Vim tias tus nqi tooj liab thiab nyiaj tseem siab, cov chaw tsim khoom siv tub yees thiab HVAC tab tom tsiv cov tsev, cov taub hau, cov lim dej thiab cov khoom sib txuas los ntawm tooj liab mus rau hlau tsis xeb. Cov raj tooj liab uas tseem tshuav tseem yuav tsum tau txuas rau lawv. Phau ntawv qhia no qhia txog qhov ua rau qhov sib koom ua ke ntawd txawv ntawm tooj liab mus rau tooj liab, cov sib koom ua ke twg tuaj yeem siv cov khoom siv tooj dag pheej yig, uas xav tau nyiaj, thiab seb kev siv hluav taws xob thiab hluav taws kub ua haujlwm li cas.
Vim li cas ob lub hlau ua haujlwm sib txawv
Qhov kev nthuav dav thermal ntawm 304 stainless (kwv yees li 17.2 µm/m·K) thiab tooj liab (kwv yees li 16.8) yuav luag sib npaug, yog li qhov tsis sib xws ntawm thermal-expansion tsis yog qhov teeb meem tseem ceeb. Qhov teeb meem yog qhov cua sov ntws thiab chemistry ntawm qhov chaw.
| Khoom | Tooj liab (C12200) | 304 / 304L stainless hlau | Nws txhais li cas hauv kev sib koom ua ke |
|---|---|---|---|
| Kev ua kom sov, W/m·K | ~ 385 | ~ 16 | Tooj liab ua kom cua sov tawm; stainless hlau tseem kub hauv zos |
| Kev tiv thaiv hluav taws xob, µΩ·cm | ~ 1.7 | ~ 72 | Stainless hlau ua kom sov tau yooj yim los ntawm kev siv induction; tooj liab tsis sib txuas zoo |
| Zaj duab xis nto | Cu2O / CuO, yooj yim rau flux | Cr2O3 txheej txheem tsis ua haujlwm | Stainless xav tau cov flux muaj zog dua thiab ntub sai |
| Melting point, ° C | 1083 | 1400-1450 | Ob qho tib si deb tshaj qhov twg brazing filler |
Qhov tshwm sim tiag tiag: yog tias koj ua kom sov sib npaug, sab tooj liab yuav kub ua ntej, cov khoom siv yuav yaj rau ntawd, thiab sab stainless tseem txias dhau uas yuav tsis ntub. Cov khoom siv ces yuav nyob zoo li lub hlaws dai ntawm tooj liab thiab yeej tsis lo rau hlau. Kev ua kom sov tsis sib npaug yog qhov ua rau pob qij txha zoo li tiav lawm tab sis nws yuav tawg.
Xaiv cov khoom sau: thaum twg tooj dag tau thiab thaum twg xav tau nyiaj
| muab tub lim | Qhov ntau yam ntws | Siv rau ntawm cov pob qij txha stainless-tooj liab | Caw saib |
|---|---|---|---|
| BAg-7 (56% Ag, Sn-bearing, Cd-free) | 650-760 ° C | Cov kab txias, phab ntsa nyias, cov pob qij txha hermetic | Tus nqi ntim khoom siab tshaj plaws; ntws zoo heev ntawm stainless |
| BAg-28 (40% Ag) | 680-790 ° C | Kev sib haum xeeb zoo ntawm tus nqi thiab kev ntws | Ntau yam melting me ntsis dav dua |
| BAg-5 (45% Ag, Cu-Zn) | 745-870 ° C | Kev pabcuam dav dav, qhov sib txawv loj dua | Zinc pa luam yeeb ntawm qhov kawg sab saud |
| RBCuZn-A / RBCuZn-D (tooj dag / npib tsib xee nyiaj) | 900-980 ° C | Cov phab ntsa tuab dua, cov pob qij txha, cov kav dej lossis roj, cov phaj thiab cov taub hau | Tooj liab oxidation, yaig ntawm tooj liab nyias nyias, cua sov nkag siab |
| BCuP (Cu-P, nrog lossis tsis muaj Ag) | 700-810 ° C | Tsis yog rau cov hlau tsis xeb | Txheej phosphide nkig ntawm cov hlau |
Txoj cai uas peb siv thaum tsim cov qauv: nyiaj qhov twg phab ntsa nyias lossis qhov sib koom ua ke yuav tsum tuav cov khoom txias, tooj dag qhov twg phab ntsa yog 1.5 hli lossis ntau dua thiab qhov sib koom ua ke yog ib qho khoom siv tshuab lossis muaj kev pheej hmoo tsawg. Tooj dag ntws li ntawm 250–300°C kub dua li 56% cov khoom siv nyiaj. Ntawm qhov kub ntawd, phab ntsa tooj liab 0.8–1.0 hli yuav mos, loj hlob cov oxide hnyav thiab tuaj yeem yaj los ntawm cov khoom siv yaj. Qhov twg tus qauv tsim tso cai rau cov tooj liab hnyav dua lossis lub tes tsho tooj liab luv luv, tooj dag feem ntau ua tau zoo, thiab kev txuag cov khoom siv yog qhov loj.
