Valve sealing nto khoom valve vuam tsis xws luag yuav ua li cas nrog

Valve sealing nto khoom valve vuam tsis xws luag yuav ua li cas nrog

Valve sealing nto yog lub ntsej muag ua haujlwm tseem ceeb ntawm lub valve, sealing nto zoo yog cuam tshuam nrog kev pabcuam lub neej ntawm lub valve, feem ntau sealing cov khoom siv los xav txog kev tiv thaiv corrosion, abrasion kuj, yaig kuj, oxidation kuj thiab lwm yam. Feem ntau muab faib ua ob pawg: cov ntaub ntawv mos, cov ntaub ntawv nyuaj sealing.
Valve sealing nto yog lub ntsej muag ua haujlwm tseem ceeb ntawm lub valve, sealing nto zoo yog cuam tshuam nrog kev pabcuam lub neej ntawm lub valve, feem ntau sealing cov khoom siv los xav txog kev tiv thaiv corrosion, abrasion kuj, yaig kuj, oxidation kuj thiab lwm yam.
Feem ntau muaj ob pawg loj:
(1) Cov khoom siv mos
1, roj hmab (xws li roj hmab butadiene, fluorine roj hmab, thiab lwm yam)
2, yas (PTFE, nylon, thiab lwm yam)
(2) cov ntaub ntawv nyuaj sealing
1, tooj liab alloy (rau tsis tshua muaj siab valve)
2, chromium stainless hlau (rau zoo tib yam siab siab valve)
3, Sitai alloy (rau siab kub thiab siab siab li qub thiab muaj zog corrosion li qub)
4. Nickel puag alloy (rau corrosive media)
Valve sealing nto khoom xaiv rooj
Valve sealing nto khoom siv kub / ℃ hardness siv nruab nrab bronze valve sealing nto -273 ~ 232 dej, dej hiav txwv, cua, oxygen, saturated chav 316L valve sealing nto -268 ~ 31614HRC chav dej, dej, roj, roj, roj liquefied, thiab lwm yam corrosion me ntsis thiab tsis muaj yaig ntawm nruab nrab 17-4PH valve sealing nto -40 ~ 40040 ~ 45HRC nrog me ntsis corrosive tab sis corrosive media Cr13 valve sealing ntsej muag -101 ~ 40037 ~ 42HRC nrog me ntsis corrosive tab sis corrosive media Stalli alloy valve sealing lub ntsej muag -2 ~ 65040 ~ 45HRC (chaw kub)
38HRC (650 ° C) nrog corrosive thiab corrosive media Monel alloy KS valve sealing nto -240 ~ 48227 ~ 35HRC
30 ~ 38HRC alkali, ntsev, zaub mov, kua qaub tsis muaj cua, thiab lwm yam Hasloy CB valve sealing nto 371
5 3814 tzs
23HRC Corrosive mineral acid, sulfuric acid, phosphoric acid, ntub hydrochloric acid gas, chloric acid dawb tov, muaj zog oxidation nruab nrab No. 20 alloy valve sealing nto -45.6 ~ 316
-253 ~ 427 oxidizing nruab nrab thiab ntau yam ntawm sulfuric acid
Yuav ua li cas nrog valve welding defects
1, lub ntsiab lus ntawm lub
Ntawm lub siab li qub nyob rau hauv cov kav dej, cam khwb cia steel li qub yog nrov rau lawv cov nqi pheej yig thiab hloov tau yooj yim. Txawm li cas los xij, vim muaj qhov txwv ntawm qhov loj me, phab ntsa tuab, kev nyab xeeb, cov khoom siv raw thiab kev tsim kho, kev ua haujlwm tsis zoo xws li trachholes, pores, tawg, shrinkage porosity, shrinkage qhov thiab inclusions tuaj yeem tshwm sim, tshwj xeeb tshaj yog nyob rau hauv alloy steel castings nrog xuab zeb casting. Vim tias cov ntsiab lus alloying ntau dua hauv cov hlau, qhov ua rau cov kua dej tsis zoo, qhov tsis xws luag yuav tshwm sim ntau dua. Yog li ntawd, qhov tsis xws luag thiab kev tsim cov qauv tsim nyog, kev lag luam, kev tsim kho thiab txhim khu kev qha vuam txheej txheem kom ntseeg tau tias kev kho vuam valve ua tau raws li qhov yuav tsum tau ua tau dhau los ua ib qho kev txhawj xeeb ntawm kev ua haujlwm kub thiab txias. Daim ntawv no qhia txog kev kho vuam txoj kev thiab kev paub txog ntau yam tsis xws luag ntawm steel castings (lub electrode yog sawv cev los ntawm lub qub hom).
