321 chitsulo chosapanga dzimbiri chophimbidwa ndi machubu opangidwa ndi mankhwala Kapangidwe ka makina ndi khalidwe la dzimbiri la weld yachitsulo chosapanga dzimbiri chokhala ndi electrode yatsopano

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Chitsulo Chosapanga 321 Coil Tube Chemical Mapangidwe

Kapangidwe kake ka 321 koyilo yachitsulo chosapanga dzimbiri ndi motere:
- Mpweya: 0.08% Max
- Manganese: 2.00% max
Nickel: 9.00% min

Zida Zamakina Zazitsulo Zachitsulo 321 Coil Tube

Malinga ndi Stainless Steel 321 Coil Tube Manufacturer, makina amakina a zitsulo zosapanga dzimbiri 321 machubu amalembedwa pansipa: Kulimba Kwambiri (psi) Kuchuluka Kwambiri (psi) Elongation (%)

Kugwiritsa Ntchito ndi Kugwiritsa Ntchito Stainless Steel 321 Coil Tube

M'zinthu zambiri zamainjiniya, makina ndi corrosion katundu wa duplex stainless steel (DSS) welded nyumba ndizofunikira kwambiri.Kafukufuku wapano adafufuza momwe makina amagwirira ntchito komanso kukana kwa dzimbiri kwa ma welds achitsulo chosapanga dzimbiri a duplex m'malo omwe amatengera 3.5% NaCl pogwiritsa ntchito ma elekitirodi opangidwa mwapadera popanda kuphatikizira ma alloying pazitsanzo za flux.Mitundu iwiri yosiyanasiyana ya fluxes yokhala ndi index yayikulu ya 2.40 ndi 0,40 idagwiritsidwa ntchito pamagetsi E1 ndi E2 pakuwotcherera matabwa a DSS, motsatana.Kukhazikika kwa kutentha kwa nyimbo za flux kunayesedwa pogwiritsa ntchito kusanthula kwa thermogravimetric.Kapangidwe kakemidwe komanso mawonekedwe amakanikidwe ndi dzimbiri pamalumikizidwe owotcherera adawunikidwa pogwiritsa ntchito ma emission spectroscopy motsatira miyezo yosiyanasiyana ya ASTM.X-ray diffraction imagwiritsidwa ntchito kudziwa magawo omwe ali mu ma welds a DSS, ndipo ma electron ojambulira ndi EDS amagwiritsidwa ntchito poyang'ana microstructure ya welds.Kulimba kwamphamvu kwa ma welds opangidwa ndi ma elekitirodi a E1 anali mkati mwa 715-732 MPa, ndi ma elekitirodi a E2 - 606-687 MPa.Kuwotcherera pakali pano kwawonjezeka kuchoka pa 90 A mpaka 110 A, ndipo kuuma kwawonjezeka.Zolumikizira zowotcherera zokhala ndi ma elekitirodi a E1 zokutidwa ndi zoyambira zoyambira zimakhala ndi makina abwinoko.Kapangidwe kachitsulo kamakhala ndi kukana kwambiri kwa dzimbiri mu 3.5% NaCl chilengedwe.Izi zimatsimikizira kugwira ntchito kwa zolumikizira zowotcherera zopangidwa ndi maelekitirodi omwe angopangidwa kumene.Zotsatira zimakambidwa pokhudzana ndi kuchepa kwa zinthu za alloying monga Cr ndi Mo zomwe zimawonedwa mu ma welds okhala ndi ma elekitirodi E1 ndi E2, komanso kutulutsidwa kwa Cr2N mu ma welds opangidwa pogwiritsa ntchito ma elekitirodi E1 ndi E2.
M'mbiri, kutchulidwa koyamba kwa duplex zitsulo zosapanga dzimbiri (DSS) kudayamba mu 1927, pomwe kumangogwiritsidwa ntchito popanga zinthu zina ndipo sikunagwiritsidwe ntchito pazinthu zambiri zaukadaulo chifukwa chokhala ndi mpweya wambiri1.Koma pambuyo pake, zomwe zili mu mpweya wa kaboni zinachepetsedwa kufika pamtengo wapatali wa 0.03%, ndipo zitsulozi zinagwiritsidwa ntchito kwambiri m'madera osiyanasiyana2,3.DSS ndi banja la aloyi okhala ndi pafupifupi ofanana kuchuluka kwa ferrite ndi austenite.Kafukufuku wasonyeza kuti gawo la ferritic mu DSS limapereka chitetezo chabwino kwambiri ku chloride-induced stress corrosion cracking (SCC), yomwe inali nkhani yofunika kwambiri pazitsulo zosapanga dzimbiri za austenitic (ASS) m'zaka za zana la 20.Kumbali ina, m'mainjiniya ena ndi mafakitale ena kufunikira kosungirako kukukulirakulira mpaka 20% pachaka.Chitsulo chatsopanochi chokhala ndi magawo awiri austenitic-ferritic chikhoza kupezedwa mwa kusankha koyenera, mankhwala opangidwa ndi thupi ndi thermomechanical.Poyerekeza ndi chitsulo chosapanga dzimbiri cha gawo limodzi, DSS ili ndi mphamvu zokolola zapamwamba komanso kuthekera kopambana kupirira SCC5, 6, 7, 8. Mapangidwe a duplex amapatsa zitsulo izi mphamvu zosayerekezeka, kulimba komanso kukana dzimbiri m'malo aukali okhala ndi ma acid, ma asidi a kloridi, madzi a m'nyanja ndi mankhwala owononga9.Chifukwa cha kusinthasintha kwamtengo wapachaka wa ma aloyi a nickel (Ni) pamsika wamba, kapangidwe ka DSS, makamaka mtundu wa nickel otsika (zowonda DSS), zakwaniritsa zambiri zopambana poyerekeza ndi nkhope yapakati kiyubiki (FCC) iron10, 11. Vuto la mapangidwe a ASE ndikuti amakumana ndi zovuta zosiyanasiyana.Choncho, m'madipatimenti osiyanasiyana zomangamanga ndi makampani akuyesera kulimbikitsa zina otsika faifi tambala (Ni) zitsulo zosapanga dzimbiri zomwe zimagwira bwino kapena bwino kuposa ASS chikhalidwe ndi weldability oyenera ndi ntchito mafakitale ntchito monga exchangers madzi m'nyanja kutentha ndi makampani mankhwala.chidebe 13 cha malo okhala ndi ma chloride ambiri.
Pakupita patsogolo kwaukadaulo wamakono, kupanga welded kumagwira ntchito yofunika kwambiri.Nthawi zambiri, mamembala a DSS amalumikizidwa ndi kuwotcherera kwa arc otetezedwa ndi gasi kapena kuwotcherera kwa arc.The weld makamaka amakhudzidwa ndi zikuchokera elekitirodi ntchito kuwotcherera.Ma elekitirodi owotcherera amakhala ndi magawo awiri: zitsulo ndi flux.Nthawi zambiri, ma elekitirodi wokutidwa ndi flux, chisakanizo cha zitsulo kuti, pamene kuvunda, kumasula mpweya ndi kupanga slag zoteteza kuteteza kuwotcherera ku kuipitsidwa, kuonjezera bata la arc, ndi kuwonjezera alloying chigawo kuti kusintha khalidwe kuwotcherera14. .Chitsulo, aluminiyamu, chitsulo chosapanga dzimbiri, chitsulo chofatsa, chitsulo cholimba kwambiri, mkuwa, mkuwa, ndi mkuwa ndi zina mwazitsulo zowotcherera ma elekitirodi, pomwe mapadi, ufa wachitsulo, ndi haidrojeni ndi zina mwazinthu zomwe zimagwiritsidwa ntchito.Nthawi zina sodium, titaniyamu ndi potaziyamu zimaphatikizidwanso kusakaniza kwa flux.
