321 stainless hlau coiled tube tshuaj muaj pes tsawg leeg Cov khoom siv thiab cov cwj pwm corrosion ntawm duplex stainless hlau weld nrog cov electrode tshiab

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Stainless hlau 321 Coil Tube Chemical Composition

Cov tshuaj muaj pes tsawg leeg ntawm 321 stainless hlau coil tubing yog raws li nram no:
- Cov pa roj carbon: 0.08% max
- Manganese: 2.00% max
- Nickel: 9.00% min

Stainless hlau 321 Coil Tube Mechanical Properties

Raws li Stainless Hlau 321 Coil Tube Chaw Tsim Tshuaj, cov khoom siv ntawm stainless hlau 321 coil tubing yog tabulated hauv qab no: Tensile Strength (psi) Yield Strength (psi) Elongation (%)

Kev Siv & Kev Siv Cov Hlau Stainless 321 Coil Tube

Hauv ntau daim ntawv thov engineering, cov khoom siv kho tshuab thiab corrosion ntawm duplex stainless hlau (DSS) welded qauv yog qhov tseem ceeb tshaj plaws.Txoj kev tshawb fawb tam sim no tau tshawb xyuas cov khoom siv kho tshuab thiab kev tiv thaiv corrosion ntawm duplex stainless hlau welds nyob rau hauv ib puag ncig simulating 3.5% NaCl siv ib qho tshwj xeeb tsim tshiab electrode yam tsis muaj qhov sib ntxiv ntawm cov ntsiab lus alloying rau cov qauv flux.Ob hom sib txawv ntawm cov fluxes nrog qhov ntsuas nruab nrab ntawm 2.40 thiab 0.40 tau siv rau ntawm electrodes E1 thiab E2 rau vuam DSS boards, feem.Lub thermal stability ntawm cov flux compositions tau soj ntsuam los ntawm kev ntsuas thermogravimetric.Cov tshuaj muaj pes tsawg leeg nrog rau cov khoom siv kho tshuab thiab corrosion ntawm cov pob qij txha welded tau raug soj ntsuam siv emission spectroscopy raws li ntau yam qauv ASTM.X-ray diffraction yog siv los txiav txim cov theem tam sim no hauv DSS welds, thiab scanning electron nrog EDS yog siv los tshuaj xyuas cov microstructure ntawm welds.Lub zog tensile ntawm welded pob qij txha ua los ntawm E1 electrodes yog nyob rau hauv 715-732 MPa, los ntawm E2 electrodes - 606-687 MPa.Lub vuam tam sim no tau nce los ntawm 90 A mus rau 110 A, thiab qhov hardness kuj tau nce ntxiv.Welded pob qij txha nrog E1 electrodes coated nrog yooj yim fluxes muaj cov khoom zoo dua qub.Cov qauv hlau muaj kev tiv thaiv corrosion siab hauv 3.5% NaCl ib puag ncig.Qhov no lees paub qhov kev ua haujlwm ntawm cov pob qij txha welded ua nrog cov electrodes tshiab tsim.Cov txiaj ntsig tau sib tham hauv cov ntsiab lus ntawm depletion ntawm alloying ntsiab xws li Cr thiab Mo pom nyob rau hauv welds nrog coated electrodes E1 thiab E2, thiab tso tawm ntawm Cr2N nyob rau hauv welds ua siv electrodes E1 thiab E2.
Keeb kwm, thawj cov lus tshaj tawm ntawm duplex stainless hlau (DSS) hnub rov qab mus rau xyoo 1927, thaum nws tsuas yog siv rau qee yam castings thiab tsis tau siv rau hauv feem ntau cov ntawv thov vim nws cov ntsiab lus carbon siab 1.Tab sis tom qab ntawd, tus qauv carbon cov ntsiab lus raug txo mus rau qhov siab tshaj plaws ntawm 0.03%, thiab cov hlau no tau siv dav hauv ntau yam 2,3.DSS yog ib tsev neeg ntawm alloys nrog kwv yees li sib npaug ntawm ferrite thiab austenite.Kev tshawb fawb tau pom tias theem ferritic hauv DSS muab kev tiv thaiv zoo heev tiv thaiv chloride-induced stress corrosion cracking (SCC), uas yog ib qho teeb meem tseem ceeb rau austenitic stainless hlau (ASS) nyob rau hauv lub xyoo pua 20th.Ntawm qhov tod tes, hauv qee qhov engineering thiab lwm yam kev lag luam 4 qhov kev thov rau kev cia yog loj hlob ntawm tus nqi txog li 20% ib xyoos twg.Cov hlau tshiab no nrog ob-theem austenitic-ferritic qauv tuaj yeem tau txais los ntawm kev xaiv cov khoom tsim nyog, lub cev-tshuaj thiab thermomechanical refining.Piv rau ib-theem stainless hlau, DSS muaj lub zog ntau dua thiab muaj peev xwm tiv taus SCC5, 6, 7, 8. Cov qauv duplex muab cov hlau tsis muaj zog, toughness thiab nce corrosion kuj nyob rau hauv ib puag ncig hnyav uas muaj acids, acid chlorides, dej hiav txwv thiab tshuaj corrosive 9.Vim yog tus nqi txhua xyoo hloov pauv ntawm cov nickel (Ni) alloys hauv kev lag luam dav dav, cov qauv DSS, tshwj xeeb tshaj yog cov tsis tshua muaj nickel hom (lean DSS), tau ua tiav ntau yam kev ua tau zoo piv rau lub ntsej muag centered cubic (FCC) iron10, 11. Lub ntsiab teeb meem ntawm ASE designs yog nyob rau hauv uas lawv raug rau ntau yam hnyav.Yog li ntawd, ntau lub tuam tsev engineering thiab tuam txhab uas muag tau sim los txhawb lwm yam tsis tshua muaj npib tsib xee (Ni) stainless hlau uas ua tau zoo li lossis zoo dua li cov tsoos ASS nrog cov weldability tsim nyog thiab siv rau hauv cov ntawv thov xws li dej hiav txwv kub exchangers thiab kev lag luam tshuaj.thawv 13 rau ib puag ncig uas muaj cov tshuaj chloride siab.
Nyob rau hauv niaj hnub kev kawm txuj ci, welded ntau lawm plays lub luag hauj lwm tseem ceeb.Feem ntau, cov tswv cuab ntawm DSS tau koom nrog cov roj shielded arc vuam los yog roj shielded arc vuam.Lub vuam feem ntau cuam tshuam los ntawm cov khoom siv ntawm cov electrode siv rau vuam.Vuam electrodes muaj ob ntu: hlau thiab flux.Feem ntau, cov electrodes yog coated nrog flux, ib tug sib tov ntawm hlau uas, thaum decomposed, tso gases thiab tsim ib tug tiv thaiv slag los tiv thaiv lub weld los ntawm kev sib kis, ua rau kom lub stability ntawm lub arc, thiab ntxiv ib tug alloying tivthaiv los txhim kho qhov zoo ntawm vuam 14 .Cam khwb cia hlau, txhuas, stainless hlau, me me hlau, siab zog hlau, tooj liab, tooj dag, thiab tooj dag yog ib co ntawm cov vuam electrode hlau, thaum cellulose, hlau hmoov, thiab hydrogen yog ib co ntawm cov ntaub ntawv flux siv.Qee zaum sodium, titanium thiab potassium kuj ntxiv rau cov dej sib tov.
