CN114453692A - Magnesium alloy brazing method - Google Patents
Magnesium alloy brazing method Download PDFInfo
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- CN114453692A CN114453692A CN202110860957.3A CN202110860957A CN114453692A CN 114453692 A CN114453692 A CN 114453692A CN 202110860957 A CN202110860957 A CN 202110860957A CN 114453692 A CN114453692 A CN 114453692A
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- 238000005219 brazing Methods 0.000 title claims abstract description 78
- 229910000861 Mg alloy Inorganic materials 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 21
- 238000003466 welding Methods 0.000 claims abstract description 63
- 229910052751 metal Inorganic materials 0.000 claims abstract description 35
- 239000002184 metal Substances 0.000 claims abstract description 35
- 239000000945 filler Substances 0.000 claims abstract description 33
- 239000000463 material Substances 0.000 claims abstract description 28
- 239000010953 base metal Substances 0.000 claims abstract description 7
- 230000003647 oxidation Effects 0.000 claims abstract description 4
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 4
- 238000010438 heat treatment Methods 0.000 claims description 14
- 238000004321 preservation Methods 0.000 claims description 8
- 238000005498 polishing Methods 0.000 claims description 7
- 239000000919 ceramic Substances 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 230000008878 coupling Effects 0.000 claims description 4
- 238000010168 coupling process Methods 0.000 claims description 4
- 238000005859 coupling reaction Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 238000003892 spreading Methods 0.000 claims description 2
- 230000007480 spreading Effects 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 230000009466 transformation Effects 0.000 claims 3
- 239000003795 chemical substances by application Substances 0.000 claims 1
- 238000005553 drilling Methods 0.000 claims 1
- 239000004744 fabric Substances 0.000 claims 1
- 230000004907 flux Effects 0.000 claims 1
- 239000002245 particle Substances 0.000 claims 1
- 230000007547 defect Effects 0.000 abstract description 8
- 230000033228 biological regulation Effects 0.000 abstract description 6
- 239000002131 composite material Substances 0.000 abstract description 3
- 230000008020 evaporation Effects 0.000 abstract description 2
- 238000001704 evaporation Methods 0.000 abstract description 2
- 230000008646 thermal stress Effects 0.000 abstract description 2
- 239000013585 weight reducing agent Substances 0.000 abstract 1
- 238000001816 cooling Methods 0.000 description 11
- 229910000679 solder Inorganic materials 0.000 description 10
- 238000005086 pumping Methods 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 210000001519 tissue Anatomy 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000007770 graphite material Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 241000251468 Actinopterygii Species 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 238000005520 cutting process Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 210000005067 joint tissue Anatomy 0.000 description 1
- -1 magnesium nitride Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K1/00—Soldering, e.g. brazing, or unsoldering
- B23K1/008—Soldering within a furnace
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K3/00—Tools, devices, or special appurtenances for soldering, e.g. brazing, or unsoldering, not specially adapted for particular methods
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
- B23K2103/15—Magnesium or alloys thereof
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Arc Welding In General (AREA)
Abstract
The invention relates to a magnesium alloy welding method. Magnesium alloys have excellent properties and are considered to be ideal materials for driving the weight reduction industry. However, magnesium alloys are prone to evaporation, oxidation, nitridation, large thermal stress and other problems at high temperatures, and thus, often exhibit various welding defects during welding. These welding problems severely limit the widespread use of magnesium alloys. The welding defects of the magnesium alloy mostly appear under the condition of high welding temperature, and the quality of the magnesium alloy soldered joint can be effectively improved by reducing the welding temperature of the magnesium alloy. The invention adopts the current field and Joule heat composite regulation and control to the magnesium alloy welding system, and utilizes the current to break the nano oxidation layer on the surface of the magnesium alloy, thereby improving the wettability between the base metal and the brazing filler metal and realizing the high-quality welding of the magnesium alloy under the low-temperature industrial atmosphere.
Description
Technical Field
The invention relates to a magnesium alloy brazing method.
