1. Lub tee tooj liab sawv cev rau lub ntsiab lus ntawm kev cuam tshuam tseem ceeb hauv cov kav dej. Dab tsi yog ob lub ntsiab hydrodynamic phenomena uas tshwm sim ntawm ceg txuas, thiab yuav ua li cas lawv cuam tshuam rau kev xaiv ntawm ib hom tee (xws li, extruded vs. forged) rau lub siab -siab system?
Kev taw qhia ntawm lub tee tsim ib tug complex kua dynamic ib puag ncig tus yam ntxwv los ntawm ob lub ntsiab phenomena:
Flow Impingement thiab Turbulence: Hauv cov dej ntws, cov kua dej nkag mus rau ntawm lub tee thiab sim ua kom 90-degree tig mus rau hauv ceg tau muaj kev hloov pauv loj hauv lub zog. Qhov no ua rau cov dej sib cais, tsim cov vortices, thiab khaus turbulence ntawm ceg inlet. Cov kua dej tseem ceeb "piles" rau ntawm phab ntsa sab nraud tawm tsam cov ceg ua ntej swirling rau hauv nws.
Kev poob siab thiab lub zog tsis muaj zog: Kev ntxhov siab thiab kev hloov pauv hauv kev coj ua ua rau muaj kev cuam tshuam loj hauv zos (lub taub hau poob). Qhov no yog lub zog poob ntawm qhov system uas yuav tsum tau kov yeej los ntawm lub twj tso kua mis, ua rau cov nqi ua haujlwm siab dua.
Kev cuam tshuam ntawm Tee Xaiv rau High-Pressure Systems:
Cov rog no tsim kev ntxhov siab rau ntawm phab ntsa tee. Yog li ntawd, rau siab -siab tshuab, kev ncaj ncees ntawm lub tee yog qhov tseem ceeb.
Extruded Tee: Qhov no yog tus qauv rau cov kav dej tooj liab. Nws yog tsim los ntawm cua sov ib feem ntawm lub raj tooj liab thiab siv ib tug tuag los thawb tawm ceg. Cov txiaj ntsig ntawm cov qoob loo hauv cheeb tsam crotch (qhov twg cov ceg ua tau raws li kev khiav) yog txuas ntxiv thiab wrought, muab lub zog zoo. Txawm li cas los xij, cov txheej txheem tuaj yeem ua rau phab ntsa ntawm cov ntsiab lus tseem ceeb tshaj plaws.
Forged Tee (los yog Wrought Fitting): Qhov no yog qhov kev xaiv zoo tshaj plaws rau siab -siab, siab- vibration, lossis kev pabcuam tseem ceeb. Nws yog tsim los ntawm forging ib tug khoom tooj liab billet rau hauv lub tee duab nyob rau hauv lub siab thiab kub. Cov txheej txheem no:
Refines the Grain Structure: Tsim kom muaj qhov sib xws, zoo -grained microstructure thoob plaws qhov haum.
Tshem Tawm Phab Ntsa Thinning: Ua kom zoo ib yam, teev cov phab ntsa tuab txawm tias nyob hauv qhov siab - kev ntxhov siab crotch.
Muab Cov Khoom Siv Hluav Taws Xob Muaj Zog: Cov qauv wrought muaj kev tiv thaiv zoo tshaj rau cov kev ntxhov siab los ntawm kev kub ntxhov thiab kev kub ntxhov.
Rau lub siab -lub zog siab, kev txhim kho cov qauv kev ntseeg siab thiab kev ntseeg tau ntawm lub forged lossis wrought tooj liab tee ua pov thawj tias nws siv dhau tus qauv extruded tee los txo cov kev pheej hmoo los ntawm hydrodynamic rog.
