Lub casting ntawm lub valve lub cev yog ib feem tseem ceeb ntawm lub valve manufacturing txheej txheem, thiab qhov zoo ntawm lub valve casting txiav txim siab qhov zoo ntawm lub valve.Cov hauv qab no qhia txog ntau yam txheej txheem casting feem ntau siv hauv kev lag luam valve:
Sand casting:
Xuab zeb casting feem ntau siv hauv kev lag luam valve tuaj yeem muab faib ua cov xuab zeb ntsuab, cov xuab zeb qhuav, dej iav xuab zeb thiab furan resin nws tus kheej-hardening xuab zeb raws li cov ntaub ntawv sib txawv.
(1) Cov xuab zeb ntsuab yog txheej txheem molding siv bentonite ua cov ntawv khi.
Nws cov yam ntxwv yog:Cov xuab zeb ua tiav tsis tas yuav qhuav lossis tawv, cov xuab zeb pwm muaj lub zog ntub dej, thiab cov xuab zeb core thiab pwm plhaub muaj cov txiaj ntsig zoo, ua kom yooj yim los ntxuav thiab co tawm cov castings.Lub molding ntau lawm efficiency yog siab, lub voj voog ntau lawm yog luv, cov khoom siv nqi tsawg, thiab nws yog yooj yim los npaj cov kab ntau lawm.
Nws qhov tsis zoo yog:castings yog nquag mus rau qhov tsis xws luag xws li pores, xuab zeb inclusions, thiab xuab zeb adhesion, thiab qhov zoo ntawm castings, tshwj xeeb tshaj yog cov zoo intrinsic, tsis zoo tagnrho.
Qhov sib npaug thiab kev ua tau zoo ntawm cov xuab zeb ntsuab rau steel castings:
(2) Cov xuab zeb qhuav yog txheej txheem molding siv cov av nplaum ua cov ntawv khi.Ntxiv me ntsis bentonite tuaj yeem txhim kho nws lub zog ntub dej.
Nws cov yam ntxwv yog:cov xuab zeb pwm yuav tsum tau qhuav, muaj huab cua zoo permeability, tsis yooj yim rau defects xws li xuab zeb ntxuav, xuab zeb sticking, thiab pores, thiab qhov zoo ntawm cov casting yog zoo.
Nws qhov tsis zoo yog:nws xav tau cov khoom siv xuab zeb kom qhuav thiab lub voj voog ntau lawm ntev.
(3) Cov iav dej xuab zeb yog cov txheej txheem ua qauv siv cov iav dej ua cov ntawv khi.Nws cov yam ntxwv yog: dej iav muaj qhov ua haujlwm ntawm kev ua kom tawv nqaij thaum raug CO2, thiab tuaj yeem muaj ntau yam zoo ntawm cov roj hardening txoj kev ua qauv thiab cov tub ntxhais ua, tab sis muaj qhov tsis zoo xws li kev sib tsoo tsis zoo ntawm lub plhaub pwm, nyuaj rau cov xuab zeb tu. castings, thiab tsawg regeneration thiab recycling tus nqi ntawm cov xuab zeb qub.
Qhov sib npaug thiab kev ua haujlwm ntawm cov iav dej CO2 hardening xuab zeb:
(4) Furan resin self-hardening xuab zeb moulding yog txheej txheem casting siv furan resin ua tus khi.Cov xuab zeb molding solidifies vim muaj tshuaj lom neeg cov tshuaj tiv thaiv ntawm cov binder nyob rau hauv qhov kev txiav txim ntawm curing tus neeg sawv cev ntawm chav tsev kub.Nws cov yam ntxwv yog tias cov xuab zeb pwm tsis tas yuav qhuav, uas ua rau lub voj voog ntau lawm thiab txuag lub zog.Resin molding xuab zeb yog ib qho yooj yim rau compact thiab muaj zoo disintegration zog.Lub molding xuab zeb ntawm castings yog yooj yim los ntxuav.Cov castings muaj qhov siab qhov tseeb thiab qhov chaw zoo, uas tuaj yeem txhim kho qhov zoo ntawm castings.Nws qhov tsis zoo yog: cov kev xav tau zoo rau cov xuab zeb nyoos, me ntsis pungent tsw ntawm qhov chaw tsim khoom, thiab cov nqi siab ntawm cov resin.
