The hammer that follow solder is attacked prevent thin plate to solder the technology research of hot crack
- source:EASCOR CNC Machining
The basic mechanism that 1 hot crack produces prevents to solder to explain the hammer that follow solder is attacked better the fundamental of hot crack, discuss above all, groovy solder condition issues the basic mechanism that hot crack produces. Will tell from mechanical angle, solder because meet an emergency of drawing of susceptive of area metal place is affected to lead the critical meet an emergency that is more than them in welding line of brittleness temperature interval or heat,the generation of hot crack is (CST) , if pursue,1 is shown. In type, the in-house meet an emergency that ε is welding line or hot influence gets when the area is cooling or true meet an emergency, t is temperature. The E that set ε is value of apparent meet an emergency, t is thermal strain, α is hot coefficient of expansion of the metal, criterion when, can prevent to solder the generation of hot crack. 1.
The 2 hammer that follow solder are attacked prevent to solder the fundamental of hot crack is soldering in the process, hot crack often arises at brittleness temperature interval (BTR) inside, contented D ε / when condition of DT ＞ CST, can arise solder hot crack. When welding line or metal of hot influence area are in brittleness temperature interval, in bath stretch weight is placed inside rear and certain distance, follow rear and synchronous hammer attacks welding torch two side of BTR metal, if pursue,2 are shown. Because peen distance bath is closer, the metal of peen lower part is in higher temperature. Accordingly, peen hammer knocks welding line when two side metal, below the action that knocks power in peen hammer, the meeting is right the welding line that is in BTR or generation of metal of hot influence area are transverse press C of ε of meet an emergency, in order to satisfy D ε / DT-d ε C/dT<CST, quits when soldering inhomogenous heat of generation send crack pull meet an emergency, rise to prevent to solder thereby the purpose of hot crack. 2 tests result and analysis the article is soldering in the craft experiment of hot crack, solder the method is chosen communication is automatic solder of arc of tungsten pole argon, test specimen is solder the 2A12 aluminium alloy with hot crack big liability, use the kind of exterior frit apply that does not write silk to solder, use gradient cabined spend clamping apparatus, through adjusting clamping force Fr and clip hold distance Lr neatly change is cabined degree, can reflect the true crackle action below actual production condition thereby. The course is produced in actual solder deliver a child in, workpiece does not arise certainly solder hot crack, and in this experiment, use this kind of gradient cabined spend clamping apparatus to arise more slashing cabined degree, main purpose is to make experimental test specimen is soldering the generation in the process solders hot crack, so that test and verify hits control along with solder hammer,solder the effectiveness of hot crack. With crackle rate Lcr% regards assess of hot crack tendency as index in the experiment, its expression is as follows: of length of path of solder of Ltotal- of total length of crackle of the Lcr- in Lcr%=Lcr/Ltotal type 2.
1 experiment test specimen attacks craft test in the hammer that follow solder in, solder to be opposite better hot crack undertakes study, the test specimen of the × 2 Mm of 100 Mm of 150 Mm × that if the graph is shown 3 times,used. 2.
Below condition of 2 groovy solder cabined the influence that spends pair of crackle rate 2.
1 cabined force to soldering the influence of hot crack pursues 4 gave out clip holds distance Lr=20 Mm, end receiving arc of cabined force F receives =120 N.
When M, result of hot crack test solders when the arc since the change carries cabined force F to rise. By the graph knowable, when should removing arc to carry the =0 since cabined force F, crackle is caused from end removing solder, crackle rate is top, follow along with solder crack, crackle is perforative and whole solder path. Try appropriately cabined (the =20 Nom since F) , crackle rate is reduced significantly. Continue to increase cabined power, crackle rate falls change delay, weldment leaves the arc hole crackle with have certain only. Graph 5 gave out clip holds distance Lr=20 Mm, end removing arc when the =20 Nom since cabined force F, result of hot crack test solders when the change receives arc to carry of cabined force F to close. Can see by the graph, as the addition that receives arc to carry cabined power, crackle rate increases gradually and tend finally stable. 2.
