Lub luag haujlwm ntawm cov khoom siv feem ntau hauv grey cam khwb cia hlau
1.Carbon thiab silicon: Carbon thiab silicon yog cov khoom uas txhawb nqa graphitization. Cov pa roj carbon sib npaug tuaj yeem siv los qhia txog lawv cov teebmeem ntawm cov qauv metallographic thiab cov khoom siv ntawm grey cam khwb cia hlau. Ua kom cov pa roj carbon sib npaug ua rau cov graphite flakes ua coarser, nce tus lej, thiab txo qis zog thiab hardness. Ntawm qhov tsis sib xws, txo cov pa roj carbon sib npaug tuaj yeem txo cov graphites, kho cov graphite, thiab nce tus naj npawb ntawm cov thawj austenite dendrites, yog li txhim kho cov khoom siv ntawm grey cam khwb cia hlau. Txawm li cas los xij, kev txo qis cov pa roj carbon sib npaug yuav ua rau txo qis hauv kev ua haujlwm casting.
2.Manganese: Manganese nws tus kheej yog ib yam khoom uas stabilizes carbides thiab hinders graphitization. Nws muaj cov nyhuv stabilizing thiab refining pearlite hauv grey cam khwb cia hlau. Nyob rau hauv qhov ntau ntawm Mn = 0.5% mus rau 1.0%, nce tus nqi ntawm manganese yog qhov tsim nyog rau kev txhim kho lub zog thiab hardness.
3.Phosphorus: Thaum cov phosphorus cov ntsiab lus nyob rau hauv cam khwb cia hlau tshaj 0.02%, intergranular phosphorus eutectic tej zaum yuav tshwm sim. Solubility ntawm phosphorus nyob rau hauv austenite yog tsawg heev. Thaum cam khwb cia hlau solidifies, phosphorus yeej tseem nyob hauv cov kua. Thaum lub eutectic solidification yuav luag tiav, cov kua theem tseem nyob nruab nrab ntawm cov eutectic pawg nyob ze rau ternary eutectic muaj pes tsawg leeg (Fe-2%, C-7%, P). Cov kua theem no solidifies ntawm 955 ℃. Thaum cam khwb cia hlau solidifies, molybdenum, chromium, tungsten thiab vanadium yog tag nrho cov segregated nyob rau hauv lub phosphorus-nplua nuj kua theem, nce tus nqi ntawm phosphorus eutectic. Thaum cov ntsiab lus phosphorus nyob rau hauv cam khwb cia hlau yog siab, ntxiv rau qhov teeb meem ntawm phosphorus eutectic nws tus kheej, nws kuj yuav txo tau cov alloying ntsiab muaj nyob rau hauv cov hlau matrix, yog li tsis muaj zog cov nyhuv ntawm cov alloying ntsiab. Cov phosphorus eutectic kua yog mushy nyob ib ncig ntawm lub eutectic pab pawg neeg uas solidifies thiab loj hlob, thiab nws yog ib qho nyuaj rau tau replenished thaum lub sij hawm solidification shrinkage, thiab lub casting muaj ib tug ntau dua nyiam mus shrink.
4.Sulfur: Nws txo cov fluidity ntawm molten hlau thiab ua rau kom cov nyiam ntawm castings tawg kub. Nws yog ib qho teeb meem nyob rau hauv castings. Yog li ntawd, ntau tus neeg xav tias qhov qis dua cov ntsiab lus sulfur, qhov zoo dua. Qhov tseeb, thaum cov ntsiab lus sulfur yog ≤0.05%, hom cam khwb cia hlau no tsis ua haujlwm rau cov inoculant uas peb siv. Yog vim li cas yog qhov inoculation decays sai heev, thiab dawb me ntsis feem ntau tshwm nyob rau hauv lub castings.
