Kev sib xyaw ua ke ntawm cov txhuas thiab cov hlau txhuas

1. Kev ua kom kub hnyiab

Cov khoom siv brazing ntawm txhuas thiab txhuas alloys tsis zoo, feem ntau vim tias cov zaj duab xis oxide ntawm qhov chaw nyuaj rau tshem tawm. Aluminium muaj kev sib raug zoo rau oxygen. Nws yooj yim los tsim cov zaj duab xis oxide Al2O3 uas ntom, ruaj khov thiab siab melting point ntawm qhov chaw. Tib lub sijhawm, cov hlau txhuas alloys uas muaj magnesium kuj tseem yuav tsim cov zaj duab xis oxide MgO ruaj khov heev. Lawv yuav cuam tshuam loj heev rau kev ntub thiab kis ntawm cov solder. Thiab nyuaj rau tshem tawm. Thaum lub sijhawm brazing, cov txheej txheem brazing tsuas yog tuaj yeem ua tiav nrog cov dej ntws kom raug.

Qhov thib ob, kev ua haujlwm ntawm txhuas thiab txhuas alloy brazing yog qhov nyuaj. Lub ntsiab lus yaj ntawm txhuas thiab txhuas alloy tsis txawv ntawm cov hlau brazing filler siv. Qhov kub xaiv tau rau brazing yog nqaim heev. Kev tswj qhov kub me ntsis tsis raug yog qhov yooj yim ua rau overheating lossis txawm tias yaj ntawm lub hauv paus hlau, ua rau cov txheej txheem brazing nyuaj. Qee cov txhuas alloys uas muaj zog los ntawm kev kho cua sov kuj tseem yuav ua rau muaj qhov tshwm sim mos xws li laus dhau lossis annealing vim brazing cua sov, uas yuav txo cov yam ntxwv ntawm cov pob qij txha brazed. Thaum lub sijhawm nplaim taws brazing, nws nyuaj rau txiav txim siab qhov kub vim tias xim ntawm txhuas alloy tsis hloov pauv thaum lub sijhawm cua sov, uas kuj ua rau cov neeg teb xov tooj xav tau qib kev ua haujlwm ntau ntxiv.

Ntxiv mus, qhov kev tiv thaiv corrosion ntawm txhuas thiab txhuas alloy brazed pob qij txha yog yooj yim cuam tshuam los ntawm cov hlau filler thiab fluxes. Lub peev xwm electrode ntawm txhuas thiab txhuas alloy yog txawv ntawm qhov ntawm solder, uas txo qhov kev tiv thaiv corrosion ntawm pob qij txha, tshwj xeeb tshaj yog rau cov soldering pob qij txha mos. Tsis tas li ntawd, feem ntau ntawm cov fluxes siv hauv kev brazing ntawm txhuas thiab txhuas alloys muaj corrosivity muaj zog. Txawm tias lawv raug ntxuav tom qab brazing, qhov cuam tshuam ntawm fluxes rau qhov kev tiv thaiv corrosion ntawm pob qij txha yuav tsis raug tshem tawm tag nrho.

2. Cov khoom siv sib txhuam

(1) Kev sib xyaw ua ke ntawm txhuas thiab txhuas alloys yog ib txoj kev tsis tshua siv, vim tias cov khoom sib xyaw thiab electrode muaj peev xwm ntawm brazing filler hlau thiab lub hauv paus hlau sib txawv heev, uas yooj yim ua rau electrochemical xeb ntawm qhov sib koom ua ke. Cov soldering mos mos feem ntau siv zinc raws li solder thiab tin lead solder, uas tuaj yeem faib ua qis kub solder (150 ~ 260 ℃), nruab nrab kub solder (260 ~ 370 ℃) thiab kub solder (370 ~ 430 ℃) raws li qhov kub thiab txias. Thaum tin lead solder siv thiab tooj liab lossis nickel yog pre-plated rau ntawm qhov chaw txhuas rau brazing, xeb ntawm qhov sib koom ua ke tuaj yeem tiv thaiv, yog li txhim kho qhov corrosion tsis kam ntawm qhov sib koom ua ke.

