Xaiv txoj cai muaj roj tsis yog ib qho teeb meem ntawm kev xaiv lub tog raj kheej; nws yog ib qho kev txiav txim siab tseem ceeb uas cuam tshuam rau qhov zoo, kev ua tau zoo, thiab kev nyab xeeb ntawm koj txoj kev vuam thiab txiav. Qhov tsim nyog shielding gas tiv thaiv lub molten weld pas dej ua ke los ntawm atmospheric paug, thaum txoj cai txiav gas kom huv si, meej txiav. Cov lus qhia dav dav no yuav coj koj los ntawm cov ntsiab lus tseem ceeb los txiav txim siab thaum xaiv cov pa roj carbon monoxide, xyuas kom koj ua tiav cov txiaj ntsig zoo rau koj cov ntawv thov tshwj xeeb.

Nkag siab txog Shielding Gases rau Vuam

Cov pa hluav taws xob tiv thaiv yog qhov tseem ceeb hauv cov txheej txheem xws li Gas Hlau Arc Vuam (GMAW / MIG) thiab Gas Tungsten Arc Vuam (GTAW / TIG). Lawv lub luag haujlwm tseem ceeb yog tshem tawm cov pa hauv huab cua - feem ntau cov pa oxygen thiab nitrogen - los ntawm thaj chaw weld. Yog tias cov pa cua nkag mus rau hauv lub pas dej molten weld, lawv tuaj yeem ua rau porosity (qhov hauv qhov vuam), brittleness, thiab tsis zoo weld tsos.

Qhov kev xaiv ntawm shielding gas ho cuam tshuam ntau yam tseem ceeb ntawm cov txheej txheem vuam:

• Arc Stability: Qee cov roj hluav taws xob txhawb nqa qhov du, ruaj khov arc, txo qhov tawg thiab ua rau cov txheej txheem tswj tau yooj yim dua.

• Weld Penetration: Cov roj muaj pes tsawg leeg cuam tshuam qhov kub npaum li cas nkag mus rau hauv lub hauv paus hlau, cuam tshuam lub zog ntawm kev sib koom tes.

• Weld Profile: Cov duab ntawm cov hlaws weld (piv txwv li, tiaj tus, convex, lossis concave) yog ib feem txiav txim siab los ntawm cov roj tiv thaiv.

• Mechanical Properties: Cov roj tuaj yeem cuam tshuam qhov kawg lub zog, ductility, thiab corrosion kuj ntawm cov hlau vuam.

• Spatter Level: Qee cov roj sib xyaw ua kom txo qis, txo cov sij hawm tom qab vuam.

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Common Industrial Gases siv hauv Vuam

Feem Ntau nquag siv industrial gases rau welding poob rau hauv ob peb pawg thawj, txhua qhov muab cov yam ntxwv sib txawv.

Argon (ar)

Argon yog lub luag haujlwm ntawm kev tiv thaiv roj. Nws yog ib qho roj inert, txhais tau tias nws tsis hnov ​​​​mob nrog cov hlau molten.

• Daim ntawv thov: Argon yog tus qauv xaiv rau GTAW (TIG) vuam ntawm cov hlau feem ntau, tshwj xeeb yog txhuas, magnesium, thiab titanium. Nws muab zoo arc stability thiab huv si zoo li.

• Yam ntxwv: Nws ua rau nqaim, tob tob profile. Vim tias nws hnyav dua li huab cua, nws muab kev tiv thaiv zoo tshaj lub pas dej ua ke, tshwj xeeb tshaj yog nyob rau hauv txoj haujlwm welding tiaj tus.

Helium (nws)

Helium yog lwm cov roj inert, tab sis nws coj txawv txawv ntawm argon.

• Daim ntawv thov: Nws yog feem ntau siv ua ke nrog argon rau vuam cov ntaub ntawv tuab lossis hlau nrog cov thermal conductivity, xws li txhuas thiab tooj liab.

• Yam ntxwv: Helium ua rau kub kub dua li argon, ua rau kom dav, nkag mus tob dua thiab nrawm dua mus. Txawm li cas los xij, nws yog qhov sib dua li huab cua, xav tau cov nqi ntws ntau dua kom muaj kev tiv thaiv txaus, thiab nws tuaj yeem ua rau arc pib nyuaj.

Cov pa roj carbon dioxide (CO2)

Tsis zoo li argon thiab helium, carbon dioxide yog cov roj reactive. Nyob rau hauv lub kub kub ntawm lub vuam arc, nws tawg mus rau hauv carbon monoxide thiab oxygen.

• Daim ntawv thov: CO2 yog dav siv rau GMAW (MIG) vuam ntawm cov hlau. Nws feem ntau yog qhov kev xaiv pheej yig tshaj plaws.

