CN104818441B - Process compound bending deformation device and the processing method thereof of welding point - Google Patents
Process compound bending deformation device and the processing method thereof of welding point Download PDFInfo
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Abstract
The present invention provides a kind of compound bending deformation device processing welding point and processing method thereof, including the heating and heat-insulating device set gradually, send plate roller group, some to bend roller group with rolling roller group and run through described heat-insulation layer, send plate roller group, bend roller group and the passage of rolling roller group, described passage is divided into horizontal segment and bend section, described heating and heat-insulating device, plate roller group and rolling roller group is sent to be placed at described horizontal segment, described bend roller group is placed at described bend section, described bend section includes several concave curved surfaces being arranged alternately and convex surface, described bend roller group includes bend roller group and lower bend roller group, described upper bend roller group is placed at described convex surface, described lower bend roller group is placed at described concave curved surface.The weld seam that can make welding point obtains certain extension, can reduce residual stress, can be particularly suitable for, with crystal grain thinning, the welding point that mechanical property is relatively low simultaneously.
Description
Technical field
The invention belongs to welding procedure field, process the double of welding point in particular it relates to a kind of
To flexural deformation device and processing method thereof.
Background technology
Welding is mild alloy product, the key technology of processing that particularly magnesium-alloy material manufactures, but
Magnesium alloy welding performance is bad, is difficulty with being reliably connected.For this magnesium alloy structural part and magnesium
Connection between alloy and other material structure part, becomes the technical bottleneck of restriction magnesium alloy application
With one of key technology urgently to be resolved hurrily.The reliability of magnesium alloy weld joint has become its application
Pressing issues, current magnesium alloy is being applied to the manufacture of numerous load-carrying construction part, such as automobile
Magnesium alloy frame of handwheel, dynamical system automatic gear-box, the oil end, magnesium-alloy tube in manufacturing industry
Material automobile chassis etc..The strength of welded joint of these load-carrying construction parts, plasticity and fatigue behaviour etc.
Problem is the most basic of product safety reliability and most important evaluation index.Data shows,
In the inefficacy of magnesium alloy welding structure, many accidents are owing to the fracture of welding point causes
's.In practical engineering application, many Welding Structures are all to be on active service under the dynamic loading of alternation,
Now iff static load tensile strength or the yield strength considering welding point, then welding knot
Structure is easy to during normal service just occur failure fracture, causes bigger engineering accident, institute
Must take into full account welding point fatigue strength under alternate load when structure designs
Can, and for magnesium alloy welding structure, fatigue fracture is also a kind of main shape that it lost efficacy
Formula, fatigue crack the Welding Structure failure fracture accident caused accounts for the 80% of total fracture accident
Above.Magnesium alloy welding structure can be by various vibrations, pulsating load or friendship in engineer applied
The effect of varying load, security and the threat of working life that these load are used for are very big,
Fatigue crack forming core and the micro-crack extension of structure, particularly magnesium alloy joint made by flame welding can be caused.
Due to feature and the physical and chemical performance of magnesium alloy self of technique for welding itself, cause magnesium
Alloy welding point has the disadvantage in that
1. the discontinuity of joints, certainly will cause reinforcement to have stress collection with the intersection of mother metal
Middle phenomenon；
2. the discontinuity of joint microstructure, the heat affected area grain structure of magnesium alloy joint compares weld seam
Thick with the tissue of mother metal, the uneven microstructure of whole joint, discontinuous；
3. due to the shrinkage of weld metal, can produce residual stress near joints, reduction connects
The mechanical property of head；
4. joint has weld defect, owing to the chemical property of magnesium alloy is active, in welding process not
The evitable weld defect such as pore, slag inclusion that has occurs；
5. joint appearance out-of-flatness, unsightly.
