CN-122012883-A - Method for realizing functional boron stainless steel sheet tissue refinement by utilizing large deformation processing

Abstract

The invention relates to the technical field of metallurgical materials, and particularly discloses a method for realizing the tissue refinement of a functional boron stainless steel sheet by utilizing large deformation processing. The method comprises the following steps of S1 smelting, S2 sheath forging, S3 sheath rolling, S4 solution treatment and S5 surface treatment, wherein the steel ingot is subjected to surface treatment to obtain a blank, the blank is filled into a steel sheath to be packaged to form a sheath-carrying blank, the sheath-carrying blank is subjected to hot forging to obtain a sheath-carrying forged plate, the forged plate is subjected to multi-pass hot rolling to prepare a sheath-carrying hot rolled sheet, the hot rolled sheet is subjected to solution treatment to obtain a solution treatment sheet, and the surface treatment is performed after the steel sheath of the solution treatment sheet is removed to obtain the functional boron stainless steel sheet with the required specification and size. The method can prepare the boron stainless steel sheet which has excellent mechanical property and uniform thermal neutron absorption and is in line with the structural/shielding integrated material.

Inventors

• LI YONGWANG
• LIU XIAOZHEN
• WU YU
• LIU YUNMING
• LI SHULIANG
• ZHU QIMENG
• LEI XIN
• GUO ZHEN
• LIAO ZHIHAI
• ZHENG YUE
• YIN WEI
• FU DAOGUI
• HE XUEYI
• SUN ZHAN

Assignees

• 中国核动力研究设计院

Dates

Publication Date

20260512

Application Date

20260224

Claims (10)

1. 1. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing large deformation processing is characterized by comprising the following steps of: s1, smelting, namely preparing a steel ingot by a duplex process of vacuum induction smelting and electroslag remelting; S2, ladle forging, namely cleaning the surface of the steel ingot prepared in the step S1 to obtain a blank, filling the blank into a steel ladle for encapsulation to form a ladle blank, and carrying out hot forging on the ladle blank to obtain a forging plate with a ladle; S3, cladding and rolling, namely preparing a hot rolled sheet with a cladding by carrying out multi-pass hot rolling on the forged plate prepared in the step S2; S4, carrying out solution treatment on the hot rolled sheet obtained in the step S3 to obtain a solution treated sheet; S5, surface treatment, namely removing the steel sleeve of the solution treatment sheet obtained in the step S4, and performing surface treatment to obtain the functional boron stainless steel sheet with the required specification and size.
2. 2. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing large deformation processing according to claim 1, wherein in the step S2, the thickness of a steel ladle is t, wherein when a steel ingot is a round steel ingot, t is more than or equal to 0.1D, D is the diameter of a boron stainless steel round ingot, and when the steel ingot is a square steel ingot, t is more than or equal to 0.1H, and H is the thickness of a boron stainless steel square ingot.
3. 3. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing the large deformation processing according to claim 1, wherein the steel sleeve and the blank in the step S2 are packaged into the steel sleeve after being subjected to pre-oxidation treatment.
4. 4. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing the large deformation processing according to claim 1, wherein in the step S2, a blank with a sheath is heated to a soaking temperature T, and then is subjected to multi-firing forging, wherein the soaking temperature T= (1150-1200 Xb% +1000 Xc%) +/-10 ℃ and b and C are respectively the mass percentages of boron element and carbon element in the boron stainless steel ingot.
5. 5. The method for realizing the structure refinement of the functional boron stainless steel sheet by utilizing large deformation processing according to claim 4, wherein in the step S2, the single-fire deformation amount is less than 30%, the final forging temperature is more than or equal to 900 ℃, and the forging ratio is more than or equal to 3.0.
6. 6. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing the large deformation processing according to claim 1, wherein in the step S3, the forged plate prepared in the step S2 is heated to a soaking temperature T, and then is subjected to multi-pass hot rolling, wherein the soaking temperature T= (1150-1200 Xb% +1000 Xc%) +/-10 ℃ is adopted, b is the mass percentage of boron element in the boron stainless steel ingot, and C is the mass percentage of carbon element in the boron stainless steel ingot.
7. 7. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing large deformation processing according to claim 6, wherein in the step S3, the deformation of single-pass rolling is less than or equal to h, the rolling deformation is more than or equal to 90%, the finishing rolling temperature is more than or equal to 900 ℃, and h=25-4.0×b, and b is the mass percentage of boron element in the boron stainless steel ingot.
8. 8. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing large deformation processing according to any one of claims 1 to 7, wherein in the step S4, the solution treatment temperature is 900 to 1100 ℃, and the heat preservation time is 30 to 90 minutes.
9. 9. The method for realizing the tissue refinement of the functional boron stainless steel sheet by utilizing large deformation processing according to any one of claims 1 to 7, wherein in the step S2, the steel sheath is made of 304 stainless steel or 316 stainless steel.
10. 10. The method for realizing the structure refinement of the functional boron stainless steel sheet by utilizing large deformation processing according to claim 1, wherein the chemical components of the prepared functional boron stainless steel sheet are ：18.00%≤Cr≤20.00%,12.00%≤Ni≤15.00%,0.02%≤B≤2.25%,C≤0.08%,Mn≤2.0%,Si≤0.75%,P＜0.045%,S＜0.030%,Co＜0.2%, and the balance of unavoidable impurities and Fe, wherein the Mn/Si content ratio is more than or equal to 2.5, and the total amount of C, P and S is less than 0.1%.

