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CN-122012887-A - Method for reducing edge crack defect rate of 12CrNi stainless steel and 12CrNi stainless steel hot rolled plate

CN122012887ACN 122012887 ACN122012887 ACN 122012887ACN-122012887-A

Abstract

The invention belongs to the technical field of stainless steel production, and discloses a method for reducing the edge crack defect rate of 12CrNi stainless steel and a 12CrNi stainless steel hot rolled plate. The method sequentially comprises 1) optimizing steelmaking components, controlling ferrite influencing factors FF <7.5, wherein FF= (Cr+6Si+8Ti+4Mo+2Al) - [40 (C+N) +2Mn+4Ni ], wherein elements are mass percent, 2) controlling slab circulation temperature, feeding a continuous casting slab into a furnace at 100-400 ℃, 3) controlling a heating furnace heat preservation process, controlling the heat preservation temperature to be (A 4 -20) ° C to A 4 ℃, controlling the heat preservation time to be (0.9D) min to (1.2D) min, wherein A 4 is gamma-delta phase transition starting temperature, D is slab thickness (mm), 4) controlling a hot continuous rolling process, controlling rough rolling finishing temperature to be 950-1050 ℃, and starting an edge heater after rough rolling, wherein the power is 1200 kW-2000 kW. The method can remarkably reduce the incidence rate of edge crack defects in the hot rolling process.

Inventors

  • ZHAO ZIJUN
  • LIU CHUNLAI
  • DUAN XIUFENG
  • WU MIN
  • LUO GANG
  • REN JIARONG

Assignees

  • 山西太钢不锈钢股份有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. A method for reducing the edge crack defect rate of 12CrNi stainless steel, which is characterized by comprising the following steps: Controlling the molten steel components to enable the ferrite influence factor FF value of a final casting blank to be smaller than 7.5, wherein the FF value is calculated according to the following formula: FF=(Cr+6Si+8Ti+4Mo+2Al) [40(C+N)+2Mn+4Ni] wherein each element symbol represents the mass percentage content of the element symbol in steel; Step two, slab circulation temperature control, namely directly conveying the slab produced by continuous casting to a hot continuous rolling heating furnace at a temperature of 100-400 ℃; Heating the slab in a hot continuous rolling heating furnace, controlling the heat preservation temperature to be (A 4 -20) DEG C to A 4 ℃, wherein A 4 is the starting temperature of transformation of austenitic gamma phase of stainless steel to the delta phase of high-temperature ferrite, controlling the heat preservation time to be (0.9D) min to (1.2D) min, and D is the thickness of the slab, wherein the unit is mm; And fourthly, controlling a hot continuous rolling process, namely performing hot continuous rolling on the heated plate blank, controlling the finishing rolling temperature of rough rolling to 950-1050 ℃, and starting an edge heater after rough rolling is finished, and controlling the power of the edge heater to be 1200-2000 kW.
  2. 2. The method for reducing the edge crack defect rate of 12CrNi stainless steel according to claim 1, wherein the FF value ranges from 6.0 to 7.4.
  3. 3. The method for reducing the edge crack defect rate of 12CrNi stainless steel according to claim 1, wherein in the second step, the furnace charging temperature of the slab is controlled to be 100-300 ℃.
  4. 4. The method for reducing the edge crack defect rate of 12 CrNi-based stainless steel according to claim 1, wherein in the third step, the holding temperature is (a 4 -15) °c to a 4 ℃.
  5. 5. The method for reducing the edge crack defect rate of 12 CrNi-based stainless steel according to claim 1, wherein in the third step, the holding time is (0.95D) minutes to (1.1D) minutes.
  6. 6. The method for reducing the edge crack defect rate of 12 CrNi-based stainless steel according to claim 1, wherein in the fourth step, the rough rolling finishing temperature is controlled to 980 ℃ to 1030 ℃.
  7. 7. The method for reducing the edge crack defect rate of 12CrNi stainless steel according to claim 1, wherein in the fourth step, the power of the edge heater is controlled to be 1400 kW-1800 kW.
  8. 8. The method for reducing the edge crack defect rate of 12 CrNi-based stainless steel according to any one of claims 1 to 7, wherein the 12 CrNi-based stainless steel contains, in mass%, C not more than 0.03%, si not more than 0.5%, mn not more than 1.5%, cr not more than 10.5% to 12.5%, ni not more than 0.5% to 1.5%, N not more than 0.025%, and Ti not more than 0.3%.
  9. 9. The method for reducing the edge crack defect rate of 12CrNi series stainless steel according to claim 8, wherein the 12CrNi series stainless steel meets the 1.4003 brand composition requirements in european standard EN 10088-2.
  10. 10. A hot rolled 12 CrNi-based stainless steel sheet produced by the method for reducing the edge crack defect rate of a 12 CrNi-based stainless steel according to any one of claims 1 to 9, wherein the occurrence rate of edge crack defects is less than 5%, the tensile strength is not less than 550MPa, and the elongation after break is not less than 25%.

