CN-121976005-A - Preparation method of ultra-high strength steel member with fatigue impact resistance

CN121976005ACN 121976005 ACN121976005 ACN 121976005ACN-121976005-A

Abstract

The invention discloses a preparation method of an ultra-high strength steel member with anti-fatigue impact performance, which successfully realizes organic unification of ultra-low roughness, high steady-state gradient compressive stress and high uniform surface energy on the surface of the ultra-high strength steel through full chain cooperative regulation, wherein a constructed residual stress field is generated in situ without depending on external plastic deformation by a self-generated heat-force coupling process induced by laser irradiation, is solidified into a thermodynamic metastable state through subsequent multi-field cooperative action, so that the holding capacity of the member in a service temperature-variable environment is remarkably improved, and meanwhile, the anisotropy of free energy of the surface is eliminated through directional reconstruction of a surface energy field of a molecular scale, so that the preferential adsorption and electrochemical activation tendency of an environmental medium in a stress concentration area are restrained, the member can show consistent and predictable energy dissipation behavior when bearing impact load for the first time, and the fatigue performance stability and long-term service reliability are fundamentally improved.

Inventors

SHU DAYU
CAO YI
CHEN QIANG
ZHAN HONG
CHAI SHUXIN
CAO KAI
WU YANG
ZHAO QIANG
ZHANG FEIYUE
QU JUNCEN

Assignees

中国兵器装备集团西南技术工程研究所

Dates

Publication Date: 20260505
Application Date: 20260309

Claims (10)

