Cov ntsiab lus: Ib qho piv txwv ntawm Stellite 6 thiab Stellite 21, piav qhia yuav ua li cas carbon cov ntsiab lus thiab tungsten-tiv thaiv-molybdenum tsav lub hardness thiab toughness pauv.
Stellite 6 thiab Stellite 21 yog ob lub cobalt-raws li hnav alloys feem ntau piv rau ib leeg. Ib qho piv txwv zoo tshaj plaws yog qhia Stellite 6 thaum twg muaj qhov tsis paub meej. Tus cwj pwm ntawd muaj lub hauv paus tsim nyog: Stellite 6 muaj keeb kwm ntev ntawm daim ntawv thov, kev coj cwj pwm zoo, thiab kev paub ua tiav. Tab sis nyob rau hauv ob qho xwm txheej lub neej ntawd tuaj yeem qhia txog qhov tsis tseem ceeb: thaum qhov pom kev kub ceev los yog thermal poob siab, thiab thaum lub sij hawm muaj cov phab ntsa nyias nyias los yog ntu hloov pauv sai.
Stellite 21 muaj ntau heev los hais txog qhov kev txwv nruj ntawm Stellite 6 hauv cov xwm txheej ntawd. Kev nkag siab txog kev lag luam tawm ntawm ob yog qhov muaj txiaj ntsig ntau dua li kev nco txog qhov twg "zoo dua."
Qhov sib txawv ntawm qhov sib txawv ua rau kev ua haujlwm sib cais
Qhov sib txawv ntawm qhov kev ua tau zoo ntawm cov hlau no los ntawm ob qho kev xaiv sib xyaw.
Cov ntsiab lus carbon. Stellite 6 nqa cov pa roj carbon ntau dua. Raws li SAE AMS 5387, Stellite 6 castings muaj ib tug nominal muaj pes tsawg leeg ntawm 60Co-29Cr-4.5W, nrog carbon feem ntau nyob rau hauv 0.9-1.4% ntau yam rau cam khwb cia khoom. Cov pa roj carbon ntau txhais tau hais tias muaj zog carbide nag lossis daus, uas ncaj qha nce hardness thiab hnav tsis kam. Stellite 21 muaj cov pa roj carbon tsawg dua, nrog cov nominal muaj pes tsawg leeg ntawm C ~ 0.25%, Cr 25-30%, Mo 4.5-6.5%, Ni 1.5-3.5%, sib npaug Co. Cov pa roj carbon qis txhais tau hais tias qis carbide ntim feem thiab microstructure dominated los ntawm cobalt solid-solution matrix.
Tungsten piv rau molybdenum. Stellite 6 siv tungsten (W) raws li nws cov khoom tseem ceeb-kev daws teeb meem; Stellite 21 hloov feem ntau ntawm cov tungsten nrog molybdenum (Mo). Molybdenum muaj kwv yees li ib nrab ntawm atomic qhov hnyav ntawm tungsten, yog li ntawm tib qhov hnyav feem pua nws ua rau ob zaug ntau dua atoms. Molybdenum kuj tseem muaj kev sib raug zoo rau cov pa roj carbon ntau thiab nyiam txhawb kev tsim cov carbide. Hauv Stellite 21, txawm li cas los xij, qib qis carbon txwv qhov cuam tshuam, thiab cov txiaj ntsig tau txais txiaj ntsig yog qhov qis dua tag nrho cov ntsiab lus carbide ntau dua li Stellite 6.
Ua ke, ob qhov sib txawv no tsim ob qhov kev ua tau zoo sib txawv.
Stellite 6: carbide ntom hauv kev sib pauv rau hnav tsis kam
Lub microstructure ntawm Stellite 6 muaj xws li cobalt-raws li solid-solution matrix nrog ib tug kuj ntom faib ntawm hard carbide hais. Cov qauv no ua tau zoo nyob rau hauv abrasive hnav.
