CN101380654B - Deep drawing method of magnesium alloy tailor welded blanks - Google Patents

Abstract

The invention discloses a deepening and shaping method for a Mg-alloy tailor-welded blank which includes the following technique flows: 1) preparing a blank material: a lubricant is coated on the blank material of the Mg-alloy tailor-welded blank; 2) preheating a die: the die is heated to a preset temperature and the blank material is put in the die after the temperature detected by a thermoelectric couple reaches a preset value; the blank material is heated together with the die; 3) heating the blank material: after the blank material and the die are heated together for 5 to 10 minutes, deepening and shaping is prepared; 4) deepening and shaping: the deepening and shaping speed is controlled in a preset range and deepening and shaping is carried out; 5) finishing the deepening and shaping, after the deepening and shaping is finished, a workpiece is taken out. The method realizes the uniform deformation during the deepening and shaping process of the Mg-alloy tailor-welded blank, avoids the defects of cracking or serious deviation of a welding line and improves the product quality; a deepening and shaping device for the Mg-alloy tailor-welded blank can lead the blank material to realize grads temperature field distribution; besides, the temperature control method is simple which can realize different temperature grads fields only by changing the number and distribution of heating rods.

Description

A method for deep drawing of magnesium alloy tailor welded blanks

technical field

The patent of the invention relates to a method for deep-drawing of magnesium alloy tailor-welded blanks, and also a method for controlling the movement of weld seams during deep-drawing of magnesium alloy tailor-welded blanks, that is, using gradient temperature field to control the drawing deformation of magnesium alloy tailor-welded blanks Uniformity.

Background technique

Magnesium alloy is very suitable for portable electronic and electrical communication equipment due to its low density and good electromagnetic shielding properties. Control and reduce the harm to the human body.

Magnesium alloy, as a light weight, strong and tough material with good rigidity, is used in aviation, spacecraft and missiles, which can increase the payload and flight distance, and reduce the service cycle and cost. Therefore, it began to be used in aviation equipment and other fields as early as World War II. For example, magnesium alloy pipe fittings can be used for aircraft inner frame structural components.

In addition, due to its low density, impact resistance and aesthetics, magnesium alloys are widely used in sports equipment, office appliances, household tools and other portable products. Magnesium alloy structural materials have many applications in automobiles, aerospace, electronic and electrical components, sports, office and daily necessities. Such as electronic and electrical components: laptop casings, printer boards, small and medium hard disks. Others include mobile phone shells, camera shells, camera frames, magnesium alloy sacrificial anodes

At present, the processing methods of the above products are all processed by die casting. Disadvantages of the die-casting method: the strength and rigidity of the die-casting parts are low, and the density is small (not conducive to the electronic shielding effect).

In order to process high-strength, high-rigidity magnesium alloy shell-shaped parts, a new magnesium alloy plastic processing technology must be developed to meet industrial needs. If the magnesium alloy shell-shaped parts are formed by sheet metal stamping technology, the above requirements can be met, and both the strength and rigidity can meet the requirements. However, magnesium alloys have poor plasticity at room temperature, are prone to brittle cracks, and are difficult to perform plastic forming processing; according to data, magnesium alloys are prone to brittle cracks at room temperature and are difficult to perform plastic forming processing; when magnesium alloys are formed above 200 ° C, the plasticity improves significantly. . Magnesium alloys have high plasticity in the hot state, and can be deformed even under unfavorable stress-strain conditions, but the deformation speed cannot be too large.

Magnesium alloy (MB2) deforms when the deformation speed is low, and the deformation temperature has the highest plasticity in the range of 350-450 °C; when the deformation speed is high, the deformation temperature range is reduced to 350-425 °C. Since the magnesium alloy is extremely sensitive to the deformation speed, the deformation speed cannot be too large. The allowable degree of deformation during dynamic deformation is not more than 40%. During static deformation, the plasticity increases significantly, and the degree of deformation can reach more than 80% without brittle state.

Contents of the invention

The purpose of the patent of the present invention is to provide a method and device that can realize the deep drawing of a magnesium alloy tailor welded blank, control the movement of the weld seam of the tailor welded blank, and improve the quality of the workpiece.

The technical solutions adopted are:

A magnesium alloy tailored welded blank drawing forming device, comprising an upper template, a drawing punch fixing plate, a drawing punch, a blank holder, a blank, a drawing die, a heating plate, and a lower template, wherein the heating plate is located in the drawing The bottom of the deep die is the key component to realize the gradient temperature field. A plurality of electric heating rods are respectively inserted into the drawing die and the pressure ring.

A method for deep drawing of magnesium alloy tailor welded blanks, characterized by the following processes:

1) Blank preparation: Magnesium alloy tailor-welded blanks are made, and magnesium alloy tailor-welded blanks are coated with lubricant

2) Mold preheating: the mold is heated to the predetermined temperature, and when the temperature measured by the thermocouple installed in the mold reaches the predetermined value, the blank is put in, and the blank is heated together with the mold;

3) Blank heating: when the blank is heated together with the mold for 5 to 10 minutes, deep drawing begins;

4) Deep drawing: the drawing speed is controlled within the predetermined range, and the deep drawing starts;

5) End of forming: After drawing and forming, exit the workpiece.