Ofufuza ena ayesera kuphunzira momwe ma electrode kasinthidwe amagwirira ntchito pamakina ndi corrosion umphumphu wa zitsulo welded zitsulo.Singh et al.15 idafufuza momwe kupangika kwa flux kumatalikira komanso kulimba kwamphamvu kwa ma welds omwe amawotcherera ndi kuwotcherera arc pansi pamadzi.Zotsatira zikuwonetsa kuti CaF2 ndi NiO ndizomwe zimatsimikizira mphamvu yamphamvu poyerekeza ndi kukhalapo kwa FeMn.Chirag et al.16 adafufuza zosakaniza za SMAW posintha kuchuluka kwa rutile (TiO2) mu osakaniza a electrode flux.Zinapezeka kuti katundu wa microhardness anawonjezeka chifukwa cha kuchuluka kwa kuchuluka ndi kusamuka kwa carbon ndi silicon.Kumar [17] adaphunzira kamangidwe ndi kakulidwe ka ma agglomerated fluxes amiyendo arc kuwotcherera kwazitsulo zachitsulo.Nwigbo ndi Atuanya18 adafufuza za kugwiritsa ntchito zomangira za potaziyamu za sodium silicate popanga ma arc welding fluxes ndipo adapeza ma weld okhala ndi mphamvu yayikulu ya 430 MPa komanso kapangidwe kambewu kovomerezeka.Lothongkum et al.19 anagwiritsa ntchito njira ya potentiokinetic kuti aphunzire gawo la voliyumu ya austenite mu duplex zitsulo zosapanga dzimbiri 28Cr-7Ni-O-0.34N mu njira yothetsera mpweya wa NaCl pamagulu a 3.5% wt.pansi pa pH mikhalidwe.ndi 27°C.Zonse ziwiri za duplex ndi micro duplex zosapanga dzimbiri zimawonetsa zotsatira zomwezo za nayitrogeni pakuchita dzimbiri.Nayitrogeni sinakhudze kuthekera kwa dzimbiri kapena kuchuluka kwa pH 7 ndi 10, komabe, kuthekera kwa dzimbiri pa pH 10 kunali kotsika kuposa pH 7. Komano, pamiyeso yonse ya pH yophunziridwa, kuthekera kudayamba kuchulukirachulukira ndi kuchuluka kwa nayitrogeni. .Lacerda et al.20 adaphunzira kuponya zitsulo zosapanga dzimbiri za duplex UNS S31803 ndi UNS S32304 mu 3.5% NaCl yankho pogwiritsa ntchito cyclic potentiodynamic polarization.Mu 3.5 wt.% yankho la NaCl, zizindikiro za pitting zinapezeka pazitsulo ziwiri zofufuzidwa.Chitsulo cha UNS S31803 chili ndi kuthekera kwakukulu kwa dzimbiri (Ecorr), kuthekera kwa pitting (Epit) ndi kukana polarization (Rp) kuposa chitsulo cha UNS S32304.UNS S31803 chitsulo ali ndi repassivity apamwamba kuposa UNS S32304 zitsulo.Malinga ndi kafukufuku wa Jiang et al.[21], nsonga yotsitsimutsanso yofanana ndi gawo lawiri (austenite ndi ferrite gawo) la chitsulo chosapanga dzimbiri cha duplex chimaphatikizapo mpaka 65% ya ferrite, ndipo kachulukidwe ka ferrite kachulukidwe kakali pano akuwonjezeka ndikuwonjezera nthawi yochizira kutentha.Ndizodziwika bwino kuti magawo austenitic ndi ferritic amawonetsa machitidwe osiyanasiyana a electrochemical pamitundu yosiyanasiyana ya electrochemical 21,22,23,24.Abdo et al.25 anagwiritsa ntchito miyeso ya potentiodynamic ya polarization spectroscopy ndi electrochemical impedance spectroscopy kuti aphunzire kuwonongeka kwa electrochemically kwa laser-welded 2205 DSS alloy m'madzi a m'nyanja ochita kupanga (3.5% NaCl) pansi pa acidity yosiyana ndi alkalinity.Kuwonongeka kwa pitting kunawonedwa pamalo owonekera a zitsanzo zoyesedwa za DSS.Kutengera zomwe zapezedwazi, zidakhazikitsidwa kuti pali mgwirizano wolingana pakati pa pH ya sing'anga yosungunuka ndi kukana kwa filimu yomwe idapangidwa potengera kusamutsidwa, zomwe zimakhudza mwachindunji mapangidwe a pitting ndi tsatanetsatane wake.Cholinga cha kafukufukuyu chinali kumvetsetsa momwe chopangira chatsopano chowotcherera cha elekitirodi chimakhudzira kukhulupirika kwamakina ndi kusamva kuvala kwa welded DSS 2205 mu 3.5% NaCl chilengedwe.
Ma minerals otuluka (zosakaniza) omwe amagwiritsidwa ntchito popangira ma electrode coating anali Calcium Carbonate (CaCO3) ochokera ku Obajana District, Kogi State, Nigeria, Calcium Fluoride (CaF2) kuchokera ku Taraba State, Nigeria, Silicon Dioxide (SiO2), Talc Powder (Mg3Si4O10 (OH). ) )2) ndi rutile (TiO2) anapezedwa kuchokera ku Jos, Nigeria, ndi kaolin (Al2(OH) 4Si2O5) anachokera ku Kankara, Katsina State, Nigeria.Potaziyamu silicate imagwiritsidwa ntchito ngati binder, imachokera ku India.
Monga tawonera mu Table 1, ma oxides omwe amapangidwa adayesedwa pawokha pamlingo wa digito.Kenako idasakanizidwa ndi potassium silicate binder (23% mwa kulemera kwake) mu chosakaniza chamagetsi (chitsanzo: 641-048) kuchokera ku Indian Steel and Wire Products Ltd. (ISWP) kwa mphindi 30 kuti mupeze phala lofanana ndi theka-olimba.Kutuluka konyowa kosakanikirana kumakanikizidwa mu mawonekedwe a cylindrical kuchokera ku makina opangira briquetting ndikudyetsedwa m'chipinda cha extrusion pamagetsi a 80 mpaka 100 kg / cm2, ndipo kuchokera ku chipinda cha chakudya cha waya amadyetsedwa mu 3.15mm m'mimba mwake wa waya wosapanga dzimbiri.The flux amadyetsedwa kudzera nozzle / kufa dongosolo ndi jekeseni mu extruder extrude maelekitirodi.Chophimba cha 1.70 mm chinapezedwa, pomwe chinthu chophimbacho chimatanthauzidwa ngati chiŵerengero cha ma electrode awiri ndi awiri a chingwe.Ndiye maelekitirodi TACHIMATA anali zouma mu mpweya kwa maola 24 ndiyeno calcined mu muffle ng'anjo (chitsanzo PH-248-0571/5448) pa 150-250 °C\(-\) kwa 2 hours.Gwiritsani ntchito equation kuti muwerenge alkalinity ya kuyenda.(1) 26;
Kukhazikika kwa kutentha kwa zitsanzo za flux za nyimbo E1 ndi E2 zidatsimikiziridwa pogwiritsa ntchito thermogravimetric analysis (TGA).Chitsanzo cha pafupifupi 25.33 mg ya flux idakwezedwa mu TGA kuti iwunikidwe.Kuyesera kunkachitika mu sing'anga yopanda kanthu yomwe imapezeka ndi kuyenda kosalekeza kwa N2 pa mlingo wa 60 ml / min.Chitsanzocho chinatenthedwa kuchokera ku 30 ° C mpaka 1000 ° C pa kutentha kwa 10 ° C / min.Potsatira njira zotchulidwa ndi Wang et al.27, Xu et al.28 ndi Dagwa et al.29, kuwonongeka kwa kutentha ndi kulemera kwa zitsanzo pa kutentha kwina kunayesedwa kuchokera ku TGA ziwembu.
Pangani mbale ziwiri za 300 x 60 x 6 mm DSS kuti mukonzekere ku soldering.V-groove idapangidwa ndi kusiyana kwa mizu ya 3mm, dzenje la 2mm ndi ngodya ya 60 °.Kenako mbaleyo imatsukidwa ndi acetone kuti muchotse zowononga zomwe zingatheke.Wotchererani mbale pogwiritsa ntchito chotchinga chotchinga chachitsulo chotchinga (SMAW) chokhala ndi electrode positive polarity (DCEP) pogwiritsa ntchito ma elekitirodi okutira (E1 ndi E2) ndi ma elekitirodi (C) okhala ndi mainchesi 3.15 mm.Electrical Discharge Machining (EDM) (Model: Excetek-V400) idagwiritsidwa ntchito popanga zitsanzo zachitsulo zowotcherera poyesa makina komanso mawonekedwe a dzimbiri.Table 2 ikuwonetsa ma code ndi mafotokozedwe, ndipo Table 3 ikuwonetsa magawo osiyanasiyana ogwiritsira ntchito kuwotcherera omwe amagwiritsidwa ntchito powotcherera bolodi la DSS.Equation (2) imagwiritsidwa ntchito kuwerengera kutentha komwe kumayendera.
