Kubatanidza machubhu esimbi isingatsvinda uye mapaipi kunowanzoda kusukwa kwemusana neargon kana uchishandisa nzira dzechinyakare dzakadai segas tungsten arc welding (GTAW) uye shielded metal arc welding (SMAW). Asi mutengo wegesi nenguva yekugadzirisa nzira yekuchenesa zvinogona kukosha, kunyanya sezvo dhayamita nemarefu emapaipi zvichiwedzera.
Pakusanganisa simbi isingatsvinda ye300 series, makambani anogona kubvisa blowback mu open root canal welds nekuchinja kubva kuGTAW yechinyakare kana SMAW kuenda ku welding yakagadziriswa, uku vachiri kuwana weld yepamusoro, kuchengetedza ngura yezvinhu, uye kusangana neWelding Procedure Specification (WPS) inoda short-circuit gas metal arc welding (GMAW). Maitiro ekuvandudzwa kwe short-circuit GMAW anounzawo mamwe mabhenefiti mukubudirira, kushanda zvakanaka uye nyore kushandisa, zvichibatsira kuvandudza purofiti.
Zvichifarirwa nekuda kwekudzivirira ngura uye simba radzo, simbi dzisina ngura dzinoshandiswa muzvinhu zvakawanda zvemapombi nemachubhu, kusanganisira mafuta negasi, petrochemical, uye biofuels. Kunyange zvazvo GTAW yagara ichishandiswa muzvinhu zvakawanda zvesimbi dzisina ngura, ine zvimwe zvakaipa zvinogona kugadziriswa nekuvandudzwa kwe short-circuit GMAW.
Chekutanga, sezvo kushomeka kwevanowedera vane hunyanzvi kuri kuramba kuchienderera mberi, kuwana vashandi vanoziva GTAW idambudziko riri kuenderera mberi. Chechipiri, GTAW haisiyo nzira yekukurumidza yekuwedera, iyo inotadzisa makambani ari kutsvaga kuwedzera kubereka kuti agutse zvinodiwa nevatengi. Chechitatu, inoda kudzoreredza machubhu esimbi isina ngura kunotora nguva uye kunodhura.
Chii chinonzi blowback? Purge kupinza gasi panguva yekunamira kuti ubvise tsvina uye utsigire. Kunamira kumashure kunodzivirira musana weld kuti usagadzire maokisijeni anorema kana paine oxygen.
Kana chikamu chekumashure chisina kudzivirirwa panguva yekusveta migero yemidzi yakavhurika, substrate inogona kukuvara. Kuputsika uku kunonzi saccharification, zita iri nekuti kunoita kuti pamusoro paite seshuga mukati mesveta. Kuti vadzivise kupwanya, welder anoisa hose yegesi mune rimwe divi repombi uye anovhara mugumo wepombi nedamu rekupukunyudza. Vanogadzirawo pombi yekubuda mweya kune rimwe divi repombi. Vanowanzoisa tepi yakatenderedza pombi. Mushure mekuchenesa pombi, vanobvisa chikamu chetepi yakatenderedza pombi ndokutanga kusveta, vachidzokorora maitiro ekusveta nekusveta kusvika tsinga yemidzi yapera.
Bvisa blowback. Kudzosera shure kunogona kutora nguva yakawanda nemari, dzimwe nguva zvichiwedzera zviuru zvemadhora kupurojekiti. Kuchinja kune nzira yekuchinja yeGMAW yakavandudzwa kwakaita kuti kambani ikwanise kupedzisa root passes pasina backflushing muzvishandiso zvakawanda zvesimbi isina ngura. Zvishandiso zvewelding zve300 series stainless steels zvakakodzera izvi, nepo zvishandiso zvewelding zvesimbi dzisina ngura dzakapfava kwazvo parizvino zvichida GTAW yeroot passes.
Kuchengetedza kupisa kwakaderera sezvinobvira kunobatsira kuchengetedza kuramba kwengura kwechinhu chebasa. Kuderedza huwandu hweweld passes inzira imwe yekuderedza kupisa kwacho. Maitiro eGMAW epfupi akavandudzwa, akadai seRegulated Metal Deposition (RMD®), anoshandisa simbi inodzorwa nemazvo kuti ipe madonhwe akafanana. Izvi zvinoita kuti zvive nyore kuti welder adzore weld puddle, iyo inodzora kupisa kwacho uye kumhanya kwewelding. Kupisa kwakaderera kunobvumira weld puddle kuti iome nekukurumidza.
