Q: Peb tsis ntev los no tau pib ua qee yam haujlwm uas yuav tsum tau ua qee yam los ntawm 304 stainless hlau, uas yog welded rau nws tus kheej thiab rau cov hlau me me.Peb tau ntsib qee qhov teeb meem nrog kev sib tsoo ntawm cov hlau tsis muaj steel thiab stainless hlau mus txog 1.25 "tuab.Nws tau hais tias peb muaj qib ferrite tsawg.Koj puas tuaj yeem piav qhia nws yog dab tsi thiab yuav kho li cas?
A: Qhov ntawd yog ib lo lus nug zoo.Yog lawm, peb tuaj yeem pab koj nkag siab tias tsawg ferrite txhais li cas thiab yuav tiv thaiv nws li cas.
Ua ntej, cia saib lub ntsiab lus ntawm stainless hlau (SS) thiab yuav ua li cas ferrite cuam tshuam rau welded pob qij txha.Cov hlau dub thiab alloys muaj ntau tshaj 50% hlau.Qhov no suav nrog tag nrho cov pa roj carbon thiab stainless hlau, nrog rau qee cov pab pawg.Aluminium, tooj liab, thiab titanium tsis muaj hlau, yog li lawv yog cov piv txwv zoo ntawm cov hlau tsis muaj hlau.
Cov khoom tseem ceeb ntawm cov hlau no yog carbon hlau nrog cov ntsiab lus hlau tsawg kawg yog 90% thiab stainless hlau nrog cov ntsiab lus hlau ntawm 70 txog 80%.Txhawm rau muab faib ua SS, nws yuav tsum muaj tsawg kawg yog 11.5% chromium ntxiv.Cov qib chromium saum toj no qhov tsawg kawg nkaus txhawb kev tsim cov chromium oxide zaj duab xis ntawm cov hlau thiab tiv thaiv kev tsim cov oxidation xws li xeb (hlau oxide) lossis tshuaj tua kab mob corrosion.
Stainless hlau feem ntau muab faib ua peb pawg: austenitic, ferritic thiab martensitic.Lawv lub npe los ntawm cov qauv siv lead ua ntawm chav tsev kub uas lawv tau tsim.Lwm pawg yog duplex stainless hlau, uas yog qhov sib npaug ntawm ferrite thiab austenite hauv cov qauv siv lead ua.
Austenitic qib, 300 series, muaj 16% mus rau 30% chromium thiab 8% mus rau 40% npib tsib xee, tsim cov qauv siv lead ua feem ntau austenitic.Stabilizers xws li npib tsib xee, carbon, manganese, thiab nitrogen ntxiv thaum lub sij hawm steelmaking txheej txheem los pab tsim cov austenite-ferrite piv.Qee cov qib sib xws yog 304, 316 thiab 347. Muab kev tiv thaiv corrosion zoo;feem ntau yog siv rau hauv cov khoom noj, tshuaj, tshuaj thiab cryogenic industries.Tswj kev tsim ferrite muab zoo heev toughness ntawm qhov kub thiab txias.
Ferritic SS yog qib 400 series uas yog sib nqus tag nrho, muaj 11.5% mus rau 30% chromium, thiab muaj cov qauv siv lead ua ferritic feem ntau.Txhawm rau txhawb kev tsim cov ferrite, stabilizers suav nrog chromium, silicon, molybdenum thiab niobium thaum lub sijhawm tsim cov hlau.Cov hom SS no feem ntau siv nyob rau hauv lub tsheb tso hluav taws xob thiab lub zog hluav taws xob thiab muaj kev txwv kub kub.Muaj ntau hom kev siv: 405, 409, 430 thiab 446.
Martensitic qib, kuj hu ua 400 series, xws li 403, 410, thiab 440, yog hlau nplaum, muaj 11.5% mus rau 18% chromium, thiab muaj cov qauv siv lead ua martensitic.Qhov kev sib xyaw ua ke no muaj cov ntsiab lus kub qis tshaj plaws, ua rau lawv kim tshaj plaws los tsim.Lawv muab qee qhov kev tiv thaiv corrosion, lub zog zoo dua, thiab feem ntau yog siv rau hauv cov tais diav, khoom siv kho hniav thiab phais, cookware, thiab qee yam cuab yeej.
Thaum koj welding stainless hlau, hom substrate thiab nws daim ntawv thov nyob rau hauv kev pab cuam yuav txiav txim seb lub muab tub lim hlau tsim nyog siv.Yog tias koj siv cov txheej txheem tiv thaiv roj, koj yuav tsum tau them nyiaj tshwj xeeb rau kev tiv thaiv cov roj sib xyaw kom tiv thaiv qee yam teeb meem cuam tshuam nrog vuam.
Txhawm rau solder 304 rau nws tus kheej, koj yuav xav tau E308/308L electrode."L" sawv cev rau cov pa roj carbon tsawg, uas pab tiv thaiv intergranular corrosion.Cov ntsiab lus carbon ntawm cov electrodes yog tsawg dua 0.03%, yog tias tus nqi no dhau lawm, qhov kev pheej hmoo ntawm cov pa roj carbon deposition ntawm cov ciam teb thiab chromium bonding los tsim chromium carbides nce, uas zoo txo ​​cov corrosion kuj ntawm cov hlau.Qhov no yuav tshwm sim yog tias corrosion tshwm sim nyob rau hauv tshav kub-cuam tshuam cheeb tsam (HAZ) ntawm stainless hlau welds.Lwm qhov kev txiav txim siab rau qib L stainless hlau yog tias lawv muaj lub zog tensile qis ntawm kev ua haujlwm siab dua li cov qib stainless hlau ncaj.