Pogwiritsa ntchito Bruker Q8 MAGELLAN optical emission spectrometer (OES) yokhala ndi kutalika kwa 110 mpaka 800 nm ndi pulogalamu ya database ya SQL, kapangidwe kake ka ma weld joints a electrode E1, E2 ndi C, komanso zitsanzo zazitsulo zoyambira, zidatsimikiziridwa.imagwiritsa ntchito kusiyana pakati pa elekitirodi ndi chitsanzo chachitsulo poyesedwa Imapanga mphamvu yamagetsi monga spark.Chitsanzo cha zigawozo ndi vaporized ndi kupopera mbewu mankhwalawa, kutsatiridwa ndi chisangalalo cha atomiki, chomwe pambuyo pake chimatulutsa mzere wina wa sipekitiramu31.Pakuwunika kwachitsanzo, chubu la photomultiplier limayesa kupezeka kwa sipekitiramu yodzipatulira pa chinthu chilichonse, komanso kukula kwa sipekitiramu.Kenako gwiritsani ntchito equation kuti muwerenge nambala yofananira ya pitting resistance (PREN).(3) Ratio 32 ndi chithunzi cha boma cha WRC 1992 amagwiritsidwa ntchito kuwerengera chromium ndi nickel zofanana (Creq ndi Nieq) kuchokera ku equation.(4) ndi (5) ali 33 ndi 34 motsatira;
Dziwani kuti PREN imangoganizira zotsatira zabwino za zinthu zitatu zazikulu Cr, Mo ndi N, pamene nitrogen factor x ili m'kati mwa 16-30.Kawirikawiri, x amasankhidwa kuchokera pa mndandanda wa 16, 20, kapena 30. Pofufuza pazitsulo zosapanga dzimbiri za duplex, mtengo wapakati wa 20 umagwiritsidwa ntchito kwambiri powerengera PREN35,36.
Zolumikizira zowotcherera zomwe zidapangidwa pogwiritsa ntchito maelekitirodi osiyanasiyana zidayesedwa mwamphamvu pamakina oyesera padziko lonse lapansi (Instron 8800 UTM) pamlingo wopsinjika wa 0.5 mm / min malinga ndi ASTM E8-21.Mphamvu yamanjenje (UTS), 0.2% shear yield strength (YS), ndi elongation zidawerengedwa molingana ndi ASTM E8-2137.
Ma welds a DSS 2205 anali oyamba pansi ndikupukutidwa pogwiritsa ntchito makulidwe osiyanasiyana a grit (120, 220, 320, 400, 600, 800, 1000 ndi 1200) asanaunike kuuma.Zitsanzo zowotcherera zidapangidwa ndi ma elekitirodi E1, E2 ndi C. Kuuma kumayesedwa pa mfundo khumi (10) kuchokera pakatikati pa chowotcherera mpaka chitsulo choyambira ndi nthawi ya 1 mm.
X-ray diffractometer (D8 Discover, Bruker, Germany) yokonzedwa ndi pulogalamu ya Bruker XRD Commander yosonkhanitsira deta ndi ma radiation a Fe-filtered Cu-K-α okhala ndi mphamvu ya 8.04 keV yofanana ndi kutalika kwa 1.5406 Å ndi sikelo ya 3 ° Scan range (2θ) min-1 ndi 38 mpaka 103 ° pakuwunika gawo ndi ma elekitirodi a E1, E2 ndi C ndi BM omwe amapezeka mu ma welds a DSS.Njira yoyenetsera ya Rietveld idagwiritsidwa ntchito kuwonetsa magawo omwe ali nawo pogwiritsa ntchito pulogalamu ya MAUD yofotokozedwa ndi Lutterotti39.Kutengera ASTM E1245-03, kusanthula kwachitsulo kwazithunzi zazing'ono zazing'ono zolumikizira ma elekitirodi E1, E2 ndi C kunachitika pogwiritsa ntchito pulogalamu ya Image J40.Zotsatira za kuwerengera gawo la voliyumu ya gawo la ferrite-austenitic, mtengo wawo wapakati ndi kupatuka kumaperekedwa mu Table.5. Monga momwe zikuwonetsedwera mu chitsanzo kasinthidwe mkuyu.6d, optical microscopy (OM) kusanthula kunachitika pa PM ndi ma welded olowa ndi maelekitirodi E1 ndi E2 kuti aphunzire kapangidwe ka zitsanzo.Zitsanzozo zidapukutidwa ndi 120, 220, 320, 400, 600, 800, 1000, 1200, 1500, ndi 2000 grit silicon carbide (SiC) sandpaper.Zitsanzozo zinakhazikitsidwa mu njira ya 10% ya aqueous oxalic acid pa kutentha kwa mpweya wa 5 V kwa 10 s ndikuyika pa LEICA DM 2500 M microscope ya kuwala kwa morphological characterization.Kupukuta kwina kwachitsanzo kunachitika pogwiritsa ntchito pepala la 2500 grit silicon carbide (SiC) posanthula SEM-BSE.Kuphatikiza apo, zolumikizira zowotcherera zidawunikidwa kuti zikhale ndi mawonekedwe ang'onoang'ono pogwiritsa ntchito ultra-high resolution field emission scanning electron microscope (SEM) (FEI NOVA NANOSEM 430, USA) yokhala ndi EMF.Chitsanzo cha 20 × 10 × 6 mm chinagwiritsidwa ntchito pogwiritsa ntchito mapepala amtundu wa SiC osiyanasiyana kuyambira kukula kwa 120 mpaka 2500. Zitsanzozo zinakhazikitsidwa ndi electrolytically mu 40 g wa NaOH ndi 100 ml ya madzi osungunuka pamagetsi a 5 V kwa 15 s, ndiyeno wokwezedwa pa chogwirizira, chomwe chili mu chipinda cha SEM, chowunikira zitsanzo mutatsuka chipindacho ndi nayitrogeni.Mtengo wa ma elekitironi wopangidwa ndi ulusi wotenthedwa wa tungsten umapanga grating pachitsanzo kuti apange zithunzi pazokulitsa zosiyanasiyana, ndipo zotsatira za EMF zapezedwa pogwiritsa ntchito njira za Roche et al.41 ndi Mokobi 42.
Njira ya electrochemical potentiodynamic polarization molingana ndi ASTM G59-9743 ndi ASTM G5-1444 idagwiritsidwa ntchito poyesa kuwonongeka kwa mbale za DSS 2205 zowotcherera ndi ma electrode E1, E2 ndi C mu 3.5% NaCl chilengedwe.Mayeso a Electrochemical adachitidwa pogwiritsa ntchito zida zoyendetsedwa ndi kompyuta za Potentiostat-Galvanostat/ZRA (chitsanzo: PC4/750, Gamry Instruments, USA).Kuyesa kwa Electrochemical kunachitika pamayeso a electrode atatu: DSS 2205 ngati electrode yogwira ntchito, saturated calomel electrode (SCE) ngati maelekitirodi owerengera ndi ndodo ya graphite ngati ma electrode owerengera.Miyezo inachitika pogwiritsa ntchito selo la electrochemical, momwe gawo la yankho linali gawo la electrode yogwira ntchito 0,78 cm2.Miyezo idapangidwa pakati pa -1.0 V mpaka + 1.6 V kuthekera pa OCP yokhazikika (yogwirizana ndi OCP) pamlingo wa 1.0 mV/s.