1. The preparation method of the ultra-high strength steel member with the anti-fatigue impact performance is characterized by comprising the following steps: obtaining molten steel through vacuum induction melting and ingredient dynamic cooperative regulation, and carrying out controlled atmosphere electroslag remelting and solidification structure gradient refinement on the molten steel to prepare a remelted ingot; Performing thermal coupling net near forming and three-dimensional rheological homogenization on the remelted ingot serving as a blank to obtain a forging piece, and performing surface light quantitative cutting-polishing cooperative processing and quantitative stripping of a subsurface damaged layer on the forging piece to obtain a light quantitative surface with the surface roughness Ra less than or equal to 0.08 mu m; Carrying out local laser surface treatment and gradient compressive stress field in-situ construction on the basis of the light polarization surface to form a surface layer with a residual compressive stress peak value of more than or equal to-860 MPa; Carrying out in-situ solidification and heat-force historic memory elimination of the surface stress state on the surface layer, establishing a thermodynamic metastable stress field, and constructing surface energy field reconstruction and adsorption layer directional arrangement before service on the thermodynamic metastable stress field to generate a hydrophobic surface with the surface energy isotropy more than or equal to 0.97; and finishing full-period service state mapping and fatigue impact response pre-calibration based on the hydrophobic surface, and outputting the ultra-high strength steel component with traceable service state.
2. The method for preparing the ultra-high strength steel member with fatigue and impact resistance according to claim 1, wherein the vacuum induction melting and component dynamic cooperative regulation and control comprises the following steps: performing multistage pressure gradient degassing and dynamic oxygen potential control in a vacuum induction furnace to obtain a low-oxygen melt; Performing directional migration enrichment of sulfur and phosphorus elements and slag-metallographic distribution regulation and control on the low-oxygen melt; adding micro-alloy elements into the melt with reduced sulfur and phosphorus elements to realize time-series addition and solute redistribution equalization based on solidification path constraint; and (3) carrying out directional solidification primary blank preparation and central densification on the melt with the microalloy elements added under the cooperation of a multi-scale temperature field to obtain a primary blank with the central density of more than or equal to 99.86%.
3. The method for preparing the ultra-high strength steel member with fatigue and impact resistance according to claim 2, wherein the controlled atmosphere electroslag remelting and solidification structure gradient refinement comprises: taking the primary blank as a consumable electrode, and implementing low-fluorine slag system matching and slag resistivity dynamic compensation control; Under the condition of stabilizing a slag pool, carrying out molten pool form regulation and interface stability enhancement under the coupling of a double-frequency electromagnetic field; according to the stable molten pool form, implementing the regional control of the solidification structure under a radial gradient cooling system; And (3) performing high-temperature homogenization and grain boundary phase dissolution dynamics control on the remelted ingot with the solidification structure controlled, and obtaining the homogenized remelted ingot with the grain boundary phase area fraction less than or equal to 0.023%.
4. A method of producing an ultra high strength steel member having fatigue and impact resistance according to claim 3, wherein the thermally coupled net-shape and three-dimensional rheohomogenization comprises: Carrying out multistage gradient heating on the homogenized remelted ingot, and identifying the dynamic width of an austenite phase region at the same time; carrying out three-way strain tensor equalization and dynamic recrystallization volume fraction regulation and control on the forge piece subjected to metal streamline reconstruction; And (3) implementing a cooling control path after forging on the forging subjected to dynamic recrystallization, and simultaneously inhibiting precipitation of the pre-eutectoid phase, so as to finally obtain the net near-formed forging with the grain size of 18.3 mu m and without the pre-eutectoid phase.
5. The method for manufacturing an ultra-high strength steel member having fatigue and impact resistance according to claim 4, wherein the surface light quantitative cutting-polishing cooperative processing and the quantitative peeling of the subsurface damage layer comprises: Constructing a rigidity matching type high-speed cutting parameter domain for the net near-formed forging piece, and simultaneously implementing cutting force closed-loop inhibition; configuring diamond micropowder particle size gradient distribution on the surface obtained by cutting, and designing an elastic polishing pressure field; for the polished surface, enhancing electrochemical dissolution selectivity in electrolytic-mechanical composite polishing; and (3) carrying out ultrasonic-assisted nano fluid final polishing on the surface subjected to electrolytic treatment, and simultaneously promoting surface energy state homogenization to finally obtain the light-polarized surface with subsurface plastic deformation layer depth less than or equal to 1.2 mu m and surface energy less than or equal to 28.1 mN/m.
6. The method for preparing the ultra-high strength steel member with fatigue and impact resistance according to claim 5, wherein the local laser surface treatment and the in-situ construction of the gradient compressive stress field comprise the following steps: analyzing the absorption characteristics of the light-polarization surface, calculating the heat flux density space-time distribution, and determining a multi-light-spot time sequence overlapping scanning path; calculating the nucleation density of martensite according to the temperature field after heat accumulation, and determining an austenitizing-self-tempering double-stage phase transformation path; according to the tissue characteristics after phase transformation, calculating axial residual stress distribution, and determining laser-induced plastic compression parameters; and (3) calculating the stress relaxation rate by combining the stress distribution gradient, and determining the stress gradient interception and interface stress relaxation inhibition process to finally obtain the stress field without stress inversion.
7. The method for manufacturing an ultra-high strength steel member having fatigue and impact resistance according to claim 6, wherein the in-situ solidification and heat-force history memory elimination of the surface stress state comprises: Implementing a double-temperature-zone stepped thermal cycle system on the compressive stress field, designing a lattice distortion relaxation path, and synchronously loading a micro compressive stress field on the surface of the lattice distortion relaxed surface in a thermal cycle heat preservation stage to realize interface stress redistribution; And (3) carrying out martensitic carbon distribution stabilization on the forge piece with the stress redistribution completed under the constraint of a cooling path, verifying the thermodynamic metastable state of the stress field aiming at the forge piece with the carbon distribution completed, eliminating the history memory effect, and obtaining the thermodynamic metastable state stress field with the stress fluctuation range less than or equal to 0.12%.
8. The method for preparing the ultra-high strength steel member with fatigue and impact resistance according to claim 7, wherein the surface energy field reconstruction and the adsorption layer directional arrangement before service comprise: Hydroxylation pretreatment is carried out on the surface of the thermodynamic metastable stress field to calibrate the density of active sites, and difunctional silane directional grafting is carried out on the hydroxylated surface to strengthen Si-O-Fe bonding; performing epoxy end group closed-loop crosslinking on the surface of the silane grafted to realize isotropy of surface energy; On the surface energy-homogenized component, a nanoscale hydrophobic channel is constructed to form a capillary blocking effect, and a hydrophobic surface with an average pore diameter of 24nm and no capillary condensation occurs at a relative humidity of 60% is obtained.
9. The method for preparing the ultra-high strength steel member with fatigue and impact resistance according to claim 8, wherein the full-cycle service state mapping and the fatigue and impact response pre-calibration comprise: analyzing the state parameters of the hydrophobic surface, calculating the mapping relation between the surface state parameters and the fatigue life, calculating the first-period plastic dissipation work according to the fatigue life mapping relation, and determining the surface state fine tuning parameters; And calculating the sensitivity of parameter drift to fatigue life by combining the surface state after fine adjustment, setting an early warning threshold value, calculating a plurality of equivalent impact response variation coefficients for the components with the early warning threshold value, and verifying the consistency of full-period response.
10. The method for preparing the ultra-high strength steel member with fatigue and impact resistance according to claim 9, wherein the calculating the mapping relation between the surface state parameter and the fatigue life comprises: Collecting historical optimal working condition parameters and corresponding reference fatigue life thereof, and referring to the historical optimal working condition parameters, calculating sensitivity indexes of each surface state parameter to the fatigue life; According to the sensitivity index, a fatigue life prediction expression comprising an index term and an index function term is established, real-time surface state parameters are input into the fatigue life prediction expression, and the fatigue life of a component is calculated; and comparing the fatigue life obtained by calculation with the design requirement, and determining the front calibration parameters of the initial period impact response.

