Qhov nyuaj ntawm kev xaiv cov khoom siv yog qhov tseeb paub tseeb tias cov khoom siv raug xaiv haum zoo tshaj plaws nrog daim ntawv thov. Qhov no suav nrog kev xav txog kev ua haujlwm ntawm kev ua haujlwm thiab ntws cov khoom tawm.
Tseem ceeb tshaj plaws txog kev ua haujlwm ntawm kev ua haujlwm yog kom paub txog qhov ntsuas siab thiab ntsuas kub thiab rau kev tshaj xov xwm ua haujlwm yog coj los xav txog qhov muaj xeb thiab erosive. Tsis tas li ntawd, nws yuav xav tau kev txiav txim siab txog kev ua cua sov thiab lub cev, kev ntxhov siab thiab teeb meem kev phom sij.
Feem ntau tus kws ua choj rau kev xaiv khoom yuav tsum paub txog ASME B16.34 cov cai kom ua. Cov qauv no, dhau los ntawm lwm cov kev kawm, yuav tsum npog cov qauv ntsuas qhov ntsuas lub ntsuas kub, qhov loj me, cov ntaub ntawv thiab lwm yam ntawm cov qauv valve, kev tsim khoom thiab kuaj. ASME code feem ntau lees txais thoob ntiaj teb (piv txwv li Asmeskas, Canada, Australia) tab sis muaj lwm cov qauv uas hais txog cov ntawv no thiab cov cai tsim thiab cov khoom xaiv. Piv txwv li, hauv Europe cov txheej txheem series EN 12516 npog cov khoom xaiv rau lub qhov qub.
Nco ntsoov kom muaj kev paub zoo nrog cov lej no ua ntej nkag mus rau hauv cov khoom siv xaiv rau lub qub, vim yog tias tsis tas yuav tsum ua (qee qhov yuav tsum tau ua) cov ntaub ntawv thov rau cov li qub hauv cov qauv no yog los ntawm kev ua neej tiag tiag thiab yog li kev sim thiab pov thawj kom tsim nyog rau qhov kev pabcuam tshwjxeeb hauv kev coj ua.
Hais lus dav dav thaum xav txog qhov ntsuas kub tsis txaus ntawm cov pab pawg sib txawv ntawm cov ntaub ntawv Cov Lus 1. yuav tsum tau siv cov khoom siv dav dav rau kev xaiv cov khoom siv.
Muaj qee kis muaj kev cuam tshuam yuav tsum tau xaiv qhov khoom ntawd. Qee qhov kev pabcuam cov haujlwm xav tau siv cov khoom sib txawv thiab cov hlau kom tiv thaiv cov khoom tshwj xeeb ntawm cov kua dej ntws tawm. Cov ntaub ntawv no muaj nqi ntau dua li cov khoom siv hlau, yog li kev lag luam kuj tseem yog qhov ua rau xaiv cov khoom siv.
Tab sis, feem ntau ntawm cov ntawv thov valve kov cov kua dej uas tsis yog corrosive ntawm qhov tsis yog siab ua haujlwm thiab kub kom xav tau yam khoom tsis zoo. Vim li no, cam khwb cia carbon hlau yog qhov feem ntau siv cov khoom siv lub cev valve thiab tuaj yeem muab kev pabcuam txaus siab ntawm ntau tus nqi qis dua li cov khoom siv txawv txav.
Qee qhov siv roj carbon cov khoom siv rau valve lub cev yog WC steel (Wrought Carbon), ASTM A216 / A216M thiab A105 yog cov forged version ntawm cov hlau no nrog qib WCA, WCB thiab WCC.
Ntawm peb cov qhab nia hlau WCB yog qib qib rau cov ntawv thov kev ntsuas kub tsis tu ncua rau nrum steel hlau. ASTM-A216 WCB yog qhov lees txais qhov twg kev kho xeb tsis yog qhov tseem ceeb rau qhov ntsuas kub ntawm -20 * F txog 800? F.
WCC tseem tseem siv dav hlau ua cov khoom siv rau valve lub cev hauv cov kev pabcuam nruab nrab xws li huab cua, noo lossis superheated chav, tsis muaj cov kua dej uas tsis yog corrosive thiab roj. WCC tsis siv tshaj li 800? F raws li cov theem carbon cov nplua nuj tej zaum yuav hloov mus rau graphite. Nws tuaj yeem siv tau yam tsis muaj kev kho cua sov tshwj tsis yog lub hauv paus loj tshaj 1-1 / 4 nti.
Muaj ntau cov khoom sib txawv siv sib nrug los ntawm cov pa roj carbon hlau rau lub cev valve, cia hais qee qhov feem ntau siv uas tau ua raws li ASME B16.34:
- Cam Khwb Cia Hlau (ASTM A126) hauv pheej yig, cov khoom siv dej tsis zoo siv rau lub cev valve tswj cov pa, dej, roj thiab cov kua dej tsis xeb. Nws yog siv rau qhov ntsuas kub tsis tshua siab thiab siab ntsuas qhov ntsuas.
- Nrum Chromium-Molybdenum Steel (ASTM A217 Qib C5)！ Yav dhau los nws tau hais qhia ntau rau cov ntawv thov uas xav tau cov khoom siv hlau chromium-molybdenum. Txawm li cas los xij, cov khoom siv no me ntsis nyuaj rau nrum thiab muaj kev nyiam tawg thaum welded. WC9 tau hloov pauv hloov C5 hauv ntau cov ntawv thov, tab sis C5 tseem siv tau rau hauv cov ntawv thov rov qab qhov twg nws cov ntsiab lus ntau dua chromium muaj qhov zoo dua rau kev tiv thaiv kev kub siab sulfidic corrosion.
- Nrum Chromium-Molybdenum Steel (ASTM A217 Qib WC9) muaj cov khoom zoo dua casting thiab vuam hlau. WC9 tau hloov pauv C5 nyob rau hauv feem ntau cov ntawv thov, tshwj xeeb tshaj yog nyob hauv chav rhaub thiab boiler pub dej kev pabcuam. Cov chromium thiab molybdenum muab qhov kev tiv thaiv kev tiv thaiv-kev ya thiab xeb, ua rau nws pab tau rau 1100? F. WC9 xav tau preheating ua ntej welding thiab kho cua sov tom qab vuam.
- Nrum Hom 304L Stainless Hlau (ASTM A351 Qib CF3) yog cov khoom siv zoo rau kev siv tshuaj lom neeg li qub. 304L yog cov khoom siv zoo tshaj plaws rau nitric acid thiab lwm yam kev siv tshuaj lom neeg. Kev tiv thaiv zoo corrosion yog khaws cia txawm tias nyob hauv qhov xwm txheej.
- Nrum Hom 316 Stainless Hlau (ASTM A351 Qib CF8M) mus raws li kev lag luam tus qauv stainless hlau lub cev cov khoom siv. Qhov sib ntxiv ntawm molybdenum muab Hom 316 ntau dua qhov ua rau corrosion, pitting, creep thiab oxidizing kua ntau dua piv rau 304. Nws muaj qhov kub siab tshaj plaws ntawm txhua yam khoom siv txheem: -425 ᵒ F rau 1500 ᵒ F. Cov hlau nplaum tau raug kho kom sov los muab ntau tshaj plaws corrosion tsis kam.
Ceev faj yeej ib txwm paub thiab tag nrho cov tau hais los saum toj no (ntsuas kub, siab thiab lwm yam) yuav tsum tau coj mus rau hauv tus account ua ntej lees tias xaiv cov ntaub ntawv rau kev thov tshwj xeeb.