Electrochemical pitting kutentha kwambiri kuyezetsa kunachitika mu 3.5% NaCl kuwunika kukana kwa ma welds opangidwa ndi ma elekitirodi a E1, E2, ndi C.momveka bwino pazitsulo zomwe zingatheke mu PB (pakati pa madera osasunthika ndi odutsa), ndi zitsanzo zowotcherera ndi E1, E2, Electrodes C. Choncho, miyeso ya CPT imachitidwa kuti adziwe molondola mphamvu ya pitting ya zowonjezera zowonjezera.Kuyesa kwa CPT kunachitika molingana ndi malipoti a duplex osapanga dzimbiri osapanga dzimbiri45 ndi ASTM G150-1846.Kuchokera pazitsulo zonse zomwe ziyenera kuwotcherera (S-110A, E1-110A, E2-90A), zitsanzo zokhala ndi malo a 1 cm2 zinadulidwa, kuphatikizapo maziko, weld, ndi HAZ zones.Zitsanzozo zidapukutidwa pogwiritsa ntchito sandpaper ndi 1 µm alumina ufa slurry molingana ndi njira zokonzekera zitsanzo za metallographic.Pambuyo kupukuta, zitsanzo anali ultrasonically kutsukidwa mu acetone kwa 2 min.Njira yothetsera mayesero a 3.5% NaCl inawonjezeredwa ku selo yoyesera ya CPT ndipo kutentha koyambirira kunasinthidwa kukhala 25 ° C pogwiritsa ntchito thermostat (Neslab RTE-111).Pambuyo pofika kutentha koyambirira kwa 25 ° C, mpweya wa Ar unawombedwa kwa mphindi 15, ndiye zitsanzozo zinayikidwa mu selo, ndipo OCF inayesedwa kwa 15 min.Chitsanzocho chinasinthidwa pogwiritsa ntchito magetsi a 0.3 V pa kutentha koyambirira kwa 25 ° C, ndipo panopa adayezedwa kwa 10 min45.Yambani kutentha yankho pamlingo wa 1 °C/mphindi mpaka 50 °C.Pa kutentha kwa njira yoyesera, kutentha kwa kutentha kumagwiritsidwa ntchito mosalekeza kuyang'ana kutentha kwa yankho ndi kusunga nthawi ndi deta ya kutentha, ndipo potentiostat / galvanostat imagwiritsidwa ntchito poyesa zamakono.Elekitirodi ya graphite idagwiritsidwa ntchito ngati maelekitirodi owerengera, ndipo kuthekera konse kumayezedwa potengera ma elekitirodi a Ag/AgCl.Argon purge idachitidwa panthawi yonseyi.
Pa mkuyu.1 ikuwonetsa kaphatikizidwe (kulemera kwa zana) kwa zigawo za F1 ndi F2 zomwe zimagwiritsidwa ntchito popanga ma elekitirodi amchere (E1) ndi acidic (E2), motsatana.Flux basicity index imagwiritsidwa ntchito kulosera zamakina ndi zitsulo zamalumikizidwe owotcherera.F1 ndi gawo la flux yomwe imagwiritsidwa ntchito povala ma elekitirodi a E1, omwe amatchedwa alkaline flux chifukwa index yake yayikulu ndi> 1.2 (ie 2.40), ndipo F2 ndiye flux yomwe imagwiritsidwa ntchito kuvala ma elekitirodi a E2, otchedwa acid flux chifukwa cha kukhazikika kwake. index <0.9 (ie 2.40).0.40 .N'zoonekeratu kuti maelekitirodi wokutidwa ndi zoyamba fluxes nthawi zambiri amakhala bwino mawotchi katundu kuposa maelekitirodi wokutidwa ndi acidic fluxes.Chikhalidwe ichi ndi ntchito ya kulamulira kwa oxide woyambira mu dongosolo flux zikuchokera kwa elekitirodi E1.M'malo mwake, kuchotsa slag (kupatukana) ndi otsika spatter kuwonedwa mu mfundo welded ndi maelekitirodi E2 ndi khalidwe maelekitirodi ndi acidic flux ❖ kuyanika ndi mkulu zili rutile.Izi zikugwirizana ndi zomwe Gill47 apeza kuti zotsatira za rutile pa slag detachability ndi otsika spatter wa asidi flux TACHIMATA maelekitirodi zimathandiza kuti mofulumira slag kuzizira.Kaolin mu dongosolo flux ntchito kuvala maelekitirodi E1 ndi E2 ntchito ngati lubricant, ndi talc ufa bwino extrudability maelekitirodi.Zomangira za potaziyamu silicate mu makina otuluka zimathandizira kuyatsa bwino kwa arc ndi kukhazikika kwa magwiridwe antchito, ndipo, kuwonjezera pa zomatira zawo, kumathandizira kulekanitsidwa kwa slag muzinthu zowotcherera.Popeza CaCO3 ndi wosweka ukonde (slag breaker) mu flux ndipo amakonda kutulutsa utsi wambiri panthawi yowotcherera chifukwa cha kuwonongeka kwa matenthedwe mu CaO ndipo pafupifupi 44% CO2, TiO2 (monga womanga ukonde / slag wakale) amathandizira kuchepetsa kuchuluka kwake. utsi pa kuwotcherera .kuwotcherera ndipo motero kumapangitsa kuti slag awonongeke monga momwe Jing et al.48.Fluorine Flux (CaF2) ndi kusinthasintha kwamphamvu kwamankhwala komwe kumapangitsa ukhondo wa solder.Jastrzębska et al.49 idanenanso zotsatira za kapangidwe ka fluoride kaphatikizidwe ka flux iyi paukhondo wa weld.Nthawi zambiri, flux imawonjezedwa kudera la weld kuti ipititse patsogolo kukhazikika kwa arc, kuwonjezera ma alloying, kumanga slag, kukulitsa zokolola, ndikuwongolera dziwe la weld 50.
Ma curve a TGA-DTG akuwonetsedwa muzithunzi.2a ndi 2b amawonetsa kutsika kwa magawo atatu pakuwotcha pa kutentha kwa 30-1000 ° C mumlengalenga wa nayitrogeni.Zotsatira mu Zithunzi 2a ndi b zikuwonetsa kuti pazitsanzo zoyambira ndi acidic flux, ma curve a TGA amatsika molunjika mpaka pamapeto pake amakhala ofanana ndi kutentha kwa kutentha, kuzungulira 866.49 ° C ndi 849.10 ° C motsatana.Kulemera kwa 1.30% ndi 0.81% kumayambiriro kwa ma curve a TGA mu Mkuyu 2a ndi 2b chifukwa cha chinyezi chomwe chimatengedwa ndi zigawo zowonongeka, komanso kutuluka kwa mpweya ndi kutaya madzi m'thupi.Waukulu decompositions wa zitsanzo za flux waukulu pa wachiwiri ndi wachitatu magawo mkuyu.2a inachitika mu kutentha kwa 619.45 ° C-766.36 ° C ndi 766.36 ° C-866.49 ° C, ndipo kuchuluka kwa kulemera kwawo kunali 2.84 ndi 9.48%., motero.Ngakhale kuti zitsanzo za acidic flux mu Mkuyu 7b, zomwe zinali mu kutentha kwa 665.23 ° C-745.37 ° C ndi 745.37 ° C-849.10 ° C, kuchepa kwawo kulemera kunali 0.81 ndi 6.73%, motero, zomwe zinanenedwa kuwonongeka kwa kutentha.Popeza zigawo za flux ndizosakhazikika, zosinthika zimangokhala zosakanikirana ndi flux.Chifukwa chake, kuchepa ndi okosijeni ndizowopsa.Izi zikugwirizana ndi zotsatira za Balogun et al.51, Kamli et al.52 ndi Adeleke et al.53.Chiwerengero cha kutayika kwakukulu kwa chitsanzo cha flux chomwe chikuwonetsedwa mkuyu.2a ndi 2b ndi 13.26% ndi 8.43%, motero.Kutayika kochepa kwa zitsanzo za flux mu mkuyu.2b ndi chifukwa cha malo osungunuka kwambiri a TiO2 ndi SiO2 (1843 ndi 1710 ° C motsatira) monga ma oxides akuluakulu omwe amapanga kusakaniza kwa flux54,55, pamene TiO2 ndi SiO2 ali ndi malo otsika osungunuka.posungunuka Pulayimale oxide: CaCO3 (825 °C) mumkuyu.2a56.Zosintha izi pazitsulo zosungunuka za ma oxides oyambira muzosakaniza zosakanikirana zimafotokozedwa bwino ndi Shi et al.54, Ringdalen et al.55 ndi Du et al.56.Kuwona kuwonda kosalekeza mu Mkuyu 2a ndi 2b, tinganene kuti zitsanzo za flux zomwe zimagwiritsidwa ntchito mu E1 ndi E2 electrode zokutira zimawonongeka ndi sitepe imodzi, monga momwe Brown57 anafotokozera.Mtundu wa kutentha kwa ndondomekoyi ukhoza kuwonedwa kuchokera ku ma curve (wt%) mu mkuyu.2a ndi b.Popeza phokoso la TGA silingathe kufotokoza molondola kutentha kwapadera komwe dongosolo la flux limasinthira kusintha kwa gawo ndi crystallization, chotengera cha TGA chimagwiritsidwa ntchito kuti chizindikire kutentha kwapadera kwa chinthu chilichonse (kusintha kwa gawo) monga nsonga ya endothermic kukonzekera dongosolo la flux.
Mapiritsi a TGA-DTG akuwonetsa kuwonongeka kwa (a) alkaline flux kwa E1 electrode yokutira ndi (b) acidic flux ya E2 electrode yokutira.
