Izi zikumveka zabwino kwambiri kuti sizoona, ndiye vuto ndi chiyani? Kuwotcherera kumafunika kupanga pafupifupi chilichonse kuchokera pamitundu yopitilira 150 yazitsulo zosapanga dzimbiri. Kuwotcherera chitsulo chosapanga dzimbiri ndi ntchito yovuta. Zina mwa zinthuzi ndi monga kukhalapo kwa chromium oxide, momwe mungawongolere kutentha, njira yowotcherera yomwe mungagwiritse ntchito, momwe mungagwirire ndi chromium ya hexavalent ndi momwe mungachitire bwino.
Ngakhale kuli kovuta kuwotcherera ndi kumaliza nkhaniyi, zitsulo zosapanga dzimbiri zimakhalabe zotchuka ndipo nthawi zina njira yokhayo m'mafakitale ambiri. Kudziwa kugwiritsa ntchito moyenera komanso nthawi yogwiritsira ntchito kuwotcherera kulikonse ndikofunikira kuti kuwotcherera bwino. Izi zikhoza kukhala chinsinsi cha ntchito yabwino.
Nanga n’chifukwa chiyani kuwotcherera zitsulo zosapanga dzimbiri ndi ntchito yovuta chonchi? Yankho limayamba ndi mmene linalengedwera. Chitsulo chofatsa, chomwe chimadziwikanso kuti mild steel, chimasakanikirana ndi 10.5% chromium kuti apange chitsulo chosapanga dzimbiri. Chromium yowonjezeredwa imapanga chromium oxide pamwamba pa chitsulo, zomwe zimalepheretsa dzimbiri zamitundu yambiri ndi dzimbiri. Opanga amawonjezera kuchuluka kwa chromium ndi zinthu zina kuchitsulo kuti asinthe mtundu wa chinthu chomaliza, ndiyeno amagwiritsa ntchito njira ya manambala atatu kusiyanitsa magiredi.
Zitsulo zosapanga dzimbiri zomwe zimagwiritsidwa ntchito nthawi zambiri zimaphatikizapo 304 ndi 316. Zotsika mtengo kwambiri mwa izi ndi 304, zomwe zili ndi 18 peresenti ya chromium ndi 8 peresenti ya nickel ndipo zimagwiritsidwa ntchito m'chilichonse kuyambira pazitsulo zamagalimoto kupita ku zipangizo zakhitchini. 316 chitsulo chosapanga dzimbiri chili ndi chromium yocheperako (16%) ndi faifi tambala (10%), komanso ili ndi 2% molybdenum. Gululi limapereka zitsulo zosapanga dzimbiri 316 zowonjezera kukana kwa ma kloridi ndi ma klorini, zomwe zimapangitsa kukhala chisankho chabwino kwambiri pamadera am'madzi ndi mafakitale amankhwala ndi mankhwala.
Chosanjikiza cha chromium oxide chingatsimikizire mtundu wa chitsulo chosapanga dzimbiri, koma izi ndizomwe zimapangitsa kuti ma welder akhumudwe kwambiri. Chotchinga chothandizachi chimawonjezera kuthamanga kwachitsulo, kumachepetsa mapangidwe a dziwe lamadzimadzi. Cholakwika chofala ndikuwonjezera kutentha, chifukwa kutentha kwambiri kumawonjezera madzi amadzimadzi. Komabe, izi zingawononge zitsulo zosapanga dzimbiri. Kutentha kwambiri kungayambitse kuwonjezereka kwa okosijeni ndi kupindika kapena kuwotcha pazitsulo zoyambira. Kuphatikizidwa ndi zitsulo zamapepala zomwe zimagwiritsidwa ntchito m'mafakitale akuluakulu monga utsi wamagalimoto, izi zimakhala zofunika kwambiri.
Kutentha kumawononga kukana kwa dzimbiri kwa chitsulo chosapanga dzimbiri mwangwiro. Kutentha kwambiri kumagwiritsidwa ntchito pamene weld kapena malo ozungulira kutentha omwe akhudzidwa (HAZ) atembenukira. Chitsulo chosapanga dzimbiri chokhala ndi okosijeni chimapanga mitundu yodabwitsa kuyambira golide wotuwa mpaka buluu wakuda ndi wofiirira. Mitundu iyi imapanga chithunzi chabwino, koma imatha kuwonetsa ma weld omwe sangakwaniritse zofunikira zina zowotcherera. Zovuta kwambiri sizimakonda mtundu wa weld.
Anthu ambiri amavomereza kuti kuwotcherera kwa tungsten arc (GTAW) kotetezedwa ndi gasi ndikoyenera kwambiri pazitsulo zosapanga dzimbiri. M’mbiri yakale, zimenezi zakhala zowona m’lingaliro wamba. Izi zikadali zoona tikamayesa kubweretsa mitundu yolimba mtimayi muzoluka mwaluso kuti zikwaniritse miyezo yapamwamba kwambiri m'mafakitale monga mphamvu za nyukiliya ndi zakuthambo. Komabe, ukadaulo wamakono wowotcherera wa inverter wapangitsa kuti gas metal arc welding (GMAW) ikhale muyeso wopanga zitsulo zosapanga dzimbiri, osati makina ongopanga okha kapena ma robotic.