Qee cov kws tshawb fawb tau sim los kawm txog qhov cuam tshuam ntawm electrode configuration ntawm cov neeg kho tshuab thiab corrosion kev ncaj ncees ntawm welded steel qauv.Singh et al.15 tau tshawb xyuas qhov cuam tshuam ntawm flux muaj pes tsawg leeg ntawm elongation thiab tensile lub zog ntawm welds welded los ntawm submerged arc vuam.Cov txiaj ntsig tau pom tias CaF2 thiab NiO yog lub ntsiab lus txiav txim siab ntawm lub zog tensile piv rau qhov muaj FeMn.Chirag et al.16 tshawb xyuas SMAW tebchaw los ntawm kev sib txawv ntawm cov concentration ntawm rutile (TiO2) nyob rau hauv ib qho electrode flux sib tov.Nws tau pom tias cov khoom ntawm microhardness tau nce vim qhov nce hauv feem pua ​​thiab kev tsiv teb tsaws ntawm carbon thiab silicon.Kumar [17] kawm txog kev tsim thiab kev loj hlob ntawm agglomerated fluxes rau submerged arc vuam ntawm steel los xij.Nwigbo thiab Atuanya18 tau tshawb xyuas kev siv cov poov tshuaj-nplua nuj sodium silicate binders rau zus tau tej cov arc vuam fluxes thiab pom welds nrog ib tug siab tensile zog ntawm 430 MPa thiab ib tug txais tau grain qauv.Lothongkum et al.19 siv ib txoj kev potentiokinetic los kawm txog qhov ntim feem ntawm austenite nyob rau hauv duplex stainless hlau 28Cr–7Ni–O–0.34N nyob rau hauv ib tug huab cua-saturated NaCl tov ntawm ib tug concentration ntawm 3.5% wt.nyob rau hauv pH tej yam kev mob.thiab 27 ° C.Ob qho tib si duplex thiab micro duplex stainless hlau qhia tib cov txiaj ntsig ntawm nitrogen ntawm tus cwj pwm corrosion.Nitrogen tsis cuam tshuam rau corrosion muaj peev xwm lossis tus nqi ntawm pH 7 thiab 10, txawm li cas los xij, lub peev xwm corrosion ntawm pH 10 yog qis dua ntawm pH 7. Ntawm qhov tod tes, ntawm tag nrho cov pH qib kawm, lub peev xwm pib nce nrog nce nitrogen cov ntsiab lus. .Lacerda et al.20 kawm pitting ntawm duplex stainless hlau UNS S31803 thiab UNS S32304 hauv 3.5% NaCl tov siv cyclic potentiodynamic polarization.Hauv 3.5 wt.% kev daws ntawm NaCl, cov cim ntawm pitting tau pom ntawm ob daim hlau tshawb xyuas.UNS S31803 steel muaj peev xwm corrosion ntau dua (Ecorr), pitting muaj peev xwm (Epit) thiab polarization tsis kam (Rp) dua li UNS S32304 steel.UNS S31803 steel muaj ntau dua repassivity dua UNS S32304 steel.Raws li kev tshawb fawb los ntawm Jiang et al.[21], lub reactivation ncov sib haum mus rau ob theem (austenite thiab ferrite theem) ntawm duplex stainless hlau suav nrog txog li 65% ntawm cov ferrite muaj pes tsawg leeg, thiab ferrite reactivation tam sim no ceev nce nrog nce lub sij hawm kho cua sov.Nws paub zoo tias cov theem austenitic thiab ferritic muaj cov tshuaj tiv thaiv electrochemical sib txawv ntawm qhov sib txawv electrochemical muaj peev xwm21,22,23,24.Abdo et al.25 siv potentiodynamic ntsuas ntawm polarization spectroscopy thiab electrochemical impedance spectroscopy los kawm cov electrochemically induced corrosion ntawm laser-welded 2205 DSS alloy nyob rau hauv dag seawater (3.5% NaCl) nyob rau hauv tej yam kev mob ntawm txawv acidity thiab alkalinity.Pitting corrosion tau pom ntawm qhov chaw raug ntawm DSS kuaj.Raws li cov kev tshawb pom no, nws tau tsim kom muaj kev sib raug zoo ntawm pH ntawm qhov nruab nrab dissolving thiab tsis kam ntawm zaj duab xis tsim nyob rau hauv tus txheej txheem ntawm kev them nqi, uas cuam tshuam ncaj qha rau kev tsim pitting thiab nws specification.Lub hom phiaj ntawm txoj kev tshawb no yog kom nkag siab tias qhov kev tsim tshiab vuam electrode muaj pes tsawg leeg cuam tshuam rau cov neeg kho tshuab thiab hnav-tiv taus kev ncaj ncees ntawm welded DSS 2205 hauv 3.5% NaCl ib puag ncig.
Cov khoom siv flux (cov khoom xyaw) siv hauv cov txheej txheem electrode txheej yog Calcium Carbonate (CaCO3) los ntawm Obajana District, Kogi State, Nigeria, Calcium Fluoride (CaF2) los ntawm Taraba State, Nigeria, Silicon Dioxide (SiO2), Talc Powder (Mg3Si4O10(OH) ) ) 2) thiab rutile (TiO2) tau los ntawm Jos, Nigeria, thiab kaolin (Al2(OH)4Si2O5) tau los ntawm Kankara, Katsina State, Nigeria.Potassium silicate yog siv los ua cov ntawv khi, nws tau txais los ntawm Is Nrias teb.
Raws li tau pom nyob rau hauv Table 1, cov khoom siv oxides tau raug ntsuas ntawm nws tus kheej ntawm qhov sib npaug digital.Tom qab ntawd nws tau tov nrog cov poov tshuaj silicate binder (23% los ntawm qhov hnyav) nyob rau hauv ib qho hluav taws xob tov khoom (qauv: 641-048) los ntawm Indian Steel thiab Wire Products Ltd. (ISWP) rau 30 feeb kom tau ib homogeneous semi-solid paste.Cov dej ntub dej sib xyaw yog nias rau hauv cov duab cylindrical los ntawm lub tshuab briquetting thiab pub rau hauv lub tshuab extrusion ntawm lub siab ntawm 80 mus rau 100 kg / cm2, thiab los ntawm cov hlau pub chamber yog pub rau hauv 3.15mm txoj kab uas hla stainless hlau extruder.Cov flux yog pub los ntawm lub nozzle / tuag system thiab txhaj rau hauv lub extruder kom extrude cov electrodes.Qhov kev pab them nqi ntawm 1.70 mm tau txais, qhov kev pab them nqi yog txhais raws li qhov piv ntawm cov electrode txoj kab uas hla mus rau txoj kab uas hla.Tom qab ntawd cov coated electrodes tau qhuav nyob rau hauv huab cua rau 24 teev thiab ces calcined nyob rau hauv ib tug muffle furnace ( qauv PH-248-0571/5448) ntawm 150-250 ° C \ (-\) rau 2 teev.Siv qhov sib npaug los xam cov alkalinity ntawm cov ntws.(1) 26;
Lub thermal stability ntawm flux qauv ntawm cov compositions E1 thiab E2 tau txiav txim siab siv cov thermogravimetric tsom xam (TGA).Ib qho piv txwv ntawm kwv yees li 25.33 mg ntawm flux tau thauj mus rau hauv TGA rau kev tshuaj xyuas.Cov kev sim tau ua nyob rau hauv ib qho nruab nrab inert uas tau los ntawm kev nruam N2 ntawm tus nqi ntawm 60 ml / min.Cov qauv tau ua kom sov ntawm 30 ° C mus rau 1000 ° C ntawm qhov cua sov ntawm 10 ° C / min.Ua raws li cov txheej txheem hais los ntawm Wang et al.27, Xu et al.28 thiab Dagwa li al.29, thermal decomposition thiab poob phaus ntawm cov qauv ntawm qee qhov ntsuas kub tau soj ntsuam los ntawm TGA cov phiaj xwm.
Txheej ob 300 x 60 x 6 mm DSS daim hlau los npaj rau kev sib tw.V-groove tau tsim nrog 3 hli hauv paus qhov sib txawv, 2 hli hauv paus qhov thiab lub kaum sab xis 60 °.Tom qab ntawd lub phaj tau muab yaug nrog acetone kom tshem tawm cov kab mob.Weld daim hlau siv lub shielded hlau arc welder (SMAW) nrog ncaj qha tam sim no electrode polarity (DCEP) siv coated electrodes (E1 thiab E2) thiab ib tug siv electrode (C) nrog ib txoj kab uas hla ntawm 3.15 hli.Electrical Discharge Machining (EDM) (Model: Excetek-V400) yog siv los tshuab welded steel specimens rau mechanical testing thiab corrosion characterization.Table 2 qhia cov piv txwv code thiab cov lus piav qhia, thiab Table 3 qhia txog ntau yam kev ua haujlwm vuam siv los vuam DSS board.Qhov sib npaug (2) yog siv los xam cov khoom siv hluav taws xob sib xws.