Description

Method for realizing functional boron stainless steel sheet tissue refinement by utilizing large deformation processing Technical Field The invention relates to the technical field of metallurgical materials, in particular to a method for realizing the tissue refinement of a functional boron stainless steel sheet by utilizing large deformation processing. Background The boron-containing austenitic stainless steel (boron content is 0.25-2.25%) has good thermal neutron absorption and gamma-ray shielding characteristics, can still maintain stability of structure and mechanical properties in a high-temperature environment, has excellent corrosion resistance, and is widely applied to the fields of spent fuel pool storage grillwork, transportation and dry storage containers, reactor shielding systems, spent fuel post-treatment and the like. In the American ASTM A887-89 standard, boron-containing austenitic stainless steel (19 Cr-14 Ni-0.2-2.25B) is divided into eight grades, each grade being divided into two grades A and B, according to the boron content in the stainless steel. The two grades have consistent component ranges, and the essential difference is that the B-grade boron stainless steel finished plate is thicker in boride particle size and poorer in distribution uniformity compared with the A-grade boron stainless steel finished plate, so that the B-grade thin plate with the same thickness specification is inferior to the A-grade thin plate in the aspects of elongation after fracture, impact performance, uniformity of thermal neutron absorption and the like. Therefore, in the spent fuel aftertreatment system, the grade-A high-boron stainless steel is more likely to be used as a structural/shielding integrated material, and the grade-B can only be used as a functional material of thermal neutron shielding, and the structural material is needed to assist in use. Therefore, how to process the grade a boron stainless steel sheet faster and better becomes one of the main research contents for applying the same to spent fuel post-treatment procedures. At present, few reports on a preparation method of a boron stainless steel plate are provided, and a powder metallurgy method and a smelting casting method are the mainstream. The powder metallurgy method is an efficient powder forming process, and by means of powder homogeneous mixing, pressurized sintering densification and subsequent deformation regulation and control, uniform dispersion distribution of boron elements and boride in a stainless steel matrix is realized, and meanwhile coarsening and grain boundary segregation of the boride are inhibited. For example, chinese patent document CN105463293A, CN106435401a discloses a method for preparing a sheet (boron content of 0.2-3.0%) of boron-containing stainless steel powder metallurgy. Among them, the document CN105463293a mainly carries out the preparation of class a sheet by "atomizing powder-making-pressure blank-sintering-forging-rolling-heat treatment", the document CN106435401a mainly carries out the preparation of boron stainless steel sheet by "atomizing powder-making-powder rolling-sintering", and the elongation of the finished sheet prepared by the invention is only >3.0%. However, the powder metallurgy method for preparing the high-boron stainless steel or the whole preparation process has longer period and high equipment cost, or the final finished product is difficult to meet the mechanical property requirement of the plate. The core of the melt casting method is a method of forming an ingot, a casting or a billet by melting a metal or alloy material, injecting the melted material into a mold, and cooling and solidifying the melted material. Because a large number of hard, brittle and coarse eutectic boride exists in ingot steel obtained by smelting and casting, when a boron-containing stainless steel sheet is prepared based on a smelting and casting method, the hot working process is extremely easy to crack, the molding difficulty is extremely high, and the large deformation processing of the boron stainless steel is difficult to finish by the existing preparation method. For example, chinese patent document CN106702287A, CN110527929A, CN111826583A and the like disclose a preparation process for preparing a boron-containing stainless steel functional plate based on a smelting casting method. The invention mainly uses a vacuum welding mode to assemble the upper surface and the lower surface of a stainless steel square billet, and finally prepares a composite sheet with a 3-layer sandwich structure, the effective boron content of the final sectional area of the sheet prepared by the method can be reduced, and edge cracks still occur in the forming process. According to the preparation method of the boron-containing stainless steel thick plate with excellent toughness disclosed in the patent CN110527929A and the patent （Fabrication of high borated austenitic stainless steel thick plates with enhanc