Brazing ntawm stainless hlau

Brazing ntawm stainless hlau

1. Brazeability

Qhov teeb meem tseem ceeb hauv stainless hlau brazing yog tias cov oxide zaj duab xis ntawm qhov chaw cuam tshuam rau cov ntub dej thiab sib kis ntawm cov hlau. Ntau yam stainless hlau muaj ntau npaum li cas ntawm Cr, thiab qee qhov kuj muaj Ni, Ti, Mn, Mo, Nb thiab lwm yam, uas tuaj yeem tsim ntau yam oxides lossis txawm tias cov oxides sib xyaw rau saum npoo. Ntawm lawv, oxides Cr2O3 thiab TiO2 ntawm Cr thiab Ti yog qhov ruaj khov thiab nyuaj rau tshem tawm. Thaum brazing nyob rau hauv huab cua, active flux yuav tsum tau siv los tshem tawm lawv; Thaum brazing nyob rau hauv kev tiv thaiv huab cua, oxide zaj duab xis yuav txo tau tsuas yog nyob rau hauv siab purity cua nrog tsawg dew point thiab kub txaus; Nyob rau hauv lub tshuab nqus tsev brazing, nws yog ib qho tsim nyog yuav tsum muaj lub tshuab nqus tsev txaus thiab qhov kub txaus kom ua tiav cov nyhuv brazing zoo.

Lwm qhov teeb meem ntawm stainless hlau brazing yog tias cov cua kub kub muaj qhov cuam tshuam loj rau cov qauv ntawm cov hlau hauv paus. Lub brazing cua sov kub ntawm austenitic stainless hlau yuav tsum tsis txhob siab tshaj 1150 ℃, txwv tsis pub cov nplej yuav loj hlob tiag tiag; Yog tias austenitic stainless hlau tsis muaj cov khoom ruaj khov Ti lossis Nb thiab muaj cov ntsiab lus carbon siab, brazing nyob rau hauv qhov kub thiab txias (500 ~ 850 ℃) yuav tsum zam. Txhawm rau tiv thaiv corrosion los ntawm kev txo qis vim nag lossis daus ntawm chromium carbide. Kev xaiv ntawm brazing kub rau martensitic stainless hlau yog nruj dua. Ib qho yog kom phim lub brazing kub nrog lub quenching kub, thiaj li ua ke cov txheej txheem brazing nrog cov txheej txheem kev kho cua sov; Lwm qhov yog tias qhov kub ntawm lub brazing yuav tsum qis dua qhov kub thiab txias kom tiv thaiv lub hauv paus hlau los ntawm softening thaum brazing. Lub hauv paus ntsiab lus ntawm kev xaiv qhov kub thiab txias ntawm cov nag lossis daus hardening stainless hlau yog tib yam li martensitic stainless hlau, uas yog, qhov kub thiab txias yuav tsum sib haum rau kev kho cua sov kom tau txais cov khoom zoo tshaj plaws.

Ntxiv rau ob qhov teeb meem tseem ceeb saum toj no, muaj kev xav ntawm kev ntxhov siab tawg thaum brazing austenitic stainless hlau, tshwj xeeb tshaj yog thaum brazing nrog tooj liab zinc muab tub lim hlau. Txhawm rau kom tsis txhob muaj kev ntxhov siab tawg, lub workpiece yuav tsum tau ua kom muaj kev ntxhov siab annealed ua ntej brazing, thiab workpiece yuav tsum uniformly rhuab thaum lub sij hawm brazing.

2. Cov khoom siv brazing

(1) Raws li kev siv cov kev xav tau ntawm stainless hlau weldments, feem ntau siv brazing muab tub lim hlau rau stainless hlau weldments muaj xws li Tin Lead brazing muab tub lim hlau, nyiaj raws li brazing muab tub lim hlau, tooj liab raws li brazing muab tub lim hlau, manganese raws brazing muab tub lim hlau, npib tsib xee raws brazing muab tub lim hlau thiab cov hlau zoo kawg nkaus brazing muab tub lim hlau.

Tin lead solder feem ntau yog siv rau stainless hlau soldering, thiab nws tsim nyog kom muaj cov ntsiab lus siab tin. Qhov siab dua cov ntsiab lus ntawm cov tin, qhov zoo dua nws cov wettability ntawm stainless hlau. Lub zog shear ntawm 1Cr18Ni9Ti stainless hlau pob qij txha brazed nrog ntau hom tin lead solders yog teev nyob rau hauv Table 3. Vim lub zog tsis tshua muaj zog ntawm cov pob qij txha, lawv tsuas yog siv rau brazing qhov chaw uas muaj peev xwm me me.