Background
Magnesium alloy has excellent properties such as small density, high strength, large elastic modulus, good heat dissipation, good shock absorption, good corrosion resistance and the like, and is considered as an ideal material for driving the lightweight industry. However, magnesium alloys are prone to evaporation, oxidation, nitridation, large thermal stress and other problems at high temperatures, and thus, often exhibit various welding defects during welding. For example, the magnesium alloy has a large crystallization temperature range and is easy to generate thermal cracks; the magnesium alloy is easy to be burnt during welding; magnesium has high affinity to oxygen, and is easy to form oxide inclusion during welding; magnesium, when approaching the melting temperature, will combine strongly with nitrogen in the air to form brittle magnesium nitride, resulting in a significant reduction in the mechanical properties of the joint. These welding problems severely limit the widespread use of magnesium alloys.
It is found that the welding defects of the magnesium alloy mostly appear under the condition of higher welding temperature, and the quality of the magnesium alloy soldered joint can be effectively improved by reducing the welding temperature of the magnesium alloy. Currently, most of the mainstream magnesium alloy welding methods (such as friction stir welding and arc welding) adopt a welding temperature which is locally high or is close to the melting point of the magnesium alloy, so that the problems are not solved all the time. According to the technology, the traditional tube furnace is modified, and two electric terminals are added, so that the magnesium alloy system can be heated and insulated, a current field and joule heat composite regulation and control are provided for the magnesium alloy system, and high-quality brazing of the magnesium alloy in a low-temperature industrial atmosphere is realized.
Disclosure of Invention
The invention provides a current field for assisting magnesium alloy welding, and realizes low-temperature industrial atmosphere high-performance brazing.
The invention provides the following technical scheme: the traditional tube furnace is modified (see figure 1) to achieve the following purposes: under the industrial atmosphere, the current (figure 2) is stably switched in for the magnesium alloy brazing system for heat preservation in the furnace body, and the current field auxiliary magnesium alloy brazing is realized, so that the high-performance welded joint is obtained under the low-temperature condition.
The brazing method comprises the following steps:
step one, determining current field parameters (to be explained with reference to fig. 3):
1. treatment of brazing materials
(1) Placing a polished base material substrate (19) on the end face of a lower electrode of a high-purity graphite material (8), and adjusting the base material substrate to be horizontal by using a horizontal ball and a base posture adjusting system (12) of equipment;
(2) solder cube (18) cut in advance is placed on the base material substrate, and the position of the solder cube is adjusted so as to be positioned right under the graphite upper electrode (7).
2. Setting of atmosphere, temperature and current parameters
(1) Pre-pumping a vacuum chamber by a mechanical pump, finely pumping a molecular pump or subsequently introducing reducing gas according to requirements to obtain an ideal wetting experimental atmosphere;
(2) heating the wetting system to a preset temperature point and preserving heat according to the characteristics of the selected solder and the proper temperature interval of brazing;
(3) after the solder is quickly melted into spherical molten drops, the tip end of the graphite upper electrode is contacted and inserted into the spherical molten drops by utilizing the posture adjusting system (11);
(4) turning on a power-on switch of a direct current power supply (17), and determining a current test parameter interval according to the interface properties of the metal solder and the base metal; (FIG. 4)
(5) After the current intensity is preset, recording the initial moment of electrification as a starting time point, recording the end moment of electrification as an end time point, and recording experimental data. And (6) cooling to room temperature after the electrification is finished, and finishing the primary test.
3. And repeating the steps to determine a proper current parameter interval.
Step two, welding preparation:
1. setting of temperature, current parameters, atmosphere
(1) According to the temperature parameters of the first step, raising the temperature to a proper brazing temperature point in the same temperature raising mode;
(2) accurately selecting proper current intensity according to the current and the interface contact area in the step one, and setting current parameters of the coupling brazing technology;
2. and (3) processing the brazing material:
(1) arranging the materials according to the sequence of parent metal-brazing filler metal-parent metal, fixing the materials by using a ceramic bolt and a clamp, and winding a conducting wire on the ceramic bolt up and down to enable current to pass through the parent metal and the brazing filler metal;
(2) placing the placed brazing system in a glass tube and positioning the brazing system below a thermocouple;
(3) and connecting the lead of the power-on equipment with the stainless steel lead of the modified flange.
