CN102615426B - Novel welding method for laser welding of magnesium alloy - Google Patents
Novel welding method for laser welding of magnesium alloy Download PDFInfo
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- CN102615426B CN102615426B CN201210114203.4A CN201210114203A CN102615426B CN 102615426 B CN102615426 B CN 102615426B CN 201210114203 A CN201210114203 A CN 201210114203A CN 102615426 B CN102615426 B CN 102615426B
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Abstract
The invention discloses a novel welding method for the laser welding of a magnesium alloy. The method comprises the following steps of: adding an organic solvent into SiO2 active agent powder to form paste; coating the pasty SiO2 active agent on the surface of a part to be welded of the magnesium alloy uniformly to form a SiO2 active agent coating; and performing laser welding after the organic solvent in the SiO2 active agent coating is violated. By the method, due to high absorption capacity and low reflectivity of the SiO2 active agent coating for a laser beam, the loss rate of laser energy is reduced, the transmission efficiency of the energy is increased, and the energy utilization rate of the laser beam is remarkably improved; the energy utilization rate of the laser beam is remarkably improved, so that the fusion depth of a welding seam is remarkably increased, and the mechanical property of a welding joint can be obviously improved; and simultaneously, a low-power laser welding process can be utilized, so that the welding cost is reduced.
Description
Technical field
The invention belongs to laser welding technology field, be specifically related to a kind of Novel welding method for magnesium alloy laser welding.
Background technology
Magnesium alloy has the series of advantages such as density is low, specific strength is high, the good and easy recovery of electromagnetic wave shielding, is called as the green engineering material of 21st century, is widely used in the fields such as communications and transportation, consumer electronics, defence and military and Aero-Space.The research and apply of the light metal taking magnesium alloy as representative is kept the key of most advanced and sophisticated advantage as the new century by China, the U.S., Japan and European Union one after another.Along with the fast development of auto industry, energy-saving and cost-reducing require improve constantly and safety and environmental regulation increasingly strict, the requirement of automotive light weight technology is more urgent, adopts magnesium alloy to make auto parts and components and can obtain significant weight loss effect (60%-75% for steel, cast iron).China as magnesium resource big country, the commercial application of magnesium alloy oneself become one of national science and technology strategic development target.In March, 2000; the Department of Science and Technology of China starts " strategic research in early stage of Magnesium Alloy Development application and industrialization "; this project implementation has been participated in the whole nation totally 4 research institutes, 7 colleges and universities and 20 many enterprises directly; project covers the smelting of former magnesium; 7 broad aspect such as magnesium alloy industrialization production and the industrialization of magnesium alloy key technology, are devoted to promote magnesium alloy and apply in the scale of industrial circle.But really will realize the extensive application of magnesium alloy in industrial structure, its solder technology will be very crucial factor.Therefore, the development & application accelerating Welding Technology of Magnesium Alloy has very important theory and engineering significance.
But, due to magnesium alloy easy firing, oxidation at normal temperatures, thermal coefficient of expansion large and also with the feature such as the affinity of oxygen, nitrogen is strong, cause its welding performance poor, also higher to the requirement of welding procedure.Therefore, for complex structural member, the research of Welding Technology of Magnesium Alloy is the key link of its large-scale application of restriction, develop a kind of high-quality, efficient, energy-conservation and consumption reduction magnesium alloy Advanced Welding Technique oneself become the focus of research both at home and abroad.Recently, the welding method of magnesium alloy mainly concentrates on argon tungsten-arc welding, Laser Welding, friction stir welding and electron beam welding etc.Laser weld, as the welding method of a kind of novel high-energy-density, high accuracy and high automation, obtains developing rapidly and application in modern manufacturing industry.Therefore, laser welding process certainly will become the hot research direction in magnesium alloy welding technique.
