Q: Posachedwapa tayamba kugwira ntchito yomwe imafuna kuti zinthu zina zipangidwe makamaka kuchokera ku chitsulo chosapanga dzimbiri cha 304, chomwe chimalumikizidwa chokha komanso ku chitsulo chofewa. Takumana ndi mavuto ena okhudzana ndi kusweka kwa weld pakati pa chitsulo chosapanga dzimbiri ndi chitsulo chosapanga dzimbiri chofika mpaka 1.25″ makulidwe. Zanenedwa kuti tili ndi ferrite yochepa. Kodi mungalongosole kuti ndi chiyani komanso momwe mungakonzere?
A: Funso labwino limenelo. Inde, tingakuthandizeni kumvetsetsa tanthauzo la ferrite yochepa komanso momwe mungapewere.
Choyamba, tiyeni tiwone tanthauzo la chitsulo chosapanga dzimbiri (SS) ndi momwe ferrite imagwirizanirana ndi zolumikizira zolumikizidwa. Chitsulo chakuda ndi ma alloy ali ndi chitsulo choposa 50%. Izi zikuphatikizapo kaboni yonse ndi zitsulo zosapanga dzimbiri, komanso magulu ena. Aluminiyamu, mkuwa, ndi titaniyamu zilibe chitsulo, kotero ndi zitsanzo zabwino kwambiri za ma alloy osapanga dzimbiri.
Zigawo zazikulu za alloy iyi ndi chitsulo cha kaboni chokhala ndi chitsulo cha 90% ndi chitsulo chosapanga dzimbiri chokhala ndi chitsulo cha 70 mpaka 80%. Kuti chikhale mu gulu la SS, chiyenera kukhala ndi chromium ya 11.5% yowonjezeredwa. Kuchuluka kwa chromium pamwamba pa malire ochepera awa kumalimbikitsa kupangika kwa filimu ya chromium oxide pamwamba pa zitsulo ndikuletsa kupangika kwa okosijeni monga dzimbiri (iron oxide) kapena dzimbiri la mankhwala.
Chitsulo chosapanga dzimbiri chimagawidwa m'magulu atatu: austenitic, ferritic ndi martensitic. Dzina lawo limachokera ku kapangidwe ka kristalo kutentha kwa chipinda komwe amapangidwa. Gulu lina lodziwika bwino ndi chitsulo chosapanga dzimbiri, chomwe ndi mgwirizano pakati pa ferrite ndi austenite mu kapangidwe ka kristalo.
Magiredi a Austenitic, mndandanda wa 300, ali ndi 16% mpaka 30% ya chromium ndi 8% mpaka 40% ya nickel, zomwe zimapangitsa kuti kristalo ya austenitic ikhale yolimba kwambiri. Zinthu zokhazikika monga nickel, carbon, manganese, ndi nayitrogeni zimawonjezedwa panthawi yopanga zitsulo kuti zithandize kupanga chiŵerengero cha austenite-ferrite. Magiredi ena odziwika bwino ndi 304, 316 ndi 347. Amapereka kukana dzimbiri kwabwino; amagwiritsidwa ntchito makamaka m'mafakitale azakudya, mankhwala, mankhwala ndi cryogenic. Kuwongolera mapangidwe a ferrite kumapereka kulimba kwabwino kwambiri kutentha kochepa.
Ferritic SS ndi mtundu wa 400 series grade womwe uli ndi maginito okwanira, uli ndi 11.5% mpaka 30% ya chromium, ndipo uli ndi kapangidwe ka kristalo ka ferritic makamaka. Pofuna kulimbikitsa mapangidwe a ferrite, zokhazikika zimaphatikizapo chromium, silicon, molybdenum ndi niobium popanga chitsulo. Mitundu iyi ya SS imagwiritsidwa ntchito kwambiri mumakina otulutsa utsi wamagalimoto ndi ma powertrains ndipo imakhala ndi ntchito zochepa zotentha kwambiri. Mitundu ingapo yomwe imagwiritsidwa ntchito kwambiri: 405, 409, 430 ndi 446.
Magulu a Martensitic, omwe amatchedwanso mndandanda wa 400, monga 403, 410, ndi 440, ndi a maginito, ali ndi 11.5% mpaka 18% ya chromium, ndipo ali ndi kapangidwe ka kristalo wa martensitic. Kuphatikiza kumeneku kuli ndi golide wochepa kwambiri, zomwe zimapangitsa kuti zikhale zotsika mtengo kwambiri kupanga. Amapereka kukana dzimbiri, mphamvu yapamwamba, ndipo amagwiritsidwa ntchito kwambiri patebulo, zida zamano ndi opaleshoni, zida zophikira, ndi zida zina.
Mukalumikiza chitsulo chosapanga dzimbiri, mtundu wa chinthu chogwiritsidwa ntchito ndi momwe chimagwiritsidwira ntchito zidzasankha chitsulo choyenera chodzaza chomwe chingagwiritsidwe ntchito. Ngati mukugwiritsa ntchito njira yotetezera mpweya, mungafunike kusamala kwambiri ndi zosakaniza za mpweya woteteza kuti mupewe mavuto ena okhudzana ndi kuwotcherera.
Kuti musokeretse 304 yokha, mufunika electrode ya E308/308L. “L” imayimira carbon yochepa, yomwe imathandiza kupewa dzimbiri la pakati pa granular. Kuchuluka kwa kaboni m'ma electrode awa ndi kochepera 0.03%, ngati mtengo uwu wapitirira, chiopsezo cha carbon kuikidwa m'malire a tirigu ndi chromium bonding kuti apange chromium carbides chimawonjezeka, zomwe zimachepetsa bwino kukana dzimbiri kwa chitsulo. Izi zimaonekera bwino ngati dzimbiri litachitika m'dera lokhudzidwa ndi kutentha (HAZ) la welds zachitsulo chosapanga dzimbiri. Chinthu china chomwe chingaganizidwe pa chitsulo chosapanga dzimbiri cha grade L ndichakuti chimakhala ndi mphamvu zochepa zomangika pa kutentha kokwera kuposa chitsulo chosapanga dzimbiri chowongoka.
Popeza 304 ndi mtundu wa chitsulo chosapanga dzimbiri cha austenitic, chitsulo chofananacho chidzakhala ndi austenite yambiri. Komabe, electrode yokha idzakhala ndi ferrite stabilizer, monga molybdenum, kuti ilimbikitse kupanga ferrite mu chitsulo chosungunula. Opanga nthawi zambiri amalemba mndandanda wamba wa kuchuluka kwa ferrite pa chitsulo chosungunula. Monga tanenera kale, kaboni ndi chokhazikika cha austenitic champhamvu ndipo pazifukwa izi ndikofunikira kupewa kuwonjezera pa chitsulo chosungunula.
Manambala a Ferrite amachokera ku tchati cha Scheffler ndi tchati cha WRC-1992, omwe amagwiritsa ntchito ma formula ofanana ndi nickel ndi chromium kuti awerengere mtengo womwe ukajambulidwa pa tchati umapereka nambala yokhazikika. Nambala ya ferrite pakati pa 0 ndi 7 imafanana ndi kuchuluka kwa voliyumu ya kapangidwe ka ferritic crystal komwe kali mu chitsulo chosungunula, komabe, pamaperesenti apamwamba, nambala ya ferrite imawonjezeka mwachangu. Kumbukirani kuti ferrite mu SS si yofanana ndi ferrite ya carbon steel, koma gawo lotchedwa delta ferrite. Chitsulo chosapanga dzimbiri cha Austenitic sichimasintha magawo okhudzana ndi njira zotentha kwambiri monga kutentha.