Description

Method for reducing edge crack defect rate of 12CrNi stainless steel and 12CrNi stainless steel hot rolled plate Technical Field The invention relates to the technical field of stainless steel production, in particular to a method for reducing the edge crack defect rate of 12CrNi stainless steel and a 12CrNi stainless steel hot rolled plate. Background The 12CrNi stainless steel has good corrosion resistance, oxidation resistance, high strength, excellent processability and welding performance, relatively low alloy components and remarkable cost benefit, and is widely applied to the fields of building panels, rail transit, household appliance kitchen and toilet and the like. However, because the Cr content in the stainless steel is relatively low, the ferrite potential is insufficient, the transformation curve is complex in the heat treatment process, and the phenomenon of coexistence of austenite and ferrite phases often occurs. Taking Euro-standard material 1.4003 as an example, during the temperature change from high to low, a gamma austenite single-phase region, a gamma austenite+alpha ferrite two-phase region and an alpha ferrite single-phase region exist in sequence. In the hot rolling process, 12CrNi stainless steel is extremely prone to crack at the slab edge, namely "edge crack defect", due to uneven phase transformation and concentrated structural stress. The defect causes the reduction of the effective width of the product, the reduction of the yield, and even the scrapping of the whole roll when serious, thereby bringing about obvious economic loss for enterprises. In the existing production process, although certain temperature control and rolling process optimization are adopted, the occurrence rate of edge cracking is still high and is generally more than 10%, and the requirements of high-end users on the width consistency and the surface quality of the product cannot be met. Therefore, how to systematically control the structure and stress state of the 12CrNi stainless steel in the whole process of steelmaking, continuous casting, heating and rolling, and fundamentally inhibit the generation of edge crack defects becomes a technical problem to be solved in the field. Disclosure of Invention The invention aims to provide a method for reducing the edge crack defect rate of 12CrNi stainless steel and a 12CrNi stainless steel hot rolled plate, which can remarkably reduce the edge crack defect rate in the hot rolling process. The method for reducing the edge crack defect rate of the 12CrNi series stainless steel comprises the following steps: Controlling the molten steel components to enable the ferrite influence factor FF value of a final casting blank to be smaller than 7.5, and calculating the FF value according to the following formula: FF=(Cr+6Si+8Ti+4Mo+2Al)[40(C+N)+2Mn+4Ni] wherein each element symbol represents the mass percentage content of the element symbol in steel; Step two, slab circulation temperature control, namely directly conveying the slab produced by continuous casting to a hot continuous rolling heating furnace at a temperature of 100-400 ℃; Heating the slab in a hot continuous rolling heating furnace, controlling the heat preservation temperature to be (A 4 -20) DEG C to A 4 ℃, wherein A 4 is the starting temperature of transformation of austenitic gamma phase of stainless steel to the delta phase of high-temperature ferrite, controlling the heat preservation time to be (0.9D) min to (1.2D) min, and D is the thickness of the slab, wherein the unit is mm; And fourthly, controlling a hot continuous rolling process, namely performing hot continuous rolling on the heated plate blank, controlling the finishing rolling temperature of rough rolling to 950-1050 ℃, and starting an edge heater after rough rolling is finished, and controlling the power of the edge heater to be 1200-2000 kW. Further, the value range of the FF value is 6.0-7.4. Further, in the second step, the furnace charging temperature of the slab is controlled to be 100-300 ℃. Further, in step three, the holding temperature is (A 4 -15) DEG C to A 4 ℃. Further, in the third step, the incubation time is (0.95D) minutes to (1.1D) minutes. Further, in the fourth step, the rough rolling finishing temperature is controlled to 980 ℃ to 1030 ℃. Further, in the fourth step, the power of the edge heater is controlled to be 1400 kW-1800 kW. Further, in the 12CrNi stainless steel, the content of C is less than or equal to 0.03%, the content of Si is less than or equal to 0.5%, the content of Mn is less than or equal to 1.5%, the content of Cr is 10.5% -12.5%, the content of Ni is 0.5% -1.5%, the content of N is less than or equal to 0.025%, and the content of Ti is less than or equal to 0.3% by mass. Further, the 12CrNi series stainless steel meets the 1.4003 brand component requirements in European standard EN 10088-2. According to the 12 CrNi-series stainless steel hot rolled plate produced by adopting the method for reducin