In recent years, many scholars are studied magnesium alloy laser welding and report.The Nd:YAG laser instrument of 2.2KW such as the R. S. Coelho of Germany welds the thick AZ31 magnesium alloy of 2mm, obtains the weld seam that shaping surface is good, pore is few and obviously grow up without crystal grain.Canadian H. Al-Kazzaz etc. has successfully welded the thick ZE41A magnesium alloy of 2mm-6mm with the Nd:YAG laser instrument of 4KW.The people such as domestic Dalian University of Technology Liu dawn have carried out YAG laser welding to AZ31 magnesium alloy, and find that welding point does not exist obvious heat affected area, weld seam and mother metal are demarcated clearly, and welding point ultimate tensile strength maximum reaches 95% of mother metal.
Can find out, researcher mainly adopts high power laser to weld magnesium alloy both at home and abroad at present.Research in low power laser welding magnesium alloy is relatively less.This is because the reflectivity of Mg alloy surface to laser beam is high, the shortcoming such as the capacity usage ratio of laser weld is lower, cause the cost of equipment sharply to increase along with the increase of thickness of workpiece to be welded, these shortcomings limit the application of laser welding technology in magnesium alloy welding.
Summary of the invention
In view of this, the invention provides a kind of Novel welding method for magnesium alloy laser welding, laser beam energy utilization rate can be significantly improved, thus realize low power laser welding magnesium alloy, reduce welding cost, improve the object of welding joint mechanical property.
Novel welding method for magnesium alloy laser welding of the present invention, toward SiO
2add organic solvent in Agent Powder and become pasty state, then by pasty state SiO
2activating agent even application, on the surface at magnesium alloy position to be welded, forms SiO
2active agent coating, treats SiO
2laser weld is carried out after organic solvent volatilization in active agent coating.
Further, described organic solvent is acetone or alcohol;
Further, described pasty state SiO
2activating agent is 1 ~ 5mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2;
Further, described pasty state SiO
2activating agent is 40mm in the application width of magnesium alloy portion faces to be welded;
Further, at the surface application pasty state SiO at magnesium alloy position to be welded
2before activating agent, first polish and use the surface at ethanol purge magnesium alloy position to be welded;
Further, toward SiO
2before adding organic solvent in Agent Powder, first fully mill SiO
2agent Powder;
Further, when carrying out laser weld, welding equipment used is YAG solid laser working apparatus.
Beneficial effect of the present invention is: the present invention is at the surface application pasty state SiO at magnesium alloy position to be welded
2activating agent thus formed SiO
2active agent coating, utilizes SiO
2active agent coating, to the stronger absorbability of laser beam and antiradar reflectivity, makes the loss late of laser energy reduce, and energy transmission efficiency increases, thus significantly improves laser beam energy utilization rate; Owing to significantly improving laser beam energy utilization rate, therefore, weld penetration significantly increases, and the mechanical property of welding point significantly improves, and low power laser can also be adopted to weld simultaneously, thus reduce welding cost.
Accompanying drawing explanation
In order to make the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail, wherein:
Fig. 1 is the schematic diagram using the inventive method to carry out magnesium alloy laser welding;
Fig. 2 is coating SiO
2the contrast photo of appearance of weld before and after activating agent;
Fig. 3 is coating SiO
2seam cross-section fusion penetration contrast photo before and after activating agent;
Fig. 4 is coating SiO
2weld seam microstructure contrast photo before and after activating agent;
Fig. 5 is coating SiO
2the stress-strain diagram of welding point before and after activating agent;
Fig. 6 is coating SiO
2the stretching fracture pattern contrast photo of welding point before and after activating agent.
