Stainless hlau rau siab Vessels thiab nws cov yam ntxwv welding
Lub npe hu ua stainless hlau hais txog kev ntxiv qee qhov chromium rau cov hlau, kom cov hlau nyob hauv lub xeev passivated thiab muaj cov yam ntxwv ntawm tsis xeb. Yuav kom ua tiav lub hom phiaj no, nws cov ntsiab lus chromium yuav tsum siab dua 12 feem pua. Txhawm rau txhim kho kev ua haujlwm ntawm cov hlau, cov ntsiab lus xws li npib tsib xee thiab molybdenum uas tuaj yeem cuam tshuam cov hlau feem ntau ntxiv rau stainless hlau. Feem ntau hu ua stainless hlau yog lub ntsiab lus dav dav rau stainless hlau thiab acid-resistant steel. Stainless hlau tsis tas yuav acid-resistant, thiab acid-resistant steel feem ntau muaj cov khoom zoo stainless. Stainless hlau tuaj yeem muab faib ua plaub pawg raws li cov qauv ntawm cov hlau, xws li austenitic stainless hlau, ferritic stainless hlau, martensitic stainless hlau, thiab austenitic-ferritic duplex stainless hlau.
1. Austenitic stainless hlau thiab nws cov yam ntxwv vuam
Austenitic stainless hlau yog feem ntau siv stainless hlau, thiab siab Cr-Ni hom yog feem ntau. Tam sim no, austenitic stainless hlau tuaj yeem muab faib ua Cr18-Ni8 hom, Cr25-Ni20 hom, thiab Cr25-Ni35 hom. Austenitic stainless hlau muaj cov yam ntxwv hauv qab no:
① Vuam kub-plated austenitic stainless hlau muaj ib tug me me thermal conductivity thiab ib tug loj linear expansion coefficient, yog li thaum lub sij hawm vuam txheej txheem, lub high-kub nyob rau lub sij hawm ntawm lub welded ob leeg yog ntev, thiab cov weld yog ib qho yooj yim los tsim ib coarse columnar grain. qauv. Yog hais tias cov ntsiab lus ntawm impurity ntsiab xws li sulfur, phosphorus, tin, antimony, thiab niobium yog siab, ib tug tsawg melting point eutectic yuav tsim ntawm cov nplej, thiab solidification tawg yuav yooj yim tsim nyob rau hauv lub weld thaum lub welded ob leeg raug siab. tensile kev nyuaj siab. Liquefaction tawg yog tsim nyob rau hauv lub tshav kub-cuam tshuam cheeb tsam, uas tag nrho cov nyob rau hauv vuam kub tawg. Txoj hauv kev zoo tshaj plaws los tiv thaiv cov kab tawg kub yog txo cov impurity cov ntsiab lus uas nquag tsim cov ntsiab lus melting tsawg eutectics hauv cov hlau thiab vuam consumables thiab ua kom cov chromium-nickel austenitic stainless hlau muaj 4 feem pua rau 12 feem pua ferrite qauv.
② Intergranular corrosion Raws li kev tshawb xav ntawm chromium depletion, nag lossis daus ntawm chromium carbide rau ntawm qhov chaw intergranular, ua rau depletion ntawm chromium nyob rau hauv ciam teb nplej yog lub ntsiab ua rau intergranular corrosion. Yog li ntawd, xaiv ultra-low carbon welding consumables los yog vuam consumables uas muaj stabilizing ntsiab xws li niobium thiab titanium yog lub ntsiab ntsuas los tiv thaiv intergranular corrosion.
③ Kev ntxhov siab corrosion cracking Kev ntxhov siab corrosion cracking feem ntau manifests li nkig tsis ua hauj lwm, thiab cov txheej txheem kev puas tsuaj yuav siv sij hawm luv luv, yog li qhov kev puas tsuaj loj heev. Lub ntsiab ua rau kev ntxhov siab corrosion tawg ntawm austenitic stainless hlau yog vuam residual kev nyuaj siab. Cov qauv kev hloov pauv ntawm cov pob qij txha welded los yog lub hav zoov ntawm kev nyuaj siab concentration, thiab cov concentration ntawm lub zos corrosion nruab nrab kuj yog vim li cas rau kev ntxhov siab corrosion cracking.
④ σ theem embrittlement ntawm welded pob qij txha σ theem yog ib hom nkig thiab nyuaj intermetallic compound, uas feem ntau sib sau ua ke nyob rau hauv lub grain ciam teb ntawm columnar nplej. Ob theem thiab δ theem tuaj yeem dhau mus rau theem hloov pauv. Piv txwv li, thaum Cr25Ni20 hom weld yog rhuab ntawm 800 degree ~ 900 degree, muaj zog → δ transformation yuav tshwm sim. Rau chromium-nickel austenitic stainless hlau, tshwj xeeb tshaj yog chromium-nickel-molybdenum stainless hlau, δ → σ theem transformation yog nquag tshwm sim, feem ntau vim hais tias chromium thiab molybdenum ntsiab muaj pom tseeb sigma transformation, thaum lub δ ferrite cov ntsiab lus nyob rau hauv lub weld tshaj 12 feem pua. , kev hloov pauv ntawm δ → σ yog qhov pom tseeb heev, ua rau pom tseeb embrittlement ntawm cov hlau vuam, uas yog vim li cas cov txheej saum npoo ntawm cov phab ntsa sab hauv ntawm phab ntsa kub hydrogenation reactor tswj cov ntsiab lus δ ferrite ntawm 3 feem pua rau 10 feem pua. vim li cas.