Table 3 shear zog ntawm 1Cr18Ni9Ti stainless hlau ob leeg brazed nrog tin lead solder

Silver-based filler metals yog cov khoom siv feem ntau siv rau cov hlau tsis muaj steel hlau. Ntawm lawv, nyiaj tooj liab zinc thiab nyiaj tooj liab zinc cadmium muab tub lim yog siv dav tshaj plaws vim tias qhov kub ntawm lub brazing tsis cuam tshuam rau cov khoom ntawm lub hauv paus hlau. Lub zog ntawm ICr18Ni9Ti stainless hlau pob qij txha brazed nrog ntau hom nyiaj raws li cov khoom lag luam tau teev nyob rau hauv Table 4. Cov pob qij txha stainless hlau brazed nrog cov nyiaj raws li cov solders tsis tshua muaj siv hauv cov xov xwm corrosive, thiab kev ua haujlwm kub ntawm cov pob qij txha feem ntau tsis tshaj 300 ℃. Thaum brazing stainless hlau tsis muaj npib tsib xee, txhawm rau tiv thaiv corrosion ntawm brazed sib koom ua ke nyob rau hauv ib puag ncig ntub, brazing muab tub lim hlau nrog ntau nickel yuav tsum tau siv, xws li b-ag50cuzncdni. Thaum brazing martensitic stainless hlau, txhawm rau tiv thaiv softening ntawm lub hauv paus hlau, brazing muab tub lim hlau nrog brazing kub tsis tshaj 650 ℃ yuav tsum tau siv, xws li b-ag40cuzncd. Thaum brazing stainless hlau nyob rau hauv kev tiv thaiv huab cua, thiaj li yuav tshem tawm cov oxide zaj duab xis ntawm qhov chaw, lithium uas muaj tus kheej brazing flux yuav siv tau, xws li b-ag92culi thiab b-ag72culi. Thaum brazing stainless hlau hauv lub tshuab nqus tsev, txhawm rau ua kom cov hlau muab tub lim tseem muaj qhov ntub dej zoo thaum nws tsis muaj cov ntsiab lus xws li Zn thiab CD uas yooj yim rau evaporate, cov nyiaj muab tub lim hlau uas muaj cov ntsiab lus xws li Mn, Ni thiab RD tuaj yeem xaiv.

Table 4 lub zog ntawm ICr18Ni9Ti stainless hlau sib koom ua ke nrog cov nyiaj raws li muab tub lim hlau

Copper raws li brazing muab tub lim siv rau brazing sib txawv steels yog cov ntshiab tooj liab, tooj liab nickel thiab tooj liab manganese cobalt brazing muab tub lim hlau. Ntshiab tooj liab brazing muab tub lim hlau yog tsuas yog siv rau brazing nyob rau hauv kev tiv thaiv roj los yog lub tshuab nqus tsev. Kev ua haujlwm kub ntawm stainless hlau sib koom tsis ntau tshaj 400 ℃, tab sis qhov sib koom ua ke tsis zoo oxidation tsis kam. Copper nickel brazing muab tub lim hlau yog tsuas yog siv rau cov nplaim taws thiab induction brazing. Lub zog ntawm lub brazed 1Cr18Ni9Ti stainless hlau sib koom yog qhia nyob rau hauv Table 5. Nws tuaj yeem pom tias qhov sib koom ua ke muaj lub zog zoo ib yam li lub hauv paus hlau, thiab kev ua haujlwm kub siab. Cu Mn co brazing muab tub lim hlau yog tsuas yog siv rau brazing martensitic stainless hlau hauv kev tiv thaiv huab cua. Lub zog sib koom ua ke thiab ua haujlwm kub yog piv rau cov brazed nrog kub raws li muab tub lim hlau. Piv txwv li, 1Cr13 stainless hlau sib koom tes brazed nrog b-cu58mnco solder muaj qhov ua tau zoo ib yam li tib yam stainless hlau sib koom ua ke nrog b-au82ni solder (saib Daim duab 6), tab sis cov nqi tsim khoom tau txo qis heev.

