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CN-122012842-A - Production method for preventing holes of thick die steel medium plate

CN122012842ACN 122012842 ACN122012842 ACN 122012842ACN-122012842-A

Abstract

The invention provides a production method for preventing holes of a thick medium plate of thick die steel, and relates to the technical field of die steel production. The method comprises five steps of raw material pretreatment, smelting, continuous casting, rolling and cooling after rolling. The invention can inhibit the generation of hole defects from root by systematically optimizing the production flows of raw material treatment, smelting, continuous casting, rolling, cooling after rolling and the like, thereby remarkably improving the product quality and the qualification rate of the thick-specification die steel medium plate and having good industrialized application prospect.

Inventors

  • GUO LONGXIN
  • WANG ZHICONG
  • Tian Lixiao
  • GAO DONGFENG
  • GAO SHIJIE
  • YANG WEIJIE
  • SUN PAN
  • PANG HONGXUAN
  • LIU MINGSHENG
  • GUO MINGXING
  • GUO HUI

Assignees

  • 河北普阳钢铁有限公司

Dates

Publication Date
20260512
Application Date
20260211

Claims (10)

  1. 1. The production method for preventing holes of the thick die steel medium plate is characterized by comprising the following steps of: S1, raw material pretreatment, namely adopting scrap steel and molten iron with the water content less than or equal to 5% as raw materials; s2, smelting, namely smelting by a converter to ensure that the carbon content of a molten steel end point is 0.10-0.20%, the residual oxygen content is 140-280 ppm, and carrying out pre-deoxidation treatment before steel tapping alloying; S3, continuous casting, namely carrying out continuous casting operation on molten steel qualified in smelting, wherein the continuous casting pulling speed is 0.6-0.65 m/min, precisely calculating and determining the solidification end position of a casting blank through dynamic soft reduction, adopting a heavy reduction process in the solidification end region, and carrying out slow cooling after the casting blank is subjected to continuous casting; And S4, rolling, namely feeding the slowly cooled casting blank into a heating furnace for heating, wherein the heating time is 8-9 min/cm, the casting blank is ensured to be heated uniformly as a whole, and then rough rolling and finish rolling are sequentially carried out, so that no double strands are arranged on the edge of the rolled rough edge plate. S5, cooling after rolling, namely after rolling, air cooling and slow cooling are carried out to obtain the thick die steel.
  2. 2. The method for producing the thick die steel medium plate hole according to claim 1, wherein in the step S1, the water content of the scrap steel is reduced by baking the scrap steel at 280-800 ℃ for 1.5-2.5 hours.
  3. 3. The method for producing the holes of the medium plate of the thick die steel according to claim 1, wherein in the step S2, the pre-deoxidation treatment method is to add 0.35-0.65 kg/t of aluminum blocks of steel into molten steel.
  4. 4. The method for producing holes of thick steel plates of mold steel according to claim 1, wherein in the step S3, the reduction of the heavy pressing process is 15-18 mm.
  5. 5. The method for producing holes of thick steel plates for mold steel according to claim 1, wherein in the step S3, the slow cooling time is 72 h, and the temperature in the slow cooling pit is not less than 100 ℃.
  6. 6. The method for producing holes of thick steel plates of mold steel according to claim 1, wherein in the step S4, the tapping soaking temperature after heating is 1250-1270 ℃.
  7. 7. The method for producing holes of thick die steel medium plate according to claim 1, wherein in step S4, the reduction ratio of the three passes before rough rolling is greater than 15%, and the reduction ratio of the finish rolling is greater than 12%.
  8. 8. The method for producing holes of thick steel plates of mold steel according to claim 1, wherein in the step S5, the air cooling time is 1.5-2 hours, and the slow cooling time is 48 h.
  9. 9. A thick gauge die steel medium plate product obtained by the method of any one of claims 1-8.
  10. 10. The die steel medium plate according to claim 9, wherein the thickness of the die steel medium plate is 100-160 mm.

