Electromagnetic forming (EMF) is a high strain-rate forming method where a pulsed electromagnetic force is applied to a conductive metallic workpiece. To improve the performance of the EMF system, the current problems which restrict its extensive application have been analyzed. To this end, a space-time-controlled EMF technology with multi-stage and multi-direction coils system has been developed. In our new EMF system, the magnetic field generated by driving coils is much higher than in conventional EMF due to introducing design methods developed for non-destructive pulsed high field magnets. This technology enables the forming of complex, large-scale sheets and tubes that may be difficult to deform by conventional methods, as well as controlling particular properties of the work pieces.

Space-Time-Controlled Multi-Stage Pulsed Magnetic Field Forming

High-strength 7075 aluminum alloy is widely used in the aerospace industry. The forming performance of 7075 aluminum alloy is poor at room temperature. Therefore, hot forming is mainly adopted. Electromagnetic forming is a high-speed forming technology that can significantly improve the forming limit of difficult-to-deform materials. However, there are few studies on electromagnetic hot forming of 7075-T6 aluminum alloy. In this study, the deformation behavior of 7075-T6 aluminum alloy in the temperature range of 25 °C to 400 °C was investigated. As the temperature increased, the sheet forming height first decreased, then increased. When the forming temperature is between 200 °C and 300 °C, η phase coarsening leads to a decrease in stress and hardness of the material. When the forming temperature is between 300 °C and 400 °C, continuous dynamic recrystallization of 7075 aluminum alloy occurs, resulting in grain refinement and an increase in stress and hardness. The results of numerical simulations and experiments all show that the forming height and deformation uniformity of the sheet metal are optimal at 400 °C, compared to 200 °C.

Deformation Behavior and Properties of 7075 Aluminum Alloy under Electromagnetic Hot Forming.

Process optimization and in-mold sensing enabled dimensional prediction for high precision injection molding

The invention belongs to the technical field of high-speed forming of amorphous alloys and discloses a steam explosion impact thermoforming method for an amorphous alloy member. The method comprises steps as follows: copper mold casting for blank making, sheet heating and steam explosion impact thermoforming, wherein an amorphous alloy sheet is obtained by copper mold casting, then the amorphous alloy sheet is uniformly heated by current to reach the set temperature in a supercooling liquid phase area, meanwhile, a loop consisting of a capacitor and aluminum foil is connected, the aluminum foil is enabled to be rapidly vaporized by aluminum foil, and the amorphous alloy is impacted by high pressure produced through instantaneous vaporization of the aluminum foil to press the mold and is enabled to be formed. According to the method, the amorphous alloy can be uniformly heated, heating and deformation time of the amorphous alloy is effectively shortened, the forming property of the amorphous alloy is improved, crystallization and oxidization of the amorphous alloy in heating and forming processes are effectively avoided, meanwhile, the forming quality of the member is good, operation and equipment are simple, and the forming cost is low.

Steam explosion impact thermoforming method for amorphous alloy

The invention discloses a component hydroforming springback accurate compensation method based on liquid volume control, and relates to a metal curved plate forming manufacturing method. According tothe component hydroforming springback accurate compensation method, a plate liquid male die deep drawing forming method is utilized, the difference between the theoretical volume of a target part andthe volume of an actual part after springback is calculated, a die is elastically deformed by adjusting and controlling the volume of injected liquid, the elastic deformation and the springback amountof the die are controlled to be equal, the springback of a curved plate is accurately compensated, and the size of a component meets the design requirement. According to the component hydroforming springback accurate compensation method, a die does not need to be repaired, and springback caused by plate batch changes and die machining errors can be accurately compensated on line in place. According to the component hydroforming springback accurate compensation method, the springback amount compensation is realized by adopting measurable and numerically-controlled liquid volume variation, theadvantages of high compensation precision, simple process, high efficiency, short period and low production cost are achieved, and the requirements of precise springback compensation and high profileprecision control of curved plates in different batches can be met.

Component hydroforming springback accurate compensation method based on liquid volume control

In this paper, a novel electromagnetically activated high-speed hydroforming process (EAHF) is introduced. The EAHF process is compared with the electromagnetic forming process (EMF) in the forming of a low-conductive steel sheet, forming of a high-conductive thin aluminum sheet and also, in the multistage forming of an aluminum sheet. Furthermore, the effect of the process parameters on the EAHF process is investigated by the Taguchi design of experiments. Based on the results it can be concluded that the presented process is an efficient high-speed forming process that can be used for metals and non-metals with low electrical conductivity. This process has more uniform pressure and hence more uniform geometry compared to the EMF process. Furthermore, by a proper design of the process, EAHF can be used for the simultaneous forming and trimming operation.

Electromagnetically activated high-speed hydroforming process: A novel process to overcome the limitations of the electromagnetic forming process

A system and method for hydraulic forming of sheets is provided. A coil is connected to a pulse generator storing electric energy and discharging the electric energy to the coil, creating a first electromagnetic field in the coil. A conductive plate placed on the coil such that the first electromagnetic field causes creating of a second electromagnetic field in the conductive plate, in a direction opposite to the first electromagnetic field, creating a force. A pressure chamber filled with a fluid and placed on the conductive plate. A piston placed inside the pressure chamber to transfer the force to the fluid. A sheet placed on the pressure chamber, the fluid being configured to receive the force from the piston and transfer the force to the sheet. A die placed on the sheet, wherein the force transferred to the sheet from the fluid causes the sheet to take a shape of the die.

High-speed hydraulic forming of metal and non-metal sheets using electromagnetic fields

A high-speed hot forming and direct quenching method and apparatus are disclosed. A first step of the method can comprise various pre-processing steps that can prepare a workpiece for the apparatus. A second step involves a heat-treatment of the workpiece. A third step comprises hot forming the workpiece and primary quenching of the workpiece. A fourth step can comprise a secondary quenching of the workpiece.

High-speed hot forming and direct quenching

A system for universal testing of metal sheet formability is described. The system discloses a cylinder barrel including two pistons for testing formability of the metal sheets. The driving force is provided by the hydraulic pressure of an incompressible fluid. The present application also describes an apparatus to perform various formability tests on metal sheets such as the bulge test, Nakazima test, Marciniak test, cupping test, and the blanking test. The system can also be used in hydroforming metal sheets.

Rasoul Jelokhani Niaraki

Papers

Electromagnetically activated high-speed hydroforming process: A novel process to overcome the limitations of the electromagnetic forming process

High-speed hydraulic forming of metal and non-metal sheets using electromagnetic fields

High-speed hot forming and direct quenching

Apparatus for universal testing of metal sheet formability