2. Ferritic stainless hlau thiab nws cov yam ntxwv vuam
Ferritic stainless hlau muab faib ua ob pawg: zoo tib yam ferritic stainless hlau thiab ultra-ntshiab ferritic stainless hlau. Ntawm lawv, zoo tib yam ferritic stainless hlau muaj Cr12 ~ Cr14 hom, xws li 00Cr12, 0Cr13Al; Cr16 ~ Cr18 hom, xws li 1Cr17Mo; Cr25 ~ 30 hom.
Vim muaj cov ntsiab lus siab ntawm carbon thiab nitrogen nyob rau hauv zoo tib yam ferritic stainless hlau, nws yog ib qho nyuaj rau txheej txheem thiab vuam, thiab corrosion kuj yog ib qho nyuaj rau lav, yog li kev siv yog txwv. Nyob rau hauv ultra-ntshiab ferritic stainless hlau, cov pa roj carbon thiab nitrogen nyob rau hauv cov hlau yog nruj me ntsis tswj. Tag nrho cov nyiaj nitrogen feem ntau tswj tau ntawm peb theem ntawm 0.035 feem pua rau 0.045 feem pua , 0.030 feem pua , thiab 0.010% mus rau 0.015%. Nyob rau tib lub sijhawm, cov ntsiab lus tsim nyog alloying tau ntxiv los txhim kho corrosion kuj thiab kev ua tau zoo ntawm cov hlau. Piv nrog rau cov hlau zoo tib yam ferritic stainless hlau, ultra-ntshiab high-chromium ferritic stainless hlau muaj qhov zoo tiv thaiv corrosion, pitting corrosion thiab kev nyuaj siab corrosion, thiab yog dav siv nyob rau hauv petrochemical khoom. Ferritic stainless hlau muaj cov yam ntxwv hauv qab no:
① Nyob rau hauv qhov kev txiav txim siab ntawm vuam kub, cov nplej nyob rau hauv lub tshav kub cuam tshuam qhov chaw uas cov cua kub kub nce mus txog 1000 degree, tshwj xeeb tshaj yog nyob rau hauv ze seam cheeb tsam, yuav loj hlob sai heev. Txawm hais tias nws txias sai sai tom qab vuam, qhov txo qis hauv toughness thiab siab nyiam rau intergranular corrosion.
② Ferritic steel nws tus kheej muaj cov ntsiab lus chromium ntau dua, muaj teeb meem ntau yam xws li carbon, nitrogen, oxygen, thiab lwm yam., qhov kub thiab txias hloov pauv ntau dua, thiab muaj zog rhiab heev. Yog li ntawd, tom qab weld embrittlement yog qhov hnyav dua.
③ Thaum rhuab thiab txias maj mam ntawm 400 degree ~ 600 degree rau lub sij hawm ntev, embrittlement ntawm 475 degree yuav tshwm sim, uas yuav txo tau qhov toughness ntawm chav tsev kub. Tom qab cua sov rau ib lub sij hawm ntev ntawm 550 ° C ~ 820 ° C, lub σ theem yog yooj yim precipitated los ntawm ferrite, thiab nws plasticity thiab toughness kuj txo.
3. Martensitic stainless hlau thiab nws cov yam ntxwv vuam
Martensitic stainless hlau tuaj yeem muab faib ua Cr13 hom martensitic stainless hlau, qis carbon martensitic stainless hlau thiab super martensitic stainless hlau. Cr13 hom muaj kev ua haujlwm dav dav los tiv thaiv corrosion. Los ntawm Cr12-raws li martensitic stainless hlau, vim yog sib ntxiv ntawm npib tsib xee, molybdenum, tungsten, vanadium thiab lwm yam alloying ntsiab, nws tsis tsuas yog muaj tej yam corrosion kuj, tab sis kuj muaj high-temperature zog thiab high-temperature kuj. . Oxidation zog.
Vuam yam ntxwv ntawm martensitic stainless hlau: Cr13 hom martensitic stainless hlau weld seam thiab tshav kub cuam tshuam cheeb tsam muaj ib tug tshwj xeeb hardening nyiam, thiab cov welded sib koom ua tau kom tau hard thiab nkig martensite nyob rau hauv cov huab cua txias. Nyob rau hauv qhov kev txiav txim ntawm vuam, nws yog ib qho yooj yim mus tshwm welding txias tawg. Thaum qhov txias txias me me, ntxhib ferrite thiab intergranular carbides yuav tsim nyob rau hauv qhov ze seam cheeb tsam thiab weld hlau, uas yuav txo tau cov plasticity thiab toughness ntawm qhov sib koom ua ke.
Tom qab qhov chaw vuam thiab cua sov ntawm cov pa roj carbon tsawg thiab super martensitic stainless hlau tau txias, tag nrho cov ntawm lawv tau hloov mus rau hauv qis-carbon martensite, tab sis tsis muaj qhov pom tseeb hardening tshwm sim, thiab lawv muaj kev vuam zoo.