Step three, current-assisted brazing
(1) Starting a heating program of the tube furnace;
(2) when the temperature rises to the preset temperature, starting a heat preservation program, and starting the electrifying equipment to electrify;
(3) after the power is supplied for a certain time, the power supply equipment is closed, and the heating is stopped;
(4) after cooling to a certain temperature, closing the air valve and closing the tube furnace;
(5) and taking out the material to obtain a brazing finished product.
The principle of the invention is as follows: the problem of poor fluidity of the brazing filler metal at 450 ℃ originally is solved by applying a current field to generate a Joule effect during the heat preservation of the magnesium alloy system in the modified tube furnace. The composite regulation and control of current field and joule heat is adopted to drive the brazing filler metal to be advanced and promote the brazing filler metal to fill up welding seams better, so that the magnesium alloy can obtain high-performance welded joints under the condition of low temperature
Compared with the prior art, the invention has the beneficial effects that:
1. the magnesium alloy brazing method provided by the invention can effectively reduce the welding temperature of the magnesium alloy by 100-200 ℃ by adopting a current field auxiliary technology, thereby realizing energy conservation and consumption reduction and shortening the welding time.
2. The performance of the brazing joint obtained by the method under the low-temperature condition is better than that of the brazing joint obtained by the prior art.
3. The invention can be applied to production under industrial atmosphere and has low requirement on atmosphere.
4. The regulation and control parameters are converted into current parameter regulation and control, and the regulation and control method is simplified.
In conclusion, the method can fully improve the brazing efficiency and realize high-efficiency welding.
The specific case is as follows:
current field parameters were determined (as will be explained in connection with fig. 3):
1. treatment of brazing materials
(1) Placing a polished base material AZ31B substrate (19) on the end face of a lower electrode of a high-purity graphite material (8), and adjusting the base material AZ31B substrate to be horizontal by using a horizontal ball and a base posture adjusting system (12) of equipment;
(2) solder cube Zn cut in advance was placed on the base material AZ31B substrate, and the position of the solder cube was adjusted so as to be located directly below the graphite upper electrode (7).
2. Setting of direct current atmosphere, temperature and current parameters
(1) Pre-pumping a vacuum chamber by a mechanical pump and finely pumping a molecular pump to ensure that the vacuum degree in the furnace reaches 5 x 10 < -4 > Pa;
(2) carrying out heat treatment on an AZ31B/Zn system at 450 ℃ and then carrying out heat preservation at 450 ℃; setting a temperature program in a mode of continuously heating at a speed of 20 ℃/min;
(3) setting the direct current intensity to be 0-4A respectively, turning on a power-on switch of the direct current power supply 17, and starting to electrify;
(4) recording the initial moment of electrification as a starting time point, and recording the end moment of electrification as an end time point;
(5) and cooling to room temperature after electrifying is finished.
3. Setting of AC atmosphere, temperature and current parameters
(1) Pre-pumping a vacuum chamber by a mechanical pump and finely pumping a molecular pump to ensure that the vacuum degree in the furnace reaches 5 x 10 < -4 > Pa;
(2) carrying out heat treatment on an AZ31B/Zn system at 450 ℃ and then carrying out heat preservation at 450 ℃; setting a temperature program in a mode of continuously heating at a speed of 20 ℃/min;
(3) setting the alternating current intensity interval to be 0-14mA, turning on a power-on switch of a direct current power supply (17) and starting to electrify;
(4) recording the initial moment of electrification as a starting time point, and recording the end moment of electrification as an end time point;
(5) and cooling to room temperature after electrifying is finished.
Welding preparation:
1. setting of temperature, current parameters, atmosphere
(1) According to the debugged temperature parameter, raising the temperature to 450 ℃ in a temperature raising mode of 20 ℃/min;
(2) and accurately selecting proper current intensity according to the debugged current and the interface contact area, and setting current parameters of the coupling brazing technology.
(3) The atmosphere was set to a high purity inert gas, simulating an industrial atmosphere.