Gulu 4 likuwonetsa zotsatira za kusanthula kwa spectrophotometric ndi kusanthula kwa SEM-EDS kwazitsulo zoyambira za DSS 2205 ndi ma welds opangidwa pogwiritsa ntchito ma elekitirodi a E1, E2 ndi C.E1 ndi E2 adawonetsa kuti zomwe zili mu chromium (Cr) zidatsika kwambiri mpaka 18.94 ndi 17.04%, ndipo zomwe zili mu molybdenum (Mo) zinali 0.06 ndi 0.08%, motsatana.ma welds okhala ndi ma elekitirodi E1 ndi E2 ndi otsika.Izi zikugwirizana pang'ono ndi chiwerengero cha PREN chowerengedwa cha gawo la ferritic-austenitic kuchokera ku kufufuza kwa SEM-EDS.Chifukwa chake, zitha kuwoneka kuti kuponya kumayambira pa siteji ndi ma PREN otsika (zowotcherera kuchokera ku E1 ndi E2), makamaka monga momwe tafotokozera mu Table 4. Izi zikuwonetsa kuchepa ndi kotheka kwa mpweya wa aloyi mu weld.Pambuyo pake, kuchepa kwa zomwe zili mu Cr ndi Mo alloying element mu ma welds opangidwa pogwiritsa ntchito ma elekitirodi E1 ndi E2 komanso milingo yawo yotsika yofananira (PREN) ikuwonetsedwa mu Gulu 4, zomwe zimapangitsa kuti pakhale vuto loletsa kukana m'malo ankhanza, makamaka. m'malo a chloride.-okhala ndi chilengedwe.Nickel (Ni) yochuluka kwambiri ya 11.14% ndi malire ovomerezeka a manganese muzitsulo zowotcherera za E1 ndi E2 maelekitirodi angakhale ndi zotsatira zabwino pamakina a ma weldments omwe amagwiritsidwa ntchito poyerekezera madzi a m'nyanja (mkuyu 3). ).zidapangidwa pogwiritsa ntchito ntchito ya Yuan ndi Oy58 ndi Jing et al.48 pa zotsatira za nyimbo za faifi tambala ndi manganese pakuwongolera zida zamakina a DSS welded nyumba pansi pamikhalidwe yovuta kwambiri.
Zotsatira zoyezetsa za (a) UTS ndi 0.2% sag YS ndi (b) yunifolomu ndi kutalika kwathunthu ndi kupatuka kwake.
Mphamvu za zinthu zoyambira (BM) ndi zolumikizira zowotcherera zopangidwa kuchokera ku ma elekitirodi opangidwa (E1 ndi E2) ndi ma elekitirodi omwe amapezeka pamalonda (C) adawunikidwa pamitundu iwiri yowotcherera ya 90 A ndi 110 A. 3 (a) ndi (b) onetsani UTS, YS yokhala ndi 0.2% offset, pamodzi ndi kutalika kwawo ndi deta yopatuka.Zotsatira za UTS ndi YS zotsatizana za 0.2% zopezedwa kuchokera ku Nkhuyu.3a akuwonetsa milingo yabwino kwambiri yachitsanzo No.1 (BM), chitsanzo No.3 (weld E1), chitsanzo No.5 (weld E2) ndi chitsanzo no.6 (zowotcherera zokhala ndi C) ndi 878 ndi 616 MPa, 732 ndi 497 MPa, 687 ndi 461 MPa ndi 769 ndi 549 MPa, motsatana, ndi zolakwika zawo.Kuchokera mkuyu.110 A) ndi zitsanzo zowerengeka 1, 2, 3, 6 ndi 7, motsatana, zokhala ndi katundu wocheperako wovomerezeka wopitilira 450 MPa pakuyezetsa kwamakomedwe ndi 620 MPa pakuyesa kolimba koperekedwa ndi Grocki32.The elongation wa kuwotcherera toyesa ndi maelekitirodi E1, E2 ndi C, akuimiridwa ndi zitsanzo No. 2, No. 3, No. 4, No. 5, No. 6 ndi No. motero, amasonyeza pulasitiki ndi kukhulupirika.zokhudzana ndi zitsulo zoyambira.The m'munsi elongation anafotokoza ndi zotheka kuwotcherera zilema kapena zikuchokera elekitirodi flux (mkuyu. 3b).Titha kunena kuti BM duplex chitsulo chosapanga dzimbiri komanso ma elekitirodi owotcherera okhala ndi ma elekitirodi a E1, E2 ndi C ambiri amakhala ndi mphamvu zolimba kwambiri chifukwa chokhala ndi faifi tambirimbiri (Table 4), koma malowa adawonedwa m'malo olumikizirana.E2 yocheperako imapezeka kuchokera ku acidic ya flux.Gunn59 idawonetsa momwe ma aloyi a nickel amathandizira pakuwongolera makina olumikizirana owotcherera ndikuwongolera gawo lolingana ndi kugawa zinthu.Izi zikutsimikiziranso mfundo yakuti maelekitirodi opangidwa kuchokera ku nyimbo zoyambira zimakhala ndi makina abwino kwambiri kuposa maelekitirodi opangidwa kuchokera ku zosakaniza za acidic flux, monga momwe Bang et al.60 ananenera.Chifukwa chake, thandizo lalikulu laperekedwa ku chidziwitso chomwe chilipo chokhudza momwe cholumikizira chowotcherera cha electrode yatsopano yokutira (E1) yokhala ndi zinthu zabwino zamakokedwe.
Pa mkuyu.Zithunzi 4a ndi 4b zimasonyeza Vickers microhardness makhalidwe a mayesero zitsanzo za welded olowa maelekitirodi E1, E2 ndi C. 4a amasonyeza kuuma zotsatira zopezedwa mbali imodzi ya chitsanzo (kuchokera WZ kuti BM), ndi mkuyu.4b ikuwonetsa zotsatira zowuma zomwe zimapezeka mbali zonse zachitsanzo.Kuuma mfundo zopezedwa pa kuwotcherera zitsanzo No.Kuwonjezeka kwakukulu kwa kuuma kunkawoneka mu HAZ yobiriwira komanso mu HAZ yabwino kwambiri ya zitsanzo zonse No. kutenthetsa chifukwa cha zitsanzo za chromium-weld zimakhala ndi mpweya wambiri (Cr23C6).Poyerekeza ndi zitsanzo zina kuwotcherera 2, 3, 4 ndi 5, kuuma mfundo za welded mfundo za zitsanzo No. 6 ndi 7 mu nkhuyu.4a ndi 4b pamwamba (tebulo 2).Malingana ndi Mohammed et al.61 ndi Nowacki ndi Lukoje62, izi zikhoza kukhala chifukwa cha mtengo wapamwamba wa ferrite δ ndi kuchititsa kupanikizika kotsalira mu weld, komanso kuchepa kwa zinthu za alloying monga Mo ndi Cr mu weld.Kuwuma kwa zitsanzo zonse zoyeserera m'dera la BM zikuwoneka kuti ndizogwirizana.Zomwe zimachitika pazotsatira za kuuma kwa zitsanzo zowotcherera zimagwirizana ndi zomwe ofufuza ena amapeza61,63,64.
Kuuma kwa zolumikizira zowotcherera za zitsanzo za DSS (a) theka la gawo la zitsanzo zowotcherera ndi (b) gawo lonse la zolumikizira zowotcherera.
