Uncovering qhov paub tsis meej ntawm superalloy forging: tsim cov khoom siv superhero ntawm kev lag luam
Superalloy, tseem hu ua kub-resistant alloy lossis super alloy, yog cov khoom siv hlau tseem ceeb rau niaj hnub aviation xyaw, foob pob hluav taws cav, roj turbines thiab cov khoom siv tshuaj. Nws tuaj yeem tiv taus kev ntxhov siab nyob rau hauv oxidation thiab roj corrosion ntawm 600 ~ 1100 degree, thiab tuaj yeem ua haujlwm tau ntev.
Tam sim no, ntawm cov deformation superalloys, feem ntau siv yog hlau raws superalloys thiab npib tsib xee raws superalloys. Hlau-raws li alloys yog siv ntau tshaj li turbine discs, compressor discs, bearing nplhaib combustion chambers thiab hniav, thiab lawv cov yam ntxwv muaj pes tsawg leeg yog cov hlau, uas muaj ntau cov npib tsib xee, chromium thiab lwm yam khoom. Raws li nws cov yam ntxwv ntxiv dag zog, nws tuaj yeem muab faib ua lub hnub nyoog tsis muaj zog hardening hom, cov tshuaj tov hardening hom, carbide hnub nyoog hardening hom thiab intermetallic compound hnub nyoog hardening hom.
Nickel-based alloys yog siv ntau dua hauv kev tsim cov turbine blades, combustion chambers, turbine discs, compressor discs thiab compressor blades, uas nws muaj pes tsawg leeg yog tus cwj pwm los ntawm npib tsib xee puag, muaj ω (Cr) ntawm 10% mus rau 20%, sib sau nickel-based. austenite matrix. Tsis tas li ntawd, qee cov alloys kuj muaj 10% mus rau 20% ntawm ω (Co), tsim cov nickel-chromium-cobalt austenite matrix. Raws li nws cov hom kev txhawb zog, nws tuaj yeem muab faib ua cov khoom siv ntxiv dag zog thiab hom kev laus zog.
Cov khoom ntawm superalloy tsuas yog nyob ntawm seb muaj pes tsawg leeg thiab microstructure ntawm cov hlau. Hom, qauv, cov duab, qhov loj me, qhov ntau thiab kev faib tawm ntawm theem precipitated yog qhov tseem ceeb tshwj xeeb hauv microstructure. Common precipitates nyob rau hauv hlau - thiab nickel-raws li alloys yog intermetallic compounds, carbides thiab borides. Tag nrho cov tebchaw no tuaj yeem tswj hwm thiab tswj tau los ntawm kev kho cua sov, thiab lawv cov morphology thiab kev faib tawm tuaj yeem hloov pauv los ntawm deformation.
Kev kho cua sov ntawm deformed superalloys feem ntau muaj cov khoom siv kho mob, kev kho mob nruab nrab (tseem hu ua cov khoom siv tshuaj thib ob) thiab kev kho kev laus. Lub hom phiaj ntawm kev kho kev daws yog kom tau txais cov khoom sib xws supersaturated thiab tswj cov qoob loo uas tsim nyog. Lub hom phiaj ntawm kev kho cua sov nruab nrab yog hloov lub xeev ntawm carbide thiab tau txais ob lub sijhawm sib txawv nrog ntau qhov sib txawv. Lub hom phiaj ntawm kev laus kev kho mob yog ua kom lub zog muaj zog theem tag nrho thiab tusyees precipitate, kom ua tiav cov nyhuv ntawm nag lossis daus hardening, xaiv qhov kub thiab txias, lub sij hawm thiab zaus, kom tau tus naj npawb ntawm cov theem ntxiv dag zog, cov duab thiab kev faib tawm yog tsim nyog raws li cov txheej txheem. Lub hauv paus ntawm cov txheej txheem kub deformation ntawm deformed superalloys yog cov txheej txheem plasticity thiab tseem ceeb deformation ntawm ntxhib crystals.
1.Cov yam ntxwv ntawm superalloy deformation
1) Tsis tshua muaj plasticity, superalloy vim yog high degree ntawm alloying, muaj cov qauv heterogeneous thiab complex theem muaj pes tsawg leeg, yog li ntawd, cov txheej txheem plasticity yog tsawg. Tshwj xeeb tshaj yog nyob rau hauv high kub, thaum lub impurity ntsiab xws li S, Pb, Sn muaj, lub binding quab yuam ntawm cov nplej feem ntau tsis muaj zog thiab cov yas yog txo. Superalloys feem ntau siv tag nrho cov ntsiab lus ntawm ntxiv dag zog rau cov ntsiab lus txhuas thiab titanium los txiav txim siab qib ntawm plasticity, thaum tag nrho cov ntsiab lus siab dua los yog sib npaug li 6%, plasticity yuav tsawg heev. Cov txheej txheem ductility ntawm nickel raws superalloy yog qis dua li ntawm cov hlau raws superalloy. Cov txheej txheem plasticity ntawm superalloys yog rhiab heev rau deformation tus nqi thiab lub xeev kev ntxhov siab. