacturing method of a high scrap ratio fingerprint-resistant galvanized steel sheet and the steel sheet, and relates to the technical field of ferrous metallurgy. By controlling the adding proportion and chemical components of the scrap steel and combining specific process parameters, adverse effects of residual elements are effectively inhibited, hot shortness risks are reduced, surface quality and mechanical property stability are improved, and the method has the advantages of effectively controlling the content of the residual elements, reducing the hot shortness risks, improving the surface quality and mechanical property stability of the steel plate, simultaneously realizing low-carbon production under high scrap steel ratio and the like.

Inventors

  • LI JUN
  • LIN HONGCHUN
  • LIANG LIANG
  • LIN HONGTAO
  • WU JIANSHENG
  • LIU NING
  • QI JIANGHUA
  • LIU XUHUI
  • DENG ZHIXUN

Assignees

  • 湖南华菱涟钢特种新材料有限公司
  • 湖南华菱涟源钢铁有限公司

Dates

Publication Date
20260505
Application Date
20251229

Claims (10)

  1. 1. A manufacturing method of a high scrap ratio fingerprint-resistant galvanized steel sheet is characterized in that the scrap steel adding proportion of the method is 55+/-5%, and the method sequentially comprises the working procedures of steelmaking, continuous casting, hot rolling, continuous rolling, hot galvanizing and fingerprint-resistant treatment; the steel plate comprises, by weight, 0.01-0.024% of C, less than or equal to 0.050% of Si, 0.300-0.500% of Mn, less than or equal to 0.018% of P, less than or equal to 0.015% of S, 0.020-0.060% of Alt, less than or equal to 0.006% of N, less than or equal to 0.100% of Cu, less than or equal to 0.100% of Cr, less than or equal to 0.100% of Ni, less than or equal to 0.020% of Sn, less than or equal to 0.015% of As, and the balance of Fe and unavoidable impurities.
  2. 2. The method of claim 1, wherein the steelmaking process comprises: Smelting in a converter, namely adopting high-strength bottom argon blowing stirring, wherein the carbon at the end point is controlled to be 0.02-0.05%, and the tapping temperature is more than or equal to 1630 ℃; refining, namely deep desulfurization and component fine adjustment are carried out by adopting an LF furnace, so that the white slag time is ensured to be more than or equal to 15 minutes; And (3) carrying out vacuum treatment, namely carrying out RH circulation degassing treatment, wherein the vacuum degree is less than or equal to 67Pa, and the holding time is more than or equal to 15 minutes so as to ensure that the hydrogen content is less than or equal to 2.0ppm and the nitrogen content is effectively controlled.
  3. 3. The method of claim 1, wherein the hot rolling process parameters are controlled as: heating at 1145-1230 ℃; The finishing temperature is 860-900 ℃; The coiling temperature is 610-680 ℃.
  4. 4. A method according to claim 3, wherein in the hot rolling step, the slab heating time is 200 to 300 minutes, preferably 250 minutes, and the thickness of the strip after hot rolling is controlled to be 2.0 to 3.0mm, preferably 2.5mm.
  5. 5. The method according to claim 1, wherein the continuous rolling process comprises pickling the hot rolled coil, and then cold rolling to a thickness of 0.5 to 2.5mm, with a cold rolling reduction of 60 to 75%, preferably 68%.
  6. 6. The method of claim 1, wherein the hot dip galvanizing process parameters are controlled as follows: An annealing furnace zone, which is to adopt radiant tube heating and soaking two-section heating, wherein the annealing temperature is 760-780 ℃ and the dew point is controlled below-40 ℃; The zinc plating pot is characterized in that the aluminum content of zinc liquid is controlled to be 0.2-0.24%, and the zinc plating temperature is controlled to be 460+/-3 ℃.
  7. 7. The method of claim 1, wherein the fingerprint resistant process parameters are controlled as follows: The chromium-free fingerprint-resistant passivation solution is used as a treatment solution, and the main components of the treatment solution comprise acrylic resin and a silane coupling agent, wherein the pH value is controlled to be 8.5-9.5; the roller coating mode is adopted, and the coating amount is 0.8-1.5 g/m < 2 > on one side; and (5) drying and curing by hot air, wherein the temperature of the plate is controlled at 85-120 ℃.
  8. 8. The method of claim 1, wherein the value of the composite index cu+10sn of the residual element is further controlled to inhibit hot shortness risk.
  9. 9. The high scrap ratio fingerprint-resistant galvanized steel sheet prepared by the method of any one of claims 1-9 is characterized by having mechanical properties of 210-310 MPa of yield strength, 290-390 MPa of tensile strength and more than or equal to 30.5% of elongation after breaking, and having surface properties of fingerprint resistance, blackening resistance and surface resistivity of <1.0 multiplied by 10 5 ohm/m < 2 >, wherein the galvanized steel sheet has a thickness of 0.5-2.5 mm.
  10. 10. The high scrap ratio fingerprint resistant galvanized steel sheet as set forth in claim 9, characterized in that the galvanized layer surface has a uniform and dense inner oxide layer of aluminum oxide and forms a stable coating interface by fingerprint resistant treatment.