Kev sib txhuam ntawm cov txhuas thiab cov hlau txhuas yog siv dav, xws li cov ntawv qhia lim dej, evaporator, radiator thiab lwm yam khoom. Tsuas yog cov hlau ua los ntawm txhuas xwb thiaj siv tau rau kev sib txhuam ntawm cov txhuas thiab cov hlau txhuas, ntawm cov hlau txhuas silicon yog cov hlau siv dav tshaj plaws. Qhov tshwj xeeb ntawm kev siv thiab lub zog shear ntawm cov pob qij txha brazed tau qhia hauv Rooj 8 thiab Rooj 9 feem. Txawm li cas los xij, qhov chaw yaj ntawm cov solder no ze rau ntawm cov hlau hauv paus, yog li qhov kub ntawm cua sov yuav tsum tau tswj hwm nruj thiab raug thaum lub sijhawm sib txhuam kom tsis txhob kub dhau lossis yaj ntawm cov hlau hauv paus.

Rooj 8 daim ntawv thov ntawm cov hlau nplaum rau txhuas thiab txhuas alloys

Rooj 9 shear lub zog ntawm txhuas thiab txhuas alloy pob qij txha brazed nrog txhuas silicon filler hlau

Cov txhuas silicon solder feem ntau yog muab los ntawm hmoov, nplaum, hlau lossis daim ntawv. Qee zaum, cov phaj sib xyaw ua ke nrog txhuas ua lub hauv paus thiab txhuas silicon solder ua lub cladding raug siv. Hom phaj sib xyaw solder no yog ua los ntawm txoj kev hydraulic thiab feem ntau siv ua ib feem ntawm cov khoom sib xyaw. Thaum lub sijhawm sib xyaw, cov hlau sib xyaw ua ke ntawm cov phaj sib xyaw yaj thiab ntws raws li qhov kev ua ntawm capillary thiab lub ntiajteb txawj nqus kom puv qhov sib koom ua ke.

(2) Flux thiab roj tiv thaiv rau txhuas thiab txhuas alloy brazing, flux tshwj xeeb feem ntau yog siv los tshem tawm cov zaj duab xis. Cov organic flux raws li triethanolamine, xws li fs204, yog siv nrog cov solder mos mos kub qis. Qhov zoo ntawm cov flux no yog tias nws muaj me ntsis corrosion cuam tshuam rau cov hlau hauv paus, tab sis nws yuav tsim ntau cov roj, uas yuav cuam tshuam rau qhov ntub thiab caulking ntawm cov solder. Cov reactive flux raws li zinc chloride, xws li fs203 thiab fs220a, yog siv nrog nruab nrab kub thiab kub siab solder mos mos. Cov reactive flux yog corrosive heev, thiab nws cov seem yuav tsum tau tshem tawm tom qab brazing.

Tam sim no, kev siv cov hlau txhuas thiab cov hlau txhuas ua ke tseem siv cov tshuaj flux tshem tawm cov yeeb yaj kiab. Cov tshuaj flux siv rau kev siv cov tshuaj chloride thiab cov tshuaj fluoride. Cov tshuaj chloride muaj peev xwm tshem tawm cov yeeb yaj kiab oxide thiab cov dej ntws zoo, tab sis nws muaj cov tshuaj corrosive rau cov hlau puag. Nws cov seem yuav tsum tau tshem tawm tag nrho tom qab siv cov tshuaj fluoride. Cov tshuaj fluoride yog ib hom tshuaj flux tshiab, uas muaj cov tshuaj tshem tawm cov yeeb yaj kiab zoo thiab tsis muaj xeb rau cov hlau puag. Txawm li cas los xij, nws muaj qhov kub yaj siab thiab tsis ruaj khov, thiab tsuas yog siv tau nrog cov tshuaj txhuas silicon solder xwb.

