Kev casting ntawm lub cev valve yog ib feem tseem ceeb ntawm cov txheej txheem tsim valve, thiab qhov zoo ntawm qhov casting valve txiav txim siab qhov zoo ntawm lub valve. Cov hauv qab no qhia txog ntau txoj hauv kev casting uas feem ntau siv hauv kev lag luam valve:
Kev ua xuab zeb:
Cov xuab zeb casting feem ntau siv hauv kev lag luam valve tuaj yeem muab faib ua xuab zeb ntsuab, xuab zeb qhuav, xuab zeb dej iav thiab furan resin self-hardening xuab zeb raws li cov binders sib txawv.
(1) Xuab zeb ntsuab yog ib qho txheej txheem molding siv bentonite ua ib qho binder.
Nws cov yam ntxwv yog:Cov pwm xuab zeb tiav lawm tsis tas yuav qhuav lossis tawv, cov pwm xuab zeb muaj qee qhov zog ntub, thiab lub hauv paus xuab zeb thiab lub plhaub pwm muaj cov txiaj ntsig zoo, ua rau nws yooj yim los ntxuav thiab co cov castings tawm. Kev ua haujlwm ntawm cov pwm ntau lawm yog siab, lub voj voog ntau lawm luv luv, tus nqi khoom siv qis, thiab nws yooj yim rau kev npaj cov kab sib dhos.
Nws cov kev tsis zoo yog:cov castings feem ntau muaj qhov tsis zoo xws li cov qhov hws, cov xuab zeb, thiab cov xuab zeb lo rau, thiab qhov zoo ntawm cov castings, tshwj xeeb tshaj yog qhov zoo ntawm sab hauv, tsis zoo tagnrho.
Qhov sib piv thiab kev ua tau zoo ntawm cov xuab zeb ntsuab rau cov hlau castings:
(2) Xuab zeb qhuav yog ib txoj kev siv av nplaum ua ib qho khoom sib txuas. Ntxiv me ntsis bentonite tuaj yeem txhim kho nws lub zog ntub.
Nws cov yam ntxwv yog:Cov pwm xuab zeb yuav tsum tau ziab, muaj huab cua zoo permeability, tsis yooj yim rau qhov tsis zoo xws li ntxuav xuab zeb, xuab zeb lo, thiab pores, thiab qhov zoo ntawm qhov casting yog qhov zoo.
Nws cov kev tsis zoo yog:nws xav tau cov khoom siv ziab xuab zeb thiab lub voj voog tsim khoom ntev.
(3) Cov xuab zeb iav dej yog ib qho txheej txheem ua qauv siv cov iav dej ua ib qho khoom siv khi. Nws cov yam ntxwv yog: iav dej muaj lub luag haujlwm ntawm kev ua kom tawv thaum raug CO2, thiab tuaj yeem muaj ntau yam zoo ntawm txoj kev ua kom tawv roj rau kev ua qauv thiab kev ua lub hauv paus, tab sis Muaj qhov tsis zoo xws li kev tawg tsis zoo ntawm lub plhaub pwm, qhov nyuaj hauv kev ntxuav xuab zeb ntawm cov castings, thiab qis dua kev rov ua dua thiab rov ua dua ntawm cov xuab zeb qub.
Qhov sib piv thiab kev ua tau zoo ntawm cov dej iav CO2 hardening xuab zeb:
(4) Furan resin nws tus kheej hardening xuab zeb molding yog ib qho txheej txheem casting siv furan resin ua ib tug binder. Cov xuab zeb molding khov vim yog cov tshuaj lom neeg ntawm cov binder nyob rau hauv qhov kev ua ntawm tus neeg sawv cev curing ntawm chav tsev kub. Nws tus yam ntxwv yog tias cov xuab zeb pwm tsis tas yuav qhuav, uas ua rau lub voj voog ntau lawm luv dua thiab txuag hluav taws xob. Resin molding xuab zeb yog yooj yim rau compact thiab muaj cov khoom zoo disintegration. Cov xuab zeb molding ntawm castings yog yooj yim los ntxuav. Cov castings muaj qhov tseeb siab thiab qhov chaw zoo tiav, uas tuaj yeem txhim kho qhov zoo ntawm castings. Nws qhov tsis zoo yog: qhov zoo xav tau rau cov xuab zeb nyoos, me ntsis pungent tsw ntawm qhov chaw tsim khoom, thiab tus nqi siab ntawm resin.