Qhov sib npaug thiab sib tov txheej txheem ntawm furan resin tsis muaj ci xuab zeb sib tov:
Cov txheej txheem sib xyaw ntawm furan resin self-hardening xuab zeb: Nws yog qhov zoo tshaj plaws los siv cov xuab zeb txuas ntxiv los ua cov xuab zeb nws tus kheej-hardening.Cov xuab zeb nyoos, resin, curing agent, thiab lwm yam yog ntxiv rau hauv ib ntus thiab sib tov sai.Nws tuaj yeem sib xyaw thiab siv txhua lub sijhawm.
Qhov kev txiav txim ntawm kev ntxiv ntau yam raw khoom thaum sib tov resin xuab zeb yog raws li nram no:
Cov xuab zeb nyoos + curing tus neeg sawv cev (p-toluenesulfonic acid aqueous tov) - (120 ~ 180S) - cob + silane - (60 ~ 90S) - xuab zeb ntau lawm
(5) Hom xuab zeb casting txheej txheem ntau lawm:
Precision casting:
Nyob rau hauv xyoo tas los no, valve manufacturers tau them nyiaj ntau thiab ntau xim rau cov tsos zoo thiab qhov tseeb qhov tseeb ntawm castings.Vim tias qhov zoo nkauj yog qhov yuav tsum tau ua hauv kev ua lag luam, nws kuj yog qhov ntsuas qhov ntsuas rau thawj kauj ruam ntawm machining.
Feem ntau siv precision casting nyob rau hauv lub valve kev lag luam yog peev casting, uas yog luv luv qhia raws li nram no:
(1) Ob txheej txheem ntawm kev daws casting:
①Siv cov khoom siv pwm uas tsis muaj qhov kub thiab txias (stearic acid + paraffin), tsis tshua muaj siab siv quav ciab, dej iav plhaub, dej kub dewaxing, atmospheric melting thiab pouring txheej txheem, feem ntau yog siv rau carbon steel thiab tsawg alloy steel castings nrog rau cov kev cai dav dav. , Qhov tseeb qhov tseeb ntawm castings tuaj yeem ncav cuag lub teb chaws tus qauv CT7 ~ 9.
② Siv nruab nrab-kub resin-raws li pwm cov khoom, kev txhaj tshuaj muaj zog siab, silica sol pwm plhaub, chav dewaxing, ceev atmospheric lossis nqus melting casting txheej txheem, qhov tseeb qhov tseeb ntawm castings tuaj yeem ncav cuag CT4-6 precision castings.
(2) Yam txheej txheem ntws ntawm peev casting:
(3) Cov yam ntxwv ntawm peev casting:
① Lub casting muaj qhov tseeb qhov tseeb, du nto thiab zoo li zoo.
② Nws muaj peev xwm nrum qhov chaw nrog cov qauv thiab cov duab uas nyuaj rau kev ua haujlwm nrog lwm cov txheej txheem.
③ Casting cov ntaub ntawv tsis txwv, ntau yam ntaub ntawv alloy xws li: carbon steel, stainless hlau, hlau alloy, aluminium alloy, kub kub alloy, thiab precious hlau, tshwj xeeb tshaj yog alloy cov ntaub ntawv uas nyuaj rau forge, weld thiab txiav.
④ Cov khoom lag luam yooj yooj yim thiab muaj zog yoog raws.Nws tuaj yeem ua rau ntau qhov ntau, thiab tseem haum rau ib thooj lossis me me batch ntau lawm.
⑤ Kev nqis peev casting kuj muaj qee yam kev txwv, xws li: cov txheej txheem cumbersome ntws thiab lub voj voog ntev.Vim yog cov txheej txheem kev txwv tsis pub siv tau, nws lub peev xwm siab-cov kabmob tsis tuaj yeem siab heev thaum nws siv los cam khwb cia siab-cov kabmob nyias-plhaub valve castings.