Kev xaiv ntawm Stainless Hlau Vuam Consumables rau Siab Vessels
1. Kev xaiv ntawm austenitic stainless hlau vuam consumables
Lub hauv paus ntsiab lus xaiv ntawm austenitic stainless hlau vuam consumables yog los xyuas kom meej tias cov corrosion kuj thiab mechanical zog ntawm cov hlau weld yog yeej sib npaug los yog siab tshaj cov hlau puag nyob rau hauv cov kev mob ntawm tsis muaj kab nrib pleb. sib tw. Rau corrosion-resistant austenitic stainless hlau, nws yog feem ntau xav kom muaj ib tug npaum li cas ntawm ferrite, uas tsis tau tsuas yog xyuas kom meej zoo tawg kuj, tab sis kuj muaj zoo corrosion kuj. Txawm li cas los xij, hauv qee qhov tshwj xeeb tshaj tawm, xws li cov hlau vuam ntawm cov khoom siv urea, ferrite tsis pub muaj nyob, txwv tsis pub nws cov corrosion kuj yuav raug txo. Rau cov cua sov-resistant austenitic steels, kev tswj cov ntsiab lus ferrite hauv cov hlau vuam yuav tsum raug txiav txim siab. Rau austenitic steel weldments ua haujlwm ntawm qhov kub siab ntev ntev, cov ntsiab lus ferrite hauv cov hlau vuam yuav tsum tsis pub tshaj 5 feem pua. Cov neeg nyeem tuaj yeem kwv yees cov ntsiab lus ferrite sib xws raws li chromium sib npaug thiab npib tsib xee sib npaug hauv cov hlau vuam raws li daim duab Schaeffler.
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2. Kev xaiv ntawm ferritic stainless hlau vuam consumables
Muaj peb hom ferritic stainless hlau welding consumables: 1) vuam consumables uas nws muaj pes tsawg leeg yeej phim lub hauv paus hlau; 2) austenitic vuam consumables; 3) Nickel-raws li alloy vuam consumables, uas tsis tshua muaj siv vim lawv cov nqi siab.
Ferritic stainless hlau vuam consumables yuav ua tau los ntawm cov ntaub ntawv sib npaug rau lub hauv paus hlau, tab sis thaum lub degree ntawm restraint loj, tawg yooj yim tshwm sim. Kev kho cua sov tuaj yeem siv tom qab vuam los txhim kho corrosion thiab txhim kho kev sib koom ua ke. Kev siv cov austenitic vuam consumables yuav zam preheating thiab tom qab vuam thaum tshav kub kub kev kho mob, tab sis rau ntau yam steels uas tsis muaj cov ntsiab lus ruaj khov, lub rhiab heev ntawm tshav kub-cuam tshuam cheeb tsam tseem muaj, thiab 309 thiab 310 chromium-nickel austenitic vuam consumables feem ntau. siv. Rau Cr17 steel, 308 vuam consumables kuj siv tau. Vuam consumables nrog siab alloy cov ntsiab lus yog zoo los txhim kho lub plasticity ntawm welded pob qij txha. Cov hlau austenitic lossis austenitic-ferritic weld yog qhov muaj zog zoo li cov hlau ferritic, tab sis nyob rau hauv qee cov xov xwm corrosive, corrosion kuj ntawm cov weld yuav txawv heev ntawm cov hlau puag. Ua tib zoo saib thaum xaiv cov khoom siv vuam.
3. Kev xaiv ntawm martensitic stainless hlau vuam consumables
Hauv stainless hlau, martensitic stainless hlau tuaj yeem hloov kho los ntawm kev kho cua sov. Yog li ntawd, txhawm rau kom ntseeg tau tias qhov kev ua tau zoo, tshwj xeeb tshaj yog rau cov cua sov-resistant martensitic stainless hlau, qhov sib xyaw ntawm cov vuam yuav tsum nyob ze li sai tau rau cov khoom siv ntawm cov hlau hauv paus. Txhawm rau tiv thaiv cov kab mob khaub thuas, cov khoom siv austenitic welding tuaj yeem siv tau, thiab lub zog vuam ntawm lub sijhawm no yuav tsum qis dua ntawm cov hlau hauv qab.
Thaum muaj pes tsawg leeg ntawm cov vuam zoo ib yam li cov hlau hauv paus, qhov vuam thiab qhov chaw muaj kev kub nyhiab yuav ua rau tawv tawv thiab ua rau tawv nqaij tib lub sijhawm, thiab thaj chaw temper-softening yuav tshwm sim hauv thaj chaw uas muaj cua sov. Txhawm rau tiv thaiv kev tawg, cov khoom siv nrog lub thickness ntau dua 3 hli feem ntau yuav tsum tau preheated, thiab kev kho cua sov feem ntau yuav tsum tau tom qab vuam los txhim kho kev ua haujlwm ntawm kev sib koom ua ke. Txij li thaum lub thermal expansion coefficient ntawm weld hlau thiab lub hauv paus hlau yog tib yam, nws yog ua tau kom tshem tawm tag nrho cov weld tom qab kev kho cua sov. kev ntxhov siab.
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Thaum lub workpiece tsis pub preheated los yog kub kho, austenitic weld seam tuaj yeem xaiv. Vim hais tias cov weld seam muaj siab plasticity thiab toughness, nws tuaj yeem so lub vuam kev nyuaj siab thiab tuaj yeem yaj ntau hydrogen, yog li txo qhov kev ntxhov siab ntawm kev sib koom tes. Txias cracking nyiam, tab sis cov pob qij txha nrog cov ntaub ntawv tsis sib xws, vim qhov sib txawv thermal expansion coefficients, tuaj yeem tsim kev ntxhov siab nyob rau hauv fusion zone nyob rau hauv qhov chaw ua hauj lwm ntawm circulating kub, uas ua rau kev sib koom ua ke tsis ua hauj lwm.