5.Copper: tooj liab yog feem ntau ntxiv alloying caij nyob rau hauv zus tau tej cov grey cam khwb cia hlau. Qhov laj thawj tseem ceeb yog tias tooj liab muaj qhov taw tes qis qis (1083 ℃), yooj yim rau yaj, thiab muaj cov nyhuv alloying zoo. Lub peev xwm graphitization ntawm tooj liab yog li 1/5 ntawm silicon, yog li nws tuaj yeem txo qhov nyiam ntawm cam khwb cia hlau kom muaj cov cam khwb cia dawb. Tib lub sijhawm, tooj liab kuj tuaj yeem txo qhov kub thiab txias ntawm austenite transformation. Yog li ntawd, tooj liab tuaj yeem txhawb kev tsim cov pearlite, ua kom cov ntsiab lus ntawm pearlite, thiab ua kom zoo pearlite thiab ntxiv dag zog rau pearlite thiab ferrite nyob rau hauv, yog li ua kom cov hardness thiab lub zog ntawm cam khwb cia hlau. Txawm li cas los xij, qhov ntau dua cov tooj liab, qhov zoo dua. Qhov tsim nyog ntawm tooj liab ntxiv yog 0.2% rau 0.4%. Thaum ntxiv cov tooj liab ntau, ntxiv tin thiab chromium tib lub sijhawm yog teeb meem rau kev ua haujlwm txiav. Nws yuav ua rau ntau tus qauv sorbite tsim nyob rau hauv cov qauv matrix.
6.Chromium: Cov nyhuv alloying ntawm chromium muaj zog heev, feem ntau yog vim qhov sib ntxiv ntawm chromium ua rau muaj kev nyiam ntawm cov hlau molten kom muaj ib qho dawb cam khwb cia, thiab cov casting yog yooj yim rau shrink, ua rau cov khib nyiab. Yog li ntawd, tus nqi ntawm chromium yuav tsum tau tswj. Ntawm qhov tod tes, nws cia siab tias cov hlau molten muaj qee qhov chromium los txhim kho lub zog thiab hardness ntawm casting; Ntawm qhov tod tes, cov chromium yog nruj me ntsis tswj ntawm qhov qis qis kom tiv thaiv cov casting los ntawm shrinking thiab ua rau muaj kev nce hauv cov khoom seem. Ib txwm muaj kev paub hais tias thaum cov ntsiab lus chromium ntawm cov hlau molten tshaj 0.35%, nws yuav muaj kev phom sij rau kev tuag.
7. Molybdenum: Molybdenum yog cov khoom sib xyaw ua ke thiab muaj zog pearlite stabilizing keeb. Nws tuaj yeem kho cov graphite. Thaum ωMo<0.8%, molybdenum tuaj yeem kho pearlite thiab ntxiv dag zog rau ferrite hauv pearlite, yog li txhim kho lub zog thiab hardness ntawm cam khwb cia hlau.
Ntau qhov teeb meem hauv grey cam khwb cia hlau yuav tsum tau sau tseg
1.Kev ua kom kub dhau los yog ncua lub sijhawm tuav tuaj yeem ua rau cov cores heterogeneous uas twb muaj lawm hauv cov yaj ploj lossis txo lawv cov txiaj ntsig, txo cov nplej austenite.
2.Titanium muaj cov nyhuv ntawm refining thawj austenite hauv grey cam khwb cia hlau. Vim tias titanium carbides, nitrides, thiab carbonitrides tuaj yeem ua lub hauv paus rau austenite nucleation. Titanium tuaj yeem ua kom cov tub ntxhais ntawm austenite thiab ua kom zoo austenite nplej. Ntawm qhov tod tes, thaum muaj ntau Ti hauv cov hlau molten, S hauv cov hlau yuav hnov mob nrog Ti es tsis txhob Mn los ua TiS hais. Lub graphite core ntawm TiS tsis zoo li MnS. Yog li ntawd, qhov tsim ntawm eutectic graphite core yog ncua, yog li ua kom lub sij hawm nag lossis daus ntawm thawj austenite. Vanadium, chromium, txhuas, thiab zirconium zoo ib yam li titanium nyob rau hauv uas lawv yooj yim rau tsim carbides, nitrides, thiab carbonitrides, thiab tuaj yeem ua austenite cores.
