Kev Siv Cov Hlau Molybdenum Hauv Kev Lag Luam Hlau Uas Tiv Thaiv Kub
Hauv kev lag luam metallurgy niaj hnub no, qhov xav tau cov ntaub ntawv uas tuaj yeem tiv taus qhov kub siab nce ntxiv. Kev tsim hluav taws xob, petrochemical, tsheb, thiab cov khoom siv ua haujlwm txhua yam xav tau cov khoom uas tsis yog tsuas yog muaj zog xwb tab sis kuj ruaj khov nyob rau hauv lub sijhawm ntev kub. Ib qho ntawm cov khoom sib xyaw tseem ceeb tshaj plaws los ua kom tau raws li cov kev xav tau no yog molybdenum (Mo). Cov hlau no tau lees paub dav dav tias yog "kev ua kom zoo dua" hauv cov hlau, tshwj xeeb tshaj yog cov hlau uas tiv taus cua sov. Tsab xov xwm no tham txog kev siv molybdenum hauv kev lag luam hlau uas tiv taus cua sov, nws cov txheej txheem ua kom muaj zog, thiab piv txwv ntawm nws cov ntawv thov.
Kawm Txog Molybdenum Thiab Nws Cov Yam Ntxwv
Molybdenum yog ib hom hlau hloov pauv nyiaj uas muaj cov yam ntxwv tshwj xeeb: lub ntsiab lus yaj siab (kwv yees li 2623 ° C), lub zog zoo ntawm qhov kub siab, thiab lub peev xwm los tsim cov carbides ruaj khov. Hauv kev lag luam hlau, molybdenum tsis tshua siv ua hlau ntshiab rau cov khoom siv hauv tsev; es tsis txhob, nws feem ntau siv ua cov khoom sib xyaw hauv me me mus rau nruab nrab, feem ntau yog txij li tsawg dua 1% mus rau ntau feem pua, nyob ntawm qib hlau thiab cov yam ntxwv ntawm lub hom phiaj.
Qhov ua rau molybdenum tshwj xeeb yog nws lub peev xwm los txhim kho ntau yam khoom tseem ceeb ib zaug: kev tiv taus nkag, kev tiv taus cua sov softening, qee qhov kev tiv taus corrosion, thiab kev tiv taus kev tawg thiab thermal qaug zog.
Vim li cas cov hlau tiv taus cua sov thiaj xav tau Molybdenum?
Cov hlau uas tiv taus cua sov yog siv rau hauv cov ntawv thov uas cov khoom siv yuav tsum tiv taus cov khoom siv thaum raug rau qhov kub siab tas li. Piv txwv ntawm cov xwm txheej ua haujlwm no suav nrog cov kav dej siab, boilers, superheaters, reheaters, turbine Cheebtsam, thiab reactors thiab furnaces. Hauv qab cov xwm txheej no, hlau ntsib kev hem thawj loj xws li:
1. Creep: qeeb qeeb deformation vim yog lub sijhawm ntev ntawm qhov kub siab.
2. Kev ua kom cov qauv me me mos: kev hloov pauv hauv cov qauv sab hauv uas txo qhov muaj zog.
3. Kev Oxidation thiab kub xeb: kev sib xyaw nrog oxygen lossis cov txheej txheem xov xwm ntawm qhov kub siab.
4. Kev qaug zog ntawm cua sov: tawg vim yog rov ua dua qhov kub thiab txias.
Molybdenum pab daws cov teeb meem no los ntawm ntau txoj hauv kev ua hlau sib txuas.
1) Ua kom muaj kev tiv thaiv kab mob ntau ntxiv thaum kub siab
Qhov kev siv molybdenum uas paub zoo tshaj plaws hauv cov hlau uas tiv taus cua sov yog los txhim kho kev tiv taus kev nkag mus. Thaum kub siab, cov atoms hauv cov lattice siv lead ua rau txav tau ntau dua. Yog li ntawd, cov khoom siv tuaj yeem hloov pauv qeeb txawm tias nyob hauv qab kev ntxhov siab tsawg.
Molybdenum pab tiv thaiv kev nkag los ntawm:
- Kev ua kom cov kua khov kho: Mo atoms yaj hauv cov hlau matrix thiab "cuam tshuam" kev txav ntawm cov dislocations, ua rau kev hloov pauv nyuaj dua.