The basic principle of the invention patent: for magnesium alloy tailor welded blanks with different strengths, since the plates are welded together by two parts with different strengths, if a uniform temperature field is used during drawing forming, on the tailor welded blank blanks, due to The distribution of yield stress is uneven, so that the deformation of the high-strength part of the plate is smaller than that of the low-strength part, which will inevitably cause uneven deformation, easy to cause cracks or serious weld deviation, and affect product quality. If a gradient temperature field is used, that is, the temperature of the high-strength material part is higher than that of the low-strength material part, the yield stress distribution on the tailor-welded blank blank tends to be uniform, so that the plastic properties of the high-strength sheet and low-strength sheet are close, so that the degree of deformation is uniform , to avoid defects such as cracks or weld offsets, and improve product quality. Therefore, the use of gradient temperature field is one of the effective methods to realize the uniform deformation of magnesium alloy tailor welded blanks, control the movement of weld seams of tailor welded blanks, and improve the quality of workpieces.

The technical scheme of the patent of the present invention: the gradient temperature field is used to control the uniformity of the deformation of the tailor-welded blank, that is, when the magnesium alloy tailor-welded blank is deep-drawn, the predetermined temperature is realized by changing the number and distribution of the electric heating rods in the heating plate Gradient field, so that the degree of deformation tends to be uniform, avoiding the defects of cracking or serious offset of weld seam, and improving product quality.

The invention patent has the following advantages:

1. The gradient temperature field is used to make the distribution of yield stress in the deformation zone of magnesium alloy tailor welded blanks tend to be uniform, so that uniform deformation can be realized, and the deep drawing and forming of magnesium alloy tailor welded blanks can be carried out stably;

2. The gradient temperature field is used to realize the uniform deformation of the magnesium alloy tailor-welded blank during the deep-drawing forming process, avoiding the defects of cracking or serious weld seam offset, and improving the product quality;

3. Magnesium alloy tailored welded blank drawing forming device can make the blank realize the gradient temperature field distribution, and the temperature control method is simple, as long as the number and distribution of heating rods are changed, different gradient temperature fields can be realized;

4. The invention patent is suitable for stamping and forming of tailor-welded blanks with different thicknesses or different strengths.

Description of drawings

Fig. 1 is a schematic structural diagram of a magnesium alloy tailor welded blank deep drawing device.

Figure 2 is a schematic diagram of the structure of the heating plate.

Fig. 3 is a B-B sectional view of Fig. 1 .

Detailed ways

A magnesium alloy tailored welded blank drawing forming device according to the present invention comprises an upper template 1, a drawing punch fixing plate 2, a drawing punch 3, a blank holder 4, a blank 5, a drawing die 6, and a heating plate 7. The lower template 8, wherein the heating plate 7 is located below the drawing die 6, and a plurality of electric heating rods 9 are respectively inserted on the drawing die 6 and the blank holder 4. The device of the present invention has been disclosed and authorized, and the patent No. is ZL02144943.0, so the structure of the device is no longer described.

A method for deep drawing of magnesium alloy tailor welded blanks, comprising the following operations:

The deep drawing of AZ31 and AZ80 magnesium alloy tailored welded blanks is taken as an example to illustrate. Operation steps for deep drawing of AZ31 and AZ80 magnesium alloy tailored welded blanks:

1) Blank preparation: the blank is welded, and the magnesium alloy tailor welded blank blank is coated with lubricant;

2) Mold preheating: heat the mold to the predetermined temperature, and when the temperature measured by thermocouple 1 and 2 reaches the predetermined value, that is, when the temperature of the AZ31 plate part is 120-150 ° C, and the temperature of the AZ80 plate part is 190-210 ° C, magnesium The alloy tailor welded blank is put into the blank 5, and the blank is heated together with the mold;

3) Blank heating: when the blank is heated together with the mold for 5 to 10 minutes, deep drawing begins;

4) Deep drawing and forming: the drawing speed is controlled at 0.5-2mm/s for deep drawing and forming;

5) End of forming: After drawing and forming, exit the workpiece.

Table 1 Process parameters of magnesium alloy tailor welded blank deep drawing

Claims (2)

1. deep drawing method of magnesium alloy tailor welded blanks: its feature comprises following technical process: 1) blank is prepared, and magnesium alloy is welded the slab material apply lubricant; 2) mould and die preheating to predetermined temperature, when the temperature that records by the thermocouple that is arranged in the mould reaches predetermined value, is put into blank with mold heated, and blank heats with mould; 3) blank heating, blank heated 5-10 minute with mould after, prepare to begin to carry out drawing and forming; 4) drawing and forming, pull and stretch speed is controlled in the preset range, and drawing and forming begins; 5) shaping finishes, and after drawing and forming finishes, withdraws from workpiece; By the field distribution of control gradient temperature the deformed area yield stress is distributed and be tending towards evenly, thereby realized homogeneous deformation, and make stable the carrying out of magnesium alloy welding plate drawing and forming.

2. according to the described a kind of deep drawing method of magnesium alloy tailor welded blanks of claim 1, it is characterized in that: the gradient temperature field is controlled the thermograde value of blank both sides by the quantity that changes electrically heated rod with distributing.

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