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CN-122013026-A - Method for controlling rough stripes on surface of medium-chromium ferrite stainless steel cold plate

CN122013026ACN 122013026 ACN122013026 ACN 122013026ACN-122013026-A

Abstract

The invention belongs to the technical field of manufacturing of ferrite stainless steel, and discloses a method for controlling rough stripes on the surface of a medium chromium ferrite stainless steel cold plate. The method comprises the following steps of controlling the content of C in steel to be 0.03% -0.05%, the content of N to be 0.015% -0.020% and the ratio of C/N to be 1.5-3.3, continuously casting, namely adopting a crystallizer to carry out electromagnetic stirring, controlling the specific water quantity of a secondary cooling area to enable the equiaxed crystal proportion of a casting blank to be more than 55%, grinding a plate blank, namely adopting a grinding wheel with 80-120 meshes, wherein the grinding depth is 0.3-0.5mm, the surface roughness Rz after grinding is less than or equal to 100 mu m, and carrying out hot rolling, namely controlling the furnace temperature of a heating furnace to be 1180-1200 ℃, the fluctuation to be +/-10 ℃, the rough rolling outlet temperature to be 1000-1050 ℃ and the finish rolling outlet temperature to be 850-900 ℃. The method for controlling the rough stripes on the surface of the medium-chromium ferrite stainless steel cold plate solves the problems of easy occurrence of rough stripe defects, poor surface quality and low yield of the cold plate.

Inventors

  • CHENG LEI
  • YANG YONGCHAO
  • WANG SHUXIANG
  • GAN CHAO
  • LIU HUAILI
  • SONG YAN

Assignees

  • 山西太钢不锈钢股份有限公司

Dates

Publication Date
20260512
Application Date
20260401

Claims (10)

  1. 1. A method for controlling rough stripes on the surface of a medium chromium ferrite stainless steel cold plate, which is characterized by comprising the following steps: Controlling the content of C element in the chromium ferrite stainless steel to be 0.03-0.05%, the content of N element to be 0.015-0.020% and the ratio of C/N to be 1.5-3.3; Adopting a crystallizer to carry out electromagnetic stirring, and controlling the specific water quantity of a secondary cooling zone to ensure that the equiaxial crystal proportion of a casting blank reaches more than 55%; Grinding the plate blank, namely grinding the plate blank by adopting a grinding wheel with the granularity of 80-120 meshes, wherein the grinding depth is 0.3-0.5mm, and the surface roughness Rz of the plate blank after grinding is less than or equal to 100 mu m; and hot rolling, namely controlling the furnace temperature of a heating furnace to 1180-1200 ℃, the fluctuation of the furnace temperature to +/-10 ℃, the rough rolling outlet temperature to 1000-1050 ℃ and the finish rolling outlet temperature to 850-900 ℃.
  2. 2. The method for controlling surface roughness of a cold plate of a medium chromium ferrite stainless steel according to claim 1, wherein in the composition control step, the content of C element is 0.038%, the content of N element is 0.023%, and the C/N ratio is 1.65.
  3. 3. The method for controlling surface roughness of a cold plate of a chromium ferrite stainless steel according to claim 1, wherein in the continuous casting step, the stirring current of the electromagnetic stirring of the crystallizer is 300-350A, the stirring frequency is 8-10Hz, and the specific water amount in the secondary cooling zone is 0.8-1.0L/kg.
  4. 4. The method for controlling coarse streaks on a medium chromium ferrite stainless steel cold plate according to claim 3, wherein the electromagnetic stirring current of the crystallizer is 300A, the frequency is 8Hz, the specific water quantity of a secondary cooling zone is 0.8L/kg, and the equiaxed crystal proportion of a casting blank is 56%.
  5. 5. The method for controlling surface roughness of a cold plate of medium chromium ferrite stainless steel according to claim 1, wherein in the slab grinding step, the grinding speed is 1.5-2.0m/min, the grinding wheel step is 25-30mm, and the overlapping amount of adjacent grinding passes is 20% -25%.
  6. 6. The method for controlling surface roughness of a cold plate of a medium chromium ferrite stainless steel according to claim 5, wherein in the slab grinding step, a grinding wheel with a granularity of 120 meshes is used, the grinding speed is 1.5m/min, the grinding depth is 0.3mm, the grinding wheel is stepped to 25mm, the overlapping amount of grinding passes is 25%, and the surface roughness Rz of the slab after grinding is 85 μm.
  7. 7. The method for controlling surface roughness of a cold plate of medium chromium ferrite stainless steel according to claim 1, wherein in the slab grinding step, the grinding is a longitudinal reciprocating grinding.
  8. 8. The method for controlling surface roughness of a cold plate of medium chromium ferrite stainless steel according to claim 1, wherein a heating time of a heating furnace is 0.8-1.0min/mm in the hot rolling step.
  9. 9. The method for controlling surface roughness of a cold plate of a medium chromium ferrite stainless steel according to claim 1, wherein the medium chromium ferrite stainless steel is SUS430 ferrite stainless steel.
  10. 10. The method for controlling surface roughness of a cold plate of medium chromium ferrite stainless steel according to claim 1, wherein the method for controlling surface roughness of a cold plate of medium chromium ferrite stainless steel further comprises performing hood annealing, hot wire pickling, cold rolling, cold wire pickling, leveling and slitting in sequence after the hot rolling step to obtain a finished cold plate.

