CN101745730A - Method for variable polarity plasma arc welding of magnesium alloy plate with filler metal - Google Patents
Method for variable polarity plasma arc welding of magnesium alloy plate with filler metal Download PDFInfo
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- CN101745730A CN101745730A CN200910250990A CN200910250990A CN101745730A CN 101745730 A CN101745730 A CN 101745730A CN 200910250990 A CN200910250990 A CN 200910250990A CN 200910250990 A CN200910250990 A CN 200910250990A CN 101745730 A CN101745730 A CN 101745730A
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Abstract
The invention relates to a method for variable polarity plasma arc welding of a magnesium alloy plate with filler metal. The method is technically characterized in that a magnesium alloy plate is welded through a variable polarity plasma welding system with filler metal in the condition of filling backside shielding gas and front side shielding gas. The backside shielding gas hinders air from entering a metal bath, avoids inward contraction of the surface of the metal, and enables the backside of the weld seams to be effectively molded. By adopting a front side gas protecting cover, the problems that due to the oxidization of magnesium, the permissible height on the front side of the weld seams is small, the permissible height on the backside is large, and liquid metal moves to the backside of the weld seams can be effectively solved.
Description
Technical field
The present invention relates to welding technology field, relate to a kind of magnesium alloy plate Variable Polarity plasma in particular and add wire bond and connect method.
Technical background
Magnesium alloy is owing to have advantages such as specific strength height, little, the easy processing of density, good shock resistance and corrosion resistance, and is widely used in space flight, automobile, motorcycle and the electronic product, becomes the main direction of present non-ferrous metal research and development.Welding is the important means that forms structural member, and therefore the research to the magnesium alloy materials weldability has important in theory and engineering significance.
Used multiple different welding method at the connection of magnesium alloy in recent years, TIG weldering, electron beam welding (Electron beamwelding, EBW), Laser Welding (Laser beam welding, LBW), (Friction stir welding FSW) all has the scientific research personnel to study to friction stir welding.But said method all can not effectively solve magnesium alloy have that fusing point is low, linear expansion coefficient and thermal conductivity factor height, cause magnesium alloy in welding process, to occur problems such as oxidizing fire, crackle and heat affected area be wide easily.
Simultaneously, in the process of welding because magnesium alloy thermal conductivity height, rapid heat dissipation, the protection gas of Variable Polarity plasma apparatus self can't be protected whole high-temperature region.When adopting front protecting gas, during the protection of gas-protection-free cover, fillet in normal shear is narrow, and there is one deck black oxide film on the surface, the positive molten height of weld seam, and the back side is molten tall and big.The generation of oxide-film has destroyed the dynamic equilibrium of molten pool metal, orders about liquid metal and moves to back of weld, causes the magnesium alloy plate surface depressions.
Summary of the invention
For addressing the above problem, the invention provides a kind of magnesium alloy plate Variable Polarity plasma and add wire bond and connect method, it is characterized in that: Variable Polarity plasma welding welding system adds wire bond and connects magnesium alloy plate under the condition of utilization back-protective gas and front protecting gas.
It is as follows that magnesium alloy plate Variable Polarity plasma adds the method step that wire bond connects:
(1), the oxide-film on preweld cleaning wlding and packing material surface;
(2), fill back-protective gas and discharge air;
(3), continue to fill back-protective gas and fill front protecting gas, add wire bond with Variable Polarity plasma welding welding system simultaneously and connect magnesium alloy plate.
Described back-protective gas is argon gas or helium, and flow of aerating air is 3～5L/min, increases to 15L/min before welding.
Described front protecting gas is the argon gas that the argon gas of Variable Polarity plasma welding welding system self adds the input of gas shield cover; The throughput of the argon gas of Variable Polarity plasma welding welding system self is 0.8～1.5L/min.
Adding the technological parameter that wire bond connects magnesium alloy plate is: welding current is 165～200A, and speed of welding is 150～190mm/min, and wire feed rate is 500～600mm/min.