In Welding Technology of Magnesium Alloy, solve its welding point obdurability, be to ensure that magnesium alloy welds
One necessary condition of access node structure application.Studied at present have employed different welding methods and
Means eliminate or weaken the disadvantages mentioned above of magnesium alloy weld joint, but these methods are to above-mentioned
The resolution ability of problem is very limited.Due to magnesium alloy have high thermal conductivity, the big coefficient of expansion,
The characteristics such as lower fusing point and boiling point so that be easily generated overheated group in magnesium alloy weld seam Ji Jinfeng district
Knitting and coarse grains, this coarse grain can directly affect the mechanical property of joint, and magnesium can also be with
The strong chemical combination of nitrogen in air forms fragility nitride, reduces the mechanical property of joint.
Summary of the invention
The present invention is to solve drawbacks described above and deficiency present in prior art, it is provided that a kind of
Process compound bending deformation device and the processing method thereof of welding point, welding point can be made
Weld seam obtains certain extension, can reduce residual stress, simultaneously can be with crystal grain thinning, significantly
Improve intensity and the plasticity of welding point, and then improve the fatigue behaviour of welding point, especially
It is suitable for the welding point that mechanical property is relatively low.
For solving above-mentioned technical problem, the present invention provides a kind of compound bending processing welding point
Deformation device, including the heating and heat-insulating device set gradually, send plate roller group, some to bend
Roller group and rolling roller group and run through described heat-insulation layer, send plate roller group, bend roller group
With the passage of rolling roller group, described passage is divided into horizontal segment and bend section, described heating and thermal insulation
Device, send plate roller group and rolling roller group be placed at described horizontal segment, described bend roller group
Being placed at described bend section, described bend section includes several concave curved surfaces being arranged alternately and convex song
Face, described bend roller group includes bend roller group and lower bend roller group, described upper bend
Roller group is placed at described convex surface, and described lower bend roller group is placed at described concave curved surface.
Preferably, summit and the described horizontal segment of described convex surface flushes.
Preferably, the vertical range between summit and the summit of described concave curved surface of described convex surface
For 3-10mm.
Preferably, the vertical range between summit and the summit of described concave curved surface of described convex surface
For 5mm.
Preferably, the roller of described bend roller group is hollow, and the inside is provided with heater.
Preferably, described heater is resistor rod.
The method utilizing compound bending deformation device to process welding point, comprises the following steps:
Step one, uses tungsten level argon arc welding to carry out motherboard to welding, obtains the weldering of welding defect
Joint；
Step 2, welding point is flowed slowly over heating and heat-insulating device by the horizontal segment utilizing passage,
Temperature in described heating and heat-insulating device is 150-200 DEG C, and welding point fills through heating and thermal insulation
The speed put is 2.0-3.0mm/s；
Step 3, in heating and heat-insulating device, welding point out is in the effect sending plate roller group
The bending section of lower entrance passage, is made welding point produce gradient by bending section bend roller group effect
Crystal grain, finally is carried out rolling sizing by rolling roller group, described in send the pressure at plate roller group to be
50-100MPa, the pressure at described rolling roller group is 0-100MPa.
Preferably, described bending section includes several convex surfaces being arranged alternately and concave curved surface.
Preferably, it is provided with bend roller group at described convex surface, is provided with down at described concave curved surface
Bend roller group.
Preferably, the vertical range between summit and the summit of described concave curved surface of described convex surface
For 5mm.
The Advantageous Effects that the present invention is reached:
1. joint is suppressed level, eliminate discontinuity and the stress concentration phenomenon of profile, real
Existing weld seam is to mother metal gentle transition；
2. compound bending is deformed by multidirectional compression, in joint accumulation twinning deformation,
Produce twin, along with the increase of bending passage, ultimately form upper and lower surface twin density big, in
Between the little symmetric gradient tissue of density；
3. use compound bending deformation that the weld metal of contraction can be made to obtain to extend, can correct
Deforming and regulate the distribution of internal stress, the weld seam local heat treatmet before bending, can eliminate simultaneously
Welding residual stress；
4. compound bending deformation can weaken or eliminate the defect such as pore, slag inclusion；
5. after compound bending deformation, then through compacting roller group, joint can be made smooth attractive in appearance.
Accompanying drawing explanation
Fig. 1 compound bending deformation device structural representation；
Fig. 2 processes after compound bending deformation device processes and without compound bending deformation device
Magnesium alloy weld joint metallographic structure contrast picture；
Fig. 3 mother metal, welding point, the power of welding point that processes through compound bending deformation device
Learn performance curve collection of illustrative plates.