Thaum brazing txhuas thiab txhuas alloys, feem ntau siv lub tshuab nqus tsev, nruab nrab lossis inert huab cua. Thaum siv lub tshuab nqus tsev brazing, qhov degree nqus tsev feem ntau yuav tsum ncav cuag qhov kev txiav txim ntawm 10-3pa. Thaum nitrogen lossis argon roj siv rau kev tiv thaiv, nws cov purity yuav tsum siab heev, thiab cov dew point yuav tsum qis dua -40 ℃.

3. Kev siv tshuab txhuam

Kev sib txhuam ntawm txhuas thiab txhuas alloys muaj qhov yuav tsum tau ntxuav qhov chaw ua haujlwm. Yuav kom tau txais qhov zoo, cov roj av thiab cov zaj duab xis oxide ntawm qhov chaw yuav tsum tau tshem tawm ua ntej sib txhuam. Tshem tawm cov roj av ntawm qhov chaw nrog Na2CO3 kua dej ntawm qhov kub ntawm 60 ~ 70 ℃ rau 5 ~ 10 feeb, thiab tom qab ntawd yaug nrog dej huv; Cov zaj duab xis oxide ntawm qhov chaw tuaj yeem tshem tawm los ntawm kev sib tsoo nrog NaOH kua dej ntawm qhov kub ntawm 20 ~ 40 ℃ rau 2 ~ 4 feeb, thiab tom qab ntawd ntxuav nrog dej kub; Tom qab tshem tawm cov roj av thiab cov zaj duab xis oxide ntawm qhov chaw, cov haujlwm yuav tsum tau kho nrog HNO3 kua dej rau gloss rau 2 ~ 5 feeb, tom qab ntawd ntxuav hauv dej ntws thiab thaum kawg ziab. Cov haujlwm kho los ntawm cov txheej txheem no yuav tsum tsis txhob kov lossis ua qias neeg nrog lwm cov av, thiab yuav tsum tau sib txhuam hauv 6 ~ 8 teev. Nws yog qhov zoo dua los sib txhuam tam sim ntawd yog tias ua tau.

Cov txheej txheem brazing ntawm txhuas thiab txhuas alloys feem ntau suav nrog nplaim taws brazing, soldering hlau brazing thiab cub tawg brazing. Cov txheej txheem no feem ntau siv flux hauv brazing, thiab muaj cov kev cai nruj ntawm qhov kub thiab txias thiab tuav lub sijhawm. Thaum lub sijhawm nplaim taws brazing thiab soldering hlau brazing, tsis txhob ua kom sov lub flux ncaj qha los ntawm qhov chaw kub kom tiv thaiv cov flux los ntawm overheating thiab tsis ua haujlwm. Vim tias txhuas tuaj yeem yaj hauv cov solder mos nrog cov zinc ntau, cua sov yuav tsum nres thaum lub pob qij txha tau tsim kom tsis txhob muaj xeb hlau. Hauv qee kis, kev brazing ntawm txhuas thiab txhuas alloys qee zaum tsis siv flux, tab sis siv ultrasonic lossis scraping txoj kev los tshem tawm zaj duab xis. Thaum siv scraping los tshem tawm zaj duab xis rau brazing, ua ntej cua sov lub workpiece mus rau qhov kub brazing, thiab tom qab ntawd scrape lub brazing ntawm lub workpiece nrog qhov kawg ntawm tus pas nrig solder (lossis scraping cuab yeej). Thaum rhuav tshem cov zaj duab xis oxide saum npoo, qhov kawg ntawm lub solder yuav yaj thiab ntub cov hlau hauv paus.