– Kev tsim cov carbide ruaj khov: Mo tuaj yeem tsim cov carbides (piv txwv li, hom M₂C lossis cov carbides nyuaj) uas tiv thaiv cov ciam teb ntawm cov noob thiab kev txav mus los ntawm qhov kub siab. Cov carbide me me no ua haujlwm ua "xauv" hauv cov qauv me me kom tiv thaiv kev mos sai.
Yog li ntawd, cov hlau alloy uas muaj Mo feem ntau muaj lub neej ua haujlwm ntev dua ntawm qhov kub thiab txias siab, tshwj xeeb tshaj yog nyob rau hauv cov chaw teeb tsa uas ua haujlwm rau ntau txhiab txog kaum txhiab teev.
2) Txhim kho Lub Zog Kub thiab Kev Tiv Thaiv Mos
Ntxiv rau qhov nkag mus, cov khoom kub siab kuj xav tau lub zog kub zoo: lub peev xwm los tswj lub zog tensile thiab hardness ntawm qhov kub siab. Molybdenum txhim kho lub zog kub los ntawm kev sib xyaw ua ke ntawm kev txhim kho cov kua khov thiab kev ruaj khov microstructural.
Hauv qee cov hlau, qhov muaj Mo tuaj yeem ua rau qeeb qeeb ntawm cov txheej txheem ntawm "over-tempering" lossis softening vim yog kev kho cua sov thiab rov ua dua rau qhov kub siab, yog li cov khoom siv kho tshuab tseem ruaj khov dua.
3) Txhim kho qhov Hardenability thiab Kev Kho Mob Kub Ruaj Khov
Hauv ntau cov hlau sib xyaw, molybdenum kuj tseem ua lub luag haujlwm hauv kev txhim kho qhov tawv, uas yog lub peev xwm ntawm cov hlau los tsim cov qauv tawv (piv txwv li, martensite) thaum txias. Txawm hais tias ua tiav qhov tawv tshaj plaws hauv cov hlau tiv taus cua sov tsis yog lub hom phiaj tseem ceeb, qhov tawv zoo pab tau:
- tau txais cov qauv microstructure sib xws ntau dua hauv cov khoom tuab,
- ua kom muaj kev sib xyaw ua ke ntawm lub zog thiab kev tawv tom qab ua kom zoo thiab ua kom sov,
- txo qhov kev pheej hmoo ntawm kev hloov pauv ntawm cov khoom siv kho tshuab ntawm cov khoom.
Yog li, Mo txhawb nqa qhov zoo sib xws hauv cov khoom lag luam loj xws li cov kav dej tuab thiab cov hlab siab.
4) Kev Tiv Thaiv Rau Qee Qhov Kev Xeb Thiab Kev Puas Tsuaj Kub Ib puag ncig
Molybdenum kuj paub tias yuav ua rau kom tsis txhob xeb hauv qee cov hlau sib xyaw - tshwj xeeb tshaj yog hauv cov hlau tsis xeb hauv cov chaw muaj chloride. Hauv cov hlau uas tiv taus cua sov, nws cov kev pab txhawb nqa suav nrog:
- kev tiv thaiv corrosion ntau ntxiv hauv qee qhov chaw ua haujlwm (nyob ntawm cov khoom sib xyaw thiab cov xov xwm),
- pab ua haujlwm tau zoo hauv cov xwm txheej kub uas muaj cov pa dej, cov pa roj ua haujlwm, lossis qee qhov chaw tso nyiaj,
- txhawb nqa qhov ruaj khov ntawm cov txheej oxide hauv qee hom alloys.
Yuav tsum nco ntsoov tias qhov kub siab oxidation tsis kam feem ntau yog cuam tshuam los ntawm cov ntsiab lus xws li chromium (Cr) thiab txhuas (Al). Txawm li cas los xij, Mo tuaj yeem yog cov khoom txhawb nqa uas txhim kho kev ua tau zoo tag nrho thaum ua ke nrog lwm cov ntsiab lus hauv kev tsim alloy.
5) Txo Qhov Kev Pheej Hmoo ntawm Kev Nchuav thiab Ua Rau Kom Muaj Zog Dua Hauv Kev Ua Haujlwm
Cov khoom uas raug qhov kub hloov pauv yuav yooj yim tawg. Hauv kev tsim cov hlau alloy, Mo tuaj yeem pab txhawb rau kev sib xyaw ua ke zoo tom qab kev kho cua sov kom zoo. Hauv qee cov hlau Cr-Mo uas siv ntau, Mo ua haujlwm ua ke nrog chromium los tsim cov qauv kub ruaj khov, ua rau cov khoom siv tsis yooj yim rau brittleness.