Qhov sib piv thiab cov txheej txheem sib tov ntawm furan resin tsis muaj ci xuab zeb sib tov:
Cov txheej txheem sib tov ntawm furan resin self-hardening xuab zeb: Nws yog qhov zoo tshaj plaws los siv lub tshuab sib tov xuab zeb tas mus li los ua cov xuab zeb resin self-hardening. Cov xuab zeb nyoos, resin, tus neeg sawv cev kho, thiab lwm yam raug ntxiv ua ke thiab sib tov sai sai. Nws tuaj yeem sib tov thiab siv tau txhua lub sijhawm.
Qhov kev txiav txim ntawm kev ntxiv ntau yam khoom siv raw thaum sib tov cov xuab zeb resin yog raws li nram no:
Cov xuab zeb nyoos + tus neeg sawv cev kho (p-toluenesulfonic acid aqueous kua) - (120 ~ 180S) - resin + silane - (60 ~ 90S) - xuab zeb tsim tawm
(5) Cov txheej txheem tsim cov xuab zeb casting ib txwm muaj:
Kev ua kom raug:
Nyob rau hauv xyoo tas los no, cov chaw tsim khoom siv valve tau them ntau dua thiab ntau dua rau qhov zoo li cas thiab qhov tseeb ntawm cov castings. Vim tias qhov zoo li cas yog qhov yuav tsum tau ua ntawm kev ua lag luam, nws kuj yog qhov chaw ntsuas rau thawj kauj ruam ntawm kev ua haujlwm.
Cov khoom siv precision casting feem ntau siv hauv kev lag luam valve yog kev nqis peev casting, uas tau qhia luv luv raws li hauv qab no:
(1) Ob txoj kev ua cov txheej txheem ntawm kev casting kua:
①Siv cov khoom siv pwm uas muaj cov quav ciab kub tsawg (stearic acid + paraffin), txhaj tshuaj quav ciab siab tsawg, plhaub iav dej, tshem cov quav ciab kub, yaj thiab nchuav cov txheej txheem hauv huab cua, feem ntau yog siv rau cov hlau carbon thiab cov hlau tsis tshua muaj hlau nrog cov kev xav tau zoo dav dav, Qhov tseeb ntawm cov castings tuaj yeem ncav cuag tus qauv hauv tebchaws CT7 ~ 9.
② Siv cov khoom siv pwm ua los ntawm cov khoom siv pwm kub nruab nrab, kev txhaj tshuaj ciab siab, lub plhaub pwm silica sol, kev rho tawm cov pa dej, cov txheej txheem casting sai sai hauv huab cua lossis lub tshuab nqus tsev yaj, qhov tseeb ntawm cov castings tuaj yeem ncav cuag CT4-6 precision castings.
(2) Cov txheej txheem ib txwm ntawm kev nqis peev casting:
(3) Cov yam ntxwv ntawm kev nqis peev casting:
①Qhov casting muaj qhov tseeb siab, du nto thiab zoo nkauj.
② Nws muaj peev xwm ua tau cov khoom uas muaj cov qauv nyuaj thiab cov duab uas nyuaj rau ua nrog lwm cov txheej txheem.
③ Cov ntaub ntawv casting tsis txwv, ntau yam khoom siv alloy xws li: carbon hlau, stainless hlau, alloy hlau, aluminium alloy, high temperature alloy, thiab cov hlau muaj nqis, tshwj xeeb tshaj yog cov ntaub ntawv alloy uas nyuaj rau forge, weld thiab txiav.
④ Kev ywj pheej ntawm kev tsim khoom thiab kev hloov pauv tau zoo. Nws tuaj yeem tsim tau ntau yam, thiab kuj tsim nyog rau ib daim lossis ntau qhov kev tsim khoom me me.
⑤ Kev nqis peev casting kuj muaj qee qhov kev txwv, xws li: cov txheej txheem cumbersome thiab lub voj voog ntau lawm ntev. Vim yog cov txheej txheem casting txwv uas tuaj yeem siv tau, nws lub peev xwm siab-bearing tsis tuaj yeem siab heev thaum nws siv los casting siab-bearing nyias-plhaub valve castings.