Cov txheej txheem sib txuas ntawm txhuas thiab txhuas alloys feem ntau suav nrog nplaim taws brazing, cua sov brazing, dip brazing, nqus brazing thiab roj shielded brazing. Flame brazing feem ntau yog siv rau cov workpieces me me thiab ib daim ntau lawm. Yuav kom tsis txhob muaj qhov tsis ua haujlwm ntawm flux vim yog kev sib cuag ntawm cov impurities hauv acetylene thiab flux thaum siv oxyacetylene nplaim taws, nws yog qhov tsim nyog los siv roj av compressed cua nplaim taws nrog me ntsis reducibility kom tiv thaiv oxidation ntawm lub hauv paus hlau. Thaum lub sijhawm tshwj xeeb brazing, brazing flux thiab filler hlau tuaj yeem tso rau ntawm qhov chaw brazed ua ntej thiab cua sov tib lub sijhawm nrog workpiece; Lub workpiece kuj tuaj yeem raug cua sov rau qhov kub brazing ua ntej, thiab tom qab ntawd cov solder dipped nrog flux tuaj yeem xa mus rau qhov chaw brazing; Tom qab flux thiab filler hlau yaj, cua sov nplaim taws yuav tsum raug tshem tawm maj mam tom qab filler hlau puv sib npaug.

Thaum brazing txhuas thiab txhuas alloy hauv lub cub tawg cua sov, cov hlau brazing filler yuav tsum tau preset, thiab cov brazing flux yuav tsum tau yaj hauv dej distilled kom npaj tau cov tshuaj tuab nrog qhov concentration ntawm 50% ~ 75%, thiab tom qab ntawd coated lossis tsuag rau ntawm qhov chaw brazing. Ib qho nyiaj ntawm cov hmoov brazing flux tsim nyog kuj tuaj yeem npog rau ntawm cov hlau brazing filler thiab qhov chaw brazing, thiab tom qab ntawd cov weldment sib dhos yuav tsum tau muab tso rau hauv lub cub tawg rau cua sov brazing. Yuav kom tiv thaiv cov hlau hauv paus kom tsis txhob overheating lossis txawm tias yaj, qhov kub ntawm cua sov yuav tsum tau tswj hwm nruj me ntsis.

Feem ntau, cov tshuaj nplaum los yog cov ntawv ci siv rau kev sib xyaw ua ke ntawm txhuas thiab txhuas alloys. Cov khoom ua haujlwm uas tau sib dhos ua ke yuav tsum tau preheated ua ntej brazing kom nws qhov kub ze rau qhov kub brazing, thiab tom qab ntawd muab tso rau hauv cov dej sib xyaw ua ke rau brazing. Thaum brazing, qhov kub brazing thiab lub sijhawm brazing yuav tsum tau tswj hwm nruj me ntsis. Yog tias qhov kub siab dhau, cov hlau yooj yim yaj thiab cov hlau yooj yim ploj; Yog tias qhov kub qis dhau, cov hlau tsis yaj txaus, thiab tus nqi brazing txo qis. Qhov kub brazing yuav tsum txiav txim siab raws li hom thiab qhov loj ntawm cov hlau, cov khoom sib xyaw thiab qhov chaw yaj ntawm cov hlau filler, thiab feem ntau yog nyob nruab nrab ntawm qhov kub liquidus ntawm cov hlau filler thiab qhov kub solidus ntawm cov hlau base. Lub sijhawm dipping ntawm cov khoom ua haujlwm hauv lub dab dej flux yuav tsum ua kom ntseeg tau tias cov hlau tuaj yeem yaj thiab ntws tag nrho, thiab lub sijhawm txhawb nqa yuav tsum tsis txhob ntev dhau. Txwv tsis pub, cov khoom silicon hauv cov hlau solder yuav kis mus rau hauv cov hlau base, ua rau cov hlau base ze ntawm cov seam brittle.