2. Kev kho mob tsis raug
2.1 Kev txiav txim tsis raug
Nyob rau hauv PRODUCTION PRACTICE, Qee qhov CASTING DEFECTS tsis raug tso cai los kho cov vuam, xws li nkag mus rau cov kab nrib pleb, nkag mus rau qhov tsis xws luag (hauv qab), honeycomb pores, tsis tuaj yeem xuab zeb thiab slag thiab shrinkage ntawm thaj tsam ntawm ntau tshaj 65 square centimeters, thiab. lwm yam tsis xws luag uas tsis tuaj yeem kho vuam tau pom zoo hauv daim ntawv cog lus. Hom kev puas tsuaj yuav tsum tau txiav txim siab ua ntej kho vuam.
2.2. Kev tshem tawm tsis raug
Hauv cov chaw ua haujlwm, carbon arc cua gouging tuaj yeem siv los tshem tawm qhov tsis xws luag, thiab tom qab ntawd tuav lub kaum sab xis tuaj yeem siv los txhuam cov khoom tsis zoo kom txog rau thaum cov hlau nplaum raug pom. Tab sis nyob rau hauv kev xyaum ntau lawm, qhov tsis xws luag raug tshem tawm ncaj qha los ntawm kev siv cov pa roj carbon steel electrode nrog siab tam sim no thiab cov hlau luster yog hauv av los ntawm lub kaum sab xis grinder. Feem ntau, qhov tsis xws luag tuaj yeem raug tshem tawm los ntawm 2.3. Preheat qhov tsis xws luag
Cov pa roj carbon steel thiab austenitic stainless hlau castings, qhov chaw ntawm qhov kho qhov vuam yog tsawg dua 65cm2, qhov tob yog tsawg dua 20% lossis 25mm ntawm thickness ntawm cov casting, feem ntau tsis tas yuav preheating. Txawm li cas los xij, ZG15Cr1Mo1V, ZGCr5Mo thiab lwm yam pearlitic steel castings yuav tsum tau preheated ntawm qhov kub ntawm 200 ~ 400 ℃ (kho vuam nrog stainless hlau electrode, qhov kub yog me me) thiab lub sij hawm tuav yuav tsum tsis pub tsawg tshaj 60min vim lub siab hardening nyiam. ntawm steel thiab yooj yim cracking ntawm txias vuam. Xws li casting tsis tuaj yeem ua kom sov tag nrho, muaj oxygen - acetylene nyob rau hauv qhov chaw tsis xws luag thiab nthuav 20 hli tom qab rhuab mus rau 300-350 ℃ (micro rov qab pom kev pom hauv qhov tsaus liab), loj txiav hluav taws xob nruab nrab nplaim taws ua ntej oscillating hauv qhov tsis xws luag thiab ib puag ncig yog ncig rau ob peb feeb, thiab tom qab ntawd maj mam txav mus rau 10 min (nyob ntawm qhov tuab ntawm qhov tsis xws luag), ua kom cov khoom puas tag nrho tom qab preheating, sau nrawm Vuam.
3.2. Kev kho hluav taws xob
Ua ntej kho vuam, yuav tsum xub xyuas seb lub electrode yog preheated, feem ntau cov electrode yuav tsum yog 150 ~ 250 ℃ ziab 1H. Lub preheated electrode yuav tsum tau muab tso rau hauv lub thawv rwb thaiv tsev, kom nws tuaj yeem siv tau raws li qhov xav tau. Cov electrode yog preheated 3 zaug dua. Yog tias cov txheej txheem ntawm cov electrode ntog tawm, tawg thiab xeb, nws yuav tsum tsis txhob siv.
3.3. Kho lub sijhawm vuam
Rau kev kaw cia, xws li lub plhaub valve seepage tom qab kev ntsuas siab, tib feem feem ntau raug tso cai kho ib zaug xwb, thiab tsis tuaj yeem kho dua, vim tias rov kho dua vuam yuav ua rau cov hlau nplej ntxhib, cuam tshuam rau cov khoom ntawm cov casting, tshwj tsis yog tias qhov casting tuaj yeem raug kho kom sov dua tom qab vuam. Kev kho vuam ntawm tib qhov tsis muaj qhov siab yuav tsum tsis pub tshaj 3 zaug. Carbon steel castings kho ntau tshaj ob zaug nyob rau hauv tib qhov chaw yuav tsum tau kho kom tshem tawm kev ntxhov siab tom qab vuam.