Kev Tshawb Fawb Txog Cov Kev Tsis Zoo ntawm Casting
Txhua qhov kev casting yuav muaj qhov tsis zoo sab hauv, qhov muaj cov qhov tsis zoo no yuav coj kev phom sij loj rau qhov zoo sab hauv ntawm qhov casting, thiab kev kho vuam kom tshem tawm cov qhov tsis zoo no hauv cov txheej txheem ntau lawm kuj yuav coj lub nra hnyav rau cov txheej txheem ntau lawm. Hauv particular, cov li qub yog cov castings nyias-plhaub uas tiv taus siab thiab kub, thiab qhov compactness ntawm lawv cov qauv sab hauv yog qhov tseem ceeb heev. Yog li ntawd, qhov tsis zoo sab hauv ntawm castings ua qhov txiav txim siab cuam tshuam rau qhov zoo ntawm castings.
Cov qhov tsis zoo sab hauv ntawm cov khoom siv valve feem ntau suav nrog cov qhov hws, cov slag inclusions, shrinkage porosity thiab tawg.
(1) Qhov Hau:Cov qhov hws yog tsim los ntawm roj, qhov chaw ntawm cov qhov hws yog du, thiab lawv tau tsim sab hauv lossis ze ntawm qhov chaw ntawm qhov casting, thiab lawv cov duab feem ntau yog puag ncig lossis oblong.
Cov pa roj tseem ceeb uas tsim cov qhov hws yog:
① Cov nitrogen thiab hydrogen yaj hauv cov hlau muaj nyob hauv cov hlau thaum lub sijhawm ua kom khov ntawm qhov casting, tsim cov phab ntsa sab hauv kaw lossis oval nrog cov xim hlau ci.
② Cov dej noo lossis cov khoom tsis haum hauv cov khoom siv molding yuav hloov mus ua roj vim yog cua sov, tsim cov qhov hws nrog cov phab ntsa sab hauv xim av tsaus.
③ Thaum lub sijhawm nchuav cov hlau, vim yog qhov ntws tsis ruaj khov, huab cua koom nrog los tsim cov qhov hws.
Txoj kev tiv thaiv ntawm qhov tsis zoo ntawm stomatal:
① Hauv kev smelting, cov khoom siv hlau xeb yuav tsum siv tsawg li tsawg tau lossis tsis siv, thiab cov cuab yeej thiab cov tais diav yuav tsum tau ci thiab ziab.
② Kev nchuav cov hlau uas yaj yuav tsum tau ua thaum kub siab thiab nchuav thaum kub qis, thiab cov hlau uas yaj yuav tsum tau ua kom tsaug zog kom pab txhawb kev ntab ntawm cov roj.
③ Tus qauv tsim ntawm lub qhov nchuav yuav tsum ua kom lub taub hau siab ntawm cov hlau molten kom tsis txhob muaj roj nkag, thiab teeb tsa txoj kev roj dag rau cov pa tawm tsim nyog.
④Cov ntaub ntawv pwm yuav tsum tswj cov dej thiab cov roj ntim, ua kom cov huab cua permeability nce ntxiv, thiab cov pwm xuab zeb thiab cov xuab zeb core yuav tsum tau ci thiab ziab kom ntau li ntau tau.
(2) Qhov chaw ntsws (xoob):Nws yog ib qho sib xws lossis tsis sib xws puag ncig lossis tsis sib xws (qhov) uas tshwm sim sab hauv lub casting (tshwj xeeb tshaj yog ntawm qhov chaw kub), nrog rau qhov chaw sab hauv ntxhib thiab xim tsaus dua. Cov noob siv lead ua ntxhib, feem ntau yog nyob rau hauv daim ntawv ntawm dendrites, sib sau ua ke hauv ib lossis ntau qhov chaw, yooj yim xau thaum lub sijhawm kuaj hydraulic.
Qhov laj thawj rau qhov shrinkage cavity (looseness):Thaum cov hlau khov los ntawm kua mus rau khov. Yog tias tsis muaj cov hlau molten txaus rau lub sijhawm no, qhov shrinkage yuav tshwm sim. Qhov shrinkage ntawm cov hlau castings yog vim kev tswj tsis raug ntawm cov txheej txheem khov ua ntu zus. Cov laj thawj yuav suav nrog kev teeb tsa tsis raug, qhov kub siab dhau ntawm cov hlau molten, thiab cov hlau shrinkage loj.