Hauv kev siv lub tshuab nqus tsev vuam ntawm txhuas thiab txhuas alloys, cov hlau ua haujlwm activators feem ntau siv los hloov kho cov zaj duab xis oxide ntawm txhuas thiab xyuas kom meej tias cov solder ntub thiab kis. Magnesium tuaj yeem siv ncaj qha rau ntawm qhov workpiece hauv daim ntawv ntawm cov khoom me me, lossis qhia rau hauv thaj chaw brazing hauv daim ntawv ntawm cov pa dej, lossis magnesium tuaj yeem ntxiv rau aluminium silicon solder ua cov khoom sib xyaw. Rau cov workpiece nrog cov qauv nyuaj, txhawm rau kom ntseeg tau tias tag nrho cov nyhuv ntawm magnesium vapor ntawm cov hlau hauv paus thiab txhim kho qhov zoo ntawm brazing, cov txheej txheem tiv thaiv hauv zos feem ntau raug coj los siv, uas yog, cov workpiece raug muab tso rau hauv lub thawv stainless hlau (feem ntau hu ua lub thawv txheej txheem), thiab tom qab ntawd muab tso rau hauv lub cub tawg nqus tsev rau cua sov brazing. Vacuum Brazed Aluminium thiab aluminium alloy pob qij txha muaj qhov chaw du thiab cov pob qij txha ntom ntom, thiab tsis tas yuav ntxuav tom qab brazing; Txawm li cas los xij, cov khoom siv nqus tsev vuam kim heev, thiab cov pa magnesium ua rau lub cub tawg qias neeg heev, yog li nws yuav tsum tau ntxuav thiab tswj xyuas ntau zaus.

Thaum siv cov hlau txhuas thiab cov hlau txhuas ua ke hauv huab cua tsis muaj zog lossis tsis muaj zog, siv cov tshuaj magnesium activator lossis flux los tshem cov zaj duab xis. Thaum siv cov tshuaj magnesium activator los tshem cov zaj duab xis, qhov ntau ntawm magnesium uas xav tau tsawg dua li ntawm kev siv lub tshuab nqus tsev. Feem ntau, w (mg) yog li 0.2% ~ 0.5%. Thaum cov ntsiab lus ntawm magnesium siab, qhov zoo ntawm qhov sib koom ua ke yuav raug txo qis. Txoj kev siv NOCOLOK brazing siv fluoride flux thiab kev tiv thaiv nitrogen yog ib txoj kev tshiab uas tau tsim sai hauv xyoo tas los no. Txij li thaum cov seem ntawm fluoride flux tsis nqus cov dej noo thiab tsis ua rau txhuas lwj, cov txheej txheem ntawm kev tshem tawm cov seem flux tom qab brazing tuaj yeem raug tshem tawm. Nyob rau hauv kev tiv thaiv ntawm nitrogen, tsuas yog me me ntawm fluoride flux yuav tsum tau coated, cov hlau filler tuaj yeem ua rau cov hlau hauv paus ntub dej, thiab nws yooj yim kom tau txais cov pob qij txha zoo. Tam sim no, txoj kev NOCOLOK brazing no tau siv rau hauv kev tsim khoom loj ntawm cov radiator txhuas thiab lwm yam khoom.

Rau cov txhuas thiab cov hlau txhuas uas siv cov kua nplaum uas tsis yog cov kua nplaum uas muaj fluoride, cov kua nplaum uas seem yuav tsum tau muab tshem tawm tag nrho tom qab ua kom sib xyaw. Cov kua nplaum uas muaj organic brazing flux rau txhuas tuaj yeem ntxuav nrog cov kua nplaum organic xws li methanol thiab trichloroethylene, neutralized nrog sodium hydroxide aqueous solution, thiab thaum kawg ntxuav nrog dej kub thiab dej txias. Chloride yog cov kua nplaum uas muaj cov kua nplaum uas siv rau brazing flux rau txhuas, uas tuaj yeem tshem tawm raws li cov txheej txheem hauv qab no; Ua ntej, muab tso rau hauv dej kub ntawm 60 ~ 80 ℃ rau 10 feeb, ua tib zoo ntxuav cov kua nplaum ntawm qhov sib koom ua ke nrog txhuam, thiab ntxuav nrog dej txias; Tom qab ntawd muab tso rau hauv 15% nitric acid aqueous solution rau 30 feeb, thiab thaum kawg yaug nrog dej txias.