Detailed description of the invention
In order to auditor can be better understood by the technical characteristic of the present invention, technology contents and reaches
Technique effect, existing the accompanying drawing of the present invention is described in detail in conjunction with the embodiments.But,
Shown accompanying drawing, is intended merely to better illustrate technical scheme, is not the present invention's
Actual proportions and best configuration, so, ask auditor not with regard to ratio and the configuration of accompanying drawing, limit
The claims of the present invention processed.
With embodiment, patent of the present invention is further illustrated below in conjunction with the accompanying drawings.
As it is shown in figure 1, the present invention provides a kind of compound bending deformation dress processing welding point
Put, including the heating and heat-insulating device set gradually, send plate roller group, some to bend roller group
With rolling roller group and run through described heat-insulation layer, send plate roller group, bend roller group and rolling
The passage of roller group, described passage is divided into horizontal segment and bend section, described heating and heat-insulating device,
Sending plate roller group and rolling roller group to be placed at described horizontal segment, described bend roller group is placed in institute
Stating at bend section, described bend section includes several concave curved surfaces being arranged alternately and convex surface, institute
State bend roller group and include bend roller group and lower bend roller group, described upper bend roller group
Being placed at described convex surface, described lower bend roller group is placed at described concave curved surface.Described convex song
Summit and the described horizontal segment in face flush.The summit of described convex surface and the summit of described concave curved surface
Between vertical range be 3-10mm.Preferably, the summit of described convex surface and described concave curved
Vertical range between the summit in face is 5mm.The roller of described bend roller group is hollow,
The inside is provided with heater.Preferably, described heater is resistor rod.
The method utilizing compound bending deformation device to process welding point, comprises the following steps:
Step one, uses tungsten level argon arc welding to carry out motherboard to welding, obtains the weldering of welding defect
Joint；
Step 2, welding point is flowed slowly over heating and heat-insulating device by the horizontal segment utilizing passage,
Temperature in described heating and heat-insulating device is 150-200 DEG C, and welding point fills through heating and thermal insulation
The speed put is 2.0-3.0mm/s；
Step 3, in heating and heat-insulating device, welding point out is in the effect sending plate roller group
The bending section of lower entrance passage, is made welding point produce gradient by bending section bend roller group effect
Crystal grain, finally is carried out rolling sizing by rolling roller group, described in send the pressure at plate roller group to be
50-100MPa, the pressure at described rolling roller group is 0-100MPa, states bending section and includes
Several convex surfaces being arranged alternately and concave curved surface.Bend roller it is provided with at described convex surface
Group, is provided with lower bend roller group at described concave curved surface.The summit of described convex surface and described concave curved
Vertical range between the summit in face is 5mm.
In addition, it is necessary to special instruction, the present invention is suitable for processing sheet metal thickness and is less than or equal to
The welding point of 2mm, its principle is to be bent the most up and down by convex surface and concave curved surface,
Make to produce at welding point gradient crystal grain, so that the upper and lower surface crystal grain of welding point is tiny,
Middle crystal grain is slightly larger, the most both ensure that intensity, in turn ensure that plasticity simultaneously.
Embodiment
Present invention is especially suited for the welding point that mechanical property is relatively low, as magnesium alloy weld joint,
Welded joints in aluminium alloy.In order to welding point treatment effect of the present invention is described, the author selects Shandong
The Mg-Al system AZ31 magnesium alloy plate that Yin Guangmei industry Co., Ltd provides is as test mother
Material.