2. And (3) processing the brazing material:
(1) arranging the materials according to the sequence of parent metal-brazing filler metal-parent metal, fixing the materials by using a ceramic bolt and a clamp, and winding a conducting wire on the ceramic bolt up and down to enable current to pass through the parent metal and the brazing filler metal;
(2) placing the placed brazing system into a glass tube so that the brazing system is positioned below a thermocouple;
(3) connecting a lead of the electrified equipment to two terminals of the modified flange;
when no current is applied
(1) And starting a heating program of the tube furnace.
(2) And starting a heat preservation program when the temperature rises to 450 ℃, and preserving the heat for 5 min.
(3) After 5min, the heating was stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
We heat-weld the materials at 450 ℃ without electricity, and fig. 5 is a structure diagram of macro and micro morphologies of the welded interface. The fluidity of the brazing filler metal in the welding seam is extremely poor and is interrupted from a macroscopic view, and welding cracks almost penetrating through the whole welding seam exist, which indicates that the fluidity of the brazing filler metal is not good under the welding condition. Microscopic observation of the weld joint microstructure by a microscope shows that although the diffusion products at the joint part in the middle of the weld joint are distributed regularly and symmetrically, the weld cracks in the generated region almost penetrate, and the cracks appear at positions which cannot be seen in the macroscopic region.
When the direct current intensity is 1A:
(1) and starting a heating program of the tube furnace.
(2) And when the temperature rises to 450 ℃, starting a heat preservation program, starting direct current power-on equipment, and starting power-on for 5 min.
(3) After 5min, the power-on equipment is closed, and heating is stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
In fig. 6, the brazing filler metal flows seriously to one side, and intermittent welding seams with different sizes appear in a welding seam area. In the microstructure morphology observed by a microscope, the electron current of the brazing filler metal diffuses more, a longer gap still exists in a welding seam area, no obvious scaly joint tissue generated after the brazing filler metal is melted appears, and the brazing filler metal which is not melted can be found in a microstructure picture. In summary, the soldered joints were better than those without the current applied after the 1A DC current was applied, but no better condition was observed and the solder began to diffuse unevenly.
When the direct current intensity is 2A:
(1) and starting a heating program of the tube furnace.
(2) And when the temperature rises to 450 ℃, starting a heat preservation program, starting direct current power-on equipment, and starting power-on for 5 min.
(3) After 5min, the power-on equipment is closed, and heating is stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
After the 2A direct current is introduced, the appearance of the welding seam (figure 7) is obviously changed. Macroscopically, in the welding process, because gas cannot be removed in time, the defects of slag inclusion, air holes and the like are formed in the welding line, but compared with the experimental result of not electrifying or introducing 1A direct current, the method is greatly improved. The filling of the brazing filler metal to welding seams is relatively complete from the microscopic morphology, but uncertain black spots still appear at the end of an interface product, and a certain defect probably exists in the melting aspect of the brazing filler metal, and in addition, the phenomenon that the brazing filler metal migrates to a large amount in the direction of electron current is greatly improved when 2A is introduced, and the phenomenon can be observed only in a very small part of a welding area.
When the direct current intensity is 3A:
(1) and starting a heating program of the tube furnace.
(2) And when the temperature rises to 450 ℃, starting a heat preservation program, starting direct current power-on equipment, and starting power-on for 5 min.
(3) After 5min, the power-on equipment is closed, and heating is stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
And 3A direct current is introduced (figure 8), the brazing filler metal has uniform interfaces in a welding seam filling area, a small amount of intermittent welding pores exist, and the phenomenon that a large amount of brazing filler metal flows into the current polarity direction is obvious. We have found that when current flows in the downward direction, the solder actively spreads upward. Meanwhile, along with the increase of a current field, the welding quality of the welding seam is obviously improved, the spreadability of the brazing filler metal at a welding interface is obviously improved, the welding seam has no other obvious defects except a small amount of air holes, the melting spreadability of the brazing filler metal is obviously improved, and the scaly products of the welding seam are uniform.
When the alternating current intensity is 6 mA:
(1) and starting a heating program of the tube furnace.
(2) And when the temperature rises to 450 ℃, starting a heat preservation program, starting direct current power-on equipment, and starting power-on for 5 min.