Siv Bruker Q8 MAGELLAN optical emission spectrometer (OES) nrog lub wavelength ntawm 110 mus rau 800 nm thiab SQL database software, cov tshuaj muaj pes tsawg leeg ntawm weld pob qij txha ntawm electrodes E1, E2 thiab C, nrog rau cov qauv ntawm lub hauv paus hlau, tau txiav txim siab.siv qhov sib txawv ntawm cov electrode thiab cov qauv hlau nyob rau hauv kev sim Tsim hluav taws xob hluav taws xob nyob rau hauv daim ntawv ntawm lub txim.Ib qho piv txwv ntawm cov khoom yog vaporized thiab txau, ua raws li atomic excitation, uas tom qab emits ib kab spectrum31.Rau kev soj ntsuam zoo ntawm cov qauv, lub raj photomultiplier ntsuas qhov muaj cov spectrum siab rau txhua lub ntsiab lus, nrog rau qhov siv ntawm cov spectrum.Tom qab ntawd siv qhov sib npaug los xam qhov sib npaug pitting kuj tus lej (PREN).(3) Ratio 32 thiab WRC 1992 lub xeev daim duab yog siv los xam cov chromium thiab npib tsib xee sib npaug (Creq thiab Nieq) los ntawm qhov sib npaug.(4) thiab (5) yog 33 thiab 34 raws li;
Nco ntsoov tias PREN tsuas yog siv rau hauv tus account qhov kev cuam tshuam zoo ntawm peb lub ntsiab lus Cr, Mo thiab N, thaum lub nitrogen factor x nyob rau hauv thaj tsam ntawm 16-30.Feem ntau, x raug xaiv los ntawm cov npe ntawm 16, 20, lossis 30. Hauv kev tshawb fawb ntawm duplex stainless hlau, tus nqi nruab nrab ntawm 20 feem ntau yog siv los xam cov nqi PREN35,36.
Welded pob qij txha uas siv cov electrodes sib txawv yog tensile kuaj ntawm ib tug universal xeem tshuab (Instron 8800 UTM) ntawm ib tug strain tus nqi ntawm 0.5 mm / min raws li ASTM E8-21.Tensile zog (UTS), 0.2% shear yield zog (YS), thiab elongation raug xam raws li ASTM E8-2137.
DSS 2205 weldments yog thawj hauv av thiab polished siv ntau qhov sib txawv grit (120, 220, 320, 400, 600, 800, 1000 thiab 1200) ua ntej hardness tsom xam.Welded specimens tau tsim nrog electrodes E1, E2 thiab C. Hardness yog ntsuas ntawm kaum (10) cov ntsiab lus los ntawm qhov chaw ntawm lub vuam mus rau lub hauv paus hlau nrog ib ncua ntawm 1 hli.
X-ray diffractometer (D8 Discover, Bruker, Lub teb chaws Yelemees) teeb tsa nrog Bruker XRD Commander software rau kev sau cov ntaub ntawv thiab Fe-filtered Cu-K-α hluav taws xob nrog lub zog ntawm 8.04 keV sib thooj rau lub wavelength ntawm 1.5406 Å thiab tus nqi scan ntawm 3 ° Scan ntau (2θ) min-1 yog 38 txog 103 ° rau theem tsom xam nrog E1, E2 thiab C thiab BM electrodes tam sim no hauv DSS welds.Txoj kev kho kom zoo ntawm Rietveld tau siv los ntsuas cov theem ntawm cov txheej txheem siv MAUD software piav qhia los ntawm Lutterotti39.Raws li ASTM E1245-03, ib qho kev soj ntsuam ntau ntawm metallographic ntawm cov duab microscopic ntawm cov pob qij txha ntawm electrodes E1, E2 thiab C tau ua tiav siv Image J40 software.Cov txiaj ntsig ntawm kev suav cov ntim feem ntawm ferrite-austenitic theem, lawv qhov nruab nrab tus nqi thiab qhov sib txawv yog muab rau hauv Table.5. Raws li qhia nyob rau hauv tus qauv configuration nyob rau hauv daim duab.6d, optical microscopy (OM) tsom xam tau ua rau PM thiab welded pob qij txha nrog electrodes E1 thiab E2 los kawm txog morphology ntawm cov qauv.Cov qauv tau polished nrog 120, 220, 320, 400, 600, 800, 1000, 1200, 1500, thiab 2000 grit silicon carbide (SiC) sandpaper.Cov qauv no tau electrolytically etched nyob rau hauv 10% aqueous oxalic acid tov nyob rau hauv chav tsev kub ntawm voltage ntawm 5 V rau 10 s thiab muab tso rau ntawm ib tug LEICA DM 2500 M optical microscope rau morphological yam ntxwv.Ntxiv polishing ntawm cov qauv tau ua tiav siv 2500 grit silicon carbide (SiC) daim ntawv rau SEM-BSE tsom xam.Tsis tas li ntawd, cov pob qij txha welded tau kuaj xyuas microstructure siv lub tshuab ultra-high resolution emission scanning electron microscope (SEM) (FEI NOVA NANOSEM 430, USA) nruab nrog EMF.Cov qauv 20 × 10 × 6 mm yog hauv av siv ntau yam SiC sandpapers xws li qhov loj ntawm 120 mus rau 2500. Cov qauv tau electrolytically etched nyob rau hauv 40 g ntawm NaOH thiab 100 ml ntawm distilled dej ntawm ib tug voltage ntawm 5 V rau 15 s, thiab ces. mounted ntawm tus qauv tuav, nyob rau hauv SEM chamber, rau kev soj ntsuam cov qauv tom qab ntxuav lub chamber nrog nitrogen.Ib qho hluav taws xob hluav taws xob tsim los ntawm cov cua sov tungsten filament tsim cov grating ntawm cov qauv los tsim cov duab ntawm ntau qhov kev nthuav dav, thiab cov txiaj ntsig EMF tau txais los ntawm kev siv Roche li al.41 thiab Mokobi 42.
Ib txoj hauv kev electrochemical potentiodynamic polarization raws li ASTM G59-9743 thiab ASTM G5-1444 tau siv los ntsuas qhov muaj peev xwm degradation ntawm DSS 2205 daim hlau welded nrog E1, E2 thiab C electrodes hauv 3.5% NaCl ib puag ncig.Kev ntsuas hluav taws xob tau ua tiav siv lub khoos phis tawj tswj hwm Potentiostat-Galvanostat / ZRA apparatus (tus qauv: PC4/750, Gamry Instruments, USA).Kev ntsuas hluav taws xob hluav taws xob tau ua tiav ntawm kev teeb tsa peb-electrode: DSS 2205 ua haujlwm electrode, saturated calomel electrode (SCE) raws li siv electrode thiab graphite pas nrig li txee electrode.Kev ntsuas tau ua los ntawm kev siv hluav taws xob hluav taws xob, uas thaj tsam ntawm kev ua haujlwm ntawm cov tshuaj yog thaj tsam ntawm cov electrode ua haujlwm 0.78 cm2.Kev ntsuas tau ua nyob nruab nrab ntawm -1.0 V txog +1.6 V muaj peev xwm ntawm qhov ua ntej ruaj khov OCP (kwv yees rau OCP) ntawm tus nqi scan ntawm 1.0 mV / s.
Electrochemical pitting qhov ntsuas kub tseem ceeb tau ua nyob rau hauv 3.5% NaCl los ntsuas pitting tsis kam ntawm welds ua nrog E1, E2, thiab C electrodes.kom meej meej ntawm pitting peev xwm nyob rau hauv lub PB (nruab nrab ntawm lub passive thiab transpassive cheeb tsam), thiab welded qauv nrog E1, E2, Electrodes C. Yog li ntawd, CPT ntsuas yog ua kom raug txiav txim siab pitting peev xwm ntawm vuam consumables.CPT xeem tau ua raws li duplex stainless hlau weld reports45 thiab ASTM G150-1846.Los ntawm txhua qhov ntawm cov hlau yuav tsum tau welded (S-110A, E1-110A, E2-90A), cov qauv nrog thaj tsam ntawm 1 cm2 raug txiav, suav nrog cov hauv paus, vuam, thiab HAZ zones.Cov qauv no tau polished siv cov ntawv xuab zeb thiab 1 µm alumina hmoov slurry raws li tus qauv metallographic qauv npaj cov txheej txheem.Tom qab polishing, kuaj tau ultrasonically ntxuav hauv acetone rau 2 min.Ib qho 3.5% NaCl xeem cov tshuaj tau ntxiv rau CPT kuaj cell thiab thawj qhov kub thiab txias tau hloov mus rau 25 ° C siv lub ntsuas sov (Neslab RTE-111).Tom qab ncav cuag qhov ntsuas kub ntawm 25 ° C, Ar roj tau tshuab rau 15 min, tom qab ntawd cov qauv tau muab tso rau hauv lub cell, thiab OCF tau ntsuas rau 15 min.Cov qauv no tau polarized los ntawm kev siv qhov hluav taws xob ntawm 0.3 V ntawm qhov pib kub ntawm 25 ° C, thiab tam sim no tau ntsuas rau 10 min45.Pib cua sov cov tshuaj ntawm tus nqi ntawm 1 ° C / min mus rau 50 ° C.Thaum lub sij hawm cua sov ntawm cov tshuaj ntsuam xyuas, qhov ntsuas kub yog siv los ntsuas qhov ntsuas kub ntawm cov tshuaj thiab khaws lub sijhawm thiab cov ntaub ntawv kub, thiab cov potentiostat / galvanostat yog siv los ntsuas qhov tam sim no.Ib qho graphite electrode tau siv los ua lub txee electrode, thiab txhua qhov muaj peev xwm raug ntsuas txheeb ze rau Ag / AgCl siv electrode.Argon ntxuav tau ua tiav thoob plaws qhov kev sim.
