Supersonic concussion method rises solder contact exhaustion intensity

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Summary: Solder to rise structural exhaustion function, compared through the experiment mix via sample of connect of butt joint of steel of cop of supersonic percussive X65 the fatigue life that fatigue intensity reachs the sample of connect of butt joint of primitive as welded that manages without here to fall in same stress limits. The statistical result of the experiment makes clear, through the sample that supersonic concussion handles, its exhaustion intensity did not pound sample to rise relatively 37. 9% , its exhaustion life is 1 what did not pound sample. 85 ～ 11. 00 times. With the traditional solder that improves structural exhaustion performance aftertreatment measure photograph is compared, supersonic concussion processing is a kind already efficient convenient relatively good technique. Solder the weak point that contact is component wear, because this is in development is high-powered solder when component part, rise solder the fatigue intensity of contact is a very main task. General more important solder component part uses high strenth steeliness to build, as rolled steel tensile strength rise, its exhaustion intensity also increases accordingly. Consider to make clear, the welding line of high strenth steel structure that handles to treatment is not being made after solder, because be below the action of the element such as concentration of stress of solder foot place, rise and increase what its exhaustion intensity does not follow tensile strength, the advantage that reason cannot reflect be sent on a diplomatic mission to use high strenth steel [1] . Accordingly, although exceed the intensity of the itself of high strenth rolled steel such as steel of fine grain structure and service life to rise substantially, but mix in the quality that contact solders on particular steel structure function just is the main factor that restricts structural intensity and life. Undertake machining handling to welding line only, ability improves its performance at all. Consider to make clear with practice, fatigue fracture is the main form of metallic structure invalidation, especially a few accept dynamic and serious important structure. Solder the exhaustion of contact is destroyed rise commonly crack at soldering the solder foot place of contact. If can improve what solder foot is in fatigue crackle to rise,crack function, rise effectively solder fatigue intensity of the structure. Relevant and traditional method, be like tungsten pole inferior arc solder (Tung2sten Inert2gas Arc, TIG) frit is long law, mechanical burnish law, explosion law, gush pill law, overload law, local pressure delay law, local heating law and hammer to strike a law. These methodological some still stay in lab phase, some labor strength are great, and manufacturing efficiency is not tall. The real significance that traditional solder postheat handles steel products of steel of structure of fine to exceeding grain is not great. Application is at present more is average weight attacks frit of law, TIG to write law and gush pill law. Average weight attacks law noise big, efficiency strength of low, labor is great, can accuse a gender to differ and the effect is very flabby calm. TIG frit builds law construction technology complex, the operation is undeserved can cause side effect instead. Gush pill law is a actual application is more kind, but existence noise big, equipment giant, power consumption is big etc go against energy-saving, cannot move conveniently the defect such as difficulty of exercise, field construction. Because pill rebounds, return existence safety to defend problem, and pill needs to answer received in full to manage [2] author uses supersonic percussive method to rise solder contact and structural exhaustion intensity. This method has been being used domestic and internationally, the mechanism that its increase fatigue strength and hammer are attacked and gush bolus agrees basically. As a result of its actuator it is deft, good to can charge a sex, use agile and convenient, noise small, efficiency tall, applicability low and strong, cost is energy-saving environmental protection, supersonic impact is initial already show its the distinct advantage of fatigue to improving joint function. Effect of 1 supersonic concussion experiments 1.

1 ultrasonic pounds methodological mechanism to pass ultrasonic generator to be versed in the 50 Hz on electrified wire netting change of frequency alternating current becomes alternating current of 20 KHz ultrasonic frequency, use the transducer of incentive and acoustics system. Acoustics system changes electric energy into the mechanical vibration of same frequency, be in self-prossessed below the constant pressure action that reachs the outside to bring to bear on, deliver the mechanical vibration of this part ultrasonic frequency the welding line on workpiece, make solder with what solder foot is particular area of the center the model that contact surface produces enough depth changes layer. Improve welding line and intermediate zone of mother capable person effectively thereby (solder foot) outside figure, make its make the same score glide to cross, reduced solder the stress of contact centers degree, make solder near contact the metal of certain ply be able to aggrandizement, readjust solder leftover stress field, the is helpful for fatigue intensity rising surface that forms plurality value by supersonic concussion presses stress, changed microcosmic organization at the same time, improved the organization of contact area, the contact exhaustion intensity after making pound processing is able to rise significantly. 1.

2 tests data pursues 1 solder appearance of contact test specimen solders to rising to confirm supersonic concussion processing technique contact exhaustion intensity has favorable effect, undertook exhaustion of contrast of sex of test and verify experiments. Two groups of test specimen with draw materials the serves as test and verify object: from X65 cop steel? ? group is the connect of primitive butt welding without any processing sample, the 2nd group is the sample of butt joint connect after be being handled through supersonic concussion, test specimen uses bosseyed solder double-faced shape solder craft is made, contact uses form of butt joint connect. If the graph is shown 1 times,its make the form of treatment. Material of X65 cop steel is mechanical if function expresses 1 to show. Express 1 material mechanical function 1.

3 solder the supersonic concussion device that the executive method that the supersonic concussion of contact handles uses Tianjin university to develop solders to X65 steel test specimen contact undertakes pounding handling. Is specific operation method: ? Gou Zaiji of Du of awake of    makes an appointment with  steel to writing brush one  respects class bluff  to shelter quite admonish mounds the direction of welding line of edge of concussion needle array of? concussion head arranges; to bring to bear on slightly constant pressure, make its are in basically actuator (concussion gun) below self-prossessed condition, undertake pounding handling. When processing, incentive electric current is 0. 5 A, and with 0. The processing speed of 5 M /min, pound processing 4 times back and forth. In pounding processing process, concussion gun is in perpendicular swing at what the direction of welding line makes proper point of view, so that make,solder foot place obtains better smooth glide to cross an appearance. 1.