Txij li 304 yog ib hom austenitic stainless hlau, cov hlau sib txuas yuav muaj feem ntau ntawm cov austenite.Txawm li cas los xij, lub electrode nws tus kheej yuav muaj ferrite stabilizer, xws li molybdenum, los txhawb kev tsim cov ferrite hauv cov hlau weld.Cov neeg tsim khoom feem ntau teev cov kab ke ib txwm rau tus nqi ntawm ferrite rau cov hlau vuam.Raws li tau hais dhau los, carbon yog qhov muaj zog austenitic stabilizer thiab rau cov laj thawj no nws yog qhov tseem ceeb los tiv thaiv nws ntxiv rau cov hlau vuam.
Ferrite tooj yog muab los ntawm Scheffler daim ntawv thiab WRC-1992 daim ntawv, uas siv nickel thiab chromium sib npaug cov qauv los xam tus nqi uas thaum plotted rau ntawm daim ntawv muab ib tug normalized tooj.Tus naj npawb ferrite ntawm 0 thiab 7 sib raug rau qhov ntim feem pua ​​​​ntawm ferritic crystal qauv tam sim no nyob rau hauv cov hlau weld, txawm li cas los xij, ntawm feem pua ​​​​siab dua, tus lej ferrite nce nrawm dua.Nco ntsoov tias ferrite hauv SS tsis zoo ib yam li carbon steel ferrite, tab sis ib theem hu ua delta ferrite.Austenitic stainless hlau tsis dhau theem kev hloov pauv cuam tshuam nrog cov txheej txheem kub xws li kev kho cua sov.
Kev tsim cov ferrite yog qhov xav tau vim tias nws muaj ntau dua ductile dua austenite, tab sis yuav tsum tau tswj.Cov ntsiab lus ferrite tsawg tuaj yeem muab cov welds nrog kev tiv thaiv corrosion zoo hauv qee qhov kev siv, tab sis lawv tsis tshua muaj siab kub tawg thaum vuam.Rau kev siv dav dav, tus naj npawb ntawm ferrites yuav tsum nyob nruab nrab ntawm 5 thiab 10, tab sis qee qhov kev siv yuav xav tau qis dua lossis siab dua.Ferrites tuaj yeem tshawb xyuas tau yooj yim hauv qhov chaw ua haujlwm nrog lub ntsuas ferrite.
Txij li thaum koj tau hais tias koj muaj teeb meem nrog kev tawg thiab tsis tshua muaj ferrites, koj yuav tsum ua tib zoo saib ntawm koj cov hlau muab tub lim thiab xyuas kom meej tias nws tau tsim cov ferrites txaus - nyob ib ncig ntawm 8 yuav tsum ua kom yuam kev.Tsis tas li ntawd, yog tias koj siv flux-cored arc vuam (FCAW), cov hlau muab tub lim no feem ntau siv cov pa roj carbon monoxide 100% carbon dioxide los yog sib xyaw ntawm 75% argon thiab 25% CO2, uas tuaj yeem ua rau cov hlau vuam kom nqus cov pa roj carbon.Koj tuaj yeem hloov mus rau cov txheej txheem hlau arc vuam (GMAW) thiab siv 98% argon / 2% oxygen sib xyaw kom txo tau cov pa roj carbon deposits.
Thaum vuam stainless hlau rau carbon hlau, muab cov khoom siv E309L yuav tsum tau siv.Cov hlau muab tub lim no tshwj xeeb yog siv rau qhov sib txawv ntawm cov hlau vuam, tsim ib qho nyiaj ntawm ferrite tom qab carbon hlau yaj hauv qhov vuam.Vim tias carbon steel absorbs qee cov pa roj carbon monoxide, ferrite stabilizers tau ntxiv rau cov hlau muab tub lim los tiv thaiv cov pa roj carbon monoxide los ua austenite.Qhov no yuav pab tiv thaiv thermal tawg thaum vuam.
Hauv kev xaus, yog tias koj xav kho cov kub tawg hauv austenitic stainless hlau welds, xyuas kom txaus ferrite muab tub lim hlau thiab ua raws li kev siv vuam zoo.Khaws cov khoom siv hluav taws xob qis dua 50 kJ / hauv, tswj qhov nruab nrab mus rau qis qis qis, thiab xyuas kom cov pob qij txha huv si ua ntej soldering.Siv lub ntsuas ntsuas tsim nyog los xyuas cov nyiaj ferrite ntawm qhov vuam, tsom rau 5-10.
WELDER, yav tas los hu ua Practical Welding Niaj hnub no, sawv cev rau cov neeg tiag tiag uas ua cov khoom peb siv thiab ua haujlwm nrog txhua hnub.Phau ntawv xov xwm no tau ua haujlwm rau cov koom haum vuam hauv North America rau ntau tshaj 20 xyoo.
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