3.Nws muaj qhov sib txawv loj hauv cov teebmeem ntawm ntau yam inoculants ntawm cov eutectic pawg, uas tau teem rau hauv cov kev txiav txim hauv qab no: CaSi> ZrFeSi> 75FeSi> BaSi> SrFeSi. FeSi muaj Sr lossis Ti muaj qhov tsis muaj zog ntawm cov pawg eutectic. Inoculants uas muaj lub ntiaj teb tsis tshua muaj qhov zoo tshaj plaws, thiab cov nyhuv tseem ceeb dua thaum ntxiv nrog Al thiab N. Ferrosilicon uas muaj Al thiab Bi tuaj yeem ua rau muaj ntau pawg eutectic.
4. Cov nplej ntawm graphite-austenite ob-theem symbiotic kev loj hlob tsim nrog graphite nuclei raws li qhov chaw hu ua eutectic pawg. Submicroscopic graphite aggregates, residual unmelted graphite hais, thawj graphite flake ceg, siab melting point compounds thiab gas inclusions uas muaj nyob rau hauv molten hlau thiab yuav ua tau lub cores ntawm eutectic graphite kuj yog cov cores ntawm eutectic pawg. Txij li thaum lub eutectic nucleus yog qhov pib ntawm kev loj hlob ntawm eutectic pawg, tus naj npawb ntawm eutectic pawg qhia txog cov cores uas tuaj yeem loj hlob mus rau hauv graphite hauv cov kua hlau eutectic. Cov yam ntxwv cuam tshuam rau tus naj npawb ntawm eutectic pawg muaj xws li tshuaj muaj pes tsawg leeg, lub xeev tseem ceeb ntawm cov hlau molten thiab qhov cua txias.
Tus nqi ntawm cov pa roj carbon thiab silicon hauv cov tshuaj muaj pes tsawg leeg muaj qhov cuam tshuam tseem ceeb. Qhov ze dua qhov sib npaug ntawm cov pa roj carbon monoxide yog rau cov eutectic muaj pes tsawg leeg, ntau eutectic pawg muaj. S yog lwm yam tseem ceeb uas cuam tshuam rau eutectic pawg ntawm grey cam khwb cia hlau. Cov ntsiab lus tsis tshua muaj leej faj tsis zoo rau kev nce cov eutectic pawg, vim tias sulfide hauv cov hlau molten yog ib qho tseem ceeb ntawm cov graphite core. Tsis tas li ntawd, leej faj tuaj yeem txo qhov cuam tshuam ntawm lub zog ntawm cov tub ntxhais heterogeneous thiab yaj, kom ntau cov cores tuaj yeem qhib tau. Thaum W (S) tsawg dua 0.03%, tus naj npawb ntawm eutectic pawg tau txo qis, thiab cov nyhuv ntawm inoculation txo.
Thaum qhov loj ntawm Mn nyob rau hauv 2%, tus nqi ntawm Mn nce, thiab tus naj npawb ntawm eutectic pawg nce raws li. Nb yog ib qho yooj yim los tsim cov carbon thiab nitrogen tebchaw nyob rau hauv cov hlau molten, uas ua raws li ib tug graphite core kom cov eutectic pawg. Ti thiab V txo cov eutectic pawg vim vanadium txo cov pa roj carbon ntau; titanium yooj yim ntes S hauv MnS thiab MgS los tsim titanium sulfide, thiab nws lub peev xwm nucleation tsis zoo li MnS thiab MgS. N nyob rau hauv cov hlau molten nce tus naj npawb ntawm eutectic pawg. Thaum N cov ntsiab lus tsawg dua 350 x10-6, nws tsis pom tseeb. Tom qab ntau tshaj ib qho nqi, lub supercooling nce, yog li ua kom cov eutectic pawg. Oxygen nyob rau hauv molten hlau yooj yim tsim ntau yam oxide inclusions raws li cores, yog li cov pa oxygen nce, tus naj npawb ntawm eutectic pawg nce. Ntxiv nrog rau cov tshuaj muaj pes tsawg leeg, lub xeev tseem ceeb ntawm eutectic yaj yog qhov tseem ceeb cuam tshuam. Kev tswj xyuas qhov kub thiab txias dhau rau lub sijhawm ntev yuav ua rau lub hauv paus tseem ceeb ploj lossis txo qis, txo cov eutectic pawg, thiab nce txoj kab uas hla. Kev kho mob inoculation tuaj yeem txhim kho lub xeev tseem ceeb thiab ua kom muaj cov pawg eutectic. Qhov txias txias muaj qhov pom tseeb heev ntawm cov eutectic pawg. Qhov txias txias, qhov ntau eutectic pawg muaj.