Detailed description of the invention
Hereinafter with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.
embodiment 1
Fig. 1 is the schematic diagram using the inventive method to carry out magnesium alloy laser welding, and as shown in the figure, the Novel welding method for magnesium alloy laser welding of the present embodiment, comprises the following steps:
1) first fully mill SiO
2agent Powder, then toward SiO
2add acetone in Agent Powder and become pasty state; Polish and use the surface at ethanol purge magnesium alloy position to be welded, to remove oxide and greasy dirt;
2) with flat hairbrush by pasty state SiO
2activating agent even application, on the surface at magnesium alloy position to be welded, forms SiO
2(in Fig. 1,1 is magnesium alloy to active agent coating, and 2 is SiO
2active agent coating); Described pasty state SiO
2activating agent is 1mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2, described pasty state SiO
2activating agent is 40mm in the application width of magnesium alloy portion faces to be welded;
3) SiO is treated
2laser weld is carried out after acetone volatilization in active agent coating; When carrying out laser weld, welding equipment used is YAG solid laser working apparatus; Laser welding process parameter is as shown in the table:
| Pulsewidth (ms) | Frequency (HZ) | Gas flow (l.min -1） | Average output power (w) | Speed of welding (mm.min -1） |
| 3.2 | 40 | 15 | 400 | 500 |
In the present embodiment, described SiO
2agent Powder can be obtained by outsourcing, and it is a kind of by SiO
2the commercial scaling powder obtained after process; Described magnesium alloy is the AZ31 magnesium alloy plate that 5mm is thick.
embodiment 2
Only being for the Novel welding method of magnesium alloy laser welding and the difference of embodiment 1 of the present embodiment: described pasty state SiO
2activating agent is 2mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2.
embodiment 3
Only being for the Novel welding method of magnesium alloy laser welding and the difference of embodiment 1 of the present embodiment: described pasty state SiO
2activating agent is 3mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2.
embodiment 4
Only being for the Novel welding method of magnesium alloy laser welding and the difference of embodiment 1 of the present embodiment: described pasty state SiO
2activating agent is 4mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2.
embodiment 5
Only being for the Novel welding method of magnesium alloy laser welding and the difference of embodiment 1 of the present embodiment: described pasty state SiO
2activating agent is 5mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2.
The present invention experimental studies have found that through a large amount of system: first laser be concentrate in the thin layer on surface to the heating of metal, after surface heating, temperature raises, the absorbability of laser is strengthened, strong reflection is generally there is when light beam impinges upon the metal surface of clean polishing, the albedo of metal pair light beam is relevant with its free electron density, free electron density is larger, reflection power is stronger, and therefore the high reflectance of magnesium alloy to laser becomes the principal element of restriction magnesium alloy laser welded seam fusion penetration.Mg alloy surface does not apply SiO
2during activating agent, because the absorptivity of metal material to laser itself is lower, the temperature that material surface reaches is limited, and the metal vapor amount of generation is fewer, so the weld penetration obtained is relatively little.Mg alloy surface coating SiO
2after activating agent, due to SiO
2active agent coating is comparatively strong to the absorbability of laser beam, and after laser injects face coat medium, most of laser energy is absorbed by surfactant coating and is delivered to matrix skin.In addition, SiO
2the fine grained surface of activating agent is little to laser beam reflection, and particle surface is irregularly shaped, makes again the light beam of scattering be absorbed by other particle surface, and the loss late of laser energy is reduced, and energy transmission efficiency increases, and therefore, weld penetration can significantly improve.But work as SiO
2when the coating amount of activating agent exceedes certain value, matrix skin reaches very high temperature, now no longer needs the heat transfer of active agent coating.A large amount of high temperature magnesium vapors is produced after magnesium alloy is heated, melts and evaporates, the existence of these magnesium vapors will produce shielding action to sample absorbing laser energy, and make active element effect be difficult to play, thus welding penetration is caused no longer to continue to increase with the raising of heat input.
Below choose embodiment 4 as the appropriate SiO of coating
2typical Representative (the pasty state SiO of activating agent
2the unit are coating amount of activating agent is 4mg/cm
2), choose embodiment 5 as the excessive SiO of coating
2typical Representative (the pasty state SiO of activating agent
2the unit are coating amount of activating agent is 5mg/cm
2), the above-mentioned conclusion of digital proof by experiment:
Fig. 2 is coating SiO
2the contrast photo of appearance of weld before and after activating agent: (a) is uncoated SiO
2the appearance of weld of activating agent, (b) is appropriate (embodiment 4) SiO of coating
2the appearance of weld of activating agent, (c) is the excessive SiO of coating
2the appearance of weld of activating agent (embodiment 5).As can see from Figure 2, uncoated SiO
2during activating agent, weld seam is lack of penetration, applies appropriate SiO
2the appearance of weld of activating agent is good, and applies excessive SiO
2there is hole in the weld seam of activating agent, is shaped and is deteriorated.