Flux thiab huab cua
Cov chromium oxide zaj duab xis ntawm stainless hlau tsis raug tshem tawm los ntawm borax ib leeg ntawm cov kub-brazing nyiaj. Siv cov flux uas muaj fluoride: AWS FB3-A hom flux dawb rau cov khoom siv nyiaj, thiab boron-based FB1-A hom flux rau tooj dag, uas ua haujlwm txij li 760 ° C mus rau saum toj. Siv nws rau ob qho tib si, tsis yog rau ntawm tus pas nrig filler xwb.
Cov kua hlau (flux) muab tawm raws sijhawm thiab qhov kub. Thaum nws tsaus ntuj thiab zoo li iav, cov oxide tsis yaj lawm. Hauv kev siv tooj dag los ua kom sov, qhov kub qeeb qeeb yuav hlawv cov kua hlau ua ntej cov khoom siv filler mus txog qhov kub ntawm cov dej ntws, uas yog qhov ua rau cov xim av, hlawv ntawm sab stainless uas pom hauv lub raj xa dej hauv qab no. Ob txoj kev kho: siv cov kua hlau uas muaj lub qab nthab ua haujlwm siab dua, lossis ua kom lub sijhawm ua kom sov luv dua, uas yog lub zog ntawm kev siv hluav taws xob.
Rau cov voj voog tub yees, ntxuav sab hauv nrog cov nitrogen qhuav ntawm qhov ntws qis thaum lub sijhawm brazing. Txwv tsis pub, cov nplai tooj liab tsim hauv lub raj thiab tom qab ntawd mus rau compressors, capillaries thiab expansion valves. Cov seem flux ntawm stainless kuj yog corrosive thiab yuav tsum tau ntxuav tawm hauv dej kub tom qab qhov sib koom ua ke tau txias hauv qab li 100 ° C.
Nyeem cov qauv tiag tiag
Dab tsi los saib
- Liab-ntshav oxide ntawm tooj liab Nyob ze ntawm qhov sib koom ua ke yog qhov ib txwm muaj rau kev sib txhuam hauv huab cua. Nws qhia tau tias cua sov kis mus rau ntawm tooj liab. Hauv kev pabcuam refrigerant, tib thaj chaw ntawd yuav xav tau nitrogen purging sab hauv.
- Ib daim nqaij qaib daj tas mus li ntawm ob sab ntawm qhov sib koom ua ke qhia tau hais tias cov khoom siv ntub ob lub hlau. Ib lub hlaws uas tsuas yog nyob rau ntawm tooj liab yog qhov sib koom ua ke hlau txias.
- Xim av tsaus nti hlawv ntawm sab stainless hlau taw tes rau qhov nce qeeb lossis cua sov ntau dhau ntawm sab hlau tom qab qhov ntws.