Qhov twg nws haum. Valve sealing ntsej muag, lub tes tsho twj tso kua mis, slurry tuav Cheebtsam, thiab cov khoom siv feem ntau nyob rau hauv kev cuam tshuam nruab nrab yog cov kev siv Stellite 6. Nws qhov hardness feem ntau poob rau hauv Rockwell C 37-45 ntau yam, nyob ntawm seb qhov xwm txheej casting thiab kev kho cua sov tom qab, uas yog txaus rau feem ntau cov teeb meem abrasive. Nyob rau hauv oxidizing high-temperature ib puag ncig, Stellite 6 kuj tsim ib tug tiv thaiv oxide txheej raws li Cr₂O₃ thiab CoCr₂O₄, nrog ib tug qis oxidation tus nqi tshaj Stellite 21.
Qhov twg cov kev txwv tshwm. Cov carbide ntom ntom muaj ib qho kev phiv: nyob rau hauv thermal cycling ceev los yog hauv zos thermal shock, thermal expansion sib txawv ntawm carbides thiab matrix tuaj yeem ua qhov chaw pib tawg. Rau cov ntu ntu ntu, cov ntsiab lus carbon ntau dua thiab carbide tuaj yeem ua rau muaj kev pheej hmoo ntawm kev tawg thaum lub sij hawm casting thiab machining. Qhov no tsis tau txhais hais tias Stellite 6 tsis tuaj yeem siv rau hauv cov xwm txheej no, tab sis thaum thermal qaug zog yog hom tsis ua haujlwm tseem ceeb, lwm txoj hauv kev yuav tsum tau soj ntsuam tiag tiag.
Stellite 21: qis carbide cov ntsiab lus hauv kev pauv rau toughness thiab thermal qaug zog tsis kam
Stellite 21 ua raws li kev tsim qauv sib txawv. Nws cov ntsiab lus tsis tshua muaj carbon thiab molybdenum ntxiv kom txo qis cov carbide ntim feem, tawm hauv cov cobalt solid-solution matrix raws li theem uas nqa cov tshuab ua haujlwm.
Qhov tshwm sim ncaj qha: chav-kub hardness thiab ntshiab abrasive hnav tsis kam yog qis dua Stellite 6, tab sis toughness, thermal shock kuj, thiab thermal qaug zog kuj zoo dua. Raws li-cam khwb cia hardness feem ntau qhia nyob rau hauv qis-rau-mid HRC 30s, hauv qab ntawm Stellite 6 (qhov tseem ceeb nyob ntawm cov khoom thiab cov xwm txheej ntsuas - txheeb xyuas cov ntaub ntawv xa tawm ua ntej qhia). Nws qhov zoo dua yog tsis hnav cov abrasives tab sis tswj kev ua haujlwm ruaj khov nyob rau hauv thermal cycling.
Qhov twg nws haum. Stellite 21 tau siv rau hauv cov roj turbine hniav, kub ua hauj lwm li qub, kub-kub fasteners, thiab weld overlays uas yuav tsum tau buffer thermal expansion mismatch. Qhov twg Stellite 6 ua haujlwm raws li cov txheej txheem saum toj kawg nkaus thiab cov txheej txheem nruab nrab yog xav tau, Stellite 21 tau siv keeb kwm los ua qhov tsis zoo los ua kom cov thermal expansion sib txawv ntawm cov hlau substrate thiab Stellite 6 sab saum toj txheej. Kev tshawb fawb ntawm F91 steel substrates nrog Stellite 21 tsis txheej, hnub nyoog ntawm 550-650 ° C mus txog 8,760 teev, pom muaj kev cuam tshuam tseem ceeb ntawm qhov poob ntawm F91 / S21 interface, uas yog vim li cas nickel-based buffer khaubncaws sab nraud povtseg tau nce ntxiv hauv daim ntawv thov tshwj xeeb. Qhov no qhia txog lub alloy txoj hauj lwm zoo: nws tus nqi nyob rau hauv toughness nyob rau hauv tej yam kev mob, tsis nyob rau hauv hloov Stellite 6 nyob txhua qhov chaw.
