CN-121972906-A - Solid state repair method for ultrathin wall member defects

Abstract

The invention belongs to the technical field of friction stir deposition material increase repair, and particularly relates to a solid state repair method for defects of an ultrathin wall member. The method comprises the steps of preprocessing a defect area of an ultrathin-wall member to be repaired, placing a metal bar into an induction heating coil for induction heating to enable the metal bar to reach an unmelted softened state, rotating the softened metal bar at a rotating speed of 100-1000 rpm, carrying out friction stir repair on the defect area at a feeding speed of 5-50 mm/min to finish defect filling and densification, and carrying out liquid spray or air spray cooling on the repair area. The method can realize the regeneration and performance recovery of the high-quality material in the difficult-to-repair area.

Inventors

• LI YUNPING
• WANG HUI
• LIU XIAOHONG
• LAI RUILIN
• LI YIDI

Assignees

• 中南大学

Dates

Publication Date

20260505

Application Date

20251226

Claims (9)

1. 1. A method for solid state repair of defects in ultra-thin wall components, comprising: pretreating the defect area of the ultrathin-wall member to be repaired, wherein the thickness of the ultrathin-wall member is less than or equal to 4mm; placing the metal bar into an induction heating coil for induction heating to enable the metal bar to reach an unmelted softened state; Rotating the softened metal bar at a rotating speed of 100-1000 rpm, and carrying out friction stir repair at a feeding speed of 5-50 mm/min in a defect area to finish defect filling and densification; And (5) cooling the repair area by liquid spraying or air spraying.
2. 2. The method for solid state repair of defects in ultra-thin wall members according to claim 1, wherein the repair temperature is 0.6 to 0.9 times the melting point temperature of the metal bar at the time of friction stir repair.
3. 3. The method of claim 2, wherein cooling the repair area comprises cooling during friction stir repair or after repair is complete.
4. 4. A method for solid state repair of defects in ultra thin wall structures according to claim 3, wherein the cooling medium in the cooling process is one or more of compressed air, liquid carbon dioxide, liquid nitrogen or water.
5. 5. A method of solid state repair of defects in ultra-thin wall components according to claim 3, wherein the cooling rate during cooling is greater than 50 ℃ per minute.
6. 6. The method for solid state repair of defects in ultra-thin wall members according to claim 1, wherein the robotic arm is used to hold the metal bar for induction heating in an induction heating coil and the robotic arm is used to hold the metal bar for friction stir repair.
7. 7. The method for solid state repair of defects in ultra-thin wall structures according to claim 1, wherein the material of the metal bar is an aluminum alloy, a magnesium alloy or a copper alloy.
8. 8. The method for solid state repair of defects in ultra-thin wall members according to claim 7, wherein the metal bar is an aluminum alloy and the repair temperature is 500 ± 10 ℃.
9. 9. The method for solid state repair of defects of ultra-thin wall members according to claim 1, wherein the pretreatment is to clean the defect area of the ultra-thin wall member to be repaired, and remove surface oxide layers, oil stains and impurities.

Description

Solid state repair method for ultrathin wall member defects Technical Field The invention belongs to the technical field of friction stir deposition material increase repair, and particularly relates to a solid state repair method for defects of an ultrathin wall member. Background With the continuous development of equipment manufacturing industry and automobile industry, the service life of the die and the structural part is continuously prolonged, and the problems of surface defects and damage are increasingly prominent. Taking a steel die commonly used in the field of automobiles as an example, the surface of the die is easy to generate defects such as cracks, abrasion, corner collapse and the like in the long-term service and high-load cyclic use process, and the dimensional accuracy and the service performance of the die are seriously affected. In addition, for some thin-wall structural members (such as engine cases, gearbox shells and the like), defects such as air holes, inclusions, scratches and the like are difficult to avoid in the casting, machining or assembling process, if the integral parts are directly replaced, the cost is high, the production period is long, material waste can be caused, and the requirements of energy conservation, emission reduction and sustainable development in the current manufacturing industry are not met. In view of the above problems, defect repair technology has become an important direction of research and engineering applications in recent years. Traditional repair methods include welding repair, laser cladding, laser additive manufacturing, and other melt-type processes. A common feature of such methods is that the metal is locally melted and solidified by a high energy heat source to achieve material replenishment and bonding. However, the problems of hot cracking, air holes, coarsening of the structure and the like are extremely easy to occur in the solidification process of the molten pool due to the large welding heat input and the high cooling speed. These defects not only weaken the strength and toughness of the repaired area, but also may cause the mechanical properties of the repaired member not to recover to the original level, limiting further popularization in the field of high-performance manufacturing. In recent years, with the development of solid state additive manufacturing technology, a new technology derived from friction stir welding (FSW, friction STIR WELDING), AFSD (additive friction stir deposition), has been proposed. The process realizes plastic flow and deposition of materials under the solid state condition by utilizing a high-speed rotating tool, does not need to be melted, can obviously reduce heat input, avoids the common hot cracking and pore problems in the traditional melting method, and is considered as an efficient and low-heat-influence solid state repair and material adding method. In recent years, researchers have attempted to apply AFSD technology to surface repair and remanufacturing of lightweight alloy components such as aluminum alloys, magnesium alloys, and the like. However, a significant problem with existing AFSD technology in the field of defect repair is excessive process effort. Upsetting force in the AFSD process is usually in tons (often more than 3 tons), and when the upsetting force is used for repairing defects of a thin-wall structural member, the upsetting force is easy to cause bending, deformation or instability of the workpiece, so that the dimensional accuracy and mechanical properties of the structural member are affected. Disclosure of Invention The invention aims to solve the technical problems and overcome the defects and shortcomings in the background art, and provides a solid state repair method for realizing the regeneration and performance recovery of high-quality materials in areas difficult to repair. In order to solve the technical problems, the technical scheme provided by the invention is that the solid-state repair method for the defects of the ultrathin wall member comprises the following steps: pretreating the defect area of the ultrathin-wall member to be repaired, wherein the thickness of the ultrathin-wall member is less than or equal to 4mm; placing the metal bar into an induction heating coil for induction heating to enable the metal bar to reach an unmelted softened state; Rotating the softened metal bar at a rotating speed of 100-1000 rpm, and carrying out friction stir repair at a feeding speed of 5-50 mm/min in a defect area to finish defect filling and densification; And (5) cooling the repair area by liquid spraying or air spraying. In one embodiment, during friction stir repair, the repair temperature is 0.6 to 0.9 times the melting point temperature of the metal bar. In one embodiment, the cooling of the repair area includes cooling during friction stir repair or after repair is complete. In one embodiment, the cooling medium of the cooling process is one or more of compres