2 clip maintain a distance the impact that to soldering hot crack leads pursues the 6 clip when giving out to remove of =20 Nom, F to receive =120 Nom for F when cabined force maintain a distance the impact that to soldering hot crack leads. By can see in the graph, hold the addition of the distance as clip, crackle rate is reduced gradually. When clip holds a distance to be more than 60 Mm, test specimen is soldering arch goes up in the process serious, unwarrantable already solder normally. When the =20 Nom since F, F receives =120 Nom, Lr=20 Mm, generation receives arc apparently to carry crackle. 2.
The 3 hammer that follow solder attack the impact that the parameter below the condition leads to crackle to be in this experiment, for test and verify the hammer that follow solder attacks pair of control to solder the effectiveness of hot crack, used appear solder the experimental parameter with hot crack bigger liability: Clip holds distance Lr=20 Mm, end removing arc the =40 Nom since cabined force F, end receiving arc is cabined force F receives =120 Nom. Here removes arc to carry cabined force to be 40 Nom, did not use lesser cabined power, because should remove arc to carry when cabined force is lesser, crackle is removing arc to carry craze commonly, go against the craft test that has following solder hammer attacking, accordingly, used above experiment parameter. The hammer that follow solder is attacked to soldering the control of hot crack is made with, its influence parameter is more, be like: Hammer attacks force, hammer to strike a space (the distance of peen and welding torch) , hammer attacks the position, hammer to attack appearance of frequency, peen to wait. Two parameter basically discuss in the article: Hammer attacks force P and hammer to attack distance R hammer. 2.
1 hammer knocks power to soldering the influence of hot crack pursues 7 gave out hammer knocks power to soldering the influence of hot crack, hammer attacks =20 Mm of distance R hammer. Can see from inside the graph, hammer attacks force to be in be less than 2 MPa and the crackle rate of the weldment when be more than 5 MPa to all be compared big, hammer attacks force 2~5 MPa between when crackle rate is inferior, basically attribute arc hole flaw. Accordingly, when hammer attacks force to be inside this limits, can control effectively solder the generation of hot crack. Because be attacked when hammer when force is lesser, the inadequacy of quantity of meet an emergency that hammer attacks action to form solders at offsetting in the process inhomogenous heat those who form send crack pull meet an emergency, the effect that controls hot crack is not apparent. Attack when hammer when power is greater, hammer is attacked can bring about solder the oscillation with bath larger generation, can promote the farther generation of hot crack instead. Accordingly, below this experimental condition, hammer attacks force to be 2~5 MPa limits inside when, it is better that hammer strikes craft effect. 2.
2 hammer strike a space to soldering the influence of hot crack is in the experiment, hammer strikes a space to soldering the influence of hot crack also is compared apparent, if the graph is shown 8 times, experimental hammer attacks force to be P=4 MPa. The result makes clear: Rate of the crackle when hammer attacks =17 Mm of distance R hammer is older, rate of the crackle when hammer attacks =20 Mm of distance R hammer is minor, and the accretion that strikes a space along with hammer, crackle rate increases. Because be attacked when hammer when the distance is lesser, hammer attacks the position to leave solder electric arc is too close, hammer is attacked to soldering bath produces serious vibration, can promote the generation of hot crack. Attack when hammer when the space is larger, the sensitive position that the position that hammer attacks leaves generation hot crack too far, not apparent also to reducing the effect of hot crack. Accordingly, below this experimental condition, hammer attacks a distance to should be controlled control in 20~23 Mm, the effect that hammer strikes craft to control hot crack is better. 3 conclusion solder in the light of laminose component generation the drawback with hot crack big liability, the article solders to attacking craft to control along with solder hammer the effectiveness experiment of hot crack undertook study, study achievement makes clear: (The test specimen of the × 2 Mm</sub> of 100 Mm of 150 Mm × that 1) uses to this laboratory, below certain cabined power and cabined distance condition, hammer attacks force to be 2~5 MPa limits inside, when hammer attacks space control to be controlled in 20~23 Mm, the hammer that follow solder attacks technology control to solder the effect of hot crack is better, and mix to different test specimen solder condition, should use solder differently hammer hits parameter. (2) attacks craft test along with solder hammer is to be in more slashing cabined spend what undertake below the condition, but solder what hot crack rate compares groovy solder condition to fall apparently however is small, and the cabined condition in receiving production does not have actual solder so slashing. Accordingly, the hammer that follow solder attacks craft to decide effectively control to solder in actual production the generation of hot crack. CNC Milling CNC Machining