Description

Manufacturing method of fingerprint-resistant galvanized steel sheet with high scrap ratio and steel sheet Technical Field The application relates to the technical field of ferrous metallurgy, in particular to a manufacturing method of a high scrap steel ratio fingerprint-resistant galvanized steel sheet and the steel sheet. Background Under the background of the deep development of the 'two-carbon' strategy, the green low-carbon transformation in the steel industry has become a global consensus. The improvement of the electric furnace steelmaking proportion or the converter scrap steel proportion is used as a core path for reducing the carbon emission of ton steel, and has strategic significance for realizing the sustainable development of the industry. However, when the social recovery scrap steel is used as a main raw material source, residual elements such as copper, tin, chromium, nickel and the like are inevitably introduced, and are difficult to effectively remove in the conventional smelting process. With the increase of the proportion of scrap steel, the accumulation effect of residual elements in molten steel is obviously enhanced, and multiple technical bottlenecks are caused. The hot brittleness problem is particularly remarkable, copper and tin elements are enriched along grain boundaries in a slab heating stage, a low-melting eutectic phase is formed, microcracks are generated at the edge or the surface of the slab in the hot rolling process, and the rolling stability is seriously limited. Meanwhile, residual elements interfere with the iron-zinc reaction kinetics process of a galvanization link, so that surface defects such as reduced binding force of a plating layer interface, increased plating leakage points and the like are caused, and the corrosion resistance and appearance quality of the product are directly affected. In addition, the solid solution strengthening effect of the residual elements is easy to cause abnormal fluctuation of mechanical properties, and the unexpected increase of strength and the remarkable decrease of plasticity are presented, so that the stamping forming performance of the steel plate is deteriorated, and the severe requirements in the field of precision manufacturing are difficult to meet. At present, the production of high-end fingerprint-resistant galvanized products generally depends on low-residual element molten iron or high-purity scrap steel raw materials, and the raw material selection strategy not only greatly increases the production cost, but also prevents the high scrap steel ratio smelting technology from being applied to the field of high-added-value products. When the proportion of scrap steel exceeds 50%, the existing process system is difficult to consider both residual element control and surface quality stability, so that large-scale production of high-quality fingerprint-resistant galvanized steel sheets faces significant obstacle. In view of the above, there is a need in the art for improvements. Disclosure of Invention The application aims to provide a manufacturing method of a high scrap steel ratio fingerprint-resistant galvanized steel sheet and the steel sheet, which have the advantages of effectively controlling the content of residual elements, reducing the hot-shortness risk, improving the surface quality and mechanical property stability of the steel sheet, realizing low-carbon production under the high scrap steel ratio and the like. In a first aspect, the manufacturing method of the fingerprint-resistant galvanized steel sheet with high scrap ratio provided by the application adopts the following technical scheme: a manufacturing approach of high scrap ratio fingerprint-resistant galvanized steel sheet, said method scrap add proportion of 55% + -5%, pass steelmaking, continuous casting, hot rolling, tandem rolling, hot galvanizing and fingerprint-resistant treatment process sequentially; the steel plate comprises, by weight, 0.01-0.024% of C, less than or equal to 0.050% of Si, 0.300-0.500% of Mn, less than or equal to 0.018% of P, less than or equal to 0.015% of S, 0.020-0.060% of Alt, less than or equal to 0.006% of N, less than or equal to 0.100% of Cu, less than or equal to 0.100% of Cr, less than or equal to 0.100% of Ni, less than or equal to 0.020% of Sn, less than or equal to 0.015% of As, and the balance of Fe and unavoidable impurities. Optionally, the steelmaking process comprises: Smelting in a converter, namely adopting high-strength bottom argon blowing stirring, wherein the carbon at the end point is controlled to be 0.02-0.05%, and the tapping temperature is more than or equal to 1630 ℃; refining, namely deep desulfurization and component fine adjustment are carried out by adopting an LF furnace, so that the white slag time is ensured to be more than or equal to 15 minutes; And (3) carrying out vacuum treatment, namely carrying out RH circulation degassing treatment, wherein the vacuum degree is less than or equa