A kind of deep drawing method of magnesium alloy tailor welded blanks
Technical field
Patent of the present invention relates to a kind of deep drawing method of magnesium alloy tailor welded blanks, simultaneously also is a kind of method of weld movement when controlling magnesium alloy welding plate drawing and forming, promptly adopts gradient temperature field control magnesium alloy welding plate deep-drawing deformation uniformity.
Background technology
Magnesium alloy is because the little and good electromagnetic wave shielding of its density, be highly suitable for portable electronic electrical equipment Communication Equipment, when for example mobile phone shell adopts magnesium alloy, electromagnetic wave only receives and sends by antenna, reduced the loss of signal, improved communication quality, also be easy to control and reduce injury human body.
Magnesium alloy is used for Aeronautics and Astronautics device, guided missile as the obdurability material of light weight, good rigidly, can increase payload and flying distance, reduces life cycle and cost.Therefore during World War II, just begin to be applied to fields such as air material.For example aircraft inner frame quasi-structure component can be used magnesium alloy tube.
In addition, owing to characteristics such as density are little, shock-resistant and attractive in appearance, magnesium alloy is widely used in portable articles for use such as sports equipment, office furniture, family's instrument etc.The Structure of magnesium alloy material has a lot of application at aspects such as automobile, Aero-Space, electronic apparatus parts, physical culture, office and daily living articles.As the electronic apparatus parts: smallclothes in notebook computer casing, printer plate, the hard disk.Other also has mobile phone shell, shooting casing, camera frame, sacrificial magnesium alloy anode
At present, the processing method of above product all adopts casting die to process.The shortcoming that casting die exists: the strength and stiffness of die casting are low, density is little (being unfavorable for ELECTRONIC SCREENING EFFECT IN).
In order to process the magnesium alloy hull shape spare of high strength, high rigidity, must develop a kind of new magnesium alloy Technology of Plastic Processing, to satisfy industrial needs.If adopt plate stamping technology shaping magnesium alloy hull shape spare, just can satisfy above-mentioned requirements, strength and stiffness all can reach requirement.But magnesium alloy plasticity at room temperature is very poor, and embrittlement easily is difficult to carry out Plastic Forming processing; Data is introduced, and easy embrittlement under the magnesium alloy normal temperature is difficult to carry out Plastic Forming processing; Magnesium alloy is when being shaped more than 200 ℃, and plasticity improves obviously.Magnesium alloy has than high-ductility under hot, even also can be out of shape under disadvantageous stress-strain state, but deformation velocity can not be too big.
Magnesium alloy (MB2) distortion when deformation velocity is low, deformation temperature plasticity in 350~450 ℃ scope is the highest; When distortion when deformation velocity is higher, the deformation temperature scope is reduced into 350~425 ℃.Because magnesium alloy is very responsive to deformation velocity, deformation velocity can not be too big.Permission deformation extent during dynamic deformation is not more than 40%.When quiet distortion, plasticity obviously increases, and deformation extent can reach more than 80% and brittle state not occur.
Summary of the invention
The purpose of patent of the present invention provides a kind of magnesium alloy of can realizing and welds the plate drawing and forming, and can control the welding plate welding seams and move, improve workpiece method for quality and device.
The technical scheme that adopts is:
A kind of magnesium alloy welding plate drawing and forming device, comprise cope match-plate pattern, pull and stretch punch retainer, pull and stretch punch, blank holder, blank, pull and stretch die, heating plate, lower bolster, wherein heating plate is positioned at the below of pull and stretch die, is the critical component of realizing the gradient temperature field.Be inserted with a plurality of electrically heated rods on stretching die and the pressure coil respectively.
A kind of deep drawing method of magnesium alloy tailor welded blanks, its feature comprises following technical process:
1) blank is prepared: magnesium alloy welding plate is made, and magnesium alloy is welded the slab material apply lubricant
2) mould and die preheating: mold heated to predetermined temperature, when the temperature that records by the thermocouple that is arranged in the mould reaches predetermined value, is put into blank, and blank heats with mould;
3) blank heating: after blank heats 5~10 minutes with mould, 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: after drawing and forming finishes, withdraw from workpiece.