Description

Method for controlling rough stripes on surface of medium-chromium ferrite stainless steel cold plate Technical Field The invention belongs to the technical field of manufacturing of ferrite stainless steel, and particularly relates to a method for controlling rough stripes on the surface of a medium chromium ferrite stainless steel cold plate. Background Medium chromium ferritic stainless steel (such as SUS 430) has become an important material in the fields of household appliances, architectural decoration, civil industry, etc. because of its excellent corrosion resistance, good thermal conductivity and magnetic properties, and no nickel or extremely low nickel content, and its cost is significantly lower than austenitic stainless steel. In the existing production process, the surface of the medium chromium ferrite stainless steel is easy to have rough stripe defects along the rolling direction in links such as continuous casting, hot rolling, cold rolling, annealing and pickling. According to analysis, the defect is mainly formed on the following factors of 1) coarse casting blank crystal grains and poor structure uniformity caused by improper proportion of C, N elements in steel, 2) poor control of continuous casting process parameters, low equiaxial crystal proportion of casting blanks, developed columnar crystals and adverse texture in subsequent processing, 3) ineffective removal of oxide skin, fine inclusions and the like on the surface of the casting blanks, expansion amplification in the rolling process, and 4) serious oxidation or abnormal structure caused by unreasonable hot rolling temperature system. The prior art is optimized for a single process, lacks systematic solutions, is difficult to eliminate rough stripe defects at all, and causes that the surface quality of products cannot meet the severe requirements of fields such as high-end precise electronic devices, medical appliances and the like on the surface finish, and has low yield and high manufacturing cost. Disclosure of Invention The invention aims to provide a method for controlling rough stripes on the surface of a medium chromium ferrite stainless steel cold plate, which solves the problems of easy occurrence of rough stripe defects, poor surface quality and low yield of the cold plate caused by comprehensive influences of components, continuous casting, grinding and hot rolling processes in the prior art. The method for controlling the rough stripes on the surface of the medium chromium ferrite stainless steel cold plate comprises the following steps of controlling the content of C element in the chromium ferrite stainless steel to be 0.03-0.05%, the content of N element to be 0.015-0.020% and the C/N ratio to be 1.5-3.3, adopting a crystallizer to carry out electromagnetic stirring, controlling the specific water quantity of a secondary cooling area to enable the equiaxed crystal ratio of a casting blank to be more than 55%, polishing a plate blank by adopting a grinding wheel with the granularity of 80-120 meshes, polishing the depth to be 0.3-0.5mm, and controlling the surface roughness Rz of the polished plate blank to be less than or equal to 100 mu m, and carrying out hot rolling, wherein the furnace temperature of a heating furnace is controlled to be 0-1200 ℃, the fluctuation of the furnace temperature is +/-10 ℃, the rough rolling outlet temperature is 1000-1050 ℃, and the finish rolling outlet temperature is 850-900 ℃. Further, in the component control step, the content of C element was 0.038%, the content of N element was 0.023%, and the C/N ratio was 1.65. Further, in the continuous casting step, the electromagnetic stirring current of the crystallizer is 300-350A, the stirring frequency is 8-10Hz, and the specific water quantity of the secondary cooling zone is 0.8-1.0L/kg. Further, the electromagnetic stirring current of the crystallizer is 300A, the frequency is 8Hz, the specific water quantity of the secondary cooling zone is 0.8L/kg, and the equiaxed crystal proportion of the casting blank is 56%. Further, in the slab grinding step, the grinding speed is 1.5-2.0m/min, the grinding wheel step is 25-30mm, and the overlapping amount of adjacent grinding passes is 20% -25%. Further, in the slab grinding step, a grinding wheel with granularity of 120 meshes is adopted, the grinding speed is 1.5m/min, the grinding depth is 0.3mm, the grinding wheel step is 25mm, the grinding pass overlapping amount is 25%, and the surface roughness Rz of the ground slab is 85 mu m. Further, in the slab grinding step, the grinding is a longitudinal reciprocating grinding. Further, in the hot rolling step, the heating time of the heating furnace is 0.8-1.0min/mm. Further, the medium chromium ferritic stainless steel is SUS430 ferritic stainless steel. Further, the method for controlling the rough stripes on the surface of the medium-chromium ferrite stainless steel cold plate further comprises the steps of carrying out cover annealing, h