Fig. 3 is coating SiO
2seam cross-section fusion penetration contrast photo before and after activating agent: (a) is uncoated SiO
2the weld penetration of activating agent, (b) is appropriate (embodiment 4) SiO of coating
2the weld penetration of activating agent, (c) is the excessive SiO of coating
2the weld penetration of activating agent (embodiment 5).As can see from Figure 3, uncoated SiO
2during activating agent, weld penetration is less, applies appropriate SiO
2after activating agent, weld penetration obviously increases, and applies excessive SiO
2the weld penetration of activating agent reduces to some extent.
Fig. 4 is coating SiO
2weld seam microstructure contrast photo before and after activating agent: (a) is uncoated SiO
2the seam organization of activating agent, (b) is appropriate (embodiment 4) SiO of coating
2the seam organization of activating agent, (c) is the excessive SiO of coating
2the seam organization of activating agent (embodiment 5).As can see from Figure 4, uncoated SiO
2during activating agent, weld grain is more tiny, applies appropriate SiO
2after activating agent, weld grain size increases to some extent and occurs belt-like zone, applies excessive SiO
2the obvious alligatoring of weld grain after activating agent and belt-like zone broaden.
Fig. 5 is coating SiO
2the stress-strain diagram of welding point before and after activating agent: (a) is the stress-strain diagram of mother metal, (b) is uncoated SiO
2the stress-strain diagram of activating agent, (c) is the appropriate SiO of coating
2the stress-strain diagram of activating agent (embodiment 4), (d) is the excessive SiO of coating
2the stress-strain diagram of activating agent (embodiment 5).As can see from Figure 5, uncoated SiO
2during activating agent, the mechanical property of welding point is poor, applies appropriate SiO
2after activating agent, the mechanical property of welding point is obviously improved (ultimate tensile strength reaches more than 80% of mother metal), applies excessive SiO
2after activating agent, the mechanical property of welding point decreases.
Fig. 6 is coating SiO
2the stretching fracture pattern contrast photo of welding point before and after activating agent: (a) is the stretching fracture of mother metal, and (b) is uncoated SiO
2the stretching fracture of activating agent, (c) is the appropriate SiO of coating
2the stretching fracture of activating agent (embodiment 4), (d) is the excessive SiO of coating
2the stretching fracture of activating agent (embodiment 5).As can see from Figure 6, SiO is applied
2after activating agent, fracture has the dimple feature that is significantly elongated and has occurred some lamellar structures, belongs to tough crisp mixed fracture.
Pasty state SiO
2the unit are coating amount of activating agent is 1 ~ 4mg/cm
2time, SiO
2the coating amount of activating agent is in right amount, with uncoated SiO
2the weld seam of activating agent is compared, and its appearance of weld is good, and weld penetration significantly increases, and the mechanical property of welding point significantly improves; And as pasty state SiO
2the unit are coating amount of activating agent reaches 5mg/cm
2time above, SiO
2the coating amount of activating agent is excessive, although with uncoated SiO
2the weld seam of activating agent is compared, and increases in the mechanical property of weld penetration, welding point, but with coating appropriate SiO
2the weld seam of activating agent is compared, and decreases on the contrary in the mechanical property of appearance of weld, weld penetration, welding point.
In the present invention, the acetone in embodiment 1 ~ 5 is replaced with other organic solvent, such as ethanol, also can reach same technique effect.