Ntawm daim duab.1 qhia tau hais tias muaj pes tsawg leeg (hauv qhov hnyav feem pua) ntawm flux Cheebtsam F1 thiab F2 siv rau kev tsim cov alkaline (E1) thiab acidic (E2) electrodes, feem.Lub flux Basicity Performance index yog siv los kwv yees lub tshuab thiab metallurgical zog ntawm welded pob qij txha.F1 yog cov khoom siv ntawm cov flux siv los pleev xim rau E1 electrodes, uas yog hu ua alkaline flux vim nws qhov Performance index yog> 1.2 (ie 2.40), thiab F2 yog cov flux siv los pleev xim rau E2 electrodes, hu ua acid flux vim nws qhov yooj yim. index <0.9 (ie 2.40).0.40 Nws.).Nws yog tseeb hais tias electrodes coated nrog yooj yim fluxes nyob rau hauv feem ntau muaj zoo mechanical zog dua electrodes coated nrog acidic fluxes.Cov yam ntxwv no yog kev ua haujlwm ntawm kev tswj hwm ntawm cov oxide yooj yim hauv cov txheej txheem flux rau electrode E1.Ntawm qhov tsis sib xws, kev tshem tawm slag (kev sib cais) thiab tsis tshua muaj tawg tau pom nyob rau hauv cov pob qij txha welded nrog E2 electrodes yog cov yam ntxwv ntawm electrodes nrog acidic flux txheej nrog cov ntsiab lus siab ntawm rutile.Qhov kev soj ntsuam no yog ua raws li qhov kev tshawb pom ntawm Gill47 tias qhov cuam tshuam ntawm cov ntsiab lus rutile ntawm slag detachability thiab qis qis ntawm cov kua qaub flux coated electrodes pab txhawb kom ceev slag khov.Kaolin nyob rau hauv lub flux system siv los coated electrodes E1 thiab E2 yog siv los ua lubricant, thiab talc hmoov txhim kho cov extrudability ntawm cov electrodes.Potassium silicate binders nyob rau hauv flux systems pab txhawb kom zoo dua arc ignition thiab kev ua haujlwm ruaj khov, thiab, ntxiv rau lawv cov khoom nplaum, txhim kho slag sib cais hauv cov khoom siv welded.Txij li thaum CaCO3 yog ib tug net breaker (slag breaker) nyob rau hauv lub flux thiab nyhav tsim cov pa taws ntau thaum lub vuam vim thermal decomposition rau CaO thiab txog 44% CO2, TiO2 (raws li ib tug net builder / slag qub) pab txo tus nqi. ntawm cov pa luam yeeb thaum vuam.vuam thiab yog li txhim kho slag detachability raws li qhia los ntawm Jing li al.48.Fluorine Flux (CaF2) yog cov tshuaj lom neeg muaj zog uas txhim kho kev huv huv.Jastrzębska et al.49 tau tshaj tawm cov txiaj ntsig ntawm fluoride muaj pes tsawg leeg ntawm cov tshuaj flux no ntawm cov khoom siv vuam huv.Feem ntau, flux yog ntxiv rau thaj tsam weld los txhim kho arc stability, ntxiv alloying ntsiab, tsim slag, nce productivity, thiab txhim kho qhov zoo ntawm weld pas dej ua ke 50.
TGA-DTG nkhaus qhia hauv daim duab.2a thiab 2b qhia qhov poob peb-theem thaum cua sov nyob rau hauv qhov kub ntawm 30-1000 ° C hauv cov cua nitrogen.Cov txiaj ntsig hauv daim duab 2a thiab b qhia tau hais tias rau cov qauv yooj yim thiab acidic flux, TGA nkhaus poob ncaj mus txog rau thaum nws thaum kawg ua tib yam rau qhov kub thiab txias, nyob ib ncig ntawm 866.49 ° C thiab 849.10 ° C feem.Qhov hnyav poob ntawm 1.30% thiab 0.81% thaum pib ntawm TGA curves hauv daim duab 2a thiab 2b yog vim cov dej noo absorbed los ntawm cov flux Cheebtsam, raws li zoo raws li evaporation thiab lub cev qhuav dej ntawm nto noo noo.Lub ntsiab decompositions ntawm cov qauv ntawm lub ntsiab flux nyob rau theem thib ob thiab thib peb hauv daim duab.2a tshwm sim nyob rau hauv qhov kub ntawm 619.45 ° C-766.36 ° C thiab 766.36 ° C-866.49 ° C, thiab feem pua ​​​​ntawm lawv qhov hnyav poob yog 2.84 thiab 9.48%., raws.Thaum rau cov qauv acidic flux hauv daim duab 7b, uas nyob rau hauv qhov kub thiab txias ntawm 665.23°C–745.37°C thiab 745.37°C–849.10°C, lawv qhov feem pua ​​​​yuav poob yog 0.81 thiab 6.73%, feem, uas yog ntaus nqi. thermal decomposition.Txij li cov flux Cheebtsam yog inorganic, cov volatiles yog txwv rau cov flux sib tov.Yog li ntawd, kev txo qis thiab oxidation yog txaus ntshai.Qhov no yog ua raws li cov txiaj ntsig ntawm Balogun et al.51, Kamli et al.52 thiab Adeleke li al.53.Cov txiaj ntsig ntawm qhov poob loj ntawm cov qauv flux pom hauv daim duab.2a thiab 2b yog 13.26% thiab 8.43%, feem.Tsawg loj poob ntawm cov qauv flux hauv daim duab.2b yog vim cov ntsiab lus siab melting ntawm TiO2 thiab SiO2 (1843 thiab 1710 ° C feem) raws li cov oxides tseem ceeb uas ua rau cov flux sib tov 54,55, thaum TiO2 thiab SiO2 muaj cov ntsiab lus qis dua.melting point Primary oxide: CaCO3 (825 ° C) hauv cov qauv flux hauv daim duab.2a56 ua.Cov kev hloov pauv no hauv cov ntsiab lus melting ntawm thawj oxides hauv flux mixs yog zoo qhia los ntawm Shi li al.54, Ringdalen li al.55 thiab Du li al.56.Kev soj ntsuam tas li poob phaus hauv daim duab 2a thiab 2b, nws tuaj yeem xaus lus tias cov qauv flux siv hauv E1 thiab E2 electrode coatings undergo ib-kauj ruam decomposition, raws li qhia los ntawm Brown57.Qhov ntsuas kub ntawm cov txheej txheem tuaj yeem pom los ntawm cov derivative curves (wt%) hauv daim duab.2a ib b.Txij li thaum TGA nkhaus tsis tuaj yeem piav qhia meej txog qhov kub thiab txias ntawm qhov flux system tau hloov pauv thiab crystallization, TGA derivative yog siv los txiav txim siab qhov ntsuas kub ntawm txhua qhov tshwm sim (theem hloov) raws li qhov kawg ntawm qhov kawg los npaj cov flux system.
TGA-DTG nkhaus qhia thermal decomposition ntawm (a) alkaline flux rau E1 electrode txheej thiab (b) acidic flux rau E2 electrode txheej.
