01 Taw Qhia
5A06 aluminium alloy yog dav siv nyob rau hauv tsheb, aerospace, thiab siab hlab ntsha industries vim nws lub zog siab thiab zoo heev corrosion kuj. Txawm li cas los xij, nws cov thermal conductivity, tsis tshua muaj viscosity, thiab siab reflectivity ua laser vuam nyuaj, feem ntau ua rau tsis zoo formability thiab loj porosity defects. Piv nrog ib lub laser lossis MIG vuam, laser-MIG hybrid vuam ua kom pom lub zog sib txuas zoo dua, molten pas dej ua ke ruaj khov, thiab kev tsim kho, txhim kho kev sib sib zog nqus thiab tiv thaiv porosity. Txawm li cas los xij, rau 5A06 aluminium alloy, evaporation ntawm magnesium thiab solubility hloov pauv ntawm hydrogen tseem ua rau muaj teeb meem loj porosity, yuav tsum tau tshawb xyuas ntxiv rau hauv pore tsim mechanisms thiab txheej txheem optimization. Txoj kev tshawb no tsom mus rau 6.9 hli tuab 5A06 aluminium alloy, tshuaj xyuas cov microstructure, porosity faib, pore tsim mechanisms, thiab microhardness variations ntawm welded pob qij txha nyob rau hauv hybrid vuam. Nws kuj tseem tshawb nrhiav kev sib xyaw ua ke ntawm vuam ceev thiab lub zog laser.
02 Txheej txheem cej luam
Kev tshawb fawb soj ntsuam cov yam ntxwv ntawm cov qauv thiab cov teeb meem porosity ntawm 6.9 hli tuab 5A06 aluminium alloy pob qij txha hauv qab laser-MIG hybrid vuam. Nws qhia tau hais tias vuam ceev yog qhov tseem ceeb parameter cuam tshuam rau formability, porosity tus nqi, thiab mechanical kev ua tau zoo. Txoj kev tshawb no txheeb xyuas qhov porosity yog qhov tsis xws luag, tshwm sim los ntawm ob yam tseem ceeb: hydrogen gas precipitating thaum lub sij hawm ceev ceev, thiab magnesium evaporation ntawm qhov kub thiab txias ua npuas. Cov pores no feem ntau yog concentrated nyob rau hauv ib nrab ntawm lub weld. Lub xub ntiag ntawm pores ho txo qhov sib koom ua ke hardness. Thaum grain coarsening ua rau softening nyob rau hauv lub tshav kub- cuam tshuam cheeb tsam (HAZ), softening nyob rau hauv lub weld cheeb tsam (WB) yog feem ntau yog vim lub pores. Cov kev tshawb fawb qhia tias qhov porosity muaj qhov cuam tshuam ntau dua rau kev txo qis dua li cov nplej coarsening, nrog rau hauv zos hardness poob qis li 29% ntawm tus nqi nruab nrab. Qhov sib txawv vuam ceev tau muab piv rau: tsawg dhau (2 m / min) ua rau cov pore aggregation thiab qis hardness, thaum siab dhau (3.5 m / min) coj mus rau txheej txheem-induced pores ntawm weld cag. Qhov zoo tshaj plaws vuam ceev tau pom tias yog 3 m / min, uas ua tiav zoo, sib npaug ntawm qhov pores, nkag mus zoo, thiab siab dua hardness.
03 Daim duab thiab tsom xam
Daim duab 1 qhia txog macroscopic morphology ntawm welds nyob rau hauv cov txheej txheem sib txawv. Kev nkag mus tau zoo tau ua tiav ntawm qhov nrawm ntawm 2-3.5 m / min, nrog kev tsim cov vuam tiav thiab tsis muaj kab nrib pleb, qhia txog kev ua tau zoo ntawm laser-MIG hybrid vuam piv rau MIG ib leeg.
Daim duab 2 qhia txog cov yam ntxwv ntawm microstructural ntawm welded pob qij txha, suav nrog weld zone (WB), tshav kub-ffected zone (HAZ), thiab lub hauv paus hlau (BM). Lub weld cheeb tsam feem ntau muaj equiaxed dendrites, nrog cov nplej hloov los ntawm columnar mus rau equiaxed ze ntawm fusion kab. Metallurgical pores ntawm 29-52 μm tau pom nyob rau hauv WB.
Daim duab 3 nthuav qhia cov pore faib hauv ntau thaj tsam. Pores nyob rau hauv lub qaum weld (Tebchaws A) feem ntau yog metallurgical, tsim los ntawm kev cuam tshuam ntawm npuas khiav thaum lub sij hawm solidification.
Daim duab 4 qhia txog microhardness faib thoob plaws cov pob qij txha. Ob lub WB thiab HAZ tau nthuav tawm muag muag, nrog cov pores ua rau muaj kev cuam tshuam ntau dua rau kev txo qis dua li cov nplej coarsening. Cov vuam nrawm dua nce qhov nruab nrab hardness, nrog me ntsis hardness pom nyob rau hauv lub qaum weld cheeb tsam.
04 Xaus
Txoj kev tshawb no ntawm 6.9 hli tuab 5A06 aluminium alloy pob qij txha nyob rau hauv laser-MIG hybrid vuam muab cov lus xaus hauv qab no:
1. Laser-MIG hybrid welding ua tiav qhov kev nkag tau zoo ntawm 2–3.5 m / min, txhim kho qhov vuam zoo.
2. Cov pores feem ntau yog tsom rau thaj tsam qaum weld, tshwm sim los ntawm hydrogen nag lossis daus thiab magnesium evaporation. Porosity muaj qhov cuam tshuam ntau dua rau kev sib koom ua ke softening dua li nplej coarsening.
3. Optimal parameters: laser hwj chim 4.5 kW thiab vuam ceev 3 m/min, yielding tsawg porosity, me pore loj, thiab haum microhardness tis.
4. Kev tswj cov txheej txheem kom zoo (kev ntxuav saum npoo av, tiv thaiv roj, thiab vuam ceev optimization) yog qhov tseem ceeb los txo qhov porosity thiab txhim kho weld kev ua tau zoo.
Kev siv
Kev tshaj tawm thawj zaug: Phau ntawv Journal of Manufacturing Processes, https://doi.org/10.1016/j.jmapro.2018.08.011