In sum, the present invention is at the surface application pasty state SiO at magnesium alloy position to be welded
2activating agent thus formed SiO
2active agent coating, utilizes SiO
2active agent coating, to the stronger absorbability of laser beam and antiradar reflectivity, makes the loss late of laser energy reduce, and energy transmission efficiency increases, thus significantly improves laser beam energy utilization rate; Owing to significantly improving laser beam energy utilization rate, therefore, weld penetration significantly increases, and the mechanical property of welding point significantly improves, and low power laser can also be adopted to weld simultaneously, thus reduce welding cost.
What finally illustrate is, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although by referring to the preferred embodiments of the present invention, invention has been described, but those of ordinary skill in the art is to be understood that, various change can be made to it in the form and details, and not depart from the spirit and scope of the present invention that appended claims limits.
Claims (6)
1. for a Novel welding method for magnesium alloy laser welding, it is characterized in that: toward SiO
2add organic solvent in Agent Powder and become pasty state, then by pasty state SiO
2activating agent even application, on the surface at magnesium alloy position to be welded, forms SiO
2active agent coating, treats SiO
2laser weld is carried out, described pasty state SiO after organic solvent volatilization in active agent coating
2activating agent is 1 ~ 5mg/cm at the unit are coating amount of magnesium alloy portion faces to be welded
2.
2. the Novel welding method for magnesium alloy laser welding according to claim 1, is characterized in that: described organic solvent is acetone or alcohol.
3. the Novel welding method for magnesium alloy laser welding according to claim 1, is characterized in that: described pasty state SiO
2activating agent is 40mm in the application width of magnesium alloy portion faces to be welded.
4. the Novel welding method for magnesium alloy laser welding according to claims 1 to 3 any one, is characterized in that: at the surface application pasty state SiO at magnesium alloy position to be welded
2before activating agent, first polish and use the surface at ethanol purge magnesium alloy position to be welded.
5. the Novel welding method for magnesium alloy laser welding according to claims 1 to 3 any one, is characterized in that: toward SiO
2before adding organic solvent in Agent Powder, first fully mill SiO
2agent Powder.
6. the Novel welding method for magnesium alloy laser welding according to claim 1, is characterized in that: when carrying out laser weld, welding equipment used is YAG solid laser working apparatus.
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| CN103894758B (en) * | 2014-03-31 | 2017-01-11 | 南昌航空大学 | Activator for nickel-base superalloy laser welding and application method thereof |
| CN104043914B (en) * | 2014-07-10 | 2016-02-17 | 辽宁工业大学 | Hollow piston lever of reducer laser weld special active agent and its preparation method and application |
| CN105414804B (en) * | 2015-10-14 | 2018-06-22 | 丹东思诚科技有限公司 | Laser welding enhances the application of coating and waveform in copper, aluminium welding |
| CN107662048A (en) * | 2016-07-20 | 2018-02-06 | 北京科易动力科技有限公司 | A kind of method of laser stirring welding |
| CN107775213B (en) * | 2017-10-10 | 2019-09-27 | 北京航天新风机械设备有限责任公司 | A kind of almag laser welding activating agent and its application |
| CN112894141B (en) * | 2021-01-21 | 2022-06-14 | 天津修船技术研究所(中国船舶重工集团公司第六三一三研究所) | Laser welding method for special engine air inlet section component |
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| CN1041555A (en) * | 1988-10-03 | 1990-04-25 | 苏联立陶宛科学院物理研究所 | Laser Processing is made the method for filter and is realized the device of this method |
| CN100443241C (en) * | 2001-04-02 | 2008-12-17 | 太阳诱电株式会社 | Method for machining translucent material by laser beam and machined translucent material |
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| CN100371125C (en) * | 2004-05-27 | 2008-02-27 | 兰州理工大学 | Soldering agent and method for laser welding Al-Mg alloy plates with different thicknesses |
| CN102079013A (en) * | 2009-12-01 | 2011-06-01 | 南车青岛四方机车车辆股份有限公司 | Aluminum alloy laser welding method |
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