Rau qhov yooj yim Cr13 hom martensitic steel, thaum lub weld nrog austenitic qauv tsis siv, tsis muaj ntau chav rau kev hloov kho ntawm weld muaj pes tsawg leeg, uas feem ntau yog tib yam li lub hauv paus hlau matrix, tab sis muaj teeb meem impurities xws li S, P thiab Si yuav tsum txwv. Si tuaj yeem txhawb kev tsim ntawm coarse martensite hauv Cr13 martensitic steel welds. Txo cov ntsiab lus ntawm C yog qhov zoo los txo cov hardenability, thiab muaj ib tug me me ntawm cov ntsiab lus xws li Ti, N los yog Al nyob rau hauv lub weld kuj muaj peev xwm ua kom cov nplej thiab txo cov hardenability.
Rau ntau cov khoom siv alloyed Cr12-raws li martensitic tshav kub-lub zog steel, lub hom phiaj tseem ceeb yog tshav kub tsis kam, thiab austenitic vuam consumables feem ntau tsis siv, thiab weld muaj pes tsawg leeg yuav tsum nyob ze rau lub hauv paus hlau. Thaum kho qhov muaj pes tsawg leeg, nws yuav tsum tau xyuas kom meej tias cov vuam tsis tshwm sim rau theem ferrite, vim tias nws muaj kev phom sij heev rau kev ua haujlwm, vim tias cov khoom tseem ceeb ntawm Cr13-raws li martensitic tshav kub-lub zog steel feem ntau yog ferrite ntsiab ( xws li Mo, Nb, W, V, thiab lwm yam), txhawm rau xyuas kom meej tias tag nrho cov qauv zoo li martensite, nws yuav tsum sib npaug nrog cov ntsiab lus austenite, uas yog, yuav tsum muaj cov ntsiab lus tsim nyog xws li C, Ni, Mn, thiab N.
Martensitic stainless hlau muaj lub siab nyiam rau qhov txias txias, yog li nws yog ib qho tsim nyog yuav tsum nruj me ntsis tswj cov hydrogen tsawg, txawm tias tsis tshua muaj hydrogen, thiab qhov no yuav tsum tau them sai sai rau thaum xaiv cov khoom siv vuam.
Cov ntsiab lus tseem ceeb ntawm Stainless Hlau Vuam rau Cov Nkoj Siab
1. Cov ntsiab lus tseem ceeb ntawm austenitic stainless hlau vuam
Feem ntau, austenitic stainless hlau muaj qhov zoo tshaj plaws weldability. Yuav luag txhua fusion vuam txoj kev tuaj yeem siv los vuam austenitic stainless hlau, thiab cov khoom siv thermophysical thiab microstructure yam ntxwv ntawm austenitic stainless hlau txiav txim siab cov ntsiab lus tseem ceeb ntawm nws txoj kev vuam.
① Vim yog cov thermal conductivity me me thiab loj thermal expansion coefficient ntawm austenitic stainless hlau, nws yog ib qho yooj yim los tsim loj deformation thiab vuam kev nyuaj siab thaum vuam, yog li txoj kev vuam nrog concentrated vuam zog yuav tsum tau xaiv ntau li ntau tau.
② Vim lub thermal conductivity me me ntawm austenitic stainless hlau, nws tuaj yeem tau txais qhov tob tob dua li cov hlau tsis tshua muaj hlau nyob rau hauv tib lub tam sim no. Nyob rau tib lub sijhawm, vim nws qhov kev tiv thaiv siab, txhawm rau kom tsis txhob muaj qhov liab ntawm cov electrode thaum lub sij hawm arc vuam, qhov vuam tam sim no me dua li ntawm cov hlau los yog cov hlau tsis tshua muaj hlau electrodes ntawm tib txoj kab uas hla.
③ Vuam specifications. Feem ntau tsis txhob siv cov tswv yim loj rau vuam. Rau electrode arc vuam, nws raug nquahu kom siv cov electrode me me rau kev sib txuas ceev ceev. Rau cov welds xav tau siab, txawm hliv dej txias kom ceev kom txias. Rau cov ntshiab austenitic stainless hlau thiab super austenitic stainless hlau, vim thermal tawg rhiab heev yog tias nws loj, cov vuam kab hluav taws xob yuav tsum nruj me ntsis tswj kom tsis txhob muaj kev loj hlob ntawm weld nplej thiab qhov tshwm sim ntawm vuam kub tawg.
④ Txhawm rau txhim kho cov thermal cracking tsis kam thiab corrosion kuj ntawm vuam, tshwj xeeb yuav tsum tau them nyiaj rau qhov huv ntawm qhov chaw vuam thaum vuam kom tsis txhob muaj teeb meem ntawm kev nkag mus rau qhov vuam.
⑤ Austenitic stainless hlau feem ntau tsis tas yuav preheating thaum vuam. Txhawm rau tiv thaiv kev loj hlob ntawm cov qoob loo thiab carbide nag lossis daus hauv qhov vuam seam thiab tshav kub cuam tshuam, thiab xyuas kom lub plasticity, toughness thiab corrosion kuj ntawm cov welded sib koom, qhov kub interlayer yuav tsum tau tswj, feem ntau tsis tshaj 150 degree.