2. Nyob rau hauv ib tug potable dej system, ib tug tooj liab tee yuav tsum tau koom nrog kev ntseeg siab. Sib piv cov txheej txheem ntawm kev sib txuas (muab thiab tawv) thiab brazing, qhov sib txawv ntawm qhov sib txawv ntawm qhov sib koom ua ke lawv tsim yog dab tsi, thiab qhov sib txawv no txhais li cas rau qhov kev pabcuam kub ntawm cov kav dej sib dhos?
Qhov sib txawv tseem ceeb nyob rau hauv qhov kub ntawm cov txheej txheem thiab cov txiaj ntsig metallurgical daim ntawv cog lus, uas ncaj qha dictates qhov sib koom ua ke qhov kub thiab txias.
Soldering (Soft & Hard):
Cov txheej txheem kub: qis dua 450℃(840℃F). Mos solder (Tin-Lead/Silver) melts ntawm ~ 180-250℃; nyuaj solder (feem ntau Tin-Silver) melts ntawm ~ 220-450℃.
Microstructural Joint: Soldering vam khom ntawm capillary nkaus thiab nto adhesion / diffusion. Lub solder alloys ntub cov tooj liab nto thiab tsim ib txheej nyias intermetallic, tab sis nws tsis fuse nrog lub hauv paus hlau. Qhov sib koom ua ke yog ib qho khoom siv thiab nplaum nplaum.
Kev Pabcuam Kev Kub Ntxhov: Qhov kev pabcuam kub ntawm lub cev yuav tsum nyob qis dua qhov kub ntawm lub solder. Yog hais tias lub kaw lus dej los yog ambient kub puas tau ze los yog tshaj qhov point no, lub solder yuav soften thiab yaj, ua rau muaj kev puas tsuaj rau kev sib koom tes. Qhov no txwv cov txheej txheem soldered kom txo cov kev siv kub (feem ntau qis dua 150℃/ 300℃F rau hard solder).
Brazing:
Cov txheej txheem kub: Tshaj 450℃(840℃F), feem ntau yog siv BCuP lossis BAg series muab tub lim hlau uas yaj ntawm 600-900 degree.
Microstructural Joint: Brazing tsim ib daim ntawv cog lus metallurgical. Lub hauv paus hlau (tooj liab) tsis melted, tab sis cov molten muab tub lim hlau dissolves ib tug microscopic txheej ntawm tooj liab thiab diffuses rau hauv nws, tsim ib tug muaj zog, nruam alloy cheeb tsam ntawm lub interface.
Kev Pabcuam Kev Kub Ntxhov: Txij li cov hlau hauv paus teeb tsa lub zog ntawm kev sib koom ua ke thiab cov hlau muab tub lim muaj ntau dua melting point, ib qho kev sib koom ua ke tuaj yeem tiv taus qhov kev pabcuam kub ntau ze rau lub hauv paus tooj liab txwv. Lub zog sib koom ua ke feem ntau siab dua cov yeeb nkab tooj liab nws tus kheej. Qhov no ua rau brazing yuav tsum tau rau siab -kub dej, chav dej, los yog refrigerant kab.
3. Rau cov txheej txheem tshuaj yeeb dej caw tuav cov kua qaub me me, qhov kev tiv thaiv corrosion ntawm tooj liab tee yog ib qho kev txhawj xeeb. Dab tsi tshwj xeeb ntawm corrosion yog tee tshwj xeeb tshaj yog raug rau, thiab qhov kev xaiv hlau alloy (xws li, C12200 vs. C44300) thiab tom qab- txheej txheem ntxuav tu yuav txo qhov kev pheej hmoo no li cas?
Lub tee yog qhov cuam tshuam rau Crevice Corrosion.