Table 4 qhia cov txiaj ntsig ntawm spectrophotometric tsom xam thiab SEM-EDS tsom xam ntawm DSS 2205 puag hlau thiab welds ua siv E1, E2 thiab C electrodes.E1 thiab E2 tau pom tias cov ntsiab lus ntawm chromium (Cr) txo qis rau 18.94 thiab 17.04%, thiab cov ntsiab lus ntawm molybdenum (Mo) yog 0.06 thiab 0.08%, feem.qhov tseem ceeb ntawm welds nrog electrodes E1 thiab E2 yog qis dua.Qhov no yog me ntsis nyob rau hauv txoj kab nrog rau kev suav PREN tus nqi rau ferritic-austenitic theem los ntawm SEM-EDS tsom xam.Yog li ntawd, nws tuaj yeem pom tias pitting pib ntawm theem nrog qis PREN qhov tseem ceeb (welds los ntawm E1 thiab E2), raws li tau piav qhia hauv Table 4. Qhov no yog qhov qhia txog kev depletion thiab tuaj yeem nag lossis daus ntawm cov hlau hauv qhov vuam.Tom qab ntawd, qhov txo qis hauv cov ntsiab lus ntawm Cr thiab Mo alloying cov ntsiab lus hauv welds tsim siv cov electrodes E1 thiab E2 thiab lawv cov pitting sib npaug qis (PREN) yog qhia hauv Table 4, uas tsim teeb meem rau kev tswj xyuas qhov kev tiv thaiv hauv kev ua phem, tshwj xeeb tshaj yog. nyob rau hauv ib puag ncig chloride.- muaj ib puag ncig.Cov ntsiab lus siab nickel (Ni) ntawm 11.14% thiab qhov tso cai txwv ntawm manganese cov ntsiab lus hauv cov pob qij txha welded ntawm E1 thiab E2 electrodes tej zaum yuav muaj txiaj ntsig zoo rau cov khoom siv ntawm cov khoom siv vuam siv nyob rau hauv cov xwm txheej simulating dej hiav txwv (Daim duab 3. ).tau tsim los ntawm kev ua haujlwm ntawm Yuan thiab Oy58 thiab Jing li al.48 ntawm cov txiaj ntsig ntawm cov nickel thiab manganese siab sib xyaw ntawm kev txhim kho cov khoom siv kho tshuab ntawm DSS welded qauv nyob rau hauv kev ua haujlwm hnyav.
Tensile xeem tau rau (a) UTS thiab 0.2% sag YS thiab (b) uniform thiab tag nrho elongation thiab lawv cov qauv sib txawv.
Lub zog ntawm cov khoom siv hauv paus (BM) thiab cov pob qij txha welded ua los ntawm cov khoom siv hluav taws xob tsim (E1 thiab E2) thiab cov khoom siv hluav taws xob (C) tau raug soj ntsuam ntawm ob qhov sib txawv vuam tam sim no ntawm 90 A thiab 110 A. 3(a) thiab (b) qhia UTS, YS nrog 0.2% offset, nrog rau lawv cov ntaub ntawv elongation thiab tus qauv sib txawv.UTS thiab YS offset tau los ntawm 0.2% tau los ntawm Fig.3a qhia cov txiaj ntsig zoo rau cov qauv no.1 (BM), nr.3 (weld E1), qauv no.5 (weld E2) thiab qauv no.6 (welds nrog C) yog 878 thiab 616 MPa, 732 thiab 497 MPa, 687 thiab 461 MPa thiab 769 thiab 549 MPa, raws li, thiab lawv cov qauv sib txawv.Los ntawm fig.110 A) yog cov qauv suav nrog 1, 2, 3, 6 thiab 7, raws li, nrog qhov tsawg kawg nkaus pom zoo tensile zog tshaj 450 MPa hauv tensile test thiab 620 MPa hauv tensile xeem tau npaj los ntawm Grocki32.Qhov elongation ntawm vuam cov qauv nrog electrodes E1, E2 thiab C, sawv cev los ntawm cov qauv No. Feem ntau, qhia txog plasticity thiab kev ncaj ncees.cuam ​​tshuam rau cov hlau hauv paus.Qhov qis elongation tau piav qhia los ntawm qhov muaj peev xwm welding tsis xws luag lossis muaj pes tsawg leeg ntawm electrode flux (Fig. 3b).Nws tuaj yeem txiav txim siab tias BM duplex stainless hlau thiab welded pob qij txha nrog E1, E2 thiab C electrodes feem ntau muaj zog tensile ntau dua vim lawv cov ntsiab lus siab nickel (Table 4), tab sis cov cuab yeej no tau pom hauv cov pob qij txha.Tsis tshua muaj txiaj ntsig E2 yog tau los ntawm acidic muaj pes tsawg leeg ntawm cov flux.Gunn59 tau qhia txog cov txiaj ntsig ntawm nickel alloys ntawm kev txhim kho cov khoom siv kho tshuab ntawm welded pob qij txha thiab tswj cov theem sib npaug thiab cov khoom faib.Qhov no rov lees paub qhov tseeb tias electrodes ua los ntawm cov txheej txheem flux yooj yim muaj cov khoom siv zoo dua li cov khoom siv hluav taws xob ua los ntawm cov kua qaub flux sib tov, raws li tau hais los ntawm Bang li al.60.Yog li, ib qho txiaj ntsig tseem ceeb tau ua rau cov kev paub uas twb muaj lawm txog cov khoom ntawm cov welded sib koom ntawm cov coated electrode tshiab (E1) nrog cov khoom tensile zoo.
Ntawm daim duab.Daim duab 4a thiab 4b qhia Vickers microhardness yam ntxwv ntawm kev sim cov qauv ntawm welded pob qij txha ntawm electrodes E1, E2 thiab C. 4a qhia cov hardness tau los ntawm ib qho kev taw qhia ntawm tus qauv (los ntawm WZ mus rau BM), thiab nyob rau hauv daim duab.4b qhia cov txiaj ntsig hardness tau ntawm ob sab ntawm cov qauv.Lub hardness qhov tseem ceeb tau txais thaum lub sij hawm vuam ntawm cov qauv Nos. 2, 3, 4 thiab 5, uas yog welded pob qij txha nrog electrodes E1 thiab E2, yuav yog vim lub coarse-grained qauv thaum solidification nyob rau hauv vuam cycles.Ib qho kev nce ntxiv hauv cov tawv tawv tau pom ob qho tib si hauv cov ntxhib-grained HAZ thiab hauv cov nplua-grained HAZ ntawm tag nrho cov qauv Nos. 2-7 (saib cov lej lej hauv Table 2), uas tuaj yeem piav qhia los ntawm kev hloov pauv hauv microstructure. cov weld raws li qhov tshwm sim ntawm chromium-weld qauv yog nplua nuj nyob rau hauv emissions (Cr23C6).Piv nrog rau lwm yam welding qauv 2, 3, 4 thiab 5, hardness qhov tseem ceeb ntawm cov welded pob qij txha ntawm cov qauv No. 6 thiab 7 nyob rau hauv daim duab.4a thiab 4b saum toj no (Table 2).Raws li Mohammed li al.61 thiab Nowacki thiab Lukoje62, qhov no tej zaum yuav yog vim lub siab ferrite δ tus nqi thiab induced residual stresses nyob rau hauv lub weld, thiab depletion ntawm alloying ntsiab xws li Mo thiab Cr nyob rau hauv lub weld.Lub hardness qhov tseem ceeb ntawm tag nrho cov kev soj ntsuam kuaj nyob rau hauv lub cheeb tsam ntawm BM zoo li zoo ib yam.Cov qauv hauv cov txiaj ntsig ntawm hardness tsom xam ntawm cov qauv welded yog raws li cov lus xaus ntawm lwm cov kws tshawb fawb61,63,64.
Hardness qhov tseem ceeb ntawm welded pob qij txha ntawm DSS specimens (a) ib nrab ntawm cov welded specimens thiab (b) tag nrho seem ntawm welded pob qij txha.
Ntau theem tam sim no nyob rau hauv welded DSS 2205 nrog E1, E2 thiab C electrodes tau txais thiab XRD spectra rau lub diffraction lub kaum sab xis 2\(\theta\) yog qhia nyob rau hauv daim duab 5. Peaks ntawm austenite (\(\gamma\) ) thiab ferrite (\(\alpha\)) theem tau txheeb xyuas ntawm qhov sib txawv ntawm 43 ° thiab 44 °, ua kom ntseeg tau tias cov khoom sib txuas yog ob-theem 65 stainless hlau.uas DSS BM qhia tsuas yog austenitic (\(\gamma\)) thiab ferritic (\(\alpha\)) theem, lees paub cov txiaj ntsig microstructural nthuav tawm hauv daim duab 1 thiab 2. 6c, 7c thiab 9c.ferritic (\(\alpha\)) theem pom nrog DSS BM thiab lub siab ncov nyob rau hauv lub weld rau electrode C yog qhia txog nws corrosion kuj, txij li thaum lub sij hawm no aims mus nce lub corrosion kuj ntawm cov hlau, raws li Davison thiab Redmond66 muaj. hais tias, muaj cov ferrite stabilizing cov ntsiab lus, xws li Cr thiab Mo, zoo stabilizes passive zaj duab xis ntawm cov khoom nyob rau hauv ib puag ncig uas muaj chloride.Table 5 qhia txog theem ferrite-austenitic los ntawm ntau qhov metallography.Qhov piv ntawm qhov ntim feem ntawm ferrite-austenitic theem nyob rau hauv cov welded pob qij txha ntawm cov electrode C yog tiav kwv yees li (≈1: 1).Qhov qis ferrite (\(\alpha\)) theem muaj pes tsawg leeg ntawm weldments siv E1 thiab E2 electrodes nyob rau hauv lub ntim feem (Table 5) qhia tau hais tias muaj peev xwm rhiab heev rau ib tug corrosive ib puag ncig, uas tau lees paub los ntawm electrochemical tsom xam.paub tseeb (Fig. 10a, b)), txij li thaum ferrite theem muab siab zog thiab tiv thaiv chloride-induced kev nyuaj siab corrosion cracking.Qhov no tau lees paub ntxiv los ntawm qhov qis hardness qhov tseem ceeb pom nyob rau hauv welds ntawm electrodes E1 thiab E2 hauv daim duab.4a,b, uas yog tshwm sim los ntawm qhov tsis muaj feem ntawm ferrite nyob rau hauv cov qauv steel (Table 5).Lub xub ntiag ntawm unbalanced austenitic (\(\gamma\)) thiab ferritic (\(\alpha\)) theem nyob rau hauv welded pob qij txha siv E2 electrodes qhia qhov tseeb vulnerability ntawm hlau rau uniform corrosion nres.Ntawm qhov tsis sib xws, XPA spectra ntawm ob-theem steels ntawm welded pob qij txha nrog E1 thiab C electrodes, nrog rau cov txiaj ntsig ntawm BM, feem ntau qhia tias muaj cov ntsiab lus austenitic thiab ferritic stabilizing, uas ua rau cov khoom siv tau zoo hauv kev tsim kho thiab kev lag luam petrochemical. , vim argued Jimenez li al.65;Davidson & Redmond66;Shamant thiab lwm tus 67.