2. Ferritic stainless hlau vuam cov ntsiab lus
Ferritic stainless hlau muaj cov ntsiab lus ntau dua ferrite-forming, kuj tsis tshua muaj austenite-forming ntsiab, thiab cov khoom tsis tshua muaj siab tawv thiab txias tawg. Nyob rau hauv qhov kev txiav txim ntawm vuam thermal voj voog ntawm ferritic stainless hlau, cov nplej nyob rau hauv lub tshav kub-cuam tshuam cheeb tsam loj hlob obviously, thiab lub toughness thiab plasticity ntawm kev sib koom ua ke txo sharply. Lub degree ntawm grain loj hlob nyob rau hauv lub tshav kub-tshem tawm tsam nyob ntawm qhov kub siab tshaj plaws mus txog thaum vuam thiab nws lub sij hawm tuav. Yog li ntawd, thaum vuam ferritic stainless hlau, ib txoj kab me me zog yuav tsum tau siv ntau li ntau tau, uas yog, ib txoj kev ntawm lub zog concentration, xws li me me tam sim no TIG, phau ntawv welding nrog me txoj kab uas hla electrodes, thiab lwm yam. Tib lub sij hawm, kev ntsuas xws li qhov sib txawv nqaim groove, siab vuam ceev thiab ntau txheej vuam yuav tsum tau txais ntau li ntau tau, thiab qhov kub ntawm cov txheej yuav tsum nruj me ntsis tswj.
Vim yog cov txiaj ntsig ntawm vuam cua sov lub voj voog, feem ntau ferritic stainless hlau yog rhiab heev nyob rau hauv qhov kub thiab txias cheeb tsam ntawm tshav kub cuam tshuam cheeb tsam, thiab intergranular corrosion tshwm sim nyob rau hauv ib co xov xwm. Tom qab vuam, nws yog annealed ntawm 700 ~ 850 degree kom homogenize cov chromium thiab rov qab nws corrosion kuj.
Ordinary high-chromium ferritic stainless hlau tuaj yeem welded los ntawm electrode arc vuam, roj shielded vuam, submerged arc vuam thiab lwm txoj kev vuam. Vim yog qhov tsis tshua muaj plasticity ntawm high-chromium steel, nrog rau cov qoob loo loj hlob hauv thaj chaw tshav kub thiab kev sib sau ntawm carbides thiab nitrides ntawm cov ciam teb uas tshwm sim los ntawm kev sib hloov cua sov, cov plasticity thiab toughness ntawm welded pob qij txha yog heev. qis. Kev tawg yuav tshwm sim thaum vuam consumables uas zoo sib xws cov tshuaj muaj pes tsawg leeg rau lub hauv paus hlau yog siv thiab cov degree ntawm restraint loj. Txhawm rau tiv thaiv cov kab nrib pleb thiab txhim kho kev sib koom ua ke ntawm plasticity thiab corrosion kuj, kev siv electrode arc vuam ua piv txwv, cov kev ntsuas hauv qab no tuaj yeem ua.
① Preheat ntawm li 100 ~ 150 degree kom vuam cov khoom nyob rau hauv ib lub xeev tawv. Qhov siab dua cov ntsiab lus chromium, qhov siab dua qhov preheating kub yuav tsum yog.
② Vuam nrog lub zog me me thiab tsis muaj viav vias. Thaum lub sij hawm ntau txheej vuam, qhov kub ntawm cov khaubncaws sab nraud povtseg yuav tsum tau tswj kom tsis txhob siab tshaj 150 degree, thiab nruam vuam yuav tsum tsis txhob siv los txo cov teebmeem ntawm kub kub embrittlement thiab 475 degree embrittlement.
③ Tom qab vuam, annealing ntawm 750 ~ 800 degree tuaj yeem rov kho qhov corrosion thiab txhim kho cov yas ntawm kev sib koom ua ke vim yog spheroidization ntawm carbides thiab kev faib tawm ntawm chromium. Tom qab annealing, nws yuav tsum tau txias sai sai los tiv thaiv qhov tshwm sim ntawm σ theem thiab brittleness ntawm 475 degree.
3. Martensitic stainless hlau vuam cov ntsiab lus
Rau Cr13 hom martensitic stainless hlau, thaum siv electrodes ntawm tib cov khoom siv rau vuam, thiaj li yuav txo tau qhov rhiab heev ntawm cov kab nrib pleb thiab ua kom cov yas thiab toughness ntawm cov pob qij txha welded, tsawg-hydrogen electrodes yuav tsum tau xaiv thiab cov kev ntsuas hauv qab no yuav tsum yog. coj tib lub sijhawm:
① Preheat. Lub preheating kub nce nrog qhov nce ntawm cov ntsiab lus carbon ntawm cov hlau, feem ntau nyob rau hauv thaj tsam ntawm 100 degree mus rau 350 degree.
② Tom qab cua sov. Rau cov welded pob qij txha uas muaj cov ntsiab lus carbon siab los yog siab ceev, kev ntsuas tom qab cua sov yuav tsum tau ua tom qab vuam los tiv thaiv vuam hydrogen-induced tawg.
