A multi-station continuous hot stamping production line, the production line comprising a loading platform (2), a feeding robot (3), a pressure generator set (4, 9, 11), a conveying robot (5), quenching apparatuses (6, 12), a discharging robot (7), and a conveyor belt (8) arranged in sequence; the pressure generator set comprises a heating apparatus, a moulding apparatus, and at least one pressure generator for mounting said moulding apparatus, the heating apparatus being used for heating all or part of a preformed blank (1) to obtain a hot blank, the moulding apparatus being used for stamping and moulding the hot blank and constant pressure shaping, trimming, and punching same to obtain a hot stamped piece. The present production line can continuously implement rapid heating, stamping, constant pressure shaping, trimming, punching, and quenching, increasing heating efficiency, and avoiding a transportation process prior to stamping the hot blank; blanking a steel plate stamping piece at a high temperature avoids the cutting difficulties as a result of producing martensite tissue at room temperature, reducing the blanking force and obtaining a better blanking edge. Also disclosed is a multi-station continuous hot stamping method.

Multi-station continuous hot stamping production line and method

Even though high-strength steel is a favourable material because of its high strength and good formability, this material poses new challenges on the structure of stamping dies owing to potential damages of the die during production. Stamping dies are conventionally produced according to design manuals and standard manufacturing guidelines, where a high safety factor is specified to ensure that the stamping die is heavy and thick. A structural topology optimization method for a stamping die is presented in this study based on finite element simulations of the sheet metal stamping process. The finite element model of the stamping die is first established. Next, the boundary forces acting on the sheet metal are obtained from simulations and these forces are applied to the punch surface by means of load mapping during topology optimization. These forces are equivalent to the interaction between the blank and die. The objective function is to maximize the static stiffness under multi-conditions, which is defined by using the compromise programming approach. The analytic hierarchy process method is used to determine the weight ratio of the body stiffness in various load conditions and conduct topology optimization of the comprehensive objective function. The results show that the weight of the optimal punch is reduced while its performance is improved. More importantly, the reconstructed punch can be manufactured practically.

Structural topology optimization of a stamping die made from high-strength steel sheet metal based on load mapping

The invention relates to a low-pressure thermal forming method for a high-strength or low-plasticity material hollow component. The low-pressure thermal forming method comprises the following steps that a die is prepared; an initial pipe blank is prepared, the initial pipe blank with the proper size is selected, a left sealing punch and a right sealing punch are used for sealing the end portion of the pipe blank, and then the left sealing punch and the right sealing punch move to designated positions together; a left electrode and a right electrode move to make contact with the initial pipe blank, a pressure reducing valve is adjusted, a power switch is closed, an upper die descends, the pipe blank is promoted to be further formed, and internal air pressure is controlled till the die is closed; pressure holding is conducted continuously till the pipe blank is formed; and the power switch is cut off, a cooling medium switch is opened, a cooling medium is led into the pipe blank, the left sealing punch, the right sealing punch, the left electrode and the right electrode retreat till taking-out of the formed component is not affected, the die is opened, and the formed component is taken out. The low-pressure thermal forming method has the beneficial effect that the problems that when an existing device and technology are used for forming the high-strength or low-plasticity hollow component, deformation resistance is high, the wall thickness uniformity of the formed component is poor, the shape accuracy is not high, cracking is likely to happen, efficiency is low, and heat treatment cannot be synchronously conducted are solved.

Low-pressure thermal forming method for high-strength or low-plasticity material hollow component

The invention discloses a current auxiliary heat forming device with flexible clamping adopted. The device comprises a hydraulic system, a gas pressure control system, an upper platform, an upper die, flexible clamping systems, steel and copper composite electrode plates, a lower die and a lower platform. The upper die and the lower die are arranged between the upper platform and the lower platform. The hydraulic system installed on the upper platform controls the upper die to move towards the lower die. The steel and copper composite electrode plates are arranged at the two ends of the lower die, panel blanks are placed on the steel and copper composite electrode plates, and the flexible clamping systems are arranged at the two ends of the panel blanks. Each flexible clamping system comprises a semi-closed structure with one end open and a flexible pipe. The gas pressure control system provides gas pressure for the flexible pipes, the pipes are expanded out from the opening ends, and then the panel blanks are pressed. The forming of panels can be achieved when the dies are under the normal temperature state, the heat loss of the dies in the heating process and the energy needed for heating the dies to the set temperature do not exist, the forming efficiency of metal-based composite materials, titanium alloy, magnesium alloy, aluminum lithium alloy and other material panels hard to deform can be improved, the energy source consumption is reduced, and a very good energy saving effect is achieved.