Table 5 shear zog ntawm 1Cr18Ni9Ti stainless hlau ob leeg brazed nrog kub kub tooj liab puag muab tub lim hlau

Table 6 shear zog ntawm 1Cr13 stainless hlau brazed sib koom

Manganese raws li brazing muab tub lim hlau yog tsuas yog siv rau roj shielded brazing, thiab cov purity ntawm cov roj yuav tsum siab. Txhawm rau kom tsis txhob muaj cov qoob loo loj hlob ntawm cov hlau hauv paus, cov hlau sib txuas sib txuas nrog cov brazing kub qis dua 1150 ℃ yuav tsum raug xaiv. Txaus siab rau cov nyhuv brazing tuaj yeem tau txais rau cov pob qij txha stainless hlau brazed nrog manganese raws li cov khoom siv, raws li qhia hauv Table 7. Kev ua haujlwm kub ntawm qhov sib koom ua ke tuaj yeem ncav cuag 600 ℃.

Table 7 shear zog ntawm lcr18ni9fi stainless hlau ob leeg brazed nrog manganese raws li muab tub lim hlau

Thaum stainless hlau yog brazed nrog npib tsib xee puag muab tub lim hlau, qhov sib koom ua ke muaj kev ua haujlwm kub zoo. Cov hlau muab tub lim no feem ntau yog siv rau gas shielded brazing lossis nqus brazing. Txhawm rau kom kov yeej qhov teeb meem uas muaj cov khoom sib txuas ntau dua yog tsim nyob rau hauv kev sib koom ua ke thaum lub sij hawm sib koom ua ke, uas ua rau txo lub zog thiab plasticity ntawm kev sib koom tes, qhov sib txawv ntawm qhov sib koom yuav tsum tau txo kom tsawg los xyuas kom meej tias cov ntsiab lus yooj yim los ua nkig theem nyob rau hauv lub solder yog tag nrho diffused rau hauv lub hauv paus hlau. Txhawm rau tiv thaiv qhov tshwm sim ntawm lub hauv paus hlau nplej loj hlob vim yog lub sijhawm tuav ntev ntawm qhov kub thiab txias, cov txheej txheem ntsuas ntawm lub sijhawm luv luv thiab kev kho diffusion ntawm qhov kub thiab txias (piv nrog brazing kub) tom qab vuam tuaj yeem siv.

Noble hlau brazing muab tub lim siv rau brazing stainless hlau feem ntau muaj xws li kub-raws li muab tub lim hlau thiab palladium uas muaj cov hlau muab tub lim, uas feem ntau yog b-au82ni, b-ag54cupd thiab b-au82ni, uas muaj zoo wettability. Lub brazed stainless hlau sib koom ua ke muaj qhov kub thiab txias zog thiab oxidation tsis kam, thiab qhov siab tshaj plaws ua haujlwm kub tuaj yeem ncav cuag 800 ℃. B-ag54cupd muaj cov yam ntxwv zoo sib xws rau b-au82ni thiab nws tus nqi qis, yog li nws nyiam hloov b-au82ni.

(2) Qhov saum npoo ntawm stainless hlau nyob rau hauv flux thiab cua sov cua muaj oxides xws li Cr2O3 thiab TiO2, uas tsuas yog tshem tawm los ntawm kev siv flux nrog muaj zog ua hauj lwm. Thaum stainless hlau yog brazed nrog tin lead solder, qhov haum flux yog phosphoric acid aqueous tov los yog zinc oxide hydrochloric acid tov. Lub sijhawm ua haujlwm ntawm phosphoric acid aqueous tov yog luv, yog li txoj kev brazing ceev ceev yuav tsum tau saws. Fb102, fb103 lossis fb104 fluxes tuaj yeem siv rau brazing stainless hlau nrog nyiaj raws li cov khoom siv hlau. Thaum brazing stainless hlau nrog tooj liab raws li muab tub lim hlau, fb105 flux yog siv vim lub siab brazing kub.