The basic principle of patent of the present invention: for the magnesium alloy welding plate of varying strength, because sheet material is welded together by the different two parts of intensity, therefore when drawing and forming, if the employing homogeneous temperature field is on welding slab material, because the yield stress skewness, the sheet deformation amount of high strength part is less than the sheet material of low-intensity part like this, must cause that distortion is inhomogeneous, easy generation is broken or weld seam is offset seriously, influences product quality.If adopt the gradient temperature field, be that the high-strength material portion temperature is higher than the low-intensity material part, yield stress on the welding slab material distributes and is tending towards even like this, the plastic property of high-strength panel and low-strength board is approaching like this, make deformation extent even, avoided producing and broken or defective such as weld seam skew, improved product quality.Therefore adopting the gradient temperature field is to realize the homogeneous deformation of magnesium alloy welding plate drawing and forming, and can control the welding plate welding seams and move, improve one of effective ways of workpiece quality.
The technical scheme of patent of the present invention: the uniformity that adopts the distortion of gradient temperature field control welding plate, promptly when magnesium alloy welding plate drawing and forming, by changing the quantity and the distribution of electrically heated rod in the heating plate, realize the temperature gradient field be scheduled to, thereby make deformation extent be tending towards even, avoid the defective that generation is broken or the weld seam skew is serious, improved product quality.
Patent of the present invention has following advantage:
1, adopts the gradient temperature field, make the yield stress distribution of magnesium alloy welding plate drawing and forming deformed area be tending towards evenly can realizing homogeneous deformation, and realize stable the carrying out of magnesium alloy welding plate drawing and forming;
2, adopt the gradient temperature field, realized the homogeneous deformation of magnesium alloy welding plate drawing and forming process, avoided the defective that generation is broken or the weld seam skew is serious, improved product quality;
3, magnesium alloy welding plate drawing and forming device can make blank realize the gradient temperature field distribution, and temperature-controlled process is simple, as long as change the quantity and the distribution of heating rod, just can realize different gradient temperatures field;
4, patent of the present invention is suitable for the welding plate stamping and forming of different-thickness or varying strength.
Description of drawings
Fig. 1 is the structural representation of magnesium alloy welding plate drawing and forming device.
Fig. 2 is the heating board structure schematic diagram.
Fig. 3 is the B-B cutaway view of Fig. 1.
The specific embodiment
A kind of magnesium alloy welding plate drawing and forming device of the present invention, comprise cope match-plate pattern 1, pull and stretch punch retainer 2, pull and stretch punch 3, blank holder 4, blank 5, pull and stretch die 6, heating plate 7, lower bolster 8, wherein heating plate 7 is positioned at the below of pull and stretch die 6, is inserted with a plurality of electrically heated rods 9 on pull and stretch die 6 and the blank holder 4 respectively.Device of the present invention is open, and has authorized, and the patent No. is ZL02144943.0, so no longer the structure of this device is narrated.
A kind of deep drawing method of magnesium alloy tailor welded blanks comprises following operating process:
With AZ31 and AZ80 magnesium alloy welding plate drawing and forming is that example describes.Weld plate drawing and forming operating procedure at AZ31 and AZ80 magnesium alloy:
1) blank is prepared: blank welds, and magnesium alloy is welded slab material coating lubricant;
2) mould and die preheating: mold heated is arrived predetermined temperature, when treating that temperature that thermocouple 1 and 2 records reaches predetermined value, promptly when 120-150 ℃ of AZ31 sheet material portion temperature, during 190-210 ℃ of AZ80 sheet material portion temperature, magnesium alloy welding plate is put into blank 5, and blank heats with mould;
3) blank heating: after blank heats 5~10 minutes with mould, begin to carry out drawing and forming;
4) drawing and forming: pull and stretch speed is controlled at 0.5~2mm/s, carries out drawing and forming;
5) shaping finishes: after drawing and forming finishes, withdraw from workpiece.
Table 1 magnesium alloy welding plate drawing and forming technological parameter