Magawo osiyanasiyana omwe amapezeka mu welded DSS 2205 ndi E1, E2 ndi C electrodes anapezedwa ndipo mawonekedwe a XRD a diffraction angle 2 \ (\ theta \) akuwonetsedwa mu Chithunzi 5. Nsonga za austenite (\ (\ gamma \) ) ndi magawo a ferrite (\ (\ alpha\)) adazindikiritsidwa pamakona a diffraction a 43 ° ndi 44 °, akutsimikizira kuti kupangidwa kwa weld ndi magawo awiri a 65 zitsulo zosapanga dzimbiri.kuti DSS BM imasonyeza magawo austenitic okha (\(\ gamma\)) ndi ferritic (\(\ alpha\)), kutsimikizira zotsatira za microstructural zomwe zimaperekedwa mu Zithunzi 1 ndi 2. 6c, 7c ndi 9c.Gawo la ferritic (\(\ alpha\)) lomwe limawonedwa ndi DSS BM ndi nsonga yayikulu mu weld to electrode C zikuwonetsa kukana kwake kwa dzimbiri, popeza gawoli likufuna kukulitsa kukana kwa chitsulo, monga Davison ndi Redmond66 ali nazo. inanena , kukhalapo kwa zinthu zokhazikika za ferrite, monga Cr ndi Mo, kumapangitsa kuti filimuyi ikhale yokhazikika m'malo okhala ndi kloridi.Gulu 5 likuwonetsa gawo la ferrite-austenitic mwa kuchuluka kwa metallography.Chiŵerengero cha gawo la voliyumu ya gawo la ferrite-austenitic m'magulu otsekemera a electrode C amapindula pafupifupi (≈1: 1).The otsika ferrite (\(\ alpha\)) gawo kapangidwe ka weldments ntchito E1 ndi E2 maelekitirodi mu voliyumu kagawo zotsatira (Table 5) zimasonyeza zotheka tilinazo ku malo dzimbiri, amene anatsimikiziridwa ndi electrochemical kusanthula.kutsimikiziridwa (mkuyu 10a, b)), popeza gawo la ferrite limapereka mphamvu zambiri komanso chitetezo ku chloride-induced stress corrosion cracking.Izi zimatsimikiziridwa ndi kuuma kochepa komwe kumawonedwa mu ma welds a electrode E1 ndi E2 mumkuyu.4a,b, zomwe zimayambitsidwa ndi gawo lochepa la ferrite muzitsulo zachitsulo (Table 5).Kukhalapo kwa austenitic osayenerera (\(\ gamma\)) ndi ferritic (\(\ alpha\)) magawo muzitsulo zowotcherera pogwiritsa ntchito maelekitirodi a E2 amasonyeza kusatetezeka kwenikweni kwachitsulo ku yunifolomu yowonongeka.M'malo mwake, mawonekedwe a XPA a magawo awiri azitsulo zolumikizana ndi ma elekitirodi a E1 ndi C, pamodzi ndi zotsatira za BM, nthawi zambiri akuwonetsa kukhalapo kwa zinthu zokhazikika za austenitic ndi ferritic, zomwe zimapangitsa kuti zinthuzo zikhale zothandiza pomanga ndi mafakitale a petrochemical. , chifukwa adatsutsa Jimenez et al.65;Davidson & Redmond66;Shamant ndi ena67.
Kuwala kwa ma micrograph a ma welded joints a ma elekitirodi a E1 okhala ndi ma weld geometries osiyanasiyana: (a) HAZ yowonetsa mzere wophatikizika, (b) HAZ yowonetsa mzere wophatikizika pakukula kwapamwamba, (c) BM ya gawo la ferritic-austenitic, (d) weld geometry , (e) Ikuwonetsa zone yosinthira pafupi, (f) HAZ ikuwonetsa gawo la ferritic-austenitic pakukula kwapamwamba, (g) Weld zone ikuwonetsa gawo la ferritic-austenitic gawo Tensile.
Kuwala kwa ma micrograph a E2 electrode welds pama weld geometries osiyanasiyana: (a) HAZ yowonetsa mzere wophatikizika, (b) HAZ yowonetsa mzere wophatikizika pakukula kwapamwamba, (c) BM ya gawo la ferritic-austenitic bulk, (d) weld geometry , (e) ) kuwonetsa zone yosinthira pafupi, (f) HAZ yowonetsa gawo la ferritic-austenitic pakukula kwapamwamba, (g) zone yowotcherera yomwe ikuwonetsa gawo la ferritic-austenitic.
Zithunzi 6a-c ndipo, mwachitsanzo, zikuwonetsa kapangidwe kazitsulo kazitsulo za DSS zowotcherera pogwiritsa ntchito ma elekitirodi a E1 pamitundu yosiyanasiyana yowotcherera (Chithunzi 6d), kuwonetsa komwe ma micrograph amawu adatengedwa pakukula kosiyanasiyana.Pa mkuyu.6a, b, f - madera osinthika a ma welded olowa, kuwonetsa gawo lofanana la ferrite-austenite.Zithunzi 7a-c ndi mwachitsanzo zikuwonetsanso OM ya olowa DSS wowotcherera pogwiritsa ntchito ma elekitirodi a E2 pamitundu yosiyanasiyana yowotcherera (Chithunzi 7d), kuyimira kusanthula kwa OM pazokulitsa zosiyanasiyana.Pa mkuyu.7a,b,f akuwonetsa zone yosinthira ya cholumikizira cholumikizira mu ferritic-austenitic equilibrium.OM muzowotcherera (WZ) akuwonetsedwa mkuyu.1 ndi fg.2. Welds kwa maelekitirodi E1 ndi E2 6g ndi 7g, motero.OM pa BM ikuwonetsedwa mu Zithunzi 1 ndi 2. Mu mkuyu.6c, e ndi 7c, e akuwonetsa nkhani ya ma welded olowa ndi ma elekitirodi E1 ndi E2, motsatana.Malo owala ndi gawo la austenite ndipo dera lakuda lakuda ndi gawo la ferrite.Phase equilibria mu gawo lokhudzidwa ndi kutentha (HAZ) pafupi ndi mzere wosakanikirana umasonyeza kupangidwa kwa Cr2N precipitates, monga momwe ziwonetsedwera mu SEM-BSE micrographs mu Fig.8a,b ndi kutsimikiziridwa mu mkuyu.9 ndi,b.Kukhalapo kwa Cr2N kumawonedwa mu gawo la ferrite la zitsanzo mu Fig.8a,b ndi kutsimikiziridwa ndi SEM-EMF mfundo kusanthula ndi EMF mzere zithunzi za welded mbali (mkuyu. 9a-b), ndi chifukwa cha kutentha kuwotcherera kutentha.Kuzungulira kumathandizira kuyambitsa kwa chromium ndi nayitrogeni, popeza kutentha kwambiri mu weld kumawonjezera kufalikira kwa nayitrogeni.Zotsatirazi zimathandizira maphunziro a Ramirez et al.68 ndi Herenyu et al.69 akuwonetsa kuti, mosasamala kanthu za kuchuluka kwa nayitrogeni, Cr2N nthawi zambiri imayikidwa pa njere za ferrite, malire a tirigu, ndi malire a α/\(\ gamma\), monga momwe adafotokozeranso. ofufuza ena.70.71.
(a) malo kusanthula SEM-EMF (1, 2 ndi 3) wa welded olowa ndi E2;
Mapangidwe apamwamba a zitsanzo zoyimilira ndi ma EMF awo ofanana akuwonetsedwa muzithunzi.10a-c.Pa mkuyu.Zithunzi 10a ndi 10b zikuwonetsa ma micrographs a SEM ndi mawonekedwe awo a EMF a zolumikizira zowotcherera pogwiritsa ntchito maelekitirodi E1 ndi E2 muzowotcherera, motsatana, komanso mkuyu.10c ikuwonetsa ma micrograph a SEM ndi mawonekedwe a EMF a OM okhala ndi austenite (\(\gamma\)) ndi ferrite (\(\alpha\)) magawo popanda mafunde aliwonse.Monga momwe zasonyezedwera mu EDS spectrum mu Fig. 10a, chiwerengero cha Cr (21.69 wt.%) ndi Mo (2.65 wt.%) poyerekeza ndi 6.25 wt.% Ni imapereka chidziwitso cha gawo lolingana la gawo la ferrite-austenitic.Mipangidwe yaying'ono yokhala ndi kuchepa kwakukulu kwa zomwe zili mu chromium (15.97 wt.%) ndi molybdenum (1.06 wt.%) poyerekeza ndi nickel wambiri (10.08 wt.%) mu microstructure ya welded joint electrode E2, yowonetsedwa mu chith.1. Yerekezerani.Chithunzi cha EMF10bMawonekedwe acicular okhala ndi mawonekedwe owoneka bwino a austenitic omwe amawonedwa mu WZ akuwonetsedwa mkuyu.10b imatsimikizira kutha kwa zinthu za feteleza (Cr ndi Mo) mu weld ndi mpweya wa chromium nitride (Cr2N) - gawo la austenitic.Kugawidwa kwa tinthu tamvula timadutsa malire a austenitic (\(\ gamma\)) ndi ferritic (\(\ alpha\))) magawo a DSS welded joints amatsimikizira mawu awa72,73,74.Izi zimabweretsanso kusachita bwino kwa dzimbiri, popeza Cr amaonedwa kuti ndiye chinthu chachikulu chopanga filimu yokhazikika yomwe imapangitsa kuti kutukuka kwa m'deralo kuwonongeke kwazitsulo59,75 monga momwe tawonetsera pa Chithunzi 10b.Zitha kuwoneka kuti BM mu SEM micrograph mu Fig. 10c imasonyeza kukonzanso kwambewu kwamphamvu monga zotsatira zake za EDS spectrum zimasonyeza Cr (23.32 wt%), Mo (3.33 wt%) ndi Ni (6.32 wt).%) katundu wabwino wamankhwala.%) ngati chinthu chofunikira chothandizira kuyang'ana mawonekedwe amtundu wa ferrite-austenitic gawo la DSS76.Zotsatira za kusanthula kwa mawonekedwe a EMF a ma welded olowa a elekitirodi ya E1 zimatsimikizira kugwiritsidwa ntchito kwake pomanga ndi malo owopsa pang'ono, popeza oyambitsa austenite ndi okhazikika a ferrite mu microstructure amatsatira muyezo wa DSS AISI 220541.72 wolumikizira mafupa, 77.