Description

Production method for preventing holes of thick die steel medium plate Technical Field The invention relates to the technical field of die steel, in particular to a production method for preventing holes of a thick die steel medium plate. Background The thick die steel medium plate has excellent performances of high strength, high hardness, good wear resistance, toughness and the like, and is widely applied to the fields of manufacturing high-end equipment such as mechanical manufacturing, automobile industry, aerospace and the like. However, in the production process of thick-gauge die steel medium plates, hole defects are one of the more common and difficult problems to solve. The holes mainly comprise air holes, shrinkage holes, looseness and the like, and the production reasons are complex and mainly relate to factors such as overhigh water content of raw materials, insufficient deoxidization in the smelting process, uneven solidification in the continuous casting process, unreasonable technological parameters in rolling heating and pressing, uneven cooling after rolling and the like. The existence of the hole defects can seriously reduce the mechanical property and the use reliability of the thick die steel medium plate, so that the problems of easy breakage, failure and the like of products in the subsequent processing or service process are caused, the quality and the qualification rate of the products are greatly influenced, and the production cost of enterprises is increased. At present, in the prior art, control measures for hole defects of a thick medium plate of thick die steel are scattered, a systematic solution is lacking, and effective suppression of the hole defects is difficult to realize. Therefore, the production method capable of comprehensively and effectively preventing the holes of the thick die steel medium plate is developed, and has important practical significance for improving the quality of the thick die steel medium plate and the economic benefit of enterprises. Disclosure of Invention In view of the above, the invention provides a production method for preventing holes of a thick die steel medium plate. The invention can inhibit the generation of hole defects from root by systematically optimizing the whole production processes of raw material treatment, smelting, continuous casting, rolling, cooling after rolling and the like, thereby remarkably improving the product quality and the qualification rate of the thick-specification die steel medium plate. The first aspect of the invention provides a production method for preventing holes of a thick plate of thick die steel, which comprises the following steps: S1, raw material pretreatment, namely, adopting molten iron and scrap steel as raw materials, baking the scrap steel at 280-800 ℃ for 1.5-2.5 hours, strictly controlling the water content of the baked scrap steel to be not more than 5%, or adding the scrap steel into an empty furnace for baking to remove water, and avoiding the decomposition of the water in the smelting process to generate gases such as hydrogen, oxygen and the like, thereby reducing the gas content in molten steel and reducing the risk of air hole defects; S2, smelting, namely adopting a converter smelting process to implement conventional high-carbon-pulling low-residual-oxygen operation, ensuring that the carbon content of a molten steel end point reaches a target value of 0.10-0.20%, and simultaneously controlling the residual oxygen content of the molten steel to be at a lower level of 140-280 ppm; S3, continuous casting, namely, continuously casting molten steel which is qualified in smelting, controlling the pulling rate to be in a low pulling rate range of 0.6-0.65 m/min in the continuous casting process, and carrying out slow cooling treatment of 72-h after casting is finished, wherein the temperature in a slow cooling pit is not lower than 100 ℃ so as to reduce or eliminate shrinkage cavity, looseness and central segregation and negative segregation of the casting blank generated in the solidification process, determining the solidification end position (solid phase ratio fs=0.3-0.85) of the casting blank through dynamic soft reduction technology, adopting a heavy pressure process in the solidification end region, reducing the reduction of 15-18 mm, eliminating internal gaps formed in the solidification process of the casting blank by utilizing the heavy pressure effect, and improving the compactness of the casting blank; s4, rolling, namely feeding the slowly cooled casting blank into a heating furnace for heating, adopting a heating concept of low-temperature slow burning to control the heating speed to uniformly raise the temperature, guaranteeing the heating quality of a middle plate, controlling the heating temperature to 1250-1270 ℃ and the heating time to 8-9 min/cm, enabling the internal temperature of the casting blank to be uniform and consistent, improving the plasticity and workabilit