Ukuwelda iityhubhu zentsimbi engagqwaliyo kunye neepayipi kudla ngokufuna ukucoca i-back-purging nge-argon xa kusetyenziswa iinkqubo zemveli ezifana nokuwelda i-arc yegesi ye-tungsten (GTAW) kunye nokuwelda i-arc yesinyithi esikhuselweyo (SMAW). Kodwa ixabiso legesi kunye nexesha lokuseta inkqubo yokucoca linokubaluleka, ngakumbi njengoko ububanzi kunye nobude bepayipi busanda.
Xa behlanganisa intsimbi engagqwaliyo yochungechunge lwama-300, abakhi banokususa umva kwi-open root canal welds ngokutshintshela kwi-GTAW yendabuko okanye kwi-SMAW ukuya kwinkqubo yokudibanisa ephuculweyo, ngelixa besafumana umgangatho ophezulu we-weld, begcina ukumelana nokugqwala kwezinto, kwaye behlangabezana ne-Welding Procedure Specification (WPS) ifuna inkqubo yokudibanisa i-arc yegesi ye-arc yegesi emfutshane (GMAW). Inkqubo ye-GMAW emfutshane ephuculweyo ikwazisa neenzuzo ezongezelelweyo kwimveliso, ukusebenza kakuhle kunye nokulula kokusetyenziswa, okunceda ukuphucula inzuzo.
Isetyenziswa kakhulu ngenxa yokumelana nokugqwala kunye namandla ayo, ii-alloys zentsimbi engagqwali zisetyenziswa kwizicelo ezininzi zemibhobho kunye neetyhubhu, kubandakanya ioyile negesi, i-petrochemical, kunye ne-biofuels. Nangona i-GTAW ibisoloko isetyenziswa kwizicelo ezininzi zentsimbi engagqwali, ineengxaki ezithile ezinokulungiswa yi-GMAW ephuculiweyo ye-short-circuit.
Okokuqala, njengoko ukunqongophala kwabawelda abanobuchule kuqhubeka, ukufumana abasebenzi abaqhelene ne-GTAW ngumceli mngeni oqhubekayo. Okwesibini, i-GTAW ayisiyonkqubo yokuwelda ekhawulezayo, ethintela iinkampani ezifuna ukwandisa imveliso ukuze zihlangabezane neemfuno zabathengi. Okwesithathu, ifuna ukucoca i-backflushing yentsimbi engagqwaliyo ixesha elide kwaye kubiza kakhulu.
Yintoni i-blowback? I-Purge kukungenisa igesi ngexesha lenkqubo yokuwelda ukususa izinto ezingcolisayo nokubonelela ngenkxaso. I-purge engasemva ikhusela umva we-weld ekubeni wenze ii-oxide ezinzima xa kukho ioksijini.
Ukuba umva awukhuselekanga ngexesha lokuwelda kweengcambu ezivulekileyo, umonakalo kwisiseko unokubakho. Olu qhekeko lubizwa ngokuba yi-saccharification, olu gama libizwa ngokuba yi-saccharification kuba lubangela umphezulu ofana neswekile ngaphakathi kwi-weld. Ukuthintela ukuxutywa, umthungi ufaka ipayipi yegesi kwelinye icala lombhobho aze afake isiphelo sombhobho ngedama lokucoca. Bakwadala nomoya kwelinye icala lombhobho. Bahlala bebeka iteyipu ejikeleze umngxuma wombhobho. Emva kokucoca umbhobho, bakhupha icandelo leteyipu ejikeleze umngxuma baze baqalise ukuwelda, bephinda inkqubo yokuhluba nokuwelda de intsimbi yeengcambu igqitywe.
Susa i-blowback. Ukubuyisela izinto ezilahlekileyo kunokubiza ixesha elininzi kunye nemali, kwezinye iimeko kongeze amawaka eedola kwiprojekthi. Utshintsho kwinkqubo ye-GMAW ye-short-circuit ephuculweyo luye lwenza inkampani yakwazi ukugqiba ii-root pass ngaphandle kokusebenzisa i-backflushing kwii-applications ezininzi ze-stainless steels. I-applications ze-welding ze-300 series stainless steels zifanelekile koku, ngelixa i-applications ze-welding ze-high-purity duplex stainless steels okwangoku zifuna i-GTAW kwi-root pass.
Ukugcina igalelo lobushushu liphantsi kangangoko kunokwenzeka kunceda ukugcina ukumelana nokugqwala kwesixhobo somsebenzi. Ukunciphisa inani lee-weld passes yenye indlela yokunciphisa igalelo lobushushu. Iinkqubo ze-GMAW eziphuculweyo ze-short-circuit, ezifana ne-Regulated Metal Deposition (RMD®), zisebenzisa ukudluliselwa kwesinyithi okulawulwa ngokuchanekileyo ukubonelela nge-droplet deposition efanayo. Oku kwenza kube lula kumgcini we-weld ukulawula idama le-weld, elilawula igalelo lobushushu kunye nesantya se-welding. Igalelo lobushushu eliphantsi livumela idama le-weld ukuba liqine ngokukhawuleza.