SEM micrographs of welded joints, kumene (a) elekitirodi E1 ya kuwotcherera zone ali EMF sipekitiramu, (b) elekitirodi E2 wa kuwotcherera zone ali EMF sipekitiramu, (c) OM ndi EMF sipekitiramu.
M'zochita, zawonedwa kuti ma welds a DSS amakhazikika munjira ya ferritic (F-mode), yokhala ndi ma nuclei austenite nucleating pansi pa kutentha kwa ferritic solvus, komwe kumadalira kwambiri chiŵerengero cha chromium kupita ku faifi tambala (Creq/Nieq) (> 1.95 imapanga mode F) Ofufuza ena awona zotsatira za chitsulo izi chifukwa cha mphamvu yamphamvu yofalikira ya Cr ndi Mo monga zinthu zopanga ferrite mu ferrite phase8078,79.N'zoonekeratu kuti DSS 2205 BM ili ndi kuchuluka kwa Cr ndi Mo (kusonyeza apamwamba Creq), koma ali ndi otsika Ni okhutira kuposa weld ndi E1, E2 ndi C maelekitirodi, amene amathandiza kuti apamwamba Creq / Nieq chiŵerengero.Izi zikuwonekeranso mu kafukufuku wamakono, monga momwe tawonetsera mu Table 4, pamene chiwerengero cha Creq / Nieq chinatsimikiziridwa kwa DSS 2205 BM pamwamba pa 1.95.Zitha kuwonedwa kuti ma welds okhala ndi ma elekitirodi E1, E2 ndi C amawumitsa mu austenitic-ferritic mode (AF mode), austenitic mode (A mode) ndi ferritic-austenitic mode, motero, chifukwa chazomwe zili pamwamba pamitundu yambiri (FA mode) .), monga momwe tawonetsera mu Table 4, zomwe zili mu Ni, Cr ndi Mo mu weld ndizochepa, zomwe zimasonyeza kuti chiwerengero cha Creq / Nieq ndi chochepa kuposa cha BM.Ferrite yoyamba mu ma electrode welds a E2 anali ndi vermicular ferrite morphology ndipo chiŵerengero chotsimikizika cha Creq/Nieq chinali 1.20 monga momwe tafotokozera mu Table 4.
Pa mkuyu.11a ikuwonetsa Open Circuit Potential (OCP) motsutsana ndi nthawi ya AISI DSS 2205 chitsulo kapangidwe mu 3.5% NaCl yankho.Zitha kuwoneka kuti mapindikidwe a ORP amasintha kupita kuzinthu zabwino kwambiri, zomwe zikuwonetsa kuwoneka kwa filimu yopanda kanthu pamwamba pa chitsulo chachitsulo, kutsika kwamphamvu kukuwonetsa dzimbiri, komanso kuthekera kosalekeza pakapita nthawi kukuwonetsa kupanga filimu yopanda nthawi., Pamwamba pa chitsanzocho ndi chokhazikika ndipo chili ndi Sticky 77. Mipiringidzo imasonyeza magawo oyesera pansi pa mikhalidwe yokhazikika ya zitsanzo zonse mu electrolyte yomwe ili ndi 3.5% NaCl yankho, kupatulapo chitsanzo 7 (weld joint ndi C-electrode), zomwe zikuwonetsa kusakhazikika pang'ono.Kusakhazikika kumeneku kungayerekezedwe ndi kukhalapo kwa ayoni a kloridi (Cl-) mu yankho, lomwe limatha kufulumizitsa kwambiri dzimbiri, potero kukulitsa kuchuluka kwa dzimbiri.Zowonera pakuwunika kwa OCP popanda kugwiritsa ntchito zidawonetsa kuti Cl momwemo ingakhudzire kukana ndi kukhazikika kwa thermodynamic kwa zitsanzo m'malo ankhanza.Ma et al.81 ndi Lotho et al.5 idatsimikizira zonena kuti Cl- imachita nawo gawo pakukulitsa kuwonongeka kwa makanema ongokhala pamagawo, zomwe zimapangitsa kuti avale.
Kusanthula kwa Electrochemical kwa zitsanzo zophunzira: (a) kusinthika kwa RSD kutengera nthawi ndi (b) potentiodynamic polarization ya zitsanzo mu 3.5% NaCl solution.
Pa mkuyu.11b ikupereka kusanthula koyerekeza kwa potentiodynamic polarization curves (PPC) ya welded joints of electrodes E1, E2 ndi C mothandizidwa ndi 3.5% NaCl solution.Zitsanzo za welded BM mu PPC ndi yankho la 3.5% la NaCl limasonyeza khalidwe losasamala.Gulu 5 likuwonetsa magawo a electrochemical kusanthula kwa zitsanzo zomwe zapezedwa kuchokera ku ma curve a PPC, monga Ecorr (kuthekera kwa corrosion) ndi Epit (pitting corrosion potential) ndi zopatuka zomwe zimayenderana nazo.Poyerekeza ndi zitsanzo zina No. ).The apamwamba passivating zimatha akale poyerekeza ndi yotsirizira ndi chifukwa muyezo wa microstructural zikuchokera zitsulo (austenitic ndi ferritic magawo) ndi ndende ya zinthu alloying.Chifukwa cha kukhalapo kwa magawo a ferrite ndi austenitic mu microstructure, Resendea et al.82 idathandizira kungokhala chete kwa DSS pama media aukali.Kuchepa kwa zitsanzo zowotcherera ndi ma elekitirodi a E1 ndi E2 kumatha kulumikizidwa ndi kuchepa kwa zinthu zazikuluzikulu zolumikizira, monga Cr ndi Mo, muzowotcherera (WZ), popeza zimakhazikika gawo la ferrite (Cr ndi Mo), chitani ngati passivators Aloyi mu austenitic gawo la zitsulo oxidized.Zotsatira za zinthu izi pakukana kwa pitting ndizokulirapo mu gawo la austenitic kuposa gawo la ferritic.Pachifukwa ichi, gawo la ferritic limadutsa mofulumira kuposa gawo la austenitic lomwe limagwirizanitsidwa ndi dera loyamba la passivation la polarization curve.Zinthu izi zimakhudza kwambiri kukana kwa DSS chifukwa cha kukana kwawo kwapamwamba mu gawo la austenitic poyerekeza ndi gawo la ferritic.Chifukwa chake, kufulumira kwa gawo la ferrite ndi 81% kuposa gawo la austenite.Ngakhale Cl- mu yankho ali amphamvu zoipa zotsatira passivating luso la chitsulo film83.Chifukwa chake, kukhazikika kwa filimu yocheperako yachitsanzo kudzachepetsedwa kwambiri84.Kuchokera ku Table.6 ikuwonetsanso kuti kuthekera kwa dzimbiri (Ecorr) kwa zolumikizira zowotcherera zokhala ndi ma elekitirodi a E1 ndizokhazikika pang'onopang'ono poyerekeza ndi zolumikizira zowotcherera zomwe zili ndi electrode ya E2.Izi zimatsimikiziridwa ndi kutsika kwa kuuma kwa ma welds pogwiritsa ntchito maelekitirodi E1 ndi E2 mumkuyu.4a,b, yomwe imachokera kuzinthu zochepa za ferrite (Table 5) ndi zochepa za chromium ndi molybdenum (Table 4) muzitsulo zopangidwa ndizitsulo.Titha kunena kuti kukana kwa dzimbiri m'malo ofananirako am'madzi kumawonjezeka ndi kuchepa kwa kuwotcherera kwapano ndikuchepa ndi Cr ndi Mo zotsika komanso zotsika za ferrite.Mawuwa akugwirizana ndi kafukufuku wa Salim et al.85 pa zotsatira za kuwotcherera magawo monga kuwotcherera panopa pa dzimbiri kukhulupirika kwa zitsulo welded.Pamene kloridi imalowa muzitsulo kudzera m'njira zosiyanasiyana monga kuyamwa kwa capillary ndi kufalikira, maenje (pitting corrosion) a