(3) After 5min, the power-on equipment is closed, and heating is stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
When 6mA alternating current (figure 9) is introduced, the phenomenon that the direct current 2A intervenes in welding of the welding seam already occurs. The brazing filler metal generates a relatively complete phase in the middle of the welding seam, welding products are irregularly shaped and spread towards two sides, and defects such as air holes, slag inclusion and the like appear in the middle of the welding seam. The observation of the macro-morphology of the welded seam after cutting shows that many longer welding cracks, air holes and the like are still distributed on the welded seam, which indicates that the micro alternating current is helpful for magnesium alloy brazing, but the effect is still not obvious.
When the alternating current intensity is 8 mA:
(1) and starting a heating program of the tube furnace.
(2) And when the temperature rises to 450 ℃, starting a heat preservation program, starting direct current power-on equipment, and starting power-on for 5 min.
(3) After 5min, the power-on equipment is closed, and heating is stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
When 8mA constant current AC is introduced, the welding interface has obvious change. From its microscopic morphology (fig. 10) it can be seen that the spreadability of the solder in the weld is significantly improved. Symmetrical fish scale-shaped welding products appear on the left side and the right side of the welding line, and the distribution is very uniform.
When the alternating current intensity is 12 mA:
(1) and starting a heating program of the tube furnace.
(2) And when the temperature rises to 450 ℃, starting a heat preservation program, starting direct current power-on equipment, and starting power-on for 5 min.
(3) After 5min, the power-on equipment is closed, and heating is stopped.
(4) And after cooling to a certain temperature, closing the air valve and closing the tube furnace.
(5) And taking out the material to obtain a brazing finished product.
When a constant current alternating current of 12mA is introduced, a more ideal weld joint structure is obtained (figure 11). From the figure, we can observe that from the macroscopic perspective, the welding seam is symmetrical and uniform, the brazing filler metal does not flow outwards, and no obvious gap or air hole is seen from the welding seam. The observation of the microstructure of the welding head after polishing can show that the new phase regions generated by diffusion are regular and symmetrical, the scaly products generated on two sides of the welding line are arranged neatly and uniformly, and compared with the situation that 1A direct current and 6mA alternating current are introduced, the spreading degree of the brazing filler metal is far higher than that of the brazing filler metal, which indicates that the wettability of the brazing filler metal relative to the base metal is obviously improved under the existing welding conditions, and accordingly, the welding joint has good performance.
In summary, the weldability of the magnesium alloy can be improved by applying a proper current field, and a low-temperature magnesium alloy high-performance welded joint is obtained.
Drawings
FIG. 1 is a schematic structural view of a modified tube furnace
FIG. 2 is a circuit diagram of a brazing system in a tube furnace (a is direct current, and b is alternating current)
FIG. 3 is a system diagram for determining a current parameter
FIG. 4 is a circuit diagram of current parameter control (a is DC, b is AC)
FIG. 5 weld morphology tissue under unpowered (100 times magnification)
FIG. 6 shows the weld morphology under 1A DC current (100 times magnification)
FIG. 7 shows the morphology of the weld after passing 2A DC (100 times magnification)
FIG. 8 shows the weld morphology under the input of 3A direct current (magnification 100 times)
FIG. 9 shows the tissue morphology under the condition of introducing 6mA alternating current (amplified by 100 times)
FIG. 10 shows the tissue morphology under the condition of passing 8mA alternating current (amplified by 100 times)
FIG. 11 shows the structural morphology of a weld bead with 12mA alternating current (magnified 100 times).
Claims (6)
1. A magnesium alloy brazing method is characterized by comprising the following steps:
1.1: industrial atmosphere furnace current coupling transformation
a) Drilling circular holes with the diameter of about 5mm at two sides of an air outlet flange of the tubular atmosphere furnace;
b) stainless steel wires wrapped by insulating ceramics are embedded into the round holes, so that current can be continuously introduced in the heating and heat preservation process.
1.2: pretreatment of magnesium alloy base metal
a) Aiming at various magnesium alloy base metals needing to be welded;
b) grinding the welding surface by using abrasive paper with various particle sizes until a single and uniform trace is ground by using No. 2000;
c) and (4) polishing by matching a metallographic polishing machine with polishing paste with proper granularity until no scratch appears and a mirror surface effect appears.