Ngokudluliselwa kwesinyithi okulawulwayo kunye nokuqandisa ngokukhawuleza ichibi lokuwelda, ichibi lokuwelda alinazidubedube kangako kwaye igesi yokukhusela ishiya umpu we-GMAW ungaphazanyiswanga kangako. Oku kuvumela igesi yokukhusela ukuba idlule kwingcambu evulekileyo, isuse umoya kwaye ithintele ukungcoliswa okanye ukubola ngasemva kwe-weld. Olu gquma lwegesi luthatha ixesha elifutshane kuba amadama aqandisa ngokukhawuleza kakhulu.
Uvavanyo lubonise ukuba inkqubo ye-GMAW ye-short-circuit eguquliweyo ihlangabezana nemigangatho yomgangatho we-weld ngelixa igcina ukumelana nokugqwala kwentsimbi engagqwali njengaxa i-root bead yayidityaniswe ne-GTAW.
Utshintsho kwinkqubo yokuwelda lufuna inkampani ukuba iphinde iqinisekise i-WPS yayo, kodwa olo tshintsho lunokuvelisa imbuyekezo enkulu yexesha kunye nokonga iindleko zomsebenzi omtsha wokuvelisa nokulungisa.
Ukuwelda umjelo ovulekileyo kusetyenziswa inkqubo ye-GMAW ephuculiweyo ye-short-circuit kunika iingenelo ezongezelelweyo kwimveliso, ukusebenza kakuhle kunye noqeqesho lwabawelda. Ezi ziquka:
Isusa amathuba okuba kubekho imijelo eshushu ngenxa yokukwazi ukufaka isinyithi esingaphezulu ukuze kwandiswe ubukhulu bomjelo ongundoqo.
Ukunyamezelana okugqwesileyo kokungalungelelani okuphezulu nokuphantsi phakathi kwamacandelo emibhobho. Ngenxa yokudluliselwa kwesinyithi okugudileyo, le nkqubo inokuvala izikhewu ngokulula ukuya kuthi ga kwi-intshi ezi-3⁄16.
Ubude be-arc buhlala bufana nokuba i-electrode yolulwelo ingakanani na, nto leyo ehlawulela abaqhubi abasokola ukugcina ulwandiso oluhambelanayo. Idama le-weld elilawulwa lula kunye nokudluliselwa kwesinyithi okuhlala kufana kunokunciphisa ixesha loqeqesho lwabashicileli abatsha.
Nciphisa ixesha lokungasebenzi kweenkqubo zokutshintsha. Olu cingo kunye negesi yokukhusela ingasetyenziselwa iingcambu, ukuzalisa kunye neetshaneli zesiciko. Inkqubo ye-pulsed GMAW ingasetyenziswa ukuba itshaneli zizaliswe kwaye zigqunywe nge-80% yegesi yokukhusela i-argon.
Kwimisebenzi ejonge ukuphelisa i-backflush kwizicelo zentsimbi engagqwaliyo, kubalulekile ukulandela iingcebiso ezintlanu eziphambili zempumelelo xa utshintshela kwinkqubo ye-GMAW ye-short-circuit eguquliweyo.
Coca ingaphakathi nangaphandle kwemibhobho ukuze ususe naziphi na izinto ezingcolisayo. Sebenzisa ibrashi yentsimbi eyenzelwe intsimbi engagqwaliyo ukucoca umva wejoyinti ubuncinane i-intshi enye ukusuka emphethoni.
Sebenzisa isinyithi esingenasici esinomthamo ophezulu we-silicon, njenge-316LSi okanye i-308LSi. Umthamo ophezulu we-silicon unceda ukumanzisa ichibi lokuwelda kwaye usebenza njenge-deoxidizer.
Ukuze usebenze kakuhle, sebenzisa umxube wegesi yokukhusela eyenzelwe ngokukodwa le nkqubo, njenge-90% ye-helium, i-7.5% ye-argon, kunye ne-2.5% ye-carbon dioxide. Olunye ukhetho yi-98% ye-argon kunye ne-2% ye-carbon dioxide. Umthengisi wegesi yokuthunga unokuba nezinye iingcebiso.
Ukuze ufumane iziphumo ezilungileyo, sebenzisa incam enciphileyo kunye ne-nozzle yokuvula iingcambu ukuze ufumane indawo egqunywe yigesi. I-nozzle ekhonkrithi ene-gas diffuser eyakhelwe ngaphakathi inika indawo egqunywe kakuhle.
Qaphela ukuba ukusebenzisa inkqubo ye-GMAW ye-short-circuit eguquliweyo ngaphandle kwegesi exhasayo kuvelisa isikali esincinci ngasemva kwe-weld. Oku kudla ngokuqhekeka njengoko i-weld iphola kwaye ihlangabezana nemigangatho yomgangatho wepetroleum, i-power plant kunye ne-petrochemical applications.
UJim Byrne nguMphathi weeNtengiso kunye neeNkqubo zeMiller Electric Mfg. LLC, 1635 W. Spencer St., Appleton, WI 54912, 920-734-9821, www.millerwelds.com.
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