3.4. Kho qhov siab ntawm lub vuam txheej
Kev kho vuam qhov siab ntawm lub casting yog feem ntau txog 2 hli siab tshaj lub dav hlau casting, uas yog yooj yim rau machining. Kho vuam txheej yog tsawg dhau, yooj yim los qhia vuam caws pliav tom qab machining. Kho welding txheej yog siab dhau, siv sijhawm ntev thiab siv zog ua haujlwm
4, kho vuam tom qab kho
4.1. Tseem ceeb kho vuam
Nyob rau hauv ASTMA217 / A217M-2007, castings nrog to thaum lub sij hawm hydraulic xeem, castings nrog kho vuam cheeb tsam> 65cm2, castings nrog qhov tob> 20% ntawm casting phab ntsa thickness los yog 25 hli yog xam raws li ib tug tseem ceeb kho vuam. Nws tau pom zoo nyob rau hauv A217 STANDARD uas Stress tshem tawm los yog ua kom rov ua kom tiav yuav tsum tau nqa tawm, thiab xws li kev nyuaj siab tshem tawm los yog ua kom tiav REheating yuav tsum tau nqa tawm nyob rau hauv ib tug QUARTIFIED cov txheej txheem, WEB CERTIFICATION tseem ceeb kho welding. Raws li ASTMA352 / A352M2006, kev ntxhov siab los yog kev kho cua sov tom qab kho qhov vuam loj yog qhov yuav tsum tau ua. Nyob rau hauv kev lag luam suav suav tus qauv JB / T5263-2005 ntawm A217 / A217M, qhov tseem ceeb kho vuam yog txhais tau tias yog "kev puas tsuaj loj". Tab sis nyob rau hauv qhov tseeb, ntxiv rau lub casting dawb paug tuaj yeem ua tiav kev kho mob, ntau yam tsis xws luag feem ntau pom nyob rau hauv cov txheej txheem tiav, tsis tuaj yeem kho kom sov. Yog li ntawd, nyob rau hauv kev xyaum ntau lawm, nws yog feem ntau daws nyob rau hauv ib tug zoo txoj kev nyob rau hauv lub site los ntawm ib tug paub txog welder nrog ib tug siab hlab ntsha vuam daim ntawv pov thawj.
4.2. Tshem tawm kev ntxhov siab
Qhov tsis xws luag pom tom qab ua tiav kev kho vuam, tsis tuaj yeem ua tag nrho cov kev ntxhov siab tshem tawm kev kho cua sov, feem ntau tuaj yeem siv qhov tsis xws luag ntawm cov pa oxygen-acetylene nplaim taws hauv zos cua sov tempering txoj kev. Lub teeb loj loj yog siv los maj mam viav vias cov nplaim nruab nrab rov qab los, thiab cov casting yog rhuab kom txog thaum lub ntsej muag pom tsaus liab (li 740 ℃), thiab cov casting yog sov (2min / mm, tab sis tsis tsawg tshaj li 30min. ). Cov kev tsis xws luag yuav tsum tau them nrog asbestos panels tam sim ntawd tom qab kev kho kev ntxhov siab. Pearlitic steel valve txoj kab uas hla tsis xws luag, kho vuam yuav tsum tau sau nyob rau hauv txoj kab uas hla ntawm asbestos phaj, thiaj li hais tias lub qeeb txias. Qhov kev ua haujlwm no yog qhov yooj yim thiab kev lag luam, tab sis xav kom tus welder muaj qee qhov kev ua tau zoo.