Nekutamiswa kwesimbi kwakarongwa uye kuomeswa kwedziva re weld nekukurumidza, dziva re weld harina kuvhiringika zvakanyanya uye gasi rekudzivirira rinosiya pfuti yeGMAW isina kukanganiswa zvakanyanya. Izvi zvinobvumira gasi rekudzivirira kuti ripfuure nemumidzi yakavhurika, zvichibvisa mhepo uye kudzivirira kusachena kana oxidation kumashure kwe weld. Kufukidzwa kwegasi uku kunotora nguva pfupi chete nekuti madziva anoomeswa nekukurumidza.
Kuedzwa kwakaratidza kuti maitiro ekugadzirisa mapfupi eGMAW anosangana nezvinodiwa zvemhando ye weld ukuwo achiramba achidzivirira ngura yesimbi isingatsvedzereki sezvakaita apo root bead yakasungirirwa neGTAW.
Kuchinja kwemaitiro ekunamira kunoda kuti kambani igadzirise patsva WPS yayo, asi kuchinja kwakadaro kunogona kuunza purofiti yakawanda uye kuchengetedza mari yekugadzira nekugadzirisa zvinhu zvitsva.
Kubatanidza migero yemidzi uchishandisa nzira yepfupi yeGMAW inopa mamwe mabhenefiti mukubudirira, kushanda zvakanaka uye kudzidziswa kwekubatanidza migero. Izvi zvinosanganisira:
Inobvisa mukana wekuti pave nemachannel anopisa nekuda kwekukwanisa kuisa simbi yakawanda kuti iwedzere ukobvu hwemugero wemidzi.
Kushivirira kwakanaka kwazvo pakusarongeka kwakanyanya uye kushoma pakati pezvikamu zvepombi. Nekuda kwekutamiswa kwesimbi kwakapfava, maitiro acho anogona kuvhara zviri nyore mipata inosvika 3⁄16 inches.
Hurefu hwearc hunoenderana zvisinei nekuwedzerwa kweelectrode, izvo zvinotsiva vanoshanda vanonetseka kuchengetedza kuwedzerwa kwakafanana. Dziva reweld rinodzorwa zviri nyore uye kutamiswa kwesimbi kwakafanana zvinogona kuderedza nguva yekudzidzira kune vanowelder vatsva.
Deredza nguva yekusashanda kwemagetsi ekuchinja mashandiro. Waya imwecheteyo negasi rekudzivirira zvinogona kushandiswa pamidzi, kuzadza uye kuvhara nzira. Maitiro eGMAW anoputika anogona kushandiswa chero bedzi nzira dzacho dzazadzwa uye dzakavharwa ne80% argon shielding gas.
Kune mabasa ari kutsvaga kubvisa backflush mukushandiswa kwesimbi isingatsvi, zvakakosha kutevedzera mazano mashanu akakosha ekubudirira kana uchichinja kuenda kune yakagadziriswa nzira yeGMAW yepfupi.
Chenesa mukati nekunze kwemapaipi kubvisa chero tsvina. Shandisa bhurashi rewaya rakagadzirirwa simbi isingatsvi kuti uchenese kumashure kwejoini iri chinhambwe cheinenge 1 inch kubva kumucheto.
Shandisa simbi isina ngura ine silicon yakawanda, yakaita se316LSi kana 308LSi. Silicon yakawanda inobatsira kunyorovesa mvura mudziva re weld uye inoshanda se deoxidizer.
Kuti zvishande zvakanaka, shandisa musanganiswa wegasi rekudzivirira wakagadzirirwa basa iri, wakadai se90% helium, 7.5% argon, uye 2.5% carbon dioxide. Imwe sarudzo ndeye 98% argon uye 2% carbon dioxide. Mupi wegasi rekubatanidza anogona kunge aine mamwe mazano.
Kuti uwane mhedzisiro yakanaka, shandisa muromo wakatetepa nemuromo wemuromo kuti ubvise gasi rakawanda. Mumuromo wemuromo une gasi rakagadzirwa mukati unopa kufukidza kwakanaka.
Ziva kuti kushandisa nzira yeGMAW yakachinjwa isina gasi rinodzosera simba kunoita kuti pave nehukuru hushoma kumashure kweweld. Izvi zvinowanzo pera simba sezvo weld ichitonhora uye ichisangana nezvinodiwa zvemafuta, magetsi uye petrochemical applications.
Jim Byrne ndiye Maneja weKutengesa neKushandisa Mapurogiramu eMiller Electric Mfg. LLC, 1635 W. Spencer St., Appleton, WI 54912, 920-734-9821, www.millerwelds.com.
Tube & Pipe Journal yakava magazini yekutanga yakatsaurirwa kushandira indasitiri yemapombi esimbi muna 1990. Nhasi uno, ichiri magazini yega muNorth America yakatsaurirwa indasitiri iyi uye yave sosi yeruzivo rwakavimbika kune nyanzvi dzemapombi.
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