Thaum brazing stainless hlau nyob rau hauv lub cub tawg, lub tshuab nqus tsev los yog kev tiv thaiv huab cua xws li hydrogen, argon thiab decomposition ammonia feem ntau yog siv. Thaum lub tshuab nqus tsev vacuum, lub tshuab nqus tsev siab yuav tsum qis dua 10-2Pa. Thaum brazing nyob rau hauv ib qho chaw tiv thaiv, lub lwg taw tes ntawm cov roj yuav tsum tsis txhob siab tshaj -40 ℃ Yog hais tias cov roj purity tsis txaus los yog lub brazing kub tsis siab, ib tug me me ntawm cov roj brazing flux, xws li boron trifluoride, yuav muab ntxiv rau cov cua.

2. Brazing tshuab

Stainless hlau yuav tsum tau ntxuav kom nruj dua ua ntej brazing kom tshem tawm cov roj thiab roj zaj duab xis. Nws yog qhov zoo dua rau braze tam sim ntawd tom qab ntxuav.

Stainless hlau brazing tuaj yeem txais cov nplaim hluav taws kub, induction thiab cua sov txoj kev nruab nrab cua sov. Lub qhov cub rau brazing nyob rau hauv lub cub tawg yuav tsum muaj kev tswj qhov kub thiab txias (qhov sib txawv ntawm brazing kub yuav tsum yog ± 6 ℃) thiab tuaj yeem txias sai. Thaum siv hydrogen los ua cov roj tiv thaiv rau brazing, qhov yuav tsum tau muaj rau hydrogen nyob ntawm qhov kub thiab txias ntawm lub hauv paus hlau, uas yog, qhov qis dua qhov kub ntawm lub brazing, ntau lub hauv paus hlau muaj stabilizer, thiab qhov qis qis ntawm hydrogen yog xav tau. Piv txwv li, rau martensitic stainless hlau xws li 1Cr13 thiab cr17ni2t, thaum brazing ntawm 1000 ℃, lub lwg point ntawm hydrogen yuav tsum tau qis dua -40 ℃; Rau 18-8 chromium nickel stainless hlau tsis muaj stabilizer, lub lwg taw tes ntawm hydrogen yuav tsum qis dua 25 ℃ thaum brazing ntawm 1150 ℃; Txawm li cas los xij, rau 1Cr18Ni9Ti stainless hlau uas muaj titanium stabilizer, hydrogen dew point yuav tsum qis dua -40 ℃ thaum brazing ntawm 1150 ℃. Thaum brazing nrog argon tiv thaiv, purity ntawm argon yuav tsum siab dua. Yog tias tooj liab lossis npib tsib xee plated rau ntawm qhov chaw ntawm cov hlau tsis muaj steel, qhov yuav tsum tau ua rau lub purity ntawm shielding gas yuav raug txo. Txhawm rau kom tshem tawm cov oxide zaj duab xis rau ntawm qhov chaw ntawm cov hlau tsis huv, BF3 gas flux kuj tuaj yeem raug ntxiv, thiab lithium lossis boron uas muaj tus kheej flux solder tuaj yeem siv tau. Thaum lub tshuab nqus tsev brazing stainless hlau, qhov yuav tsum tau rau lub tshuab nqus tsev kawm ntawv nyob ntawm qhov kub ntawm qhov brazing. Nrog rau qhov nce ntawm brazing kub, lub tshuab nqus tsev yuav tsum tau txo.

Cov txheej txheem tseem ceeb ntawm stainless hlau tom qab brazing yog los ntxuav cov seem flux thiab residual flow inhibitor, thiab nqa tawm tom qab brazing kev kho cua sov yog tias tsim nyog. Nyob ntawm txoj kev siv flux thiab brazing, residual flux tuaj yeem ntxuav nrog dej, mechanically ntxuav los yog tshuaj ntxuav. Yog tias siv cov abrasive los ntxuav cov kua nplaum uas seem lossis oxide zaj duab xis nyob rau hauv qhov chaw sov so ze ntawm qhov sib koom ua ke, cov xuab zeb lossis lwm yam tsis yog xim hlau zoo yuav tsum tau siv. Cov khoom ua los ntawm martensitic stainless hlau thiab nag lossis daus hardening stainless hlau xav tau kev kho cua sov raws li qhov tshwj xeeb ntawm cov khoom siv tom qab brazing. Stainless hlau pob qij txha brazed nrog Ni Cr B thiab Ni Cr Si muab tub lim hlau feem ntau kho nrog diffusion tshav kub kho tom qab brazing kom txo tau qhov yuav tsum tau rau brazing sib txawv thiab txhim kho cov microstructure thiab cov khoom ntawm cov pob qij txha.