5.Tus naj npawb ntawm eutectic pawg ncaj qha qhia txog cov tuab ntawm cov nplej eutectic. Feem ntau, cov nplej zoo tuaj yeem txhim kho kev ua haujlwm ntawm cov hlau. Nyob rau hauv lub premise ntawm tib yam tshuaj muaj pes tsawg leeg thiab graphite hom, raws li tus naj npawb ntawm eutectic pawg nce, lub tensile lub zog nce, vim hais tias cov graphite nplooj nyob rau hauv lub eutectic pawg ua finer raws li tus naj npawb ntawm eutectic pawg nce, uas tsub kom lub zog. Txawm li cas los xij, nrog kev nce ntawm cov ntsiab lus ntawm silicon, tus naj npawb ntawm eutectic pawg nce ntau, tab sis lub zog txo qis dua; Lub zog ntawm cam khwb cia hlau nce nrog qhov nce ntawm superheat kub (txog 1500 ℃), tab sis nyob rau lub sijhawm no, tus naj npawb ntawm eutectic pawg txo qis. Kev sib raug zoo ntawm txoj cai hloov pauv ntawm tus naj npawb ntawm eutectic pawg tshwm sim los ntawm kev kho mob mus ntev inoculation thiab kev nce hauv lub zog tsis tas yuav muaj qhov sib txawv. Lub zog tau txais los ntawm kev kho mob nrog FeSi uas muaj Si thiab Ba yog siab dua qhov tau txais nrog CaSi, tab sis tus naj npawb ntawm eutectic pawg ntawm cam khwb cia hlau yog tsawg dua li ntawm CaSi. Nrog rau qhov nce ntawm tus naj npawb ntawm eutectic pawg, lub shrinkage nyiam ntawm cam khwb cia hlau nce. Txhawm rau tiv thaiv kev tsim ntawm shrinkage nyob rau hauv me me, tus naj npawb ntawm eutectic pawg yuav tsum tau tswj hauv qab 300 ~ 400 / cm2.
6. Ntxiv cov ntsiab lus hlau (Cr, Mn, Mo, Mg, Ti, Ce, Sb) uas txhawb nqa supercooling hauv graphitized inoculants tuaj yeem txhim kho qib ntawm supercooling ntawm cam khwb cia hlau, refine cov nplej, nce tus nqi ntawm austenite thiab txhawb kev tsim ntawm pearlite. Cov ntsiab lus ntxiv saum npoo av (Te, Bi, 5b) tuaj yeem adsorbed rau saum npoo ntawm graphite nuclei kom txwv kev loj hlob ntawm graphite thiab txo qhov loj ntawm graphite, thiaj li ua tiav lub hom phiaj ntawm kev txhim kho cov cuab yeej siv dav dav, txhim kho kev sib koom ua ke, thiab nce kev tswj hwm. Lub hauv paus ntsiab lus no tau siv rau hauv kev xyaum ua cov pa roj carbon monoxide siab (xws li nres qhov chaw).
Post lub sij hawm: Jun-05-2024