1) raw-material selection
Test plate (panel) a size of 2000mm × 600mm × 2mm, welding material selects the said firm to carry
The AZ31 magnesium alloy solder wire with mother metal homogeneity of confession, specification is φ 3.0mm.Magnesium alloy mother metal
Main chemical compositions and mechanical property see Tables 1 and 2:
The chemical composition (wt.%) of table 1 AZ31 magnesium alloy
The mechanical property of table 2 AZ31 magnesium alloy
2) Welding Method & Equipment are chosen
With 2 pieces of secondary butt welding of sheet material composition 1 of a size of 2000mm × 600mm × 2mm
Test plate (panel).Test piece for welding opens the double V-groove of 60 °, and root gap controls 3～4mm.With
Acetone remove test plate (panel) surface greasy dirt, by within welding region 20-30mm with sand papering extremely
Exposing metallic luster, groove face removes oxide-film through scraping, it is ensured that welding start before to be welded
Region does not has pollutant.Test uses TPS4000 to digitize argon arc welding/soldering multi-functional welding
Equipment carries out manual welding, and tungsten electrode end grinder buffing becomes hemispherical, a diameter of 2.5mm,
Nozzle diameter 7mm, electric arc height 4mm.Front welding 2 layers during welding, back side welding 1
Layer, forms the double welded joint with certain reinforcement.
3) welding point processes
Allow the processing method that welding point provides according to the present invention at compound bending deformation device
Reason, by the two-way alternating bending of convex surface-concave curved surface, carries out the flexural deformation of 6 passages altogether,
One convex surface or a concave curved surface are 1 passage, the wherein temperature of heating and heat-insulating device
150 DEG C～200 DEG C, the pressure sending plate roller group is 100MPa, and the pressure of rolling roller group is
100MPa, sending plate speed is 2mm/s.
4) structure and performance characterization
As in figure 2 it is shown, wherein (a) is that the magnesium alloy welding processed through compound bending deformation device connects
The metallurgical tissue picture of head, (b) is the magnesium alloy welding processed without compound bending deformation device
The metallurgical tissue picture of joint, as seen from the figure, processes through compound bending deformation device
AZ31B magnesium alloy weld joint is after alternating bending deforms, and the little crystal grain in weld metal zone still keeps
Equiax crystal pattern, there is less twinning therein, and in bigger crystal grain,
Occur in that obvious twin phenomenon, and have many twins parallel to each other.Can from figure
Go out, the weld seam surface layer grain after bending is accumulated more twinning deformation, produce at weld seam near surface
The twin of more intersection.Face of weld twin density is relatively big, and volume fraction is substantially saturated,
The little crystal grain generated mainly appears at crystal boundary and twin boundary, and little crystal grain is in being similar to strip row
Row.In bending deformation process, the sliding of little crystal particle crystal boundary has coordinated to deform the deformation of weld metal zone；
Intermediate layer only has a small amount of twin all the time and produces, and it is big or middle that material trends towards forming top layer twin density
The gradient structure that interbed twin density is little.
Fig. 3 mother metal, welding point, the power of welding point that processes through compound bending deformation device
Learn performance curve collection of illustrative plates, as seen from the figure, the welding point after compound bending deformation device processes
Tensile strength up to the tensile strength of 230MPa, AZ31 magnesium alloy (no-welding-seam) mother metal
Measured result is 238MPa, illustrate welding point after compound bending deformation process, tension is strong
Degree has reached the 96.6% of base metals.And the tensile strength of as-welded joint generally 150～
Between 190MPa, only the 60%～75% of base metals tensile strength.It can be considered that
The strength of joint of postwelding compound bending deformation process, already close to the strength level of base metals, connects
Head intensity tool improves significantly.From the point of view of the percentage elongation of tension test, as-welded joint
Percentage elongation is between 6%～8%, and the joint percentage elongation after compound bending deformation generally exists
Between 11%～16%.
In sum, AZ31 magnesium alloy TIG welding weldering after compound bending deformation device processes
The various mechanical performance indexs of joint are superior to as-welded joint, and the high temperature of two-way alternating bending moves
State be plastically deformed promote the internal hardening constituent of nonequilibrium freezing welding joint structure disperse educt and
Welding point supersaturation alloying element homogenization diffusion, makes the intensity of magnesium alloy weld joint and moulds
Property is superior to as-welded joint, close to mother metal performance.The fracture location of magnesium alloy joint made by flame welding is main
Occur in heat affected area, be also the portion that phenomenon of rupture often occurs near the fusion area of heat affected area
Position.The reduction of joint performance is main and heat affected area Grain Boundary Melting Down, grain coarsening and brittlement phase
β-Mg17Al12Distribution along crystal boundary is relevant.