Txawm li cas los xij, zoo li lwm cov khoom sib xyaw, cov teebmeem ntawm Mo yuav tsum sib npaug. Cov ntsiab lus siab dhau lossis kev kho cua sov tsis raug tuaj yeem ua rau muaj kev pheej hmoo ntawm kev tsim theem tsis xav tau lossis cuam tshuam rau weldability. Yog li ntawd, kev xaiv cov ntsiab lus Mo feem ntau ua raws li cov qauv khoom siv thiab kev paub hauv kev lag luam.
Piv txwv ntawm Cov Hlau Uas Tiv Thaiv Kub Siv Molybdenum
Ib qho ntawm cov tsev neeg khoom siv uas paub zoo tshaj plaws yog Cr-Mo (chromium-molybdenum) alloy steels. Cov hlau no siv dav hauv:
- cov kav dej boiler thiab cov kav dej,
- cov hlab ntsha siab rau qhov kub siab,
- cov khoom siv petrochemical thiab cov khoom siv refinery,
- lub kaw lus pa dej siab.
Hauv qhov kub siab dua thiab cov ntawv thov hnyav dua, cov hlau hloov kho nrog cov ntsiab lus ntxiv xws li vanadium (V), niobium (Nb), thiab tungsten (W) kuj tau tsim, tab sis Mo feem ntau tseem yog ib qho tseem ceeb vim nws qhov kev pab txhawb rau kev tiv thaiv creep.
Hauv cov hlau tsis xeb uas tiv taus cua sov, Mo kuj tseem yuav tshwm sim hauv qee qib kom ua rau muaj kev tiv taus rau qee qhov chaw ib puag ncig thiab txhim kho cov khoom kub siab, txawm hais tias lub luag haujlwm tseem ceeb ntawm kev tiv thaiv oxidation feem ntau yog ua si los ntawm chromium siab dua.
Kev Cuam Tshuam Txog Kev Lag Luam thiab Kev Xav Txog Kev Tsim Khoom
Molybdenum yog ib qho khoom siv alloying uas muaj nqis heev nrog rau cov khoom siv thoob ntiaj teb. Kev ntxiv Mo yeej ua rau cov nqi khoom siv kim dua, tab sis feem ntau ntau dua qhov kev pheej hmoo ntawm kev ua tsis tiav ntawm cov khoom lossis cov nqi kaw lub Hoobkas. Hauv cov chaw ua haujlwm hnyav, cov txiaj ntsig tseem ceeb ntawm kev siv Mo yog:
– lub neej ntawm cov khoom siv ntev dua,
- lub sijhawm txij nkawm tsawg dua,
- kev nyab xeeb ntxiv,
- kev ua haujlwm zoo ntawm qhov kub siab dua.
Los ntawm qhov kev xam pom ntawm cov txheej txheem, cov neeg ua hlau yuav tsum tswj hwm cov khoom sib xyaw thiab kev kho cua sov kom zoo kom tau txais txiaj ntsig ntawm Mo. Kev tswj cov txheej txheem vuam kuj tseem ceeb heev, tshwj xeeb tshaj yog rau Cr-Mo hlau, kom tiv thaiv kev tawg ntawm vuam thiab xyuas kom meej tias cov pob qij txha nkag tau zoo.
Xaus
Molybdenum yog ib qho tseem ceeb ntawm cov khoom sib xyaw hauv kev lag luam hlau uas tiv taus cua sov vim nws muaj peev xwm txhim kho kev tiv taus kev nkag, tswj lub zog ntawm qhov kub siab, ruaj khov lub microstructure, thiab txhawb nqa kev tiv taus rau qee qhov xwm txheej ib puag ncig. Hauv cov ntawv thov xws li boilers, cov kav dej pa, cov hlab ntsha siab, thiab cov chaw ua lag luam petrochemical, cov hlau uas muaj molybdenum muab kev ntseeg siab dua thiab lub neej ua haujlwm ntev dua. Thaum nws ntxiv tus nqi, nws cov kev pab rau kev nyab xeeb, kev ua tau zoo, thiab kev ua haujlwm zoo ua rau molybdenum yog ib qho ntawm cov khoom nyuaj tshaj plaws los hloov hauv cov qauv hlau tiv taus cua sov niaj hnub.
