Line heating board bending forming technology method

Abstract

The invention discloses a line heating board bending forming technology method. According to the technical scheme, a current passes through boards through one electrode and passes through the other electrode to form a loop, the gradient current density is formed in the thickness direction, and the problem that at present, during whole heat treatment of a large-width tailored welding blank, performance cannot be optimum is solved. The method comprises the following steps: firstly, the electrodes make contact with the metal boards, and the boards include a steel board, an aluminum alloy board, high-strength steel and a titanium alloy; secondly, a power source is powered on, the current passes through the metal boards through one electrode and passes through the other electrode to form the loop, and the current density is gradually reduced from top to bottom in the thickness direction; thirdly, the electrodes move relative to the metal boards, and move according to the reserved heating line, and resistance heat is used for locally heating the boards; fourthly, metal is heated to expand to have elastic plastic deformation, and angular deformation is formed; and fifthly, the heated portion is subject to tracking cooling, and in the elastic plastic deformation, elastic deformation is restored to plastic deformation, and angular deformation is reserved.

Description

technical field [0001] The invention relates to the field of advanced manufacturing, in particular to a process method for bending and forming a wire-heated plate. Background technique [0002] At present, the double-curvature bending forming method of medium and thick plates is mainly the water-fire bending process. Usually, heat source is used for wire heating and then rapid water cooling. After the metal plate is partially cooled by high temperature, it will produce local thermal elastic plastic shrinkage deformation, thus forming the required three-dimensional curved surface. At present, the most commonly used heat source for wire heating forming is oxyacetylene flame, which heats the surface of the metal sheet with the flame, and heats the underlying metal through heat conduction. The heating method of oxyacetylene flame has its shortcomings, which are manifested in the following aspects: (1) Low efficiency. During the heating process of the oxyacetylene flame, the he...

AI Technical Summary

Problems solved by technology

The heating method of oxyacetylene flame has its shortcomings, which are manifested in the following aspects: (1) low efficiency

During the heating process of the oxyacetylene flame, the heat is mainly transferred from the surface to the inside of the workpiece through conduction. A large amount of heat is lost to the surrounding air, and the heat absorbed by the metal plate is only 30% to 50%, so the thermal efficiency is very low.

(2) Difficult to control and low precision

In the process of using oxyacetylene flame processing, the stability of air flow pressure and flow rate, the uniformity of the mixing ratio of oxygen and acetylene gas, the distance and angle between the flame nozzle and the metal plate during processing, etc. are not easy to control.

In addition, it is also affected by environmental temperature, humidity and other factors, so it is difficult to use accurate mathematical models for research and calculation in thermal deformation calculation, so it is difficult to carry out precise control in actual processing

(3) Poor safety performance

The use of oxyacetylene flame heating can easily lead to fire or even explosion, and safety issues must be attached great importance to

(4) Large amount of pollutant discharge and poor working environment

Because the flame heating is to heat the surface of the metal plate, the underlying metal is heated through heat conduction, and the temperature of the metal plate surface is too high, which will cause the crystal phase of the metal plate to change, and the overall performance will deteriorate

For high-strength metal sheets, the required deformation cannot be produced at a low temperature, but when the processing temperature exceeds 500°C, the material will change or even crack, and may even cause the metal sheet to be scrapped. Therefore, the difference between the processing temperature and the forming effect There is a contradiction between them, as mentioned in (2), it is very difficult to control this more balanced temperature

(6) The process in the form of oxyacetylene heat source has high labor intensity, high technical difficulty, low processing efficiency and poor quality stability

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