Description

Preparation method of ultra-high strength steel member with fatigue impact resistance Technical Field The invention relates to the technical field of steel members, in particular to a preparation method of an ultra-high strength steel member with anti-fatigue impact performance. Background In the fields of high-end equipment such as aerospace, deep sea engineering, high-speed rail traffic and the like, the ultra-high strength steel member is in long-term service in a severe environment with high stress amplitude and sudden impact load coupling action. The existing mainstream preparation process generally adopts the technical route of conventional smelting, ingot forming, multi-firing forging, tempering heat treatment, finish machining and surface shot peening strengthening. Although the surface compressive stress level can be improved to a certain extent by the method, the method has inherent limitations that residual compressive stress introduced by shot peening depends on plastic deformation of a surface layer, is uneven in distribution and steep in gradient, is easy to be accompanied by surface roughness increase, microcrack initiation, amorphous white layer and other derivative damages, and more importantly, the mechanical induced stress has poor thermal stability, is obviously relaxed under the influence of slight temperature fluctuation in service, and is difficult to maintain effective inhibition of fatigue crack initiation. Therefore, the key technical problems faced by the prior art include incapability of constructing a composite surface state with high amplitude, slow gradient, thermodynamic stability and uniform surface energy on the premise of ensuring ultra-low surface roughness and lossless surface layer structure, and the problems of discrete response, unpredictable fatigue performance and insufficient service reliability of the component under the first-period impact load. Disclosure of Invention The invention aims to provide a preparation method of an ultra-high strength steel member with anti-fatigue impact performance, which eliminates the anisotropy of free energy of a surface and suppresses the preferential adsorption and electrochemical activation tendency of an environmental medium in a stress concentration area through directional reconstruction of a surface energy field of a molecular scale. In order to achieve the purpose, the technical scheme adopted by the invention is that the preparation method of the ultra-high strength steel member with the anti-fatigue impact performance comprises the following steps: obtaining molten steel through vacuum induction melting and ingredient dynamic cooperative regulation, and carrying out controlled atmosphere electroslag remelting and solidification structure gradient refinement on the molten steel to prepare a remelted ingot; Performing thermal coupling net near forming and three-dimensional rheological homogenization on the remelted ingot serving as a blank to obtain a forging piece, and performing surface light quantitative cutting-polishing cooperative processing and quantitative stripping of a subsurface damaged layer on the forging piece to obtain a light quantitative surface with the surface roughness Ra less than or equal to 0.08 mu m; Carrying out local laser surface treatment and gradient compressive stress field in-situ construction on the basis of the light polarization surface to form a surface layer with a residual compressive stress peak value of more than or equal to-860 MPa; Carrying out in-situ solidification and heat-force historic memory elimination of the surface stress state on the surface layer, establishing a thermodynamic metastable stress field, and constructing surface energy field reconstruction and adsorption layer directional arrangement before service on the thermodynamic metastable stress field to generate a hydrophobic surface with the surface energy isotropy more than or equal to 0.97; and finishing full-period service state mapping and fatigue impact response pre-calibration based on the hydrophobic surface, and outputting the ultra-high strength steel component with traceable service state. Preferably, the vacuum induction smelting and the dynamic cooperative component regulation and control comprise: performing multistage pressure gradient degassing and dynamic oxygen potential control in a vacuum induction furnace to obtain a low-oxygen melt; Performing directional migration enrichment of sulfur and phosphorus elements and slag-metallographic distribution regulation and control on the low-oxygen melt; adding micro-alloy elements into the melt with reduced sulfur and phosphorus elements to realize time-series addition and solute redistribution equalization based on solidification path constraint; and (3) carrying out directional solidification primary blank preparation and central densification on the melt with the microalloy elements added under the cooperation of a multi-scale temperature field to obtain