• Yam ntxwv: Nws muab kev nkag mus tob tab sis nyhav los tsim cov arc tsis tshua muaj zog thiab ua rau muaj kev sib tsoo ntau dua li cov pa roj ntsha tsis zoo lossis argon sib tov. Qhov tshwm sim weld profile feem ntau dav thiab me ntsis oxidized.

Cov pa oxygen (O2)

Oxygen yog reactive heev thiab yeej tsis siv los ua ib qho kev tiv thaiv roj ntawm nws tus kheej.

• Daim ntawv thov: Cov pa me me (feem ntau 1-5%) feem ntau ntxiv rau argon rau vuam cov pa roj carbon thiab cov hlau tsis tshua muaj hlau, thiab qee zaum stainless hlau.

• Yam ntxwv: Oxygen txhim kho arc stability, txo qhov nro ntawm cov hlau molten (tso cia nws ntws tawm ntau dua), thiab tuaj yeem txhim kho kev nkag mus rau hauv qee yam kev siv.

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Xaiv Gases rau cov txheej txheem vuam tshwj xeeb

Qhov kev xaiv roj zoo nyob ntawm qhov hnyav ntawm cov txheej txheem vuam thiab cov khoom siv hauv paus.

Gas Metal Arc Vuam (GMAW / MIG)

MIG welding cia siab ntau rau cov roj sib xyaw ua kom haum rau cov hlau tshwj xeeb.

• Carbon Steel:

  • 100% CO2: Qhov kev xaiv kim tshaj plaws, muab qhov tob tob tab sis siab dua spatter. Zoo rau cov ntaub ntawv tuab.

  • Argon / CO2 Mixtures (piv txwv li, 75% Ar / 25% CO2 lossis "C25"): Feem ntau xaiv rau kev fabrication. Lawv muab qhov sib npaug ntawm qhov zoo arc stability, qis qis dua li cov ntshiab CO2, thiab zoo heev weld hlaws zoo li. Tsawg qis CO2 feem pua ​​(piv txwv li, 5-15%) yog siv rau cov ntaub ntawv nyias lossis MIG vuam.

  • Argon / Oxygen Mixtures (piv txwv li, 95% Ar / 5% O2): Siv rau cov tshuaj tsuag hloov vuam ntawm cov hlau, ua kom cov dej sib sib zog nqus thiab sib sib zog nqus.

• Stainless hlau:

  • Argon / CO2 (piv txwv li, 98% Ar / 2% CO2): Ib qho kev xaiv, tab sis cov ntsiab lus CO2 yuav tsum tau khaws cia kom tsawg kom txo qis cov pa roj carbon monoxide, uas tuaj yeem txo qhov kev tiv thaiv corrosion.

  • Tri-Mixes (Argon / Helium / CO2): Feem ntau siv rau luv luv-circuit vuam ntawm nyias stainless hlau, muab cov yam ntxwv zoo arc thiab txo qis distortion.

• Aluminium:

  • 100% Argon: Tus qauv xaiv rau feem ntau MIG vuam ntawm txhuas mus txog li 1/2 nti tuab.

  • Argon / Helium Mixtures (piv txwv li, 50% Ar / 50% Nws lossis 25% Ar / 75% Nws): Siv rau thicker aluminium seem kom nce cua sov nkag thiab nkag mus.

Gas Tungsten Arc Welding (GTAW / TIG)

TIG welding feem ntau xav tau cov pa roj inert los tiv thaiv cov khoom siv tsis siv tungsten electrode thiab lub pas dej ua ke.

• Tag nrho cov hlau (tshwj tsis yog ntu tuab heev): 100% Argon yog qhov kev xaiv thoob ntiaj teb, muab qhov zoo tshaj plaws arc pib, ruaj khov, thiab ntxuav kev ua haujlwm (tshwj xeeb yog qhov tseem ceeb rau txhuas).

• Thick Aluminium los yog tooj liab: Argon / Helium sib tov (feem ntau 50/50 los yog 75/25 Helium / Argon) yog siv los ua kom cov arc voltage thiab cua sov input, tso cai rau kev nkag mus tob dua thiab ceev ceev mus los ntawm cov khoom siv hluav taws xob.

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Xaiv Gases rau cov txheej txheem txiav

Cov txheej txheem txiav yuav tsum muaj cov pa roj rau cov nplaim hluav taws, tshuab molten hlau, lossis ob qho tib si.

Oxy-Fuel Txiav

Cov txheej txheem no siv cov roj av sib xyaw nrog cov pa ntshiab huv los ua kom sov cov hlau rau nws qhov kub thiab txias, thiab tom qab ntawd cov kwj dej siab ntawm cov pa oxygen yog siv los ua kom oxidize sai (hlawv) thiab tshuab tawm cov hlau. Kev xaiv cov roj av cuam tshuam rau kev txiav ceev thiab zoo.