- Kev npog qhov txhaws hauv cov qauv qhib: tshuaj xyuas cov ntsej muag tawg. Cov khoom siv ntxiv yuav tsum muaj nyob rau ntawm ob qho tib si hlau thiab tooj liab ntsej muag thaum tooj liab tawg, es tsis txhob sib cais huv si ntawm cov hlau.
Kev tsim ua ke
- Clearance: 0.05–0.15 hli ib sab ntawm qhov kub brazing rau cov khoom siv nyiaj; txog li 0.20 hli rau tooj dag. Qhov nruj dhau ua rau qhov sib koom ua tsis tau zoo; qhov dav dhau ua rau cov khoom siv khiav dhau.
- Sib tshooj: tsawg kawg yog peb npaug ntawm cov phab ntsa nyias dua, thiab feem ntau yog 6–10 hli rau cov raj xa dej txias.
- Qhov chaw muab cov khoom sau: siv lub nplhaib uas tau ua tiav lawm lossis cov nplaum rau sab tooj liab, nrog rau qhov kub nyob rau ntawm stainless kom cov khoom sau raug rub mus rau cov hlau kub dua.
- qib: 304L lossis 316L txwv tsis pub muaj chromium carbide nag lossis daus hauv qhov kub ntawm 425–815 ° C, txawm hais tias qhov sib koom ua ke tuav rau ntawd tsuas yog ob peb feeb xwb tsis tshua muaj kev pheej hmoo.
- Kev huv huv: tshem cov roj tawm ua ntej sib dhos. Cov roj ntawm stainless hlau hlawv tawm ua cov pa roj carbon uas thaiv cov dej noo.
Induction brazing: cov chaw teeb tsa ua haujlwm
Stainless muaj li plaub caug npaug ntawm qhov resistivity ntawm tooj liab, yog li ntawd lub kauj induction nchuav lub zog rau hauv cov hlau ncaj qha thiab rau hauv tooj liab tsuas yog tsis muaj zog xwb. Qhov ntawd haum rau qhov sib koom ua ke no: cov hlau ncav cuag qhov kub ntws sai sai, thiab tooj liab ua raws li kev sib txuas. Feem ntau cov raj me me sib koom ua tiav hauv 3-15 vib nas this.
- Zaus: 20–50 kHz rau cov khoom siv loj dua thiab phab ntsa tuab dua; 100–200 kHz rau phab ntsa nyias thiab cov raj hauv qab 12 hli. Qhov tob ntawm daim tawv nqaij hauv 304 ntawm 30 kHz yog kwv yees li 2.5 hli, yog li cov raj phab ntsa nyias raug cua sov los ntawm phab ntsa yuav luag ib zaug.
- Txoj hauj lwm ntawm lub kauj: Muab lub kauj tso rau hauv nruab nrab ntawm qhov kawg ntawm qhov sib tshooj, lossis me ntsis rau nws. Tsis txhob muab nws tso rau hauv nruab nrab ntawm tooj liab.
- Nruab nrab: ib qho kev nce ceev mus txog li 20°C qis dua qhov chaw ntws, tom qab ntawd ib ntus ntub dej, ua kom cov dej ntws ua haujlwm thiab tiv thaiv kev ntws ntau dhau.
- Ntau qhov sib txuas: ib lub kauj uas tig ntau lossis ntau qhov chaw tuaj yeem ua rau tsib lossis ntau dua ntawm lub taub hau hauv ib lub voj voog, zoo li hauv daim duab piv txwv thawj zaug.
- Kev Tswj: Kev tswj lub sijhawm fais fab lossis kev tawm tswv yim infrared pyrometer muab cov txiaj ntsig zoo sib xws. Nco ntsoov tias stainless thiab tooj liab muaj cov emissivities sib txawv, yog li calibrate lub pyrometer ntawm qhov chaw tiag tiag.