Optical micrographs ntawm welded pob qij txha ntawm E1 electrodes nrog sib txawv weld geometries: (a) HAZ qhia cov fusion kab, (b) HAZ qhia cov fusion kab ntawm ntau dua magnification, (c) BM rau ferritic-austenitic theem, (d) weld geometry , ( e) Qhia qhov kev hloov chaw nyob ze, (f) HAZ qhia cov theem ferritic-austenitic ntawm kev nthuav dav dua, (g) Weld cheeb tsam qhia txog theem ferritic-austenitic Tensile theem.
Optical micrographs ntawm E2 electrode welds ntawm ntau yam weld geometries: (a) HAZ qhia cov kab fusion, (b) HAZ qhia cov kab fusion ntawm ntau dua magnification, (c) BM rau ferritic-austenitic bulk theem, (d) weld geometry, (e)) qhia txog kev hloov chaw nyob ib puag ncig, (f) HAZ qhia txog theem ferritic-austenitic ntawm kev nthuav dav dua, (g) vuam cheeb tsam qhia txog theem ferritic-austenitic.
Daim duab 6a-c thiab, piv txwv li, qhia cov qauv metallographic ntawm DSS cov pob qij txha welded siv E1 electrode ntawm ntau qhov vuam geometries (Daim duab 6d), qhia qhov twg cov optical micrographs raug coj mus rau qhov sib txawv magnifications.Ntawm daim duab.6a, b, f - kev hloov chaw ntawm cov pob qij txha welded, qhia txog theem sib npaug ntawm ferrite-austenite.Cov duab 7a-c thiab piv txwv kuj qhia OM ntawm DSS sib koom ua ke siv E2 electrode ntawm ntau qhov vuam geometries (Daim duab 7d), uas sawv cev rau OM tsom xam cov ntsiab lus ntawm qhov sib txawv magnifications.Ntawm daim duab.7a,b,f qhia qhov kev hloov pauv ntawm qhov sib koom ua ke hauv ferritic-austenitic equilibrium.OM hauv thaj chaw vuam (WZ) yog qhia hauv daim duab.1i siv.2. Welds rau electrodes E1 thiab E2 6g thiab 7g, feem.OM ntawm BM muaj nyob rau hauv daim duab 1 thiab 2. Nyob rau hauv daim duab.6c, e thiab 7c, e qhia cov ntaub ntawv ntawm welded pob qij txha nrog electrodes E1 thiab E2, feem.Qhov chaw teeb pom kev zoo yog theem austenite thiab thaj chaw tsaus dub yog theem ferrite.Theem equilibria nyob rau hauv lub tshav kub-cuam tshuam cheeb tsam (HAZ) nyob ze ntawm lub fusion kab qhia qhov tsim ntawm Cr2N precipitates, raws li qhia nyob rau hauv lub SEM-BSE micrographs nyob rau hauv daim duab.8a, b thiab tau lees paub hauv daim duab.9a, ib.Lub xub ntiag ntawm Cr2N pom nyob rau hauv ferrite theem ntawm cov qauv hauv Fig.8a,b thiab tau lees paub los ntawm SEM-EMF taw tes tsom xam thiab EMF kab kab kos duab ntawm welded qhov chaw (Fig. 9a-b), yog vim qhov kub ntawm qhov kub ntawm vuam ntau dua.Circulation accelerates cov kev taw qhia ntawm chromium thiab nitrogen, txij li thaum kub kub nyob rau hauv weld nce lub diffusion coefficient ntawm nitrogen.Cov txiaj ntsig no txhawb kev tshawb fawb los ntawm Ramirez li al.68 thiab Herenyu li al.69 qhia tias, tsis hais txog cov ntsiab lus nitrogen, Cr2N feem ntau tso rau ntawm ferrite nplej, grain ciam teb, thiab α/\(\gamma\) ciam teb, raws li tau hais los ntawm lwm cov kws tshawb fawb.70.71 ib.
(a) SEM-EMF tsom xam (1, 2 thiab 3) ntawm kev sib koom ua ke nrog E2;
Qhov saum npoo morphology ntawm cov qauv neeg sawv cev thiab lawv cov EMFs sib xws tau qhia hauv Fig.10 a-c.Ntawm daim duab.Daim duab 10a thiab 10b qhia SEM micrographs thiab lawv EMF spectra ntawm welded pob qij txha siv electrodes E1 thiab E2 nyob rau hauv vuam cheeb tsam, feem, thiab nyob rau hauv daim duab.10c qhia SEM micrographs thiab EMF spectra ntawm OM uas muaj austenite (\(\gamma\)) thiab ferrite (\(\alpha\)) theem yam tsis muaj precipitates.Raws li pom hauv EDS spectrum hauv daim duab 10a, qhov feem pua ​​​​ntawm Cr (21.69 wt.%) thiab Mo (2.65 wt.%) piv rau 6.25 wt.% Ni muab kev nkag siab ntawm qhov sib npaug ntawm ferrite-austenitic theem.Microstructure nrog kev txo qis hauv cov ntsiab lus ntawm chromium (15.97 wt.%) thiab molybdenum (1.06 wt.%) piv nrog cov ntsiab lus siab nickel (10.08 wt.%) hauv microstructure ntawm welded sib koom ntawm electrode E2, qhia hauv fig.1. Sib piv.EMF spectrum 10b.Cov duab acicular nrog finer-grained austenitic qauv pom nyob rau hauv WZ qhia nyob rau hauv daim duab.10b lees paub qhov muaj peev xwm depletion ntawm ferritizing ntsiab (Cr thiab Mo) nyob rau hauv lub vuam thiab nag lossis daus ntawm chromium nitride (Cr2N) - theem austenitic.Kev faib tawm ntawm cov nag lossis daus raws cov ciam teb ntawm austenitic (\(\gamma\)) thiab ferritic (\(\alpha\)) theem ntawm DSS welded pob qij txha lees paub cov nqe lus no72,73,74.Qhov no kuj ua rau nws cov kev ua haujlwm tsis zoo corrosion, txij li Cr raug suav hais tias yog lub hauv paus tseem ceeb rau kev tsim cov yeeb yaj kiab tsis zoo uas txhim kho lub zos corrosion kuj ntawm steel59,75 raws li qhia hauv daim duab 10b.Nws tuaj yeem pom tau tias BM hauv SEM micrograph hauv daim duab 10c qhia tau hais tias muaj zog grain refinement raws li nws cov EDS spectrum tshwm sim qhia Cr (23.32 wt%), Mo (3.33 wt%) thiab Ni (6.32 wt).%) zoo tshuaj muaj zog.%) raws li ib qho tseem ceeb alloying caij rau kev kuaj xyuas qhov sib npaug microstructure ntawm ferrite-austenitic theem ntawm DSS76 qauv.Cov txiaj ntsig ntawm EMF spectroscopic tsom xam ntawm cov welded pob qij txha ntawm E1 electrode pom zoo rau kev siv hauv kev tsim kho thiab ib puag ncig aggressive me ntsis, txij li thaum lub austenite qub thiab ferrite stabilizers nyob rau hauv microstructure ua raws li DSS AISI 220541.72 tus qauv rau welded pob qij txha, 77.