Below disclose the present invention with preferably embodiment, so itself and be not used to limit this
Bright, that all schemes taking equivalent or equivalent transformation are obtained technical scheme, all falls within this
In the protection domain of invention.
Claims (1)
1. utilize the method that compound bending deformation device processes magnesium alloy weld joint, the most two-way
Flexural deformation device includes the heating and heat-insulating device set gradually, send plate roller group, some to curved
Road roller group and rolling roller group and run through described heating and heat-insulating device, send plate roller group, curved
Road roller group and the passage of rolling roller group, described passage is divided into horizontal segment and bend section, described
Heating and heat-insulating device, send plate roller group and rolling roller group be placed at described horizontal segment, described curved
Road roller group is placed at described bend section, and described bend section includes several concave curveds being arranged alternately
Face and convex surface, described bend roller group includes bend roller group and lower bend roller group, institute
Stating bend roller group and be placed at described convex surface, described lower bend roller group is placed in described concave curved
At face, summit and the described horizontal segment of described convex surface flush, the summit of described convex surface and institute
Stating the vertical range between the summit of concave curved surface is 5mm, and the roller of described bend roller group is
Hollow, the inside is provided with heater, it is characterised in that: the method comprises the following steps:
Step one, uses tungsten level argon arc welding to carry out magnesium alloy motherboard to welding, obtains welding
Defect welding point；
Step 2, welding point is flowed slowly over heating and heat-insulating device by the horizontal segment utilizing passage,
Temperature in described heating and heat-insulating device is 150-200 DEG C, and welding point fills through heating and thermal insulation
The speed put is 2.0-3.0mm/s；
Step 3, in heating and heat-insulating device, welding point out is in the effect sending plate roller group
The bending section of lower entrance passage, is made welding point produce gradient by bending section bend roller group effect
Crystal grain, finally is carried out rolling sizing by rolling roller group, described in send the pressure at plate roller group to be
100MPa, the pressure at described rolling roller group is 100MPa.
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| CN105642714B (en) * | 2016-01-11 | 2018-05-22 | 上海应用技术学院 | Prepare the rolling device of sheet metal gradient structure |
| CN107083477B (en) * | 2017-04-22 | 2018-10-23 | 南京工程学院 | A kind of realization welding point full-automatic bidirectional multi-angle flexural deformation device and its application method |
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| JPH01170596A (en) * | 1987-12-26 | 1989-07-05 | Nippon Mining Co Ltd | Heat treatment of after non-consumable electrode type gas shielded arc welding |
| CN102127724B (en) * | 2010-11-11 | 2012-06-06 | 中南大学 | Method for preparing magnesium alloy plate strip with grain size in symmetric gradient distribution along plate thickness direction |
| CN102154597A (en) * | 2011-02-22 | 2011-08-17 | 中南大学 | Processing method for refining crystal grains and improving texture of double surface layers of magnesium alloy plate strip |
| CN102409273B (en) * | 2011-11-02 | 2013-03-20 | 中南大学 | Method for weakening cardinal plane texture of magnesium alloy plate strip |
| CN102534446B (en) * | 2012-01-20 | 2013-08-07 | 重庆大学 | Method for improving mechanical property of magnesium alloy friction stir welded joint |
| CN103074557B (en) * | 2013-01-22 | 2015-04-08 | 重庆大学 | Method for improving weld structure and performance of magnesium alloy |
| CN103526142B (en) * | 2013-09-27 | 2015-12-09 | 重庆大学 | A kind of magnesium alloy weld seam heat rolls reinforcing process |
| CN204625753U (en) * | 2015-05-13 | 2015-09-09 | 南京工程学院 | The compound bending deformation device of process welding joint |
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Effective date of registration: 20190701 Address after: 214253 New Town of Yixing City, Wuxi City, Jiangsu Province Patentee after: Wuxi Tongrui Electric Power Automation Equipment Co.,Ltd. Address before: 211167 1 Hong Kong Avenue, Jiangning Science Park, Nanjing, Jiangsu Patentee before: Nanjing Institute of Technology |
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