Hluav taws xob brazing: qhov twg nws tseem haum
Kev siv hluav taws xob los ua kom kub hnyiab yooj ywm thiab tsis tas siv cov cuab yeej ntau. Nws zoo rau kev ua haujlwm pabcuam, cov tsev loj thiab cov kab uas tsis muaj zog. Siv lub teeb oxy-fuel lossis oxy-propane nrog lub nplaim taws me ntsis, thiab ua kom nplaim taws txav mus rau qhov tsis xeb. Qhov tsis zoo yog qhov rov ua dua tsawg dua, cua sov kis mus deb tshaj qhov sib koom ua ke, thiab kev vam khom rau kev txawj ntawm tus neeg ua haujlwm. Ntau tus neeg siv khoom siv hluav taws xob los ua cov qauv thiab kev siv hluav taws xob los tsim khoom. Ob txoj kev muab cov khoom sib koom ua ke zoo sib xws yog tias siv cov khoom sau thiab cov kua dej sib xws.
Qhov twg qhov kev hloov khoom siv ua rau muaj kev nkag siab
Cov hlau tsis xeb hloov tooj liab tau zoo tshaj plaws hauv cov khoom uas tsis tas yuav ua kom sov: cov plhaub lim dej qhuav, cov khoom siv sib sau ua ke, cov lub cev valve, cov manifolds thiab cov headers, cov tsev sensor, cov connectors thiab cov khoom siv kawg uas muaj siab. Cov raj pauv cua sov tseem yog tooj liab lossis txhuas. Txhua qhov hloov pauv yuav tsum tau lees paub los ntawm kev sim qhov xau, kev sim siab lossis kev sim tawg, kev sim kev co, thiab kev kuaj xeb hauv qhov chaw ib puag ncig, vim tias qhov sib koom ua ke sib txawv tuaj yeem xeb galvanically yog tias nws nyob ntub.
Kev pabcuam kuaj qauv
KETCHAN khiav induction thiab nplaim taws brazing rau ob qho tib si hlau. Xa cov duab kos lossis cov khoom siv lub cev, thiab peb tuaj yeem sim ntau yam flux thiab filler sib xyaw ua ke, txheeb xyuas cov pob qij txha twg tuaj yeem siv tooj dag thiab cov twg xav tau nyiaj, thiab xa rov qab cov qauv seem nrog cov cua sov rau koj tus kheej kev tsim nyog.
Lus nug cov lus nug
Puas yog cov yeeb nkab stainless hlau tuaj yeem brazed rau cov yeeb nkab tooj liab?
Yog. Siv cov kua uas tshem tawm cov zaj duab xis chromium oxide, cov khoom siv nyiaj lossis tooj dag uas tsim nyog, thiab cua sov mus rau sab stainless.
Cov khoom siv tooj dag puas tuaj yeem hloov cov khoom siv nyiaj?
Yog rau cov phab ntsa tuab dua thiab cov pob qij txha uas tsis tseem ceeb, yog. Tooj dag ntws ntawm li 900–980°C thiab tuaj yeem ua rau tooj liab nyias nyias lwj, yog li cov pob qij txha txias ntawm phab ntsa nyias feem ntau siv cov nyiaj ntxiv.
Vim li cas ho tsis siv BCuP filler rau ntawm cov hlau tsis xeb?
Phosphorus reacts nrog hlau thiab nickel los tsim cov phosphides brittle ntawm qhov interface, thiab qhov sib koom ua ke tuaj yeem tawg thaum muaj kev co lossis thermal cycling.
Puas yog induction lossis nplaim taws brazing zoo dua rau qhov sib koom ua ke no?
Kev siv hluav taws xob induction muab cua sov sai, nyob rau hauv ib cheeb tsam, thiab rov ua dua, yog li nws haum rau kev tsim khoom. Kev siv hluav taws xob brazing haum rau kev kho, cov khoom loj thiab cov khoom me me.
Kuv yuav ua li cas thiaj paub tseeb tias cov khoom siv sib txuas nrog cov hlau tsis xeb?
Txiav los yog qhib ib qho qauv. Cov khoom sau yuav tsum pom ntawm ob sab, thiab qhov sib txuas uas sib cais ntawm cov hlau tsis tau ntub dej.