Useful technique effect of the present invention is: adopt Variable Polarity plasma welding welding system to add wire bond under the condition of utilization back-protective gas and front protecting gas and connect magnesium alloy plate.The back-protective vapour lock hinders air to enter metal bath, avoids contracting in the metal surface, makes the effective moulding of back of weld.Adopt positive gas shield cover, avoid the positive because positive face height that the oxidation of magnesium causes of weld seam effectively, the back side holds tall and big, the problem that liquid metal moves to back of weld.The Variable Polarity plasma adds wire bond, and to connect the magnesium alloy bead contour that method welds out even, and weld seam and mother metal transition are steady, positive full no undercut phenomenon, and there is the black granular oxide negative electrode range of atomization, weld seam both sides, and root reinforcement is evenly suitable.
Description of drawings
Fig. 1 is the profile of gas shield cover
In the accompanying drawing: 1 gas hood, 2 return ducts, the fixing card of 3 welding guns, 4 recirculated waters cooling pipe, 5 recirculated water conduits, 6 gas outlets, 7 air inlets.
The specific embodiment
The vertical longitudinal joint automatic plasma of the LWV-3000-XM welding system that the present invention adopts AMET Welding Automation Technology (Beijing) Co., Ltd. to produce adds wire bond and connects 8mm AZ31B magnesium alloy plate.Concrete steps are as follows:
(1), the oxide-film on preweld cleaning wlding and packing material surface.
(2), the back-protective gas that adopts is 99.99% argon gas, adopts the 3-5L/min flow slowly to discharge air, inflationtime decide according to welded blank length, increase back-protective throughput is to 15L/min before welding.
(3), adopt the Variable Polarity plasma to add wire bond and connect method welding magnesium alloy plate.In plasma arc welding with adjustable polarity parameters, the factor of perforation molten bath change procedure and last stable state mainly is three parameters such as welding current, plasma gas flow rate and speed of welding during the influence perforation.In operation process, tungsten electrode neck-in, nozzle remain unchanged to the height and the protection throughput of rifle.Speed of welding only determined energy input what, so the perforation starting the arc process in, welding current and plasma gas flow rate are the main sources of arc heat and arc force.Amplitude and timing variations by control welding current and plasma gas flow rate can realize different perforation excavation and heating process.And then the aperture stable state that forms constantly of influence perforation and form the transition situation.
Filling back-protective gas and filling under the condition of front protecting gas.φ 3.2mm tungsten electrode is adopted in welding, neck-in is controlled at 3.4 ± 0.1mm, change welding current, plasma gas flow rate, speed of welding and four main welding parameters of wire feed rate in the test successively, welding current changes in 165～200A scope, plasma gas flow rate changes in 0.8～1.5L/min scope, speed of welding changes in 150～190mm/min scope, and the wire feed rate scope is 500～600mm/min.The magnesium alloy bead contour that Variable Polarity plasma orifice method welds out is even, and weld seam and mother metal transition are steady, positive full no undercut phenomenon, and there is the black granular oxide negative electrode range of atomization, weld seam both sides, and root reinforcement is evenly suitable.
Described front protecting gas is the argon gas that the argon gas of Variable Polarity plasma welding welding system self adds the input of gas shield cover.
The structure of gas shield cover is referring to accompanying drawing 1: be provided with protection gas induction system and circulating water cooling system in the gas hood 1 of gas shield cover.
Described protection gas induction system is made up of air inlet 7, return duct 2 and gas outlet 6, and described circulating water cooling system is made up of recirculated water cooling pipe 4 and recirculated water conduit 5.
Air inlet 7 return ducts 2 connected vertically, and air inlet 7 is perpendicular to the gas outlet 6 of gas hood 1 below; Recirculated water conduit 5 connects the two ends of U font recirculated water cooling pipe 4 respectively; Return duct 2 is positioned in the middle of the n word pipeline of recirculated water conduit 5; The plane parallel of recirculated water conduit 5 is 6 planes in the gas outlet; Protect gas to drag cover 1 leading portion to be provided with and be used for fixing the fixing card 3 of welding gun on welding gun.
The argon gas of employing 99.99% is protected gas as inertia, when argon gas from air inlet at a relatively high speed during the gas hood 1 of inflow gas protective cover, a return duct 2 is installed in the air inlet of the gas hood 1 of gas shield cover, when argon gas enters gas hood 1 at a relatively high speed, because the obstruction of return duct 2 makes gas produce and refluxes, reduce flowing velocity, argon gas is fully diffusion in the space of gas hood 1; Formed like this atmosphere sectional area is designed gas outlet sectional area size, makes the protection effect of gas be improved.The obstruction of return duct 2 makes air velocity reduce; the gas outlet 6 of gas hood 1 forms and the equirotal protective atmosphere of gas outlet 6 areas; argon gas is fully used, and simultaneously therefrom gas pressure and the density difference outside the mind-set is less in the atmosphere that forms, and has effectively utilized argon gas.The gas shield cover is fixed on the welding gun, and in the process that welding gun upwards welds, the argon gas that flows out from the gas shield cover covers on the molten pool metal, hinders air and contacts with the molten bath of hot state, so just prevents that the molten pool metal under the high temperature is oxidized.
