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CN-119456674-B - Method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling

CN119456674BCN 119456674 BCN119456674 BCN 119456674BCN-119456674-B

Abstract

The invention provides a method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling, which comprises the following steps of carrying out hot forging on a 316L steel ingot to obtain a forged 316L steel plate, carrying out heating treatment on the forged 316L steel plate, carrying out DS rolling on the heated 316L steel plate, repeating the steps b and c ten to twenty times, and carrying out leveling treatment on the 316L steel plate to obtain a high-strength high-toughness 316L austenitic stainless steel plate. Compared with synchronous warm rolling technology, the invention obviously improves the mechanical property of 316L austenitic stainless steel, has yield strength of 845 MPa and elongation of 22 percent at room temperature, has yield strength of 1130 MPa and maximum tensile strength of 1712 and MPa at-196 ℃ of liquid nitrogen, has elongation of more than 58 percent, has obviously improved mechanical property and low technical difficulty, and can be widely used in the fields of manufacturing low-temperature containers, ships, marine chemical industry and nuclear industry.

Inventors

  • WANG YUHUI
  • Zhao tengxiang
  • HUANG XIAOXU
  • XU LONGFEI
  • ZHANG CHENGHAO
  • KONG LING
  • PENG YAN

Assignees

  • 燕山大学

Dates

Publication Date
20260508
Application Date
20241122

Claims (7)

  1. 1. The method for preparing the high-strength high-toughness 316L stainless steel by DS warm rolling is characterized by comprising the following steps of: step a, hot forging is carried out on the 316L steel ingot to obtain a forged 316L steel plate; Step b, heating the forged 316L steel plate, wherein the temperature of the heated steel plate is 500-600 ℃; step c, performing DS rolling on the heated 316L steel plate; Step d, repeating steps b and c ten to twenty times; step e, leveling the 316L steel plate to obtain a high-strength high-toughness 316L austenitic stainless steel plate; when DS rolling is carried out on the 316L steel plate, the upper working rolls in odd-pass rolling are small-diameter rolls, the lower working rolls in even-pass rolling are large-diameter rolls, and the lower working rolls in even-pass rolling are small-diameter rolls; in all pass rolling processes, the 316L steel plate is contacted with a large-diameter roller.
  2. 2. The method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling according to claim 1, wherein in the step a, the initial forging temperature of hot forging is more than or equal to 1100 ℃, the final forging temperature is more than or equal to 850 ℃ and the heat preservation time is 100-120 min.
  3. 3. The method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling according to claim 1, wherein the diameter ratio of the large diameter roller to the small diameter roller is k,1<k is less than or equal to 1.2.
  4. 4. The method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling according to claim 1, wherein the small-diameter roller and the large-diameter working roller are provided with horizontal dislocation d in the horizontal direction, and d ranges from 1.5 mm to 4 mm.
  5. 5. The method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling according to claim 4, wherein the values of the horizontal dislocation d in each pass are different, and the ratio d/h of the horizontal dislocation d in each pass to the thickness h of the plate is constant.
  6. 6. The method for producing high-strength high-toughness 316L stainless steel by DS warm rolling according to claim 1, wherein when DS rolling is performed on the 316L steel sheet, each time rolling is completed, the 316L steel sheet is rotated 180 ° about the rolling direction and then subjected to the next rolling.
  7. 7. The method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling according to any one of claims 1 to 6, wherein the rolling reduction of each pass in step c is 3.7-7.5%, and the overall rolling reduction after step d is 56% -95%.

Description

Method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling Technical Field The invention belongs to the technical field of 316L austenitic stainless steel preparation, and particularly relates to a method for preparing high-strength high-toughness 316L stainless steel by DS warm rolling. Background With the rapid development of controllable nuclear fusion technology and the application development of clean energy sources (such as liquefied natural gas and hydrogen energy), the demand for low-temperature steel is increasing. Meanwhile, the mechanical property of the low-temperature steel at low temperature is also provided with higher requirements. 316L austenitic stainless steel is widely used in industrial fields such as low-temperature containers, construction materials in severe cold regions, and low-temperature superconducting armor in controlled nuclear fusion due to its excellent low-temperature properties, heat-insulating properties, low magnetism, and corrosion resistance. However, annealed 316L austenitic stainless steel has coarse grains and very low yield strength, which is only 200-400 MPa at normal temperature, which limits its use in critical load bearing components. According to the Hall-Petch relation, refining grains can obviously improve the strength of the material. In general, high strength 316L austenitic stainless steel is obtained by introducing a large amount of strain inside the alloy through Severe Plastic Deformation (SPD) processes such as high-pressure torsion, multi-directional forging, etc., thereby achieving grain refinement. However, the SPD process begins to drastically reduce its plasticity while strengthening 316L austenitic stainless steel. The SPD technology can introduce a large amount of stacking faults and dislocation accumulation into the material to promote the formation of martensite, so that part of austenite is subjected to martensitic transformation in advance, and the embrittlement of the material is induced. The essential is that SPD technology is complex in technology and small in sample size in actual production, and cannot be used for large-scale production. Another way to refine the grains is rolling. In the traditional synchronous rolling process, synchronous rolling is limited by the rolling force, the shearing force cannot penetrate into the center of the plate, and the thinning effect on the center of the plate is not obvious. The rotation speeds of the upper roller and the lower roller are different through asynchronous rolling, so that a pair of shearing forces are introduced in the rolling process, the shearing forces penetrate into the core of the plate, an obvious refining effect is achieved on the central crystal grains, and the distribution of the crystal grains of the plate is more uniform. However, the asynchronous rolling causes the sheet to bend toward the slow roll side, and the rolling is performed after rotating 90 ° in the rolling direction, and the sheet cannot be smoothly bitten due to the excessive bending degree. Disclosure of Invention Aiming at the technical problems of low strength, uneven grain distribution in the thickness direction, overlarge plate-shaped bending degree and the like in the prior art for preparing 316L austenitic stainless steel, the invention provides a method for preparing high-strength high-toughness 316L austenitic stainless steel by DS warm rolling, which can produce 316L austenitic stainless steel plates with larger size, has high efficiency and is suitable for large-scale production. In order to solve the technical problems, the technical scheme adopted by the invention is that the method for preparing the high-strength high-toughness 316L stainless steel by DS warm rolling comprises the following steps: step a, hot forging is carried out on the 316L steel ingot to obtain a forged 316L steel plate; Step b, heating the forged 316L steel plate, wherein the temperature of the heated steel plate is 500-600 ℃; step c, performing DS rolling on the heated 316L steel plate; Step d, repeating steps b and c ten to twenty times; and e, leveling the 316L steel plate to obtain the high-strength high-toughness 316L austenitic stainless steel plate. Further, in the step a, the initial forging temperature of hot forging is more than or equal to 1100 ℃, the final forging temperature is more than or equal to 850 ℃, and the heat preservation time is 100-120 min. Further, in the DS rolling of the 316L steel sheet, the upper work rolls for odd-pass rolling are small-diameter rolls, the lower work rolls for large-diameter rolls, and the upper work rolls for even-pass rolling are large-diameter rolls, and the lower work rolls for small-diameter rolls. Further, the diameter ratio of the large diameter roller to the small diameter roller is k,1<k is less than or equal to 1.2. Further, in all pass rolling processes, the 316L steel plate is firstly contacted with a large-diameter roller. Further, the