Current auxiliary heat forming device and method with flexible clamping adopted

The invention provides a heterogeneous material tailor-welded blank hot stamping forming device and method with a controllable temperature field, and relates to a hot stamping forming device and method. The heterogeneous material tailor-welded blank hot stamping forming device and method aim at solving the problems that the hot stamping forming effect of an existing heterogeneous material tailor-welded blank is poor and even hot stamping forming fails. The device is characterized in that two columns of blocking adjustable electrodes and two clamping electrodes are clamped on the upper end face and the lower end face of a heterogeneous material tailor-welded blank, two electrode insulating pressing blocks are arranged on the two columns of blocking adjustable electrodes respectively in a press-fitting mode, two electrode cross-over blocks are cushioned at the lower ends of the two clamping electrodes respectively, the outer end of each blocking adjustable electrode is connected with a thermoregulation rheostat, and the multiple thermoregulation rheostats and a heating power supply form an electrified loop through wires. The method includes the steps that the material of the heterogeneous material tailor-welded blank to be formed is selected; the heterogeneous material tailor-welded blank to be formed is clamped; the heterogeneous material tailor-welded blank to be formed is heated; the heated heterogeneous material tailor-welded blank is stamped. The device and method are used for hot stamping forming of the heterogeneous material tailor-welded blank.

Heterogeneous material tailor-welded blank hot stamping forming device and method with controllable temperature field

The invention relates to a current-assisted titanium alloy bellows hot-forming die and method, relates to a bellows hot-forming tool and method and solves the technical problem that integral heating in the plastic hot-forming process causes heat loss. The tool comprises an argon cylinder, a gas pipe, an axial loading shaft, an axial loading device fixing plate, a gas cylinder, an axial loading sleeve, a sleeve support plate, a bench, a positioning plate, positioning nuts, positioning studs, a sealing device, an electrifying device, a metal die frame, and a ceramic die. The method includes: keeping the temperature of 600-900 DEG C and inner air pressure 0.1-0.5MPa of a pipe billet for 100-250s, assembling the die, keeping the inner air pressure 2.0-3.0MPa of the pipe billet for 200-400s, powering off, relieving air pressure, and cooling to obtain a titanium alloy bellows. The die and method belonging to the field of bellows production have the advantages that heat loss consumed for the die during integral heating in the traditional plastic hot-forming process is avoided.

Current-assisted titanium alloy bellows hot-forming tool and method

The invention discloses a current-assisted rapid hot forming device and method for long and thin high-strength-steel structural components, relates to the technical field of high-strength-steel hot forming, particularly relates to a current-assisted self-resistance heating forming device and method and solves the problems that existing rapid hot forming devices are complicated to energize and existing rapid hot forming methods are applied to materials of low melting points and low hardness. The device comprises a power supply, a die, a pair of sheet clamping electrodes, two cushion blocks and two insulating mica sheets, the power supply, the sheet clamping electrodes and a sheet to be formed form an energized loop, the sheet clamping electrodes and the rest part of the die are insulated, insulation is achieved through the high-temperature-resistant insulating mica sheets, and the sheet to be formed is not in contact with the die. The method comprises that joule resistance heat produced by a current passing the sheet is used for heating the sheet directly, and after the forming temperature is reached, the rapid in-situ stamping forming is conducted. The device and the method are used for manufacturing the high-strength-steel structural components for vehicles.

Liu Shufen

Papers

Current-assisted titanium alloy bellows hot-forming tool and method

Current-assisted rapid hot forming device and method for long and thin high-strength-steel structural components

Auxiliary Current Hot Forming of High-strength Steel for Automobile Parts☆