Cov txheej txheem los tiv thaiv kom tsis txhob muaj qhov me me (qhov xoob):① Tsim cov txheej txheem nchuav ntawm cov hlau uas raug nchuav kom ua tiav cov hlau uas raug nchuav kom khov, thiab cov khoom uas khov ua ntej yuav tsum tau ntxiv cov hlau uas raug nchuav. ② Teeb tsa lub riser, kev pab nyiaj, hlau txias sab hauv thiab sab nraud kom raug thiab tsim nyog kom ntseeg tau tias cov hlau uas raug nchuav khov ua tiav. ③ Thaum cov hlau uas raug nchuav raug nchuav, kev txhaj tshuaj saum toj kawg nkaus los ntawm lub riser yog qhov zoo los xyuas kom meej tias qhov kub ntawm cov hlau uas raug nchuav thiab pub mis, thiab txo qhov tshwm sim ntawm cov qhov me me. ④ Hais txog qhov ceev ntawm kev nchuav, kev nchuav qis-ceev yog qhov zoo dua rau kev khov ua tiav dua li kev nchuav ceev. ⑸Qhov kub ntawm kev nchuav yuav tsum tsis txhob siab dhau. Cov hlau uas raug nchuav raug coj tawm ntawm lub cub tawg ntawm qhov kub siab thiab nchuav tom qab kev siv tshuaj loog, uas yog qhov zoo los txo cov qhov me me.
(3) Cov xuab zeb uas muaj nyob hauv (slag):Cov xuab zeb uas muaj cov pob zeb me me (slag), feem ntau hu ua cov pob zeb me me, yog cov qhov uas tsis sib txuas lossis tsis sib luag uas tshwm sim hauv cov castings. Cov qhov no sib xyaw nrog cov xuab zeb molding lossis cov hlau slag, nrog rau qhov loj tsis sib luag thiab sib sau ua ke hauv lawv. Ib lossis ntau qhov chaw, feem ntau ntau dua nyob rau sab saud.
Ua rau muaj xuab zeb (slag) suav nrog:Cov slag uas muaj nyob hauv yog tshwm sim los ntawm cov hlau slag uas sib cais nkag mus rau hauv qhov casting nrog rau cov hlau uas yaj thaum lub sijhawm smelting lossis pouring. Cov xuab zeb uas muaj nyob hauv yog tshwm sim los ntawm qhov tsis nruj ntawm lub pwm qhov thaum lub sijhawm molding. Thaum cov hlau uas yaj raug nchuav rau hauv lub pwm qhov, cov xuab zeb molding raug ntxuav los ntawm cov hlau uas yaj thiab nkag mus rau sab hauv ntawm qhov casting. Tsis tas li ntawd, kev ua haujlwm tsis raug thaum lub sijhawm trimming thiab kaw lub thawv, thiab qhov tshwm sim ntawm cov xuab zeb poob tawm kuj yog cov laj thawj rau cov xuab zeb uas muaj nyob hauv.
Cov txheej txheem los tiv thaiv cov xuab zeb (slag):① Thaum cov hlau uas yaj lawm raug yaj, cov pa tawm thiab cov slag yuav tsum tau tso tawm kom tag nrho li sai tau. ② Sim tsis txhob tig lub hnab ntim hlau uas yaj lawm, tab sis siv lub hnab tshuaj yej lossis lub hnab ntim hauv qab kom tiv thaiv cov slag saum cov hlau uas yaj lawm kom tsis txhob nkag mus rau hauv qhov chaw casting nrog rau cov hlau uas yaj lawm. ③ Thaum nchuav cov hlau uas yaj lawm, yuav tsum tau ua raws li cov kev ntsuas kom tiv thaiv cov slag kom tsis txhob nkag mus rau hauv qhov chaw pwm nrog rau cov hlau uas yaj lawm. ④ Txhawm rau kom txo qhov ua tau ntawm cov xuab zeb, xyuas kom meej tias cov xuab zeb pwm nruj thaum ua qauv, ceev faj kom tsis txhob poob xuab zeb thaum txiav, thiab tshuab lub qhov pwm kom huv si ua ntej kaw lub thawv.