mawonekedwe osagwirizana ndi kuya amapangidwa.Njirayi ndi yosiyana kwambiri ndi njira zapamwamba za pH zomwe magulu ozungulira (OH-) amangokopeka ndi zitsulo pamwamba pazitsulo, kukhazikika kwa filimu yokhazikika ndikupereka chitetezo chowonjezera pazitsulo zazitsulo25,86.Kukaniza bwino kwa dzimbiri kwa zitsanzo No. 1 ndi No. mlingo wa pitting dzimbiri makamaka alipo zitsulo, welded ndi njira DSS, mu austenitic-gawo dongosolo la zigawo.Chifukwa chake, kapangidwe kake ka aloyi kamakhala ndi gawo lalikulu pakuwonongeka kwa cholumikizira cholumikizira87,88.Kuphatikiza apo, zidawoneka kuti zitsanzo zowotcherera pogwiritsa ntchito ma elekitirodi a E1 ndi C mu kafukufukuyu zidawonetsa ma Ecorr otsika kuchokera pamapindi a PPC kuposa omwe amawotcherera pogwiritsa ntchito ma elekitirodi a E2 kuchokera ku ma curve a OCP (Table 5).Chifukwa chake, dera la anode limayamba pang'onopang'ono.Kusintha kumeneku kumachitika makamaka chifukwa cha kukhazikika kwapang'onopang'ono kwa gawo la passivation lomwe limapangidwa pamwamba pa sampuli ndi cathodic polarization yomwe imachitika kusanakhazikike kwathunthu kwa OCP89 kukwaniritsidwa.Pa mkuyu.12a ndi b akuwonetsa zithunzi za 3D optical profiler za zoyeserera zowonongeka pansi pamikhalidwe yosiyanasiyana yowotcherera.Tingaone kuti pitting dzimbiri kukula kwa zitsanzo ukuwonjezeka ndi m'munsi pitting dzimbiri kuthekera analengedwa ndi mkulu kuwotcherera panopa 110 A (mkuyu. 12b), poyerekeza pitting dzimbiri kukula anapezera welds ndi otsika kuwotcherera panopa chiŵerengero cha 90 A. (Mkuyu 12a).Izi zimatsimikizira kuti Mohammed90's amanena kuti slip bands amapangidwa pamwamba pa sampuli kuti awononge filimu yodutsa pamtunda powonetsa gawo lapansi ku 3.5% NaCl yankho kuti chloride iyambe kuukira, kuchititsa kuti zinthuzo zisungunuke.
Kusanthula kwa SEM-EDS mu Gulu 4 kukuwonetsa kuti mayendedwe a PREN a gawo lililonse la austenitic ndi apamwamba kuposa a ferrite mu ma welds onse ndi BM.Kuyambika kwa pitting pa mawonekedwe a ferrite / austenite kumafulumizitsa kuwonongedwa kwa zinthu zosanjikizana chifukwa cha inhomogeneity ndi tsankho la zinthu zomwe zikuchitika m'maderawa91.Mosiyana ndi gawo la austenitic, pomwe mtengo wopingasa wofanana (PRE) ndi wapamwamba, kuyambika kwa pitting mu gawo la ferritic ndi chifukwa cha mtengo wotsika wa PRE (Table 4).Gawo la austenite likuwoneka kuti lili ndi kuchuluka kwakukulu kwa austenite stabilizer (nitrogen solubility), yomwe imapereka kuchuluka kwa chinthu ichi ndipo, chifukwa chake, kukana kwambiri kwa pitting92.
Pa mkuyu.Chithunzi 13 chikuwonetsa mapindikidwe a kutentha kwa E1, E2, ndi C.Popeza kuti kachulukidwe kachulukidwe kameneka kamawonjezeka mpaka 100 µA/cm2 chifukwa cha kupindika pa mayeso a ASTM, zikuwonekeratu kuti @ 110A weld yokhala ndi E1 idawonetsa kutentha kocheperako kwa 27.5 ° C ndikutsatiridwa ndi E2 @ 90A soldering ikuwonetsa CPT ya 40. °C, ndipo ngati C@110A CPT yapamwamba kwambiri ndi 41°C.Zotsatira zomwe zawonedwa zimagwirizana bwino ndi zotsatira zomwe zawonedwa poyesa polarization.
Mawonekedwe amakanikidwe ndi machitidwe a dzimbiri a ma welds zitsulo zosapanga dzimbiri adafufuzidwa pogwiritsa ntchito ma elekitirodi atsopano a E1 ndi E2.Elekitirodi yamchere (E1) ndi electrode acidic (E2) yomwe imagwiritsidwa ntchito mu SMAW idakutidwa bwino ndi mawonekedwe a flux okhala ndi chiŵerengero cha 1.7 mm ndi ndondomeko ya alkaline ya 2.40 ndi 0.40, motsatira.Kukhazikika kwa kutentha kwa ma fluxes okonzedwa pogwiritsa ntchito TGA mu sing'anga ya inert kwawunikidwa.Kukhalapo kwa kuchuluka kwa TiO2 (%) mu masanjidwewo a flux kunapangitsa kuti ma elekitirodi azitikita ndi acidic flux (E2) achotseretu ma slag a ma elekitirodi okhala ndi acidic flux (E2).Ngakhale maelekitirodi awiri ophimbidwa (E1 ndi E2) ali ndi luso loyambira la arc.Kuwotcherera, makamaka kutentha, kuwotcherera panopa ndi liwiro, kumathandiza kwambiri kukwaniritsa gawo la austenite / ferrite gawo la ma welds a DSS 2205 ndi makina abwino kwambiri a weld.The mfundo welded ndi elekitirodi E1 anasonyeza kwambiri amakokedwa katundu (kumeta ubweya 0,2% YS = 497 MPa ndi UTS = 732 MPa), kutsimikizira kuti mfundo flux TACHIMATA maelekitirodi ndi mkulu Basicity index poyerekeza ndi asidi flux TACHIMATA maelekitirodi.Ma elekitirodi amawonetsa mawotchi abwinoko okhala ndi alkalinity yochepa.Ndizodziwikiratu kuti m'malo olumikizirana ma elekitirodi okhala ndi zokutira kwatsopano (E1 ndi E2) palibe kufananiza kwa gawo la ferrite-austenitic, lomwe linawululidwa pogwiritsa ntchito OES ndi SEM-EDS kusanthula kwa weld ndikuwerengedwa ndi gawo la voliyumu. weld.Metallography idatsimikizira kafukufuku wawo wa SEM.microstructures.Izi makamaka chifukwa cha kuchepa kwa zinthu za alloying monga Cr ndi Mo komanso kutulutsidwa kwa Cr2N panthawi yowotcherera, zomwe zimatsimikiziridwa ndi EDS line scanning.Izi zimathandizidwanso ndi kuuma kochepa komwe kumawonedwa mu ma welds okhala ndi ma elekitirodi a E1 ndi E2 chifukwa cha kuchepa kwawo kwa ferrite ndi ma alloying mu kapangidwe kachitsulo.Umboni wa Corrosion Potential (Ecorr) wa ma welds pogwiritsa ntchito elekitirodi ya E1 udawonetsa kuti sungathe kugonjetsedwa pang'ono ndi dzimbiri la yankho poyerekeza ndi ma welds omwe amagwiritsa ntchito electrode ya E2.Izi zimatsimikizira mphamvu ya maelekitirodi opangidwa kumene mu ma welds oyesedwa mu 3.5% NaCl chilengedwe popanda flux osakaniza aloyi zikuchokera.Titha kunena kuti kukana kwa dzimbiri m'malo ofananirako apanyanja kumawonjezeka ndi kuchepa kwa mawotchi apano.Choncho, mvula ya carbides ndi nitrides ndi kuchepa kwa dzimbiri kukana kwa welded mfundo E1 ndi E2 maelekitirodi anafotokozedwa ndi kuchuluka kuwotcherera panopa, zomwe zinachititsa kusalinganizika mulingo bwino gawo la mfundo zowotcherera ndi zitsulo zolinga ziwiri.
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