SEM micrographs ntawm welded pob qij txha, qhov twg (a) electrode E1 ntawm vuam cheeb tsam muaj EMF spectrum, (b) electrode E2 ntawm vuam cheeb tsam muaj EMF spectrum, (c) OM muaj EMF spectrum.
Hauv kev xyaum, nws tau pom tias DSS welds solidify nyob rau hauv tag nrho ferritic (F-hom) hom, nrog austenite nuclei nucleating hauv qab ferritic solvus kub, uas yog feem ntau nyob ntawm chromium rau nickel sib npaug piv (Creq / Nieq) (> 1.95 suav nrog hom F) Qee cov kws tshawb fawb tau pom cov txiaj ntsig ntawm cov hlau no vim qhov muaj zog diffusing muaj peev xwm ntawm Cr thiab Mo raws li ferrite-forming ntsiab nyob rau hauv ferrite theem 8078,79.Nws yog qhov tseeb tias DSS 2205 BM muaj cov nyiaj ntau ntawm Cr thiab Mo (qhia siab dua Creq), tab sis muaj cov ntsiab lus Ni qis dua li cov vuam nrog E1, E2 thiab C electrodes, uas ua rau muaj siab dua Creq / Nieq piv.Qhov no kuj pom tseeb hauv txoj kev tshawb fawb tam sim no, raws li qhia hauv Table 4, qhov twg Creq / Nieq piv tau txiav txim siab rau DSS 2205 BM saum toj 1.95.Nws tuaj yeem pom tias welds nrog electrodes E1, E2 thiab C harden nyob rau hauv austenitic-ferritic hom (AF hom), austenitic hom (A hom) thiab ferritic-austenitic hom, feem, vim yog cov ntsiab lus siab dua ntawm ntau hom (FA hom) .), raws li qhia nyob rau hauv Table 4, cov ntsiab lus ntawm Ni, Cr thiab Mo nyob rau hauv lub weld yog tsawg, qhia tau hais tias tus Creq / Nieq piv yog qis dua BM.Thawj ferrite nyob rau hauv E2 electrode welds muaj vermicular ferrite morphology thiab txiav txim siab Creq / Nieq piv yog 1.20 raws li tau piav qhia hauv Table 4.
Ntawm daim duab.11a qhia Open Circuit Potential (OCP) piv rau lub sijhawm rau AISI DSS 2205 steel qauv hauv 3.5% NaCl tov.Nws tuaj yeem pom tau tias ORP nkhaus hloov mus rau qhov muaj peev xwm zoo dua, qhia txog qhov pom ntawm cov yeeb yaj kiab tsis zoo ntawm cov qauv hlau, qhov poob ntawm qhov muaj peev xwm qhia tau tias muaj kev xeb dav dav, thiab yuav luag tas li lub peev xwm dhau lub sijhawm qhia txog kev tsim cov khoom siv hlau. passive zaj duab xis dhau sijhawm., Qhov saum npoo ntawm cov qauv yog ruaj khov thiab muaj cov nplaum nplaum 77. Cov nkhaus qhia txog qhov kev sim substrates nyob rau hauv qhov chaw ruaj khov rau tag nrho cov qauv hauv ib qho electrolyte uas muaj 3.5% NaCl tov, nrog rau cov qauv 7 (weld sib koom nrog C-electrode), uas qhia me ntsis instability.Qhov kev tsis ruaj khov no tuaj yeem muab piv rau qhov muaj cov tshuaj chloride ions (Cl-) hauv cov tshuaj, uas tuaj yeem ua kom cov tshuaj tiv thaiv corrosion zoo heev, yog li nce qib ntawm corrosion.Kev soj ntsuam thaum lub sij hawm OCP scanning yam tsis muaj peev xwm siv tau pom tias Cl nyob rau hauv cov tshuaj tiv thaiv tuaj yeem cuam tshuam qhov kev tiv thaiv thiab thermal stability ntawm cov qauv hauv ib puag ncig hnyav.Ma et al.81 and Lotho et al.5 tau lees paub qhov kev thov tias Cl- ua lub luag haujlwm hauv kev ua kom lub zog ntawm cov yeeb yaj kiab tsis zoo ntawm cov substrates, yog li ua rau kev hnav ntxiv.
Electrochemical tsom xam ntawm cov qauv kawm: (a) evolution ntawm RSD nyob ntawm lub sij hawm thiab (b) potentiodynamic polarization ntawm cov qauv hauv 3.5% NaCl tov.
Ntawm daim duab.11b nthuav qhia kev sib piv kev tshuaj xyuas ntawm cov kab hluav taws xob polarization curves (PPC) ntawm welded pob qij txha ntawm electrodes E1, E2 thiab C nyob rau hauv kev cuam tshuam ntawm 3.5% NaCl tov.Welded BM cov qauv hauv PPC thiab 3.5% NaCl tov tau pom tus cwj pwm tsis zoo.Table 5 qhia txog qhov ntsuas hluav taws xob tsis zoo ntawm cov qauv uas tau txais los ntawm PPC nkhaus, xws li Ecorr (corrosion peev xwm) thiab Epit (pitting corrosion muaj peev xwm) thiab lawv qhov sib txawv sib txawv.Piv nrog rau lwm cov qauv No. 2 thiab No. 5, welded nrog electrodes E1 thiab E2, cov qauv No. ).Qhov siab dua passivating zog ntawm lub qub piv rau yav tas los yog vim qhov sib npaug ntawm cov microstructural muaj pes tsawg leeg ntawm cov hlau (austenitic thiab ferritic theem) thiab cov concentration ntawm alloying ntsiab.Vim muaj cov ferrite thiab austenitic theem hauv microstructure, Resendea li al.82 txhawb nqa tus cwj pwm tsis zoo ntawm DSS hauv kev tawm tsam hnyav.Kev ua haujlwm qis ntawm cov qauv welded nrog E1 thiab E2 electrodes tuaj yeem cuam tshuam nrog kev txo qis ntawm cov ntsiab lus alloying tseem ceeb, xws li Cr thiab Mo, hauv thaj chaw vuam (WZ), vim tias lawv ruaj khov rau theem ferrite (Cr thiab Mo), ua raws li passivators Alloys nyob rau hauv austenitic theem ntawm oxidized steels.Cov nyhuv ntawm cov ntsiab lus ntawm pitting kuj yog ntau dua nyob rau hauv lub austenitic theem tshaj nyob rau hauv lub ferritic theem.Vim li no, theem ferritic dhau passivation sai dua li theem austenitic cuam tshuam nrog thawj cheeb tsam passivation ntawm lub polarization nkhaus.Cov ntsiab lus no muaj kev cuam tshuam loj rau DSS pitting tsis kam vim lawv qhov siab dua pitting tsis kam nyob rau theem austenitic piv rau theem ferritic.Yog li ntawd, qhov ceev passivation ntawm ferrite theem yog 81% siab dua li ntawm austenite theem.Txawm hais tias Cl- hauv kev daws muaj qhov tsis zoo rau lub peev xwm ntawm cov yeeb yaj kiab steel83.Yog li ntawd, kev ruaj ntseg ntawm cov yeeb yaj kiab passivating ntawm cov qauv yuav raug txo kom tsawg 84.Los ntawm Rooj.6 kuj qhia tau hais tias lub peev xwm corrosion (Ecorr) ntawm welded pob qij txha nrog E1 electrode yog me ntsis ruaj khov nyob rau hauv kev daws piv rau welded pob qij txha nrog E2 electrode.Qhov no kuj tau lees paub los ntawm cov nqi qis ntawm qhov hardness ntawm welds siv electrodes E1 thiab E2 hauv daim duab.4a,b, uas yog vim muaj cov ntsiab lus tsawg ntawm ferrite (Table 5) thiab cov ntsiab lus tsawg ntawm chromium thiab molybdenum (Table 4) hauv cov qauv hlau ua los ntawm.Nws tuaj yeem xaus lus tias qhov corrosion kuj ntawm steels nyob rau hauv simulated marine ib puag ncig nce nrog txo vuam tam sim no thiab txo qis nrog Cr thiab Mo cov ntsiab lus thiab cov ntsiab lus ferrite tsawg.Daim ntawv qhia no yog ua raws li kev tshawb fawb los ntawm Salim et al.85 ntawm qhov cuam tshuam ntawm vuam tsis xws li welding tam sim no ntawm corrosion ncaj ncees ntawm welded steels.Raws li cov tshuaj chloride nkag mus rau cov hlau los ntawm ntau txoj kev xws li capillary absorption thiab diffusion, pits (pitting corrosion) ntawm cov duab tsis sib xws thiab qhov tob yog tsim.Cov txheej txheem