Stainless hlau castings feem ntau tsis kho tom qab kho vuam, tab sis yuav tsum tau welded nyob rau hauv qhov chaw ventilated, thiaj li hais tias qhov kho welding cheeb tsam sai sai txias. Tshwj tsis yog nws tau qhia tias cov qauv austenitic tau hloov pauv tom qab kho vuam, lossis nws yog qhov tsis xws luag. Raws li daim ntawv cog lus thiab tej yam kev mob tso cai, cov khoom siv kho mob yuav tsum rov ua dua. Carbon STEEL CASTINGS nrog loj thiab tob qhov tsis xws luag thiab ntau yam pearLITE castings nyob rau hauv lub casting tu theem thiab nyob rau hauv ntxhib machining, tab sis nrog rau kev ua tiav, yuav tsum tau kho nrog kev ntxhov siab tshem tawm tom qab kho vuam. Cov pa roj carbon steel kev ntxhov siab tempering kub tuaj yeem teeb tsa li 600 ~ 650 ℃, ZG15Cr1Mo1V thiab ZGCr5Mo tempering kub tuaj yeem teem caij li 700 ~ 740 ℃, ZG35CrMo tempering kub yog teem li 500 ~ 550 ℃. Rau tag nrho cov hlau castings, lub tshav kub tuav lub sij hawm ntawm kev ntxhov siab-relieving tempering tsis tsawg tshaj li 120min, thiab cov castings raug tso tawm thaum lub qhov cub txias mus rau hauv qab 100 ℃.
4.3 Kev ntsuam xyuas tsis muaj kev puas tsuaj
Rau "qhov tsis xws luag" thiab "kev kho qhov loj" ntawm lub valve castings, ASTMA217A217M-2007 muab tias yog tias cov khoom tsim tau ua tau raws li cov kev cai ntawm S4 (Magnetic Particle Inspection) Cov kev xav tau ntxiv, kev kho vuam yuav tsum raug tshuaj xyuas los ntawm kev soj ntsuam cov khoom sib nqus ntawm tib yam. zoo tus qauv raws li qhov ntawm cov casting. Yog hais tias lub casting yog tsim nyob rau hauv raws li cov kev xav tau ntawm S5 (radiographic tshuaj ntsuam), tib txhaj tshuaj raws li kev soj ntsuam ntawm lub casting yuav tsum tau siv rau cov hydraulic test leakage ntawm lub casting, los yog rau kev kho welding ntawm tej casting nws qhov tob. Tshaj li 20% ntawm phab ntsa thickness los yog 1in1 (25mm) thiab rau kev kho welding ntawm tej casting uas nws qhov chaw yog kwv yees li ntau tshaj 10in2 (65cm2) Kab tshuaj xyuas yog nqa tawm. JB / T5263-2005 tus qauv qhia tias txoj kab hluav taws xob lossis kev tshuaj xyuas ultrasonic yuav tsum tau nqa tawm tom qab kho vuam ntawm qhov tsis xws luag hnyav. Ntawd yog, rau qhov tsis xws luag hnyav thiab qhov tseem ceeb kho vuam, yuav tsum muaj kev tshuaj xyuas tsis zoo, ua pov thawj tsim nyog ua ntej siv.
4.4. Kev ntsuas qib
Raws li rau qib ntawm kev tshuaj ntsuam xyuas qhov tsis zoo ntawm qhov chaw kho vuam, JB / T3595-2002 qhia tias lub valve zawj thiab kho vuam ib feem ntawm cam khwb cia hlau qhov chaw ntawm lub hwj chim chaw nres tsheb valve yuav tsum tau soj ntsuam raws li GB / T5677-1985, thiab qib yog tsim nyog. Valve taub qab vuam yuav tsum raug soj ntsuam raws li GB / T3323-1987, Qib 2 tsim nyog. JB/T644-2008 kuj tseem muab cov kev qhia meej txog kev muaj nyob ntawm ob qib sib txawv ntawm qhov tsis xws luag hauv castings tib lub sijhawm. Thaum muaj ob lossis ntau yam tsis xws luag nrog cov qib sib txawv hauv cheeb tsam kev ntsuam xyuas, qib qis tshaj yog suav tias yog qib kev ntsuam xyuas dav. Thaum muaj ob lossis ntau hom kev tsis xws luag nrog tib qib, qib kev qhia yuav raug txo los ntawm ib qib.
Rau slag suav nrog, tsis-fusion thiab tsis nkag mus ntawm qhov tsis xws luag hauv thaj chaw kho vuam, JB / T6440-2008 qhia tias cov slag suav nrog cov khoom tsis xws luag tuaj yeem soj ntsuam, thiab qhov porosity ntawm qhov tsis xws luag hauv thaj chaw kho vuam tuaj yeem suav tias yog qhov porosity. kev ntsuam xyuas ntawm casting defects.