1.3: pretreatment of brazing filler metal
a) Inspecting the components of the magnesium alloy to be welded and the parameters of a current field, and selecting a proper brazing filler metal with a smooth surface;
b) and (4) directly polishing the brazing filler metal by using polishing cloth and matching a polishing agent until a mirror surface effect appears.
1.4: final brazing process
a) Mounting the base metal obtained in 1.2 and the brazing filler metal obtained in 1.3 on a jig in the order of base metal-brazing filler metal-base metal;
b) connecting the whole clamp with the inner side of a stainless steel wire in the end flange after 1.1 transformation, and ensuring that current can sequentially pass through the clamp, the base material, the brazing filler metal, the base material and the clamp;
c) connecting an external power supply with the outer side of a stainless steel wire through a wire;
d) setting a proper temperature rise gradient and a proper heat preservation time;
e) and introducing proper current after the temperature reaches the heat preservation temperature to promote the spreading of the brazing filler metal on the interface, thereby obtaining a high-quality brazed joint.
2. The magnesium alloy brazing method according to claim 1, wherein a conventional industrial atmosphere furnace is subjected to current coupling transformation to ensure that the industrial atmosphere furnace can be electrified.
3. The method for brazing magnesium alloy according to claim 1, wherein the oxidation of magnesium alloy is suppressed only by applying an electric current without using an active flux.
4. The method for brazing a magnesium alloy according to claim 1, wherein the temperature of the entire brazing process is 80 to 120 ℃ lower than the melting point of the magnesium alloy base material.
5. The magnesium alloy brazing method according to claim 1, wherein the brazing temperature is maintained at a current intensity of 1A to 4A when a direct current is applied thereto, and the application time is 5 to 10 min.
6. The magnesium alloy brazing method according to claim 1, wherein the brazing heat preservation is performed by applying alternating current at a current intensity of 6 mA-12 mA, a frequency of 50-200 Hz, and an application time of 5-10 min.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5961853A (en) * | 1993-11-26 | 1999-10-05 | Ford Global Technologies, Inc. | Weld/brazing of light metal alloys |
| JP2003164966A (en) * | 2001-11-27 | 2003-06-10 | Hidehiko Sugimoto | Method for resistance brazing and power source unit for resistance brazing |
| CN101844260A (en) * | 2010-05-13 | 2010-09-29 | 重庆大学 | Method and device for performing electric magnetization resistance welding-braze welding compounding on dissimilar materials |
| CN101856757A (en) * | 2010-06-10 | 2010-10-13 | 重庆理工大学 | Powder medium diffusion reaction resistance soldering method of aluminum alloy |
| CN104439590A (en) * | 2014-11-07 | 2015-03-25 | 中国矿业大学 | Brazing technique for 6061 aluminum alloy and AZ31B magnesium alloy |
| CN107081495A (en) * | 2017-07-03 | 2017-08-22 | 长江师范学院 | A kind of method for welding of metal system |
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2021
- 2021-07-30 CN CN202110860957.3A patent/CN114453692A/en active Pending
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|---|---|---|---|---|
| US5961853A (en) * | 1993-11-26 | 1999-10-05 | Ford Global Technologies, Inc. | Weld/brazing of light metal alloys |
| JP2003164966A (en) * | 2001-11-27 | 2003-06-10 | Hidehiko Sugimoto | Method for resistance brazing and power source unit for resistance brazing |
| CN101844260A (en) * | 2010-05-13 | 2010-09-29 | 重庆大学 | Method and device for performing electric magnetization resistance welding-braze welding compounding on dissimilar materials |
| CN101856757A (en) * | 2010-06-10 | 2010-10-13 | 重庆理工大学 | Powder medium diffusion reaction resistance soldering method of aluminum alloy |
| CN104439590A (en) * | 2014-11-07 | 2015-03-25 | 中国矿业大学 | Brazing technique for 6061 aluminum alloy and AZ31B magnesium alloy |
| CN107081495A (en) * | 2017-07-03 | 2017-08-22 | 长江师范学院 | A kind of method for welding of metal system |
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