Simultaneously, in the gas hood 1 circulating water cooling system has been installed, this system not only can reduce the temperature of the gas hood 1 of gas shield cover in the process of welding, avoid the damage of gas hood 1.The circulating water cooling system of the cover of gas shield simultaneously also has the function to the magnesium alloy plate cooling of welding.And when the gas shield cover walk out-of-date; because the thermal conductivity height of magnesium alloy and the cooling effect of circulating water cooling system; the molten bath cools down substantially, has hindered at the gas shield cover by this kind mode and has removed the back because the oxidation in the molten bath that the surplus temperature of solder joint causes has guaranteed welding quality.
Claims (5)
1. magnesium alloy plate Variable Polarity plasma adds wire bond and connects method, it is characterized in that: Variable Polarity plasma welding welding system adds wire bond and connects magnesium alloy plate under the condition of utilization back-protective gas and front protecting gas.
2. magnesium alloy plate Variable Polarity plasma according to claim 1 adds wire bond and connects method, it is characterized in that: it is as follows that magnesium alloy plate Variable Polarity plasma adds the method step that wire bond connects:
(1), the oxide-film on preweld cleaning wlding and packing material surface;
(2), fill back-protective gas and discharge air;
(3), continue to fill back-protective gas and fill front protecting gas, add wire bond with Variable Polarity plasma welding welding system simultaneously and connect magnesium alloy plate.
3. magnesium alloy plate Variable Polarity plasma according to claim 2 adds wire bond and connects method, it is characterized in that: described back-protective gas is argon gas or helium, and flow of aerating air is 3～5L/min, increases to 15L/min before welding.
4. magnesium alloy plate Variable Polarity plasma according to claim 2 adds wire bond and connects method, it is characterized in that: described front protecting gas is the argon gas that the argon gas of Variable Polarity plasma welding welding system self adds the input of gas shield cover; The throughput of the argon gas of Variable Polarity plasma welding welding system self is 0.8～1.5L/min.
5. magnesium alloy plate Variable Polarity plasma according to claim 1 adds wire bond and connects method, it is characterized in that: adding the technological parameter that wire bond connects magnesium alloy plate is: welding current is 165～200A, speed of welding is 150～190mm/min, and wire feed rate is 500～600mm/min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN200910250990A CN101745730A (en) | 2009-12-25 | 2009-12-25 | Method for variable polarity plasma arc welding of magnesium alloy plate with filler metal |
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| CN200910250990A CN101745730A (en) | 2009-12-25 | 2009-12-25 | Method for variable polarity plasma arc welding of magnesium alloy plate with filler metal |
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| CN101745730A true CN101745730A (en) | 2010-06-23 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103551717A (en) * | 2013-09-22 | 2014-02-05 | 中国兵器工业第五二研究所 | Welding method for multistage circular welds of medium and thin wall variable-diameter aluminum alloy shell |
| CN108941862A (en) * | 2018-09-17 | 2018-12-07 | 兰州兰石能源装备工程研究院有限公司 | Titanium welds the guard method of argon gas protective cover and titanium soldered |
-
2009
- 2009-12-25 CN CN200910250990A patent/CN101745730A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103551717A (en) * | 2013-09-22 | 2014-02-05 | 中国兵器工业第五二研究所 | Welding method for multistage circular welds of medium and thin wall variable-diameter aluminum alloy shell |
| CN103551717B (en) * | 2013-09-22 | 2015-12-30 | 中国兵器科学研究院宁波分院 | The welding method of the multistage girth joint of middle thin-walled variable diameters Al-alloy casing |
| CN108941862A (en) * | 2018-09-17 | 2018-12-07 | 兰州兰石能源装备工程研究院有限公司 | Titanium welds the guard method of argon gas protective cover and titanium soldered |
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Open date: 20100623 |