Diamond takes the laser beam welding of core broach to receive

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Summary: Studied ø82, two kinds of laser beam welding that diamond takes core bit receive ø68 method and craft, analysed parameter of craft of laser beam welding to soldering the influence of quality. This technology applies successfully in actual production, have direct sense to congener product. Keyword: Diamond takes core broach laser beam welding to receive craft parameter Laser Welding Of Diamond Core DrillsZhu Haihong, tang Xiahui, zhu Guofu(National Engineering Research Center For Laser Processing, HUST, wuhan, 430074)     Abstract: This Paper Deals With The Laser Welding Of Diamond Core Drills And The Effect Of Technical Parameters Such As The Focus Position, beam Power Density And Welding Speed On The Welding Strength.

The Experiment Results Provide The Better Technical Parameters To Correct The Practical Welding Procedure.

Key   Words: Diamond of foreword of Process Parameter of   of Laser Welding of   of Diamond Core Drills takes core broach to be not only in geological exploration have important place, have drilling rate because of its more loss of material of fast, stone is small, do not destroy the distinct advantage such as circumjacent environment and be applied extensively the bore of metope of Yudalishi, granitic, reinforced concrete. Diamond bit is the join on the matrix in steel body of a kind of a kind of when become by diamond and carcass material hot pressing compound agglomeration, the head is a knife that often says. Domestic broach often uses the methodological connection of drill rod solder. When diamond takes core broach to work because rotate speed is splitting, suffer be pounded strongly and shake, need high shear strength and high temperature strength. The broach knife head of drill rod solder often gets set out to heat causes drill rod makings to fuse and fall off as a result of high speed [1] . So, abroad replaces drill rod solder with laser beam welding with respect to development from 80 time later period, laser beam welding and drill rod solder are like next advantages quite: Because matrix and knife head are metallurgy union, intensity is high, knife head falls off not easily, fall in anhydrous circumstance especially; Welding line is petty and even columnar brilliant organization, produce crackle not easily, when making sure broach is gotten in high speed will not craze and generation is dangerous; Welding line and hot influence area are extremely narrow, do not have an influence to diamond, assured the optimum behavior of the product; Implement automation easily, efficiency is tall, quality is stable and reliable, and the average cost of the product is low. If the graph is shown 1 times,diamond takes the structure of core broach. The bit of laser beam welding that at present foreign market needs curiums with laser beam welding almost piece quite, market potential is very great, profit is opposite also taller. Because diamond takes the knife head of core broach,be pulverous metallurgy material, put inevitably in hole, solder difficulty is great; Matrix and knife head are heterogeneous material solder, knife head is thicker than matrix, be hard to double-faced solder, so compared with diamond fretsaw piece will solder difficulty is greater, at present home has not discovered the coverage of this respect. The test that we pass hundreds of times and exploration, obtained better result, solved crucial technology successfully, already applied in actual production now, the product is exported entirely, user report is favorable. Fig.

Test facilities of 1   The Structure Of The Diamond Core Drills1 and methodological test are what import in the United States is fast even if flow,undertake on laser, this machine is 80 time of American advanced product, model is EFA-51, output mode is TEM00 and TEM01, power of the biggest output is 1500W. Choose the GaAs focusing lens of F=100mm, collude axis protects aeriform Ar gas to reach lens in order to protect welding line. Broach matrix and knife head are installed to be placed on appropriative clamping apparatus. Circumgyrate workbench can drive clamping apparatus and broach to make circular motion, and can be inside certain limits adjust angle, test facilities is shown 2 times like the graph. Stimulate beam of light to slant a bit at matrix a side, it is certain to be used lose from anxious. To make be identical of knife head matrix good, the beard before knife head solder grinds arc, go burr, lest energy of light leak loss; To reduce weld defects, before solder must purify solders place and the skin of smeary, oxidation near its and moisture. Base material is common 45# steel, via moving qualitative processing, thick 2mm; Because diamond issues easy graphitization in high temperature, the conference when laser beam welding is received appears in welding line empty, so, knife head needs to design 1.

The transition of 5mm ~ 2mm layer, the author passes many test, choose a kind of special Co mixture to regard as transfer layer, knife head thick 3mm. After broach solder, range estimation and with exterior of welding line of observation of 10 times magnifier, examine welding line has without air hole, bite the macroscopical blemish such as edge, crackle, use DSA standard to examine with detector of appropriative flexural strength next the flexural strength of every knife head. Fig.

2   The Schematic Diagram Of Laser Weldinga, Offset   H, β of   of Focal Point Height, result of test of Beam Incident Angle2 and analysis 2.