Kev soj ntsuam ntawm Casting Defects
Txhua qhov casting yuav muaj qhov tsis xws luag, lub neej ntawm cov kev tsis zoo no yuav ua rau muaj kev puas tsuaj loj rau sab hauv qhov zoo ntawm qhov casting, thiab kev kho vuam kom tshem tawm cov kev tsis zoo no hauv cov txheej txheem tsim khoom kuj yuav coj lub nra hnyav rau cov txheej txheem ntau lawm.Tshwj xeeb, li qub yog nyias-plhaub castings uas tiv taus siab thiab kub, thiab cov compactness ntawm lawv cov qauv sab hauv yog qhov tseem ceeb heev.Yog li ntawd, qhov tsis xws luag sab hauv ntawm castings dhau los ua qhov kev txiav txim siab cuam tshuam rau qhov zoo ntawm castings.
Internal tsis xws luag ntawm valve castings mas muaj xws li pores, slag inclusions, shrinkage porosity thiab tawg.
(1) Lub cev:Pores yog tsim los ntawm cov pa roj, qhov chaw ntawm lub qhov hws yog du, thiab lawv yog tsim nyob rau hauv los yog ze ntawm lub casting, thiab lawv cov duab yog feem ntau puag ncig los yog oblong.
Lub ntsiab qhov chaw ntawm cov pa uas tsim pores yog:
① Cov nitrogen thiab hydrogen yaj nyob rau hauv cov hlau yog muaj nyob rau hauv cov hlau thaum lub sij hawm solidification ntawm lub casting, tsim kaw lub voj voog los yog oval puab phab ntsa nrog metallic luster.
②Moisture lossis volatile tshuaj nyob rau hauv cov khoom molding yuav tig mus rau hauv cov pa roj vim cua sov, tsim pores nrog tsaus xim av sab hauv phab ntsa.
③ Thaum lub sij hawm pouring txheej txheem ntawm cov hlau, vim qhov tsis ruaj tsis khov, cov huab cua tau koom nrog tsim cov pores.
Txoj kev tiv thaiv ntawm stomatal defect:
① Hauv smelting, rusty hlau raw cov ntaub ntawv yuav tsum tau siv tsawg li tsawg tau los yog tsis, thiab cov cuab yeej thiab ladles yuav tsum tau ci thiab qhuav.
② Lub pouring ntawm molten steel yuav tsum tau ua nyob rau hauv high kub thiab poured nyob rau hauv qis kub, thiab molten hlau yuav tsum tau sedated kom zoo los pab txhawb lub floating ntawm roj.
③ Cov txheej txheem tsim ntawm lub ncuav riser yuav tsum ua kom lub taub hau siab ntawm cov hlau molten kom tsis txhob muaj roj nkag, thiab teeb tsa txoj hauv kev rau cov pa tsim nyog.
④ Moulding cov ntaub ntawv yuav tsum tswj cov dej ntsiab lus thiab roj ntim, ua kom huab cua permeability, thiab cov xuab zeb pwm thiab cov xuab zeb core yuav tsum tau ci thiab qhuav kom ntau li ntau tau.
(2) Shrinkage kab noj hniav (xoo):Nws yog ib qho kev sib txuas los yog tsis sib xws los yog kab noj tsis sib xws (kab noj hniav) uas tshwm sim hauv qhov casting (tshwj xeeb tshaj yog nyob rau ntawm qhov chaw kub), nrog rau qhov ntxhib hauv qhov chaw thiab xim tsaus.Coarse siv lead ua nplej, feem ntau nyob rau hauv daim ntawv ntawm dendrites, sib sau ua ke nyob rau hauv ib los yog ntau qhov chaw, nws muaj peev xwm to to thaum lub sij hawm hydraulic xeem.
Yog vim li cas rau shrinkage kab noj hniav (looseness):ntim shrinkage tshwm sim thaum cov hlau yog solidified los ntawm cov kua mus rau lub xeev khoom.Yog hais tias tsis muaj molten hlau txaus nyob rau lub sij hawm no, shrinkage kab noj hniav yuav inevitably tshwm sim.Lub shrinkage kab noj hniav ntawm cov hlau castings yeej yog tshwm sim los ntawm kev tswj tsis raug ntawm cov txheej txheem ua ntu zus.Cov laj thawj tuaj yeem suav nrog qhov teeb tsa tsis raug, qhov kub siab dhau ntawm cov hlau molten, thiab cov hlau loj loj.
Txoj kev los tiv thaiv shrinkage kab noj hniav (looseness):① Kev tshawb fawb tsim cov txheej txheem pouring ntawm castings kom ua tiav cov khoom sib txuas ntawm cov hlau molten, thiab cov khoom uas ua kom khov ua ntej yuav tsum tau ntxiv nrog cov hlau molten.② Ua kom raug thiab tsim nyog tau teeb tsa riser, nyiaj pab, sab hauv thiab sab nraud txias hlau kom ntseeg tau tias muaj kev sib tw.③Thaum lub molten hlau yog poured, sab saum toj txhaj los ntawm lub riser yog zoo los xyuas kom meej qhov kub ntawm cov hlau molten thiab pub, thiab txo qhov tshwm sim ntawm shrinkage kab noj hniav.④ Nyob rau hauv cov nqe lus ntawm pouring ceev, low-speed pouring yog ntau conducive rau sequential solidification tshaj high-speed pouring.⑸ Cov dej kub yuav tsum tsis txhob siab dhau.Cov hlau molten raug tshem tawm ntawm lub cub tawg ntawm qhov kub thiab txias tom qab sedation, uas yog qhov zoo los txo qis cov kab noj hniav.
(3) Sand inclusions (slag):Sand inclusions (slag), feem ntau hu ua hlwv, yog qhov sib txuas tsis tu ncua lossis qhov tsis sib xws uas tshwm sim hauv cov castings.Lub qhov yog tov nrog molding xuab zeb los yog steel slag, nrog rau qhov ntau thiab tsawg thiab aggregated nyob rau hauv lawv.Ib lossis ntau qhov chaw, feem ntau yog nyob rau sab sauv.
Ua rau cov xuab zeb (slag) suav nrog:Slag suav nrog yog tshwm sim los ntawm kev sib cais steel slag nkag mus rau hauv casting nrog rau cov hlau molten thaum lub sij hawm smelting los yog pouring txheej txheem.Sand inclusion yog tshwm sim los ntawm qhov tsis txaus nruj ntawm cov pwm kab noj hniav thaum lub sij hawm molding.Thaum cov hlau molten yog nchuav rau hauv pwm kab noj hniav, cov xuab zeb molding yog ntxuav los ntawm cov hlau molten thiab nkag mus rau sab hauv ntawm lub casting.Tsis tas li ntawd, kev ua haujlwm tsis raug thaum lub sijhawm txiav thiab lub thawv kaw, thiab qhov tshwm sim ntawm cov xuab zeb ntog tawm kuj yog vim li cas rau cov xuab zeb suav nrog.
Txoj kev los tiv thaiv cov xuab zeb inclusions (slag):① Thaum cov hlau molten yog smelted, cov pa thiab slag yuav tsum tau tas li kom huv si.② Sim tsis txhob tig lub molten steel pouring hnab hla, tab sis siv lub hnab ntim tshuaj yej lossis lub hnab ntim hauv qab los tiv thaiv cov slag saum cov hlau molten los ntawm kev nkag mus rau hauv cov kab nrib pleb nrog rau cov hlau molten.③ Thaum nchuav cov hlau molten, yuav tsum ntsuas kom tsis txhob muaj slag nkag mus rau hauv pwm kab noj hniav nrog cov hlau molten.④ Yuav kom txo tau cov xuab zeb suav nrog, xyuas kom nruj ntawm cov xuab zeb pwm thaum ua qauv, ceev faj kom tsis txhob plam xuab zeb thaum txiav, thiab tshuab pwm kab noj hniav kom huv si ua ntej kaw lub thawv.