Lub Mechanism: Qhov sib txawv me me, nruj ntawm lub tee lub khob haum thiab cov yeeb nkab ntxig yog qhov zoo tshaj plaws crevice. Stagnant kua daig nyob rau hauv qhov sib txawv no yuav depleted nyob rau hauv cov pa oxygen piv rau cov kua ntau. Qhov no tsim ib lub cell concentration qhov twg cov pa oxygen - thaj chaw nplua nuj (cov yeeb nkab ntog) dhau los ua cov cathode thiab cov pa oxygen- thaj chaw depleted (qhov crevice) dhau los ua cov anode. Cov tshuaj tiv thaiv anodic (hlau dissolution) yog concentrated nyob rau hauv lub crevice, ua rau kom ceev ceev, localized nres uas tuaj yeem nkag mus rau phab ntsa yam tsis muaj kev cuam tshuam rau lwm tus.
Mitigation Strategies:
Alloy xaiv:
C12200 (Phosphorus-Deoxidized Copper - DHP): Tus qauv rau cov dej feem ntau. Nws muaj qhov zoo dav dav corrosion tab sis tseem raug rau crevice corrosion nyob rau hauv ib puag ncig hnyav.
C44300 (Admiralty Brass - Arsenical): Rau cov dej ntxhib ntau dua, qhov no yog qhov kev xaiv zoo dua. Qhov sib ntxiv ntawm arsenic inhibits dezincification, ib hom kev xaiv leaching hauv tooj dag. Txawm li cas los xij, rau cov kev daws teeb meem acidic, cov hlau tiv taus ntau dua li C70600 (90-10 Copper-Nickel) yuav tsim nyog, vim nws tsim tau ntau qhov ruaj khov thiab tiv thaiv zaj duab xis.
Ncej -Txoj Kev Ntxuav (Passivation): Qhov no yog ib kauj ruam tseem ceeb thiab feem ntau tsis pom zoo. Tom qab brazing los yog soldering, flux residues yog acidic heev thiab corrosive. Cov txheej txheem yuav tsum tau ua kom huv si huv si nrog cov tshuaj kub, me me alkaline (piv txwv li, dej qab zib tshauv) kom tshem tawm tag nrho cov acidic flux residues. Qhov no tiv thaiv qhov crevice los ntawm kev ua ntej - thauj khoom nrog tus neeg sawv cev corrosive txij li lub sijhawm ua haujlwm.
4. Nyob rau hauv lub siab - purity gas los yog tshuaj dej system, lub puab nto tiav ntawm ib tug tooj liab tee yog ib qho tseem ceeb. Qhov kev ntsuas tus qauv no yog dab tsi, thiab kev tsim khoom siv li cas (piv txwv li, mechanical polishing, electropolishing) yog siv los ua kom tiav qhov ua tau zoo tshaj plaws los tiv thaiv particle entrapment thiab kab mob loj hlob?
Tus qauv ntsuas rau sab hauv nto tiav yog Arithmetic Nruab Nrab Roughness, qhia raws li Ra tus nqi hauv micro-inch (µin) lossis micro-meters (µm).
Standard Drawn Tee: Tej zaum yuav muaj Ra ntawm 30-50 µin.
High-Purity Tee: Yuav tsum muaj Ra ntawm<20 µin, with the most critical systems demanding <10 µin.
Txoj kev tsim khoom rau Smoothest Bore: Electropolishing
Thaum lub tshuab polishing (siv cov xov xwm abrasive) tuaj yeem ua tiav qhov qis Ra, nws yog cov txheej txheem smearing thiab impingement uas tuaj yeem tawm hauv cov khoom sib xyaw thiab tsim "khiav" uas zoo tshaj plaws rau kev cuam tshuam cov kab mob.
Electropolishing: Qhov no yog cov txheej txheem electrochemical uas zoo tshaj rau kev siv siab -purity.
Txheej txheem: Cov tooj liab tee yog ua cov anode nyob rau hauv ib tug electrochemical cell. Kev tswj kev sib cais tshwm sim, nyiam tshem cov khoom ntawm cov ntsiab lus siab (peaks) ntawm qhov profile nto.