Ib qho yooj yim overlooked txwv. Stellite 21 muaj qhov txwv tsis pub muaj kev tiv thaiv ib puag ncig nyuaj. Vim tias carbide ceev tsawg, lub matrix muaj kev tiv thaiv tsawg dua thaum cov khoom ntse tawm tsam ntawm qhov nrawm. Nyob rau hauv qis-angle yaig thiab tawv abrasive hnav, Stellite 21 feem ntau tsis yog qhov kev xaiv zoo tshaj plaws.
Ib txoj kev xaiv tswv yim
Txoj kev hauv qab no yog raws li kev ua tau zoo ntawm ob lub alloys. Nws tuaj yeem ua qhov kev ntsuam xyuas thawj zaug tab sis yuav tsum tsis txhob hloov qhov kev ntsuam xyuas engineering ntawm daim ntawv thov tshwj xeeb.
Lean mus rau Stellite 6 thaum:
- Hom tsis ua hauj lwm tseem ceeb yog abrasive lossis nplaum hnav, thiab thermal cycling tsis yog qhov loj.
- Qhov seem muaj ib ntu tuab, thiab tawg rhiab heev thaum lub sij hawm casting thiab machining yog tswj tau.
- Kev pabcuam kub yog siab nyob rau hauv qhov chaw oxidizing, thiab cov txheej tiv thaiv oxide yog ib feem ntawm kev tsim.
- Daim ntawv thov muaj keeb kwm tsim Stellite 6 nrog cov ntaub ntawv tsis ua haujlwm los siv.
Lean rau Stellite 21 thaum:
- Ib feem tau rov ua cua sov sai thiab txias, thiab thermal qaug zog tawg yog qhov kev pheej hmoo paub.
- Ib feem muaj cov phab ntsa nyias lossis ntu ntu hloov pauv, thiab toughness tseem ceeb tshaj qhov tawv tawv.
- Ib txheej hloov pauv yuav tsum tau nruab nrab ntawm cov hlau substrate thiab ib qho nyuaj rau kev tsis sib haum xeeb thermal expansion mismatch (tab sis ntev-lub sij hawm kub-kub stability yuav tsum tau soj ntsuam).
- Cov txheej txheem hnav feem ntau yog hlau-rau-hlau zawv zawg hnav lossis cavitation es tsis yog tawv-particle yaig.
Thaum twg tsis yog ib qho huv huv: Yog tias daim ntawv thov xav tau ob qho tib si abrasive hnav tsis kam thiab zoo heev thermal qaug zog tsis kam, Stellite 12 (siab dua carbon, siab hnav tsis kam) los yog Tribaloy tsev neeg ntawm intermetallic-strengthened alloys yuav tsim nyog xav txog, los yog ib feem ntawm thermal tswj tej zaum yuav tsum tau hais nyob rau hauv lub tsim theem. Cov lus qhia no mus dhau qhov kev sib piv no tab sis yog nyob rau hauv kev tshuaj xyuas cov khoom siv thaum ntxov.
Dab tsi suav nrog hauv RFQ
Qhov twg yog qhov kev xaiv alloy, ib tus neeg xa khoom thiab machining feem ntau xav tau cov hauv qab no ua ntej nws tuaj yeem muab cov lus muaj txiaj ntsig:
- Cov duab kos duab nrog rau qhov tseem ceeb qhov ntev thiab kam rau ua.
- Kev pabcuam: kub ntau, nruab nrab, thiab load hom (hnav, cuam tshuam, thermal cycling).
- Cia siab rau lub neej los yog paub hom kev ua tsis tiav, nrog ib feem keeb kwm yog muaj.
- Khoom txheem, piv txwv li seb AMS 5387 lossis lwm qhov kev qhia tshwj xeeb yuav tsum tau ua.
- Ntau, txij li ib daim, cov khoom me me, thiab cov ntim ntau lawm ua rau muaj kev xaiv sib txawv.
Rau cobalt-raws li alloy castings, nws tseem tsim nyog lees paub tias tus neeg muag khoom muaj peev xwm hauv tsev los ntawm kev ua tiav kev ua tiav, vim tias cov alloys ua hauj lwm-hardenly noticeably thiab handoff ntawm cov txheej txheem cuam tshuam rau ob qho tib si nqi thiab txhuas lub sij hawm.