(4) Kev tawg:Feem ntau ntawm cov kab nrib pleb hauv casting yog kub tawg, nrog cov duab tsis sib xws, nkag los yog tsis nkag, tsis tu ncua lossis tsis sib xws, thiab cov hlau ntawm cov kab nrib pleb tsaus nti lossis muaj oxidation nto.
yog vim li cas rau tawg, uas yog kub kub kev nyuaj siab thiab kua zaj duab xis deformation.
High-temperature stress yog cov kev ntxhov siab uas tsim los ntawm shrinkage thiab deformation ntawm molten steel nyob rau hauv high kub.Thaum qhov kev ntxhov siab dhau lub zog lossis cov yas deformation txwv ntawm cov hlau ntawm qhov kub no, cov kab nrib pleb yuav tshwm sim.Cov yeeb yaj kiab ua kua deformation yog tsim cov yeeb yaj kiab ua kua ntawm cov khoom siv lead ua thaum lub sij hawm solidification thiab crystallization txheej txheem ntawm molten hlau.Nrog rau kev nce qib ntawm solidification thiab crystallization, cov kua zaj duab xis yog deformed.Thaum tus nqi deformation thiab deformation ceev tshaj ib qho kev txwv, tawg yog generated.Qhov kub thiab txias ntawm thermal tawg yog li 1200 ~ 1450 ℃.
Factors cuam tshuam cov kab nrib pleb:
① S thiab P cov ntsiab lus hauv cov hlau yog cov teeb meem rau cov kab nrib pleb, thiab lawv cov eutectics nrog hlau txo lub zog thiab plasticity ntawm cam khwb cia hlau ntawm qhov kub thiab txias, ua rau tawg.
② Slag suav nrog thiab sib cais hauv cov hlau ua kom muaj kev ntxhov siab ntau ntxiv, yog li ua kom kub tawg.
③ Qhov ntau dua cov kab shrinkage coefficient ntawm steel hom, qhov ntau dua qhov kub kub tawg.
④ Lub thermal conductivity ntawm cov hlau ntau dua, qhov ntau dua qhov nro ntawm qhov chaw, qhov zoo dua qhov kub-kub txhua yam, thiab qhov me dua qhov kub kub tawg.
⑤ Cov qauv tsim ntawm castings tsis zoo nyob rau hauv manufacturability, xws li ib tug me me rounded fab, loj phab ntsa thickness disparity, thiab hnyav concentration concentration, uas yuav ua rau tawg.
⑥ Lub compactness ntawm cov xuab zeb pwm yog siab dhau lawm, thiab qhov tsis zoo tawm los ntawm cov tub ntxhais cuam tshuam lub shrinkage ntawm lub casting thiab ua rau kom cov kab nrib pleb.
⑦ Lwm tus, xws li kev teeb tsa tsis raug ntawm cov riser, kev ua kom txias sai heev, kev ntxhov siab ntau dhau los ntawm kev txiav cov riser thiab kev kho cua sov, thiab lwm yam yuav cuam tshuam rau tiam ntawm cov kab nrib pleb.
Raws li cov laj thawj thiab cuam tshuam ntawm cov kab nrib pleb saum toj no, cov kev ntsuas sib xws tuaj yeem raug coj los txo thiab zam qhov tshwm sim ntawm qhov tawg tsis xws luag.
Raws li kev soj ntsuam saum toj no ntawm cov laj thawj ntawm qhov tsis xws luag casting, nrhiav kom paub cov teeb meem uas twb muaj lawm thiab siv cov kev txhim kho zoo sib xws, peb tuaj yeem nrhiav kev daws teeb meem rau casting qhov tsis xws luag, uas yog qhov tsim nyog rau kev txhim kho casting zoo.
Post lub sij hawm: Aug-31-2023