③ Kev kho cua sov tom qab vuam. Txhawm rau txhim kho plasticity, toughness thiab corrosion kuj ntawm welded pob qij txha, tom qab vuam kev kho cua sov yog feem ntau 650 degree C ~ 750 degree C, thiab lub sij hawm tuav yog xam li 1h / 25mm.
Rau super thiab tsawg-carbon martensitic stainless hlau, preheating ntsuas feem ntau tsis tas yuav tsum tau. Thaum qhov kev txwv tsis pub muaj qhov loj lossis cov ntsiab lus hydrogen hauv qhov vuam siab, kev ntsuas preheating thiab postheating yog siv. Lub preheating kub yog feem ntau 100 ° C ~ 150 ° C, tom qab vuam kub kho kub yog 590 ~ 620 ° C. Rau martensitic steels nrog cov ntsiab lus carbon ntau dua. Los yog thaum ua ntej vuam preheating thiab tom qab vuam kev kho cua sov yog qhov nyuaj rau kev siv, thiab cov pob qij txha tau nruj heev, austenitic vuam consumables kuj yuav siv tau nyob rau hauv engineering los txhim kho cov yas thiab toughness ntawm welded pob qij txha thiab tiv thaiv kab nrib pleb. Tab sis lub sij hawm no, thaum cov hlau weld yog austenitic los yog austenite-raws li, nws yog ib tug uas tsis muaj zog match piv nrog lub zog ntawm lub hauv paus hlau, thiab weld hlau thiab lub hauv paus hlau yog txawv nyob rau hauv tshuaj muaj pes tsawg leeg, metallographic qauv, thermal Lub cev thiab cov khoom siv kho tshuab sib txawv heev, thiab cov vuam seem ntawm kev ntxhov siab yog qhov yuav tsum tau zam, uas tuaj yeem yooj yim ua rau muaj kev ntxhov siab corrosion lossis kub siab creep puas.
Vuam ntawm duplex stainless hlau
1. Hom duplex stainless hlau
Duplex stainless hlau muaj austenite ntxiv rau ferrite duplex qauv, thiab cov ntsiab lus ntawm ob theem qauv
Yeej zoo ib yam, yog li nws muaj cov yam ntxwv ntawm austenitic stainless hlau thiab ferritic stainless hlau. Lub zog tawm los tuaj yeem ncav cuag 400Mpa ~ 550MPa, uas yog ob npaug ntawm cov hlau tsis zoo austenitic. Piv nrog rau ferritic stainless hlau, duplex stainless hlau muaj siab toughness, tsis tshua muaj siab hloov kub, ho txhim kho intergranular corrosion kuj thiab vuam kev ua tau zoo; Nyob rau tib lub sijhawm, nws khaws qee cov yam ntxwv ntawm ferritic stainless hlau, xws li 475 degree brittleness, thermal High conductivity, me me coefficient ntawm linear expansion, superplasticity thiab magnetism. Piv nrog rau austenitic stainless hlau, lub zog ntawm duplex stainless hlau yog siab, tshwj xeeb tshaj yog lub zog tawm los yog txhim khu kev qha, thiab cov kev ua tau zoo ntawm pitting corrosion kuj, kev nyuaj siab corrosion kuj, thiab corrosion qaug zog kuj tseem ho txhim kho.
Duplex stainless hlau yog cais raws li nws cov tshuaj muaj pes tsawg leeg, thiab muab faib ua plaub hom: Cr18 hom, Cr23 (tsis suav Mo), Cr22 hom thiab Cr25 hom. Rau Cr25 duplex stainless hlau, nws tuaj yeem muab faib ua hom thiab super duplex stainless hlau, ntawm cov Cr22 hom thiab Cr25 hom tau siv dav hauv xyoo tas los. Feem ntau ntawm cov duplex stainless hlau siv hauv kuv lub teb chaws yog tsim nyob rau hauv Sweden, thiab cov qib tshwj xeeb yog: 3RE60 (Cr18 hom), SAF2304 (Cr23 hom), SAF2205 (Cr22 hom), SAF2507 (Cr25 hom).
2. Vuam yam ntxwv ntawm duplex stainless hlau
① Duplex stainless hlau muaj zoo weldability. Nws tsis yog ib qho yooj yim rau embrittle lub tshav kub-cuam tshuam cheeb tsam thaum vuam zoo li ferritic stainless hlau, thiab nws tsis yooj yim los tsim vuam kub tawg zoo li austenitic stainless hlau. Txawm li cas los xij, vim tias nws muaj ntau cov ferrite, Thaum lub rigidity siab los yog cov ntsiab lus hydrogen ntawm cov vuam yog siab, hydrogen txias tawg yuav tshwm sim, yog li nws yog ib qho tseem ceeb heev kom nruj me ntsis tswj qhov chaw ntawm hydrogen.
② Yuav kom ntseeg tau cov yam ntxwv ntawm ob-theem steel, kom ntseeg tau tias qhov kev faib ua feem ntawm austenite thiab ferrite nyob rau hauv cov qauv ntawm cov welded sib koom tsim nyog yog tus yuam sij rau vuam hom hlau. Thaum qhov txias txias ntawm qhov sib koom ua ke tom qab vuam qeeb, qhov hloov pauv theem nrab ntawm δ → yog qhov txaus, yog li cov qauv duplex nrog cov theem tsim nyog tuaj yeem tau txais nyob rau hauv chav tsev kub, uas yuav tsum muaj qhov tsim nyog loj vuam cua sov thaum lub sij hawm vuam. . Txwv tsis pub, yog tias qhov txias txias tom qab vuam ceev, δ ferrite theem yuav nce, uas ua rau muaj qhov txo qis hauv plasticity, toughness thiab corrosion kuj ntawm qhov sib koom ua ke.