yog qhov sib txawv hauv cov kev daws teeb meem siab dua pH qhov twg cov pab pawg nyob ib puag ncig (OH-) tsuas yog nyiam rau cov hlau nto, stabilizing cov zaj duab xis passive thiab muab kev tiv thaiv ntxiv rau steel nto25,86.Qhov zoo tshaj plaws corrosion kuj ntawm cov qauv No.1 thiab No.7 yog vim muaj nyob rau hauv cov steel qauv ntawm ib tug loj npaum li cas ntawm δ-ferrite (Table 5) thiab ib tug loj npaum li cas ntawm Cr thiab Mo (Table 4), txij li thaum lub theem ntawm pitting corrosion yog tam sim no nyob rau hauv steel, welded los ntawm DSS txoj kev, nyob rau hauv lub austenitic-theem qauv ntawm qhov chaw.Yog li, cov tshuaj muaj pes tsawg leeg ntawm cov hlau ua lub luag haujlwm txiav txim siab hauv kev ua haujlwm corrosion ntawm welded sib koom ua ke87,88.Tsis tas li ntawd, nws tau pom tias cov qauv welded siv E1 thiab C electrodes hauv qhov kev tshawb fawb no tau pom cov txiaj ntsig Ecorr qis dua los ntawm PPC nkhaus dua li cov welded siv E2 electrode los ntawm OCP curves (Table 5).Yog li ntawd, thaj av anode pib ntawm lub peev xwm qis dua.Qhov kev hloov pauv no feem ntau yog vim muaj kev ruaj khov ib nrab ntawm cov txheej txheem passivation tsim rau ntawm qhov chaw ntawm cov qauv thiab cathodic polarization uas tshwm sim ua ntej tag nrho stabilization ntawm OCP89 tiav.Ntawm daim duab.12a thiab b qhia 3D optical profiler dluab ntawm kev sim corroded specimens nyob rau hauv ntau yam vuam tej yam kev mob.Nws tuaj yeem pom tau tias qhov pitting corrosion loj ntawm cov qauv nce nrog qis pitting corrosion peev xwm tsim los ntawm qhov siab vuam tam sim no ntawm 110 A (Fig. 12b), piv rau pitting corrosion loj tau rau welds nrog qis vuam tam sim no piv ntawm 90 A. (Fig. 12a).Qhov no tau lees paub tias Mohammed90's thov tias cov hlua khi yog tsim rau saum npoo ntawm cov qauv los rhuav tshem cov zaj duab xis passivation los ntawm kev nthuav tawm cov substrate rau 3.5% NaCl tov kom cov tshuaj chloride pib tawm tsam, ua rau cov khoom tawg.
Kev soj ntsuam SEM-EDS hauv Table 4 qhia tau hais tias PREN qhov tseem ceeb ntawm txhua theem austenitic yog siab dua cov ferrite hauv txhua qhov welds thiab BM.Qhov pib ntawm pitting ntawm ferrite / austenite interface ua rau kom muaj kev puas tsuaj ntawm cov khoom siv hluav taws xob vim qhov tsis sib xws thiab kev sib cais ntawm cov ntsiab lus tshwm sim hauv cov cheeb tsam no91.Tsis zoo li cov theem austenitic, qhov twg pitting kuj sib npaug (PRE) tus nqi siab dua, pitting pib hauv theem ferritic yog vim qhov qis PRE tus nqi (Table 4).Lub sijhawm austenite zoo li muaj qhov tseem ceeb ntawm austenite stabilizer (nitrogen solubility), uas muab cov ntsiab lus siab dua ntawm cov khoom no thiab, yog li ntawd, siab dua rau pitting92.
Ntawm daim duab.Daim duab 13 qhia qhov tseem ceeb pitting kub nkhaus rau E1, E2, thiab C welds.Muab hais tias qhov ceev tam sim no tau nce mus rau 100 µA / cm2 vim pitting thaum lub sij hawm xeem ASTM, nws yog tseeb hais tias lub @110A weld nrog E1 pom qhov tsawg kawg nkaus pitting tseem ceeb kub ntawm 27.5 ° C ua raws li los ntawm E2 @ 90A soldering qhia ib tug CPT ntawm 40. ° C, thiab nyob rau hauv cov ntaub ntawv ntawm C @ 110A qhov siab tshaj plaws CPT yog 41 ° C.Cov txiaj ntsig tau pom zoo tau pom zoo nrog cov txiaj ntsig tau pom ntawm kev ntsuas polarization.
Cov khoom siv kho tshuab thiab cov cwj pwm corrosion ntawm duplex stainless hlau welds tau tshawb xyuas siv E1 thiab E2 electrodes tshiab.Cov alkaline electrode (E1) thiab acidic electrode (E2) siv nyob rau hauv SMAW txheej txheem tau ua tiav coated nrog ib tug flux muaj pes tsawg leeg nrog ib tug tag nrho cov kev pab cuam piv ntawm 1.7 hli thiab alkaline index ntawm 2.40 thiab 0.40, feem.Lub thermal stability ntawm fluxes npaj siv TGA nyob rau hauv ib qho inert nruab nrab tau raug soj ntsuam.Lub xub ntiag ntawm cov ntsiab lus siab ntawm TiO2 (%) hauv flux matrix txhim kho cov slag tshem tawm ntawm cov khoom siv rau electrodes coated nrog acidic flux (E2) piv rau electrodes coated nrog yooj yim flux (E1).Txawm hais tias ob coated electrodes (E1 thiab E2) muaj peev xwm pib arc zoo.Vuam tej yam kev mob, tshwj xeeb tshaj yog thaum tshav kub kub input, vuam tam sim no thiab ceev, ua lub luag hauj lwm tseem ceeb nyob rau hauv ua kom tiav lub austenite / ferrite theem tshuav nyiaj li cas ntawm DSS 2205 welds thiab cov zoo heev mechanical zog ntawm lub weld.Cov pob qij txha welded nrog E1 electrode qhia tau zoo heev tensile zog (shear 0.2% YS = 497 MPa thiab UTS = 732 MPa), paub meej tias cov flux coated electrodes muaj ib tug high theem Performance index piv rau cov kua qaub flux coated electrodes.Electrodes pom cov khoom zoo dua qub nrog cov alkalinity tsawg.Nws yog pom tseeb tias nyob rau hauv lub welded pob qij txha ntawm electrodes nrog ib tug tshiab txheej (E1 thiab E2) tsis muaj equilibrium ntawm lub ferrite-austenitic theem, uas tau qhia siv OES thiab SEM-EDS tsom xam ntawm weld thiab quantified los ntawm lub ntim feem nyob rau hauv. lub vuam.Metallography tau lees paub lawv txoj kev tshawb fawb SEM.microstructures.Qhov no feem ntau yog vim qhov depletion ntawm alloying ntsiab xws li Cr thiab Mo thiab tau tso tawm ntawm Cr2N thaum lub sij hawm vuam, uas tau lees paub los ntawm EDS kab scanning.Qhov no tau txhawb ntxiv los ntawm qhov tsis tshua muaj siab hardness pom nyob rau hauv welds nrog E1 thiab E2 electrodes vim lawv tsis tshua muaj feem ntawm ferrite thiab alloying ntsiab nyob rau hauv steel qauv.Cov ntaub ntawv pov thawj Corrosion Potential (Ecorr) ntawm cov welds siv E1 electrode ua pov thawj tias tsis tshua muaj kev tiv thaiv corrosion piv rau cov vuam siv E2 electrode.Qhov no lees paub qhov ua tau zoo ntawm cov electrodes tshiab tsim nyob rau hauv welds kuaj nyob rau hauv 3.5% NaCl ib puag ncig yam tsis muaj flux sib tov alloy muaj pes tsawg leeg.Nws tuaj yeem xaus lus tias qhov corrosion kuj nyob rau hauv simulated marine ib puag ncig nce nrog txo vuam tam sim no.Yog li, nag lossis daus ntawm carbides thiab nitrides thiab qhov txo qis hauv kev tiv thaiv corrosion ntawm welded pob qij txha siv E1 thiab E2 electrodes tau piav qhia los ntawm kev nce vuam tam sim no, uas ua rau muaj qhov tsis sib xws hauv theem sib npaug ntawm cov pob qij txha los ntawm ob lub hom phiaj.
Thaum thov, cov ntaub ntawv rau txoj kev tshawb no yuav muab los ntawm tus kws sau ntawv.
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