Qhov tshwm sim: Qhov no theem ntawm cov microscopic ncov thiab hav, uas ua rau ib tug du, daim iav -zoo li tag uas yog isotropic (nruj nyob rau hauv tag nrho cov lus qhia) thiab deburred. Qhov no ultra- du nto txo qis cov ntsiab lus adhesion rau cov khoom thiab ua rau nws nyuaj rau cov kab mob txuas thiab tsim cov biofilms, uas yog ib qho kev txhawj xeeb tseem ceeb hauv kev siv tshuaj thiab semiconductor systems.
5. Thaum lub tee tooj liab tau muab tso rau hauv lub raj xa dej uas muaj kev cuam tshuam loj heev (piv txwv li, lub hnub ci thermal lossis lub voj voog rov qab los), dab tsi yog qhov tseem ceeb ntawm kev sib koom ua ke, thiab ob qho kev tsim qauv zoo li cas - ib lub cev thiab ib txheej txheem - yog qhov tseem ceeb los tiv thaiv nws?
Lub ntsiab tsis ua hauj lwm mechanism yog Thermal Fatigue ntawm lub brazed los yog soldered sib koom.
Qhov rov nthuav dav thiab kev cog lus ntawm cov yeeb nkab tooj liab thaum nws sov thiab txias ua rau lub voj voog khoov thiab shear kev ntxhov siab rau ntawm qhov sib koom ua ke ntawm tee. Nyob rau tib lub sijhawm, qhov no tuaj yeem ua rau tawg pib thiab nthuav tawm los ntawm cov hlau muab tub lim, ua rau muaj dej ntws.
Qhov tseem ceeb tsim nta los tiv thaiv kev ua tsis tiav:
Lub cev tsim Feature: Kev txhawb nqa yeeb nkab thiab kev taw qhia
Lub cev tseem ceeb tshaj plaws yog kev siv cov yeeb nkab qhia thiab kev txhawb nqa los tswj cov thermal expansion, tsis yog nyob ze ntawm lub tee, tab sis thoob plaws hauv lub cev.
Cov ntsiab lus thauj tog rau nkoj: Kho cov yeeb nkab ntawm qhov chaw tshwj xeeb los tswj cov kev taw qhia ntawm kev nthuav dav.
Cov Ntsiab Lus Qhia: Tso cai rau cov yeeb nkab kom txav mus rau axially ( zawv zawg los ntawm cov lus qhia) tab sis tiv thaiv kev txav mus los. Qhov no ua kom qhov kev loj hlob ntawm thermal yog qhia kom deb ntawm fittings thiab mus rau hauv expansion loops los yog offsets.
Kev them nyiaj yug ze Tees: Muab kev txhawb nqa ze rau lub tee tiv thaiv qhov hnyav ntawm cov yeeb nkab los ntawm kev ntxiv lub sijhawm khoov mus rau qhov sib koom ua ke, uas yuav ua rau muaj kev ntxhov siab ntau dua.
Cov txheej txheem tsim qauv: Ib qho Kev Tsim Nyog Tsim Nyog Kev nthuav dav lossis Offset
Koj tsis tuaj yeem nres thermal expansion; koj yuav tsum tswj nws. Ib txoj hauv kev uas yuav tsum tau ua thaum lub sijhawm tsim qauv yog suav nrog kev nthuav dav loops, offsets, lossis U- khoov. Cov yam ntxwv no yog txhob txwm hloov pauv ntawm cov yeeb nkab uas nqus cov thermal txav los ntawm kev khoov elastically, yog li cais cov pob qij txha, cov pob qij txha ntawm cov tees thiab lwm yam fittings los ntawm kev ntxhov siab. Lub kaw lus yuav tsum tau tsim kho kom suav cov nyiaj tau los ntawm qhov xav tau nthuav dav thiab suav nrog cov voj voog ntawm qhov loj txaus kom haum nws yam tsis muaj kev cuam tshuam cov khoom.