Kupanga kwa ferrite ndikofunikira chifukwa ndi kofewa kwambiri kuposa austenite, koma kuyenera kulamulidwa. Kuchuluka kwa ferrite komwe kulibe kungapereke ma welds kukana dzimbiri bwino m'magwiritsidwe ena, koma nthawi zambiri amasweka kwambiri akamawotcherera. Pakugwiritsa ntchito konsekonse, chiwerengero cha ferrites chiyenera kukhala pakati pa 5 ndi 10, koma ntchito zina zingafunike mtengo wotsika kapena wapamwamba. Ferrites zitha kuwonedwa mosavuta kuntchito pogwiritsa ntchito chizindikiro cha ferrite.
Popeza mwanena kuti muli ndi vuto la ming'alu ndi ma ferrite ochepa, muyenera kuyang'anitsitsa chitsulo chanu chodzaza ndikuwonetsetsa kuti chikupanga ma ferrite okwanira - pafupifupi 8 ayenera kuchita bwino. Komanso, ngati mukugwiritsa ntchito flux-cored arc welding (FCAW), zitsulo zodzaza izi nthawi zambiri zimagwiritsa ntchito mpweya woteteza wa 100% carbon dioxide kapena chisakanizo cha 75% argon ndi 25% CO2, zomwe zingayambitse chitsulo chosungunula kuyamwa kaboni. Mutha kusintha njira yosungunula chitsulo chosungunula (GMAW) ndikugwiritsa ntchito 98% argon/2% oxygen mixture kuti muchepetse kuthekera kwa carbon deposits.
Polumikiza chitsulo chosapanga dzimbiri ku chitsulo cha kaboni, zinthu zodzaza E309L ziyenera kugwiritsidwa ntchito. Chitsulo chodzaza ichi chimagwiritsidwa ntchito makamaka polumikiza zitsulo zosiyanasiyana, kupanga kuchuluka kwa ferrite pambuyo poti chitsulo cha kaboni chasungunuka mu weld. Chifukwa chitsulo cha kaboni chimayamwa kaboni pang'ono, zokhazikika za ferrite zimawonjezedwa ku chitsulo chodzaza kuti zithetse vuto la kaboni popanga austenite. Izi zithandiza kupewa kusweka kwa kutentha panthawi yolumikiza.
Pomaliza, ngati mukufuna kukonza ming'alu yotentha mu ma weld achitsulo chosapanga dzimbiri cha austenitic, yang'anani ngati ferrite filler metal yokwanira ndikutsatira njira yabwino yowotcherera. Sungani kutentha kolowera pansi pa 50 kJ/in, sungani kutentha kwapakati mpaka kotsika pakati pa ma pass, ndikuwonetsetsa kuti malo olumikizirana ndi solder ndi oyera musanawotchetse. Gwiritsani ntchito gauge yoyenera kuti muwone kuchuluka kwa ferrite pa weld, cholinga chake ndi 5-10.
WELDER, yomwe kale inkatchedwa Practical Welding Today, ikuyimira anthu enieni omwe amapanga zinthu zomwe timagwiritsa ntchito komanso zomwe timagwira ntchito nazo tsiku lililonse. Magaziniyi yakhala ikutumikira anthu osokera ku North America kwa zaka zoposa 20.
Tsopano popeza muli ndi mwayi wopeza zonse zokhudza buku la digito la The FABRICATOR, mutha kupeza mosavuta zinthu zofunika kwambiri m'makampani.
Magazini ya digito ya The Tube & Pipe Journal tsopano ikupezeka mosavuta, zomwe zimapangitsa kuti zinthu zofunika kwambiri m'makampani zipezeke mosavuta.
Pezani mwayi wokwanira wa digito ku STAMPING Journal, yokhala ndi ukadaulo waposachedwa, njira zabwino kwambiri komanso nkhani zamakampani pamsika woponda zitsulo.
Tsopano popeza muli ndi mwayi wopeza zinthu zonse za digito ku The Fabricator en Español, mutha kupeza mosavuta zinthu zamtengo wapatali zamakampani.