1 material analyses base material to there is better weldability below condition of laser beam welding character. Knife head is different, because be pulverous metallurgy material, when soldering appear extremely easily air hole is empty even, should solder when parameter is undeserved, still can produce crackle, affected greatly solder intensity. The property of knife head is right solder the impact of function is very big, mechanical performance is good and compact knife head falls in condition of laser beam welding, should solder only parameter choice is proper, with respect to the welding line that can get according with performance characteristics, its bending strength can be achieved or exceed 1800N/mm2, break in knife head. Want to make knife head performance good when material is certain, must increase density of knife head suppress above all, can use choice grain the pulverous suppress with fine, even appearance, additional, below the premise that does not affect diamond performance, increase firing temperature and suppress pressure as far as possible, choose right heat preservation time to be opposite the mechanical performance that improves knife head very be necessary. The inevitable existence hole inside knife head, the density of knife head cannot reach theoretical value, but appropriate pressure, temperature and heat preservation time, pulverous mixture time and speed are knife head compact and even important assure, assure to have good weldability thereby can. The experiment makes clear: In 20MPa when unit pressure the left and right sides, temperature is in when time of 800 ℃ left and right sides, heat preservation is 4min, can get can satisfaction the need of laser beam welding, knife head that does not damage the mould reachs diamond function again. The density of knife head is the biggest to the influence of welding line intensity, the knife head of low density solders the welding line intensity that come out is very low, achieve place almost impossibly to need strength. 2.

2 welder art research focus position is below the condition with smooth route regular system, focal photograph deep to frit to the position of material surface, frit is wide, fused the impact of efficiency is very big. In this experiment, use negative from Jiao Ke in order to increase frit deep, it is about from anxious quantity 0.

3mm, when soldering to decrease, splatter, protect lens, drop alloying element of knife head material burn caustic, focus should deflection matrix at the same time 0.

1mm left and right sides; To achieve result of optimal fillet weld, incident laser should tilt 11 ° of 6 ° ~ are controlled; When the opposite solders, we increase an illuminator in smooth route system, inside canister of park broach matrix, will stimulate beam of light to reflex place to need the place, if the graph is shown 3 times, solved successfully because broach is bosseyed solder the problem with easy occurrence not stable intensity. Fig. Density of power of laser of density of power of laser of   of 3   Schematic Diagram Of Reverse Welding is the main parameter that decides welding line penetration. In facula diameter particular case falls, power density direct ratio at laser power. Power is higher, allow to solder board thick bigger, solder rate is rapidder, manufacturing efficiency is taller, but too great laser power can make addle of welding line exterior, because dissolve pool rolls, easy generation protuberant and empty, reduced welding line badly to bear the weight of effectively area, bending strength is reduced; Although place can be achieved to need strength in examining after solder, in cutting process because of stress among them, crackle is expanded by hole place, appear apparent fatigue fracture is characteristic; In addition, solder high the chemical physics reaction that power still can make bath medium is severe, splatter grow in quantity, pollute lens; Because transfer,the heat of a material and diamond carcass material bilges coefficient is different, soldering exorbitantly below power condition, be in two conterminous place easily to produce crackle as a result of overheat. Double-faced solder the broach of ø82, it is in facula diameter 0.

When 4mm, it is better to can be obtained with power 900W solder the effect. In the experiment we discover, the method that uses small standard to solder solders broach can have obtained solder the effect. Compared with diamond fretsaw piece, solder the laser power of broach wants relatively some taller, because laser is incident,this is the cause that is reflexed by the part on round broach matrix, if pursue,4 are shown. Fig.

  of 4   Scheme Of Laser Beam Reflection On Piece Surface solders speed solders the hot input that speed receives power to affecting weld zone region together with laser beam welding, have bigger effect to the appearance of welding line and dimension consequently, as solder the addition of speed, welding line width is reduced, frit is deep decrease, productivity rises. Pass to solder greatly speed can make welding line cannot penetrate, intensity is reduced, and the harmful gas in welding line is like N2, h2, o2 and CO have not enough time transgression, make welding line stomatic grow in quantity, affect bending strength and welding line exterior; Should solder when rate is too low, welding line is too broad, heat affects area overheat, grain is bulky, still can produce crackle sometimes, produce crackle in two conterminous place especially, affected severely solder quality, and the alloying element of knife head burns caustic serious, affected the integral performance of knife head, because bath rolls and welding line place appears many a empty. In our experiment, to ø82, ø68 two kinds of broach each 50, 900W is in laser power make choice of, rotate speed is 8r/min respectively, when 9r/min, the flexural strength of its welding line is achieved and exceed 4000N/mm2, in subsequently cutting process, the phenomenon that also did not discover a knife. The action in protecting aeriform discharge to protect gas to receive a process in laser beam welding has 3 [2] : Protective weld zone is not oxidized; Protect focusing lens; Blow medicinal powder cloud of ministry classify ion. If throughput is too small, action is less than since, welding line area is oxidized and cause mechanical function aggravation, lens pollutes attaint easily also, cost raises; Too big throughput can be blown turn over bath, affect welding line figuration, increase weld defects, reduce frit at the same time deep. Solder in ours throughput is chosen in the experiment for 0.

5L/min. 3 epilogue   (1) should make laser beam welding receives diamond to take core broach to succeed, in knife head recipe particular case falls, must make knife head compact and mechanical performance is good; (2) diamond is received to take core broach course in laser beam welding in, must choose to concern craft parameter reasonably, like laser power density, solder discharge of position of speed, focus and protective gas, ability assures to solder quality; (3) the welder that uses small standard art the efficient way that is solder good bit; (4) the reverse side that uses the method that adds an illuminator in smooth route system to be able to have bit solders, solved because broach is bosseyed solder the problem with combinative not stable strength, but this kind of method cannot solder the bit with too little diameter; (5) incommensurate still big batch produces the method that laser beam welding accepts diamond to take core bit, productivity is not tall, remain to be improved further. CNC Milling