Daim ntawv cog lus ntawm cov li qub nyob rau hauv cov kev ua haujlwm dav dav tsis kos npe rau qib ntawm lub valve castings, cia nyob ib leeg rau qib kev tsim nyog tom qab kho thiab vuam ntawm qhov tsis xws luag hauv daim ntawv cog lus, uas feem ntau coj ntau qhov tsis sib haum xeeb rau kev tsim khoom, tshuaj xyuas thiab muag khoom ntawm li qub. Raws li qhov ua tau zoo ntawm cov hlau castings hauv Suav teb thiab ntau xyoo ntawm kev paub, nws feem ntau ntseeg tias qib kev kho vuam cheeb tsam kev soj ntsuam yuav tsum tsis txhob qis dua qib 3 ntawm GB / T5677-1985, uas yog qib ⅲ ntawm ASMEE446b. txheem. Lub plhaub bearing qhov chaw ntawm cam khwb cia steel li qub thiab high-pressure cam khwb cia steel li qub nyob rau hauv acid-resistant pipeline tej yam kev mob yuav tsum feem ntau ua tau raws li ASMEE446b ⅱ los yog saum toj no cov qauv. Cov txiaj ntsig ntawm RADIOGRAPHIC EXAMINATION qhia tau tias nyob rau hauv qhov chaw tsis raug kho raws li tus qauv txheej txheem thiab cov lus qhia tshwj xeeb, qhov tsis xws luag tsim nyob rau hauv cov txheej txheem ntawm cladding yog tsawg dua thiab qib siab dua li qhov casting nws tus kheej. Hauv luv luv, kho vuam raws li ib feem ntawm cov txheej txheem tsim khoom yuav tsum tsis txhob maj maj.
4.5. Kev kuaj Hardness
Txawm hais tias qhov chaw kho vuam yog tsim nyog los ntawm kev tshuaj xyuas tsis muaj kev puas tsuaj, tab sis yog tias xav tau machining, qhov hardness ntawm qhov chaw kho vuam yuav tsum raug kuaj xyuas dua, uas kuj yog qhov kev tshuaj xyuas ntawm cov nyhuv ntawm kev tshem tawm kev ntxhov siab. Yog hais tias qhov kub thiab txias tsis txaus, los yog lub sij hawm tsis txaus, nws yuav ua rau lub vuam cheeb tsam ntawm fusion hlau lub zog siab, tsis zoo plasticity, machining vuam cheeb tsam yuav nyuaj heev, yooj yim ua rau lub cuab yeej tawg. Cov khoom ntawm lub hauv paus hlau thiab cov hlau molten tsis zoo ib yam, thiab nws yog ib qho yooj yim los ua kom muaj kev ntxhov siab hauv zos thiab pom tseeb ib txoj hauv kev kho vuam kev sib tshuam. Yog li ntawd, qhov chaw rewelded yuav tsum tau txheeb xyuas thiab kuaj nrog cov nqi hardness. Qhov chaw kho vuam tau maj mam hauv av nrog lub tes tuav, thiab peb lub ntsiab lus raug ntaus los ntawm lub tshuab nqa Brinell hardness tester. Tus nqi hardness ntawm qhov kho vuam cheeb tsam tau muab piv nrog tus nqi hardness ntawm cov cam khwb cia hlau nws tus kheej. Yog hais tias qhov hardness qhov tseem ceeb ntawm ob cheeb tsam zoo sib xws, nws qhia tau hais tias cov pa oxygen-acetylene tempering yeej ua tiav. Yog hais tias tus nqi hardness ntawm qhov kho vuam cheeb tsam yog ntau tshaj 20 hardness ntawm cov cam khwb cia hlau, nws raug nquahu kom rov ua dua kom txog thaum lub hardness yog ze rau lub hauv paus hlau. Lub hardness ntawm siab cam khwb cia hlau tom qab kev kho cua sov feem ntau yog tsim los ua 160 ~ 200HB. Tsawg dhau los yog siab dhau hardness tsis haum rau kev ua haujlwm machining. Lub hardness ntawm kev kho vuam cheeb tsam yog siab dhau lawm, uas yuav ua rau nws plasticity txo thiab txo qhov kev nyab xeeb ntawm lub valve plhaub bearing peev xwm.
5, xaus
Kev tshawb fawb kho vuam ntawm steel casting qhov tsis xws luag yog lub zog txuag remanufacturing engineering technology. Nrog rau kev pab ntawm cov kev sim niaj hnub no, kev nruam ntej thiab kev txhim kho yuav tsum tau ua hauv cov cuab yeej vuam, cov khoom siv vuam, cov neeg ua haujlwm thiab thev naus laus zis, kom paub txog kev sib koom ua ke ntawm kev tsim khoom thiab kev saib xyuas.