(4) Cov kab nrib pleb:Feem ntau ntawm cov kab nrib pleb hauv cov castings yog cov kab nrib pleb kub, nrog cov duab tsis sib xws, nkag mus lossis tsis nkag mus, txuas ntxiv lossis tsis tu ncua, thiab cov hlau ntawm cov kab nrib pleb yog tsaus lossis muaj qhov oxidation ntawm qhov chaw.
vim li cas thiaj tawg, uas yog kev ntxhov siab kub thiab kua zaj duab xis deformation.
Kev ntxhov siab kub siab yog kev ntxhov siab uas tsim los ntawm kev ntsws thiab kev hloov pauv ntawm cov hlau molten ntawm qhov kub siab. Thaum qhov kev ntxhov siab tshaj qhov txwv ntawm lub zog lossis kev hloov pauv yas ntawm cov hlau ntawm qhov kub no, yuav muaj kab nrib pleb. Kev hloov pauv zaj duab xis kua yog kev tsim cov zaj duab xis kua ntawm cov noob siv lead ua thaum lub sijhawm khov thiab crystallization ntawm cov hlau molten. Nrog rau kev nce qib ntawm kev khov thiab crystallization, zaj duab xis kua raug hloov pauv. Thaum qhov ntau thiab tsawg ntawm kev hloov pauv thiab qhov ceev ntawm kev hloov pauv tshaj qhov txwv, cov kab nrib pleb raug tsim. Qhov kub ntawm cov kab nrib pleb thermal yog li 1200 ~ 1450 ℃.
Cov yam tseem ceeb uas cuam tshuam rau cov kab nrib pleb:
① S thiab P cov ntsiab lus hauv hlau yog cov yam tsis zoo rau kev tawg, thiab lawv cov eutectics nrog hlau txo qhov muaj zog thiab plasticity ntawm cov hlau cam khwb cia ntawm qhov kub siab, ua rau muaj kev tawg.
② Kev suav nrog thiab kev sib cais ntawm cov slag hauv cov hlau ua rau muaj kev ntxhov siab ntau ntxiv, yog li ua rau muaj kev tawg kub ntau ntxiv.
③ Qhov loj dua ntawm cov coefficient linear shrinkage ntawm hom hlau, qhov ntau dua qhov nyiam ntawm kev tawg kub.
④ Qhov ntau dua qhov thermal conductivity ntawm hom hlau, qhov ntau dua qhov nto nro, qhov zoo dua qhov kub siab mechanical zog, thiab qhov me dua qhov kub cracking.
⑤ Tus qauv tsim ntawm cov castings tsis zoo hauv kev tsim khoom, xws li cov ces kaum me me dhau, qhov sib txawv ntawm phab ntsa loj, thiab kev ntxhov siab heev, uas yuav ua rau tawg.
⑥Qhov compactness ntawm cov pwm xuab zeb siab dhau, thiab qhov tsis zoo ntawm cov tub ntxhais ua rau qhov shrinkage ntawm qhov casting thiab ua rau muaj kev tawg.
⑦Lwm yam, xws li kev teeb tsa tsis raug ntawm lub riser, txias sai dhau ntawm qhov casting, kev ntxhov siab ntau dhau los ntawm kev txiav lub riser thiab kev kho cua sov, thiab lwm yam kuj yuav cuam tshuam rau tiam ntawm cov kab nrib pleb.
Raws li cov ua rau thiab cov yam cuam tshuam rau cov kab nrib pleb saum toj no, cov kev ntsuas sib xws tuaj yeem ua tau los txo thiab zam qhov tshwm sim ntawm cov kab nrib pleb.
Raws li kev tshuaj xyuas saum toj no ntawm cov ua rau muaj qhov tsis zoo ntawm kev casting, nrhiav cov teeb meem uas twb muaj lawm thiab siv cov kev ntsuas txhim kho kom zoo, peb tuaj yeem nrhiav kev daws teeb meem rau qhov tsis zoo ntawm kev casting, uas yog qhov zoo rau kev txhim kho qhov zoo ntawm kev casting.
Lub sijhawm tshaj tawm: Lub Yim Hli-31-2023