Equipment of test of 4 fatigue function and experiment of function of methodological test exhaustion are in red hill 100 KN high frequency exhaustion experiments undertake on machine. Experiment machine is static carry precision full span to be ± 0. 20% , dynamic amplitude wave motion spends full span to be ± 20% . Apply: of circumstance of to load carry on one's shoulder? Glair narrow heart acts the role of?01Hz, load type is drawing load, stress compares R = 0 circularly. 1. Result of 2 test and the bosseyed solder that analyse primitive as welded and condition of supersonic concussion processing are double-faced shape to experiment to see a table as a result to accepting the fatigue of contact test specimen 2. Express result of 2 fatigue tests according to international Institute of Welding (the data of corresponding and fatigue test of connect of the butt joint in the test of statistical method processing that exhaustion of to load of loop of IIW) steel structure devises normative regulation [3] , contact as welded and the S-N curve that contact pounds voice are shown 2 times like the graph. From the graph 2 in can see, classics is supersonic concussion is treated contact S-N curve is apparent prep above is primitive as welded connect. The σ of fatigue intensity Δ below all sorts of contact condition (2 × 106) sees a table 3. By the watch 3 calculable piece, after be being handled via supersonic concussion, fatigue intensity rose than primitive as welded 37. 9% . Graph the metabolic circumstance of the fatigue life that curve of S-N of connect of 2 test specimen leaves supersonic concussion to handle around test specimen in identical stress level to obtain, the watch 2 medium corresponding test data press equation Sm N =C to plan to close respectively [the parameter of curve of 2] (S-N sees watch 4) , reach supersonic concussion handles X65 steel to solder contact test specimen is below limits of corresponding stress of the place when life is 1 × 107 times the fatigue life of as welded test specimen and as welded test specimen are 1 × 105 times in life the exhaustion that the supersonic concussion below limits of place correspondence stress handles test specimen, result rank is expressed 5 in. Express × of 2 of σ of Δ of 3 fatigue intensity the statistic that the test result of 106 expresses data of 4 fatigue tests handles contrast of 　 of result <DIV Align=left></DIV><DIV Align=left> to express 5 Central Plains only then the fatigue life that as welded and test specimen of condition of supersonic concussion processing leave in identical stress limits, the result shows, the fatigue life that receives contact through the X65 steel butt welding that supersonic concussion handles was lengthened, crude guess is connect of primitive as welded 1. 85 ～ 11 times. </DIV> expresses 5 as welded and the fatigue life that pound voice connect to consider to make clear, solder after the structure is made, the main factor that affects intensity of welding line exhaustion is the stress concentration of welding line, and the stress of welding line centers degree with its appearance parameter (geometrical element) closely related. Make common solder when the structure, use commonly fused soldering method, certain fill metal needs below most circumstance, reason stays in contact place superabundant tall, indentation reachs all sorts of weld defects, cause serious stress concentration. In the meantime, return those who produce fair numerical value to solder remains pulls stress. Below most circumstance, remains pulls stress to soldering the influence of structural exhaustion intensity is adverse. Consider to make clear in great quantities, the surface is apart from in solder foot place 0. Place of 5 Mm left and right sides exists commonly slaggy wait for blemish, this blemish is acerber, be equivalent to fatigue crackle be being produced ahead of schedule [4] . Contact in foot of stress concentration, solder slaggy blemish is reached solder below the combined action that remains presses stress, bring about fatigue intensity to be reduced badly. Solder hind adopts supersonic concussion method, build the geometrical external form of connect of be apt to, reduce Yu Gao to the stress that cause is centered and eliminate the flaw of solder foot surface, adjust solder leftover stress field, eliminate its negative effect, made face is helpful for the directional change that fatigue intensity increases, it is substantially improvement solders apparently the main reason of the fatigue intensity of contact and structure [5 ～ 7] . Notable, the existence of weld defects is reduced inevitably solder the fatigue intensity of contact. Structural interior is passed solder the strict control of quality is OK and effective keep within limits the generation of these blemish, but exterior blemish also is a reduces fatigue intensity factor that cannot ignore. In pounding processing process, place of foot of solder of individual test specimen exposes a small Duan Jian crackle (incomplete fusion) , after be being handled via concussion, crackle disappears. Although cut area decreases somewhat relatively, but the fatigue life that did not affect this test specimen is numeric. This shows not deep to be located in the surface or bury small size defect, the method that can handle through supersonic concussion gives eliminate. This kind of action solders to rising contact exhaustion life and intensity have certain contribution. Use supersonic percussive method to rise solder the fatigue life of contact, its effect is distinct. This method is OK the fatigue strength that land of very old rate increases contact, make solder the fatigue intensity that contact is close to mother capable person, even capable person of prep above mother. So, design reasonable, connect to solder quality is good and classics is supersonic concussion is proper treated bear low stress solders dynamicly structure, solder contact will be weak point no longer. 3 conclusion solders with X65 steel contact is research target, test specimen is primitive the σ of fatigue intensity Δ of as welded (106) of 2 × is 219MPa, the σ of fatigue intensity Δ that contact solders after supersonic concussion is handled (106) of 2 × is 302MPa. The butt welding of X65 cop steel that handles through supersonic concussion receives contact, its exhaustion intensity rises relative to connect of primitive as welded 37. 9% , the fatigue life below identical stress limits is connect of primitive as welded 1. 85 ～ 11 times. Supersonic concussion processing can make butt welding of X65 steel tube receives the fatigue function of contact to be improved significantly, the experiment proves, supersonic concussion is a kind of effect remarkable and the improvement after the solder of facilitating operation solders the measure of contact exhaustion function. CNC Milling CNC Machining