Popeza GMAW ndi njira yopangira mawaya a semi-automatic, imapereka chiwongola dzanja chambiri, chomwe chimathandizira kuchepetsa kutentha. Akatswiri ena amati ndi yosavuta kugwiritsa ntchito kuposa GTAW chifukwa amadalira zochepa pa luso la kuwotcherera ndi zambiri pa luso kuwotcherera gwero la mphamvu. Izi ndizovuta, koma magetsi amakono a GMAW amagwiritsa ntchito mizere yokonzedweratu. Mapulogalamuwa adapangidwa kuti akhazikitse magawo monga apano ndi magetsi, kutengera zitsulo zodzaza ndi wogwiritsa ntchito, makulidwe azinthu, mtundu wa gasi ndi mainchesi a waya.
Ma inverters ena amatha kusintha ma arc panthawi yonse yowotcherera kuti nthawi zonse apange arc yolondola, kuwongolera mipata pakati pa magawo, ndikusunga mayendedwe othamanga kwambiri kuti akwaniritse kupanga ndi miyezo yapamwamba. Izi ndi zoona makamaka pa kuwotcherera makina kapena robotic, komanso zimagwiranso ntchito kuwotcherera pamanja. Zida zina zamagetsi pamsika zimapereka mawonekedwe owonekera pazenera ndi zowongolera zowunikira kuti zikhazikike mosavuta.
Kuwotcherera chitsulo chosapanga dzimbiri ndi ntchito yovuta. Zina mwa zinthuzi ndi monga kukhalapo kwa chromium oxide, momwe mungawongolere kutentha, njira yowotcherera yomwe mungagwiritse ntchito, momwe mungagwirire ndi chromium ya hexavalent ndi momwe mungachitire bwino.
Kusankha gasi woyenera wa GTAW nthawi zambiri zimatengera zomwe wakumana nazo kapena kugwiritsa ntchito kuyesa kuwotcherera. GTAW, yomwe imadziwikanso kuti tungsten inert gas (TIG), nthawi zambiri imagwiritsa ntchito mpweya wa inert, nthawi zambiri argon, helium, kapena osakaniza onse awiri. Jekeseni wosayenera wa gasi wotchinga kapena kutentha kungapangitse kuti weld iliyonse ikhale yozungulira kwambiri kapena ngati chingwe, ndipo izi zidzalepheretsa kusakanikirana ndi zitsulo zozungulira, zomwe zimapangitsa kuti weld ikhale yosaoneka bwino kapena yosayenera. Kudziwa kusakaniza komwe kuli koyenera pa weld iliyonse kungatanthauze kuyesa ndi zolakwika zambiri. Mizere yopanga ya GMAW yogawana imathandizira kuchepetsa nthawi yotayika pamapulogalamu atsopano, koma pakafunika mtundu wovuta kwambiri, njira yowotcherera ya GTAW imakhalabe njira yomwe amakonda.
Kuwotcherera chitsulo chosapanga dzimbiri kumakhala kowopsa kwa omwe ali ndi nyali. Choopsa chachikulu chimabwera ndi utsi womwe umatulutsidwa panthawi yowotcherera. Chromium yotentha imapanga chinthu chotchedwa hexavalent chromium, chomwe chimadziwika kuti chimawononga kupuma, impso, chiwindi, khungu ndi maso komanso kuyambitsa khansa. Owotcherera ayenera nthawi zonse kuvala zida zodzitetezera, kuphatikiza chopumira, ndikuwonetsetsa kuti chipindacho chili ndi mpweya wabwino asanayambe kuwotcherera.
Mavuto ndi chitsulo chosapanga dzimbiri samatha pambuyo kuwotcherera kwatha. Chitsulo chosapanga dzimbiri chimafunanso chidwi chapadera pomaliza. Kugwiritsa ntchito burashi yachitsulo kapena padi yopukutira yokhala ndi chitsulo cha kaboni kungawononge wosanjikiza wa chromium oxide. Ngakhale kuwonongeka sikukuwoneka, zonyansazi zimatha kupangitsa kuti chomalizidwacho chikhale ndi dzimbiri kapena dzimbiri.
Terrence Norris ndi Senior Applications Engineer ku Fronius USA LLC, 6797 Fronius Drive, Portage, IN 46368, 219-734-5500, www.fronius.us.
Rhonda Zatezalo ndi wolemba pawokha pa Crearies Marketing Design LLC, 248-783-6085, www.crearies.com.
Ukadaulo wamakono wowotcherera wa inverter wapanga gasi GMAW kukhala muyezo wopanga zitsulo zosapanga dzimbiri, osati makina odziwikiratu kapena ma robotiki.
WELDER, yemwe kale ankatchedwa Practical Welding Today, amaimira anthu enieni omwe amapanga zinthu zomwe timagwiritsa ntchito ndikugwira nazo ntchito tsiku lililonse. Magaziniyi yakhala ikugwira ntchito yowotchera zinthu ku North America kwa zaka zoposa 20.
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