• Acetylene: Ua kom muaj qhov kub thiab txias siab tshaj plaws ntawm cov roj uas muaj roj, tso cai rau lub sij hawm preheat ceev tshaj plaws. Nws yog qhov zoo heev rau beveling thiab tho tab sis yuav tsum tau ua tib zoo tuav vim nws tsis ruaj khov ntawm kev kub ntxhov.

• Propane: Kev xaiv nyiaj txiag heev, dav siv rau kev txiav thiab cua sov. Nws muaj cov nplaim hluav taws kub qis dua li acetylene, ua rau lub sijhawm ua ntej me ntsis ntev dua, tab sis nws muaj kev nyab xeeb dua rau khaws thiab thauj.

• propylene: Muab cov nplaim taws kub ntawm propane thiab acetylene. Nws muab lub sij hawm preheat sai dua li propane thiab feem ntau nyiam rau cov ntawv txiav hnyav.

• Natural Gas: Feem ntau qhov kev xaiv zoo tshaj plaws yog tias xa ncaj qha mus rau hauv qhov chaw. Nws muaj cov nplaim hluav taws kub qis, ua rau nws zoo tshaj plaws rau cov ntaub ntawv thinner lossis cov ntawv thov uas lub sijhawm preheat tsis yog qhov tseem ceeb.

Plasma Arc Txiav

Plasma txiav siv lub dav hlau siab tshaj plaws ntawm cov roj ionized (plasma) kom yaj thiab txiav cov hlau.

• Cua (Compressed Cua): Qhov kev xaiv zoo tshaj plaws thiab pheej yig tshaj plaws rau kev txiav cov pa roj carbon steel, stainless hlau, thiab txhuas. Nws yuav tsum muaj huab cua huv, qhuav, thiab tsis muaj roj.

• Nitrogen: Feem ntau siv rau kev txiav cov hlau tsis muaj steel thiab txhuas, vim nws ua kom huv si nrog cov oxidation tsawg dua piv rau cov cua compressed. Nws kuj tau nquag siv los ua cov pa hluav taws xob thib ob (cov ntaub thaiv npog) hauv cov tshuab hluav taws xob dual.

• Oxygen: Muab cov txiav ceev tshaj plaws thiab cov npoo huv tshaj plaws ntawm cov hlau, tab sis nws tsis pom zoo rau stainless hlau lossis txhuas.

• Argon / Hydrogen Mixtures (piv txwv li, H35 - 65% Ar / 35% H2): Siv rau kev txiav tuab heev stainless hlau thiab txhuas. Cov hydrogen muab cov cua kub hloov pauv, ua rau kev txiav zoo heev thiab nrawm nrawm ntawm cov ntaub ntawv nyuaj.

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Gas Selection Summary Matrix

Txhawm rau ua kom yooj yim txoj kev xaiv, saib cov lus qhia ceev no:

Kev txiav txim siab zoo thiab Purity

Lub purity ntawm koj cov pa roj yog qhov tseem ceeb. Cov kab mob xws li ya raws, oxygen (nyob rau hauv daim ntawv thov roj inert), los yog hydrocarbons tuaj yeem degrade weld zoo, ua rau porosity, brittleness, thiab cov tsos tsis zoo.

• Vuam Qib Gases: Nco ntsoov xyuas kom koj siv cov pa hluav taws xob uas tau lees paub tias yog "qib vuam," uas feem ntau muaj qib purity siab (piv txwv li, 99.99% lossis siab dua rau argon).

• Lub tog raj kheej tuav: Kev khaws cia kom zoo thiab tuav lub tog raj kheej yog qhov tseem ceeb los tswj cov roj purity. Khaws cov li qub kaw thaum tsis siv thiab tsis txhob muab lub tog raj kheej tso rau qhov kub thiab txias.

• Delivery Systems: Xyuas kom koj cov regulators, hoses, thiab flowmeters huv si, tsis muaj paug, thiab tsim rau cov roj tshwj xeeb siv.

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Tag

Xaiv cov txoj cai industrial gas rau vuam thiab txiav yog qhov tseem ceeb hauv kev ua tiav cov txiaj ntsig zoo, ua tau zoo, thiab cov txiaj ntsig zoo. Los ntawm kev nkag siab txog cov yam ntxwv ntawm cov khoom siv tiv thaiv sib txawv thiab cov roj txiav, thiab sib piv rau koj cov txheej txheem tshwj xeeb thiab cov ntaub ntawv, koj tuaj yeem ua kom zoo dua koj cov haujlwm thiab ua kom muaj kev ncaj ncees ntawm koj txoj haujlwm. Tsis txhob yig mus sab laj nrog koj tus neeg muab khoom siv roj los yog cov khoom siv vuam tshuab rau cov lus pom zoo raws li koj qhov kev thov tshwj xeeb.