3. Kev xaiv ntawm duplex stainless hlau vuam consumables
Vuam consumables rau duplex stainless hlau, uas yog yus muaj los ntawm lub weld qauv yog ib tug duplex qauv dominated los ntawm austenite, thiab cov ntsiab lus ntawm lub ntsiab corrosion-resistant ntsiab (chromium, molybdenum, thiab lwm yam) yog sib npaug rau cov hlau puag, yog li ntawd. kom ntseeg tau tib yam corrosion kuj zoo li lub hauv paus hlau sib deev. Txhawm rau kom ntseeg tau tias cov ntsiab lus ntawm austenite hauv qhov vuam, cov ntsiab lus ntawm nickel thiab nitrogen feem ntau yog nce, uas yog, qhov sib npaug ntawm npib tsib xee yog nce li ntawm 2 mus rau 4 feem pua. Hauv cov khoom siv hauv duplex stainless hlau, feem ntau muaj qee cov ntsiab lus ntawm nitrogen, thiab qee qhov ntawm cov ntsiab lus nitrogen tseem xav tau hauv cov khoom siv vuam, tab sis feem ntau nws yuav tsum tsis txhob siab dhau, txwv tsis pub cov pores yuav tshwm sim. Nyob rau hauv txoj kev no, cov ntsiab lus siab nickel tau dhau los ua qhov sib txawv loj ntawm cov khoom siv vuam thiab lub hauv paus hlau.
Raws li cov kev xav tau sib txawv ntawm kev tiv thaiv corrosion thiab kev sib koom ua ke, xaiv cov electrode uas phim cov tshuaj muaj pes tsawg leeg ntawm cov hlau hauv paus, xws li vuam Cr22 duplex stainless hlau, koj tuaj yeem xaiv Cr22Ni9Mo3 electrode, xws li E2209 electrode. Thaum siv cov kua qaub acidic, cov slag tshem tawm yog qhov zoo thiab cov duab vuam zoo nkauj, tab sis qhov cuam tshuam toughness tsawg. Thaum lub vuam hlau yuav tsum tau muaj kev cuam tshuam siab toughness thiab txhua txoj hauj lwm vuam yuav tsum tau siv, alkaline electrodes yuav tsum tau siv. Basic electrodes feem ntau yog siv thaum lub hauv paus thaub qab yog welded. Thaum muaj cov kev cai tshwj xeeb rau kev tiv thaiv corrosion ntawm cov hlau vuam, cov khoom siv hluav taws xob yooj yim nrog super duplex steel Cheebtsam yuav tsum tau siv.
Rau cov khoom siv roj tiv thaiv vuam hlau, thaum ua kom ntseeg tau tias cov hlau vuam muaj qhov zoo corrosion thiab cov khoom siv kho tshuab, yuav tsum tau them nyiaj rau nws cov txheej txheem vuam. Rau flux cored hlau, thaum lub weld zoo yuav tsum tau zoo nkauj, rutile los yog titanium Rau calcium-hom flux-cored hlau, thaum muaj kev cuam tshuam ntau dua toughness yuav tsum tau los yog vuam nyob rau hauv tej yam kev mob ntawm ntau dua restraint, ib tug flux-cored hlau nrog siab alkalinity yuav tsum tau. siv.
Rau submerged arc vuam, nws yog advisable siv vuam hlau nrog ib tug me me txoj kab uas hla kom paub ntau txheej thiab multi-pass vuam nyob rau hauv me me thiab nruab nrab-qhov loj me vuam specifications, thiaj li tiv thaiv embrittlement ntawm vuam tshav kub-tshem tawm tsam thiab vuam hlau. , thiab siv qhov sib txuam alkaline flux.
4. Vuam cov ntsiab lus ntawm duplex stainless hlau
① Kev tswj cov txheej txheem vuam cua sov Vuam lub zog hluav taws xob, qhov kub ntawm qhov sib txuas, preheating thiab cov khoom tuab yuav cuam tshuam rau tus nqi cua txias thaum lub sij hawm vuam, yog li cuam tshuam rau cov qauv thiab kev ua haujlwm ntawm cov vuam thiab cov cua sov. Kev nrawm dhau los yog qeeb dhau qhov txias txias yuav cuam tshuam rau qhov toughness thiab corrosion kuj ntawm duplex steel welded pob qij txha. Thaum cov cua txias nrawm dhau, nws yuav ua rau cov ntsiab lus ntau dhau thiab ua rau cov nag lossis daus ntawm Cr2N. Yog tias qhov txias txias qeeb dhau lawm, cov hmoov nplej siv lead ua yuav raug coarsened hnyav, thiab txawm tias qee qhov sib xyaw ua ke sib xyaw ua ke, xws li σ theem, tej zaum yuav raug precipitated. Table 1 teev qee qhov kev pom zoo vuam kab hluav taws xob thiab kev sib tshuam ntawm qhov kub thiab txias. Thaum xaiv cov kab hluav taws xob, cov khoom siv tshwj xeeb yuav tsum tau txiav txim siab. Lub sab sauv txwv ntawm txoj kab hluav taws xob nyob rau hauv lub rooj yog haum rau cov phaj tuab, thiab cov kev txwv qis yog tsim rau nyias daim hlau. Thaum vuam duplex steel nrog 25 feem pua ω (Cr) thiab super stainless hlau nrog cov ntsiab lus alloy siab, thiaj li yuav tau txais cov khoom zoo tshaj plaws ntawm cov hlau, nws raug pom zoo tias qhov siab tshaj plaws interpass kub tswj ntawm 100 degree. Thaum kev kho cua sov yuav tsum tau tom qab vuam, qhov kub ntawm qhov sib cuam tshuam yuav tsis txwv.
② Kev kho cua sov tom qab vuam Nws yog qhov zoo tshaj plaws kom tsis txhob kub-kho duplex stainless hlau tom qab vuam, tab sis thaum cov ntsiab lus ntawm theem nyob rau hauv lub xeev-welded tshaj qhov yuav tsum tau los yog thaum muaj teeb meem theem, xws li σ theem, yog precipitated, post- weld kev kho cua sov tuaj yeem siv los txhim kho. Txoj kev kho cua sov siv yog dej quenching. Thaum kho cua sov, cua sov yuav tsum ceev li sai tau, thiab lub sij hawm tuav ntawm lub tshav kub kev kho mob kub yog 5 ~ 30min, uas yuav tsum tau txaus los kho cov equilibrium ntawm cov theem. Hlau oxidation yog qhov hnyav heev thaum kho cua sov, thiab kev tiv thaiv roj inert yuav tsum xav txog. Rau lub dual-theem steel nrog 22 feem pua ω (Cr), kev kho cua sov yuav tsum tau nqa tawm ntawm qhov kub ntawm 1050 ° C ~ 1100 ° C, thaum lub dual-theem steel thiab super dual-theem steel nrog 25% ω (Cr ) xav tau kev kho cua sov ntawm qhov kub ntawm 1070 ° C ~ 1120 ° C Ua kom sov kho.
Vuam piv txwv ntawm stainless hlau siab nkoj
Lub flash tank nrog txoj kab uas hla ntawm 800mm thiab phab ntsa thickness ntawm 10mm yog ua los ntawm 0Cr18Ni9.
piv txwv:
① Txoj kab uas hla ntawm lub tog raj kheej yog 800 hli, thiab cov vuam tuaj yeem laum rau hauv lub tog raj kheej rau vuam. Yog li ntawd, lub longitudinal thiab ncig seams ntawm lub tog raj kheej yog welded ntawm ob sab los ntawm electrode arc vuam.
② Tsis muaj qhov nyob rau hauv cov cuab yeej no, yog li lub kaw vuam tuaj yeem tsuas yog welded los ntawm sab nraud. Txhawm rau kom ntseeg tau qhov vuam zoo, TIG vuam yog siv los ua tus thaub qab. Txawm li cas los xij, cov hlau rov qab yuav raug oxidized thaum lub sij hawm argon arc vuam ntawm stainless hlau. Yav dhau los, tsuas yog txoj kev sau argon rau sab nraub qaum tuaj yeem siv los tiv thaiv. tsis zoo. Yuav kom daws tau qhov teeb meem ntawm cov txheej txheem no, Vuam Division ntawm Nippon Oil & Fat Company tau tsim thiab tsim ib lub nraub qaum tiv thaiv tus kheej stainless hlau TIG vuam hlau, uas yog vuam hlau nrog cov txheej tshwj xeeb, thiab txheej txheej (uas yog, txheej txheej. ) yuav nkag mus rau hauv lub pas dej molten tom qab melting Nyob rau sab nraum qab, ib tug tuab tiv thaiv txheej yog tsim, uas yog sib npaug rau lub luag hauj lwm ntawm electrode txheej. Kev siv cov vuam hlau no zoo ib yam li cov TIG vuam hlau zoo tib yam, thiab cov txheej yuav tsis cuam tshuam rau pem hauv ntej arc thiab molten pas dej ua ke, uas zoo heev txo cov nqi vuam ntawm stainless hlau argon arc vuam. Hauv cov khoom siv no, yog siv cov argon tiv thaiv tom qab, cov khib nyiab argon yog qhov hnyav, yog li siv tus kheej-shielding vuam hlau.
③ Rau cov welds ntawm cov yeeb nkab txuas thiab lub tiaj vuam flange, thiab nruab nrab ntawm cov yeeb nkab txuas thiab lub plhaub, nyob rau hauv qhov kev pom ntawm cov duab thiab vuam tej yam kev mob ntawm cov welds ntawm qhov no, electrode arc vuam feem ntau yog siv. Yog tias txoj kab uas hla ntawm cov yeeb nkab txuas me me dhau, txhawm rau txo qhov nyuaj ntawm vuam, TIG vuam kuj tseem siv tau.
④ Cov hlua khi ntawm qhov kev txhawb nqa thiab lub plhaub yog cov khoom siv tsis muaj zog, thiab cov roj siv hluav taws xob siv tau (cov roj tiv thaiv yog CO2 ntshiab), uas muaj kev ua haujlwm siab thiab zoo vuam zoo. TFW-308L yog welding consumable grade, thiab nws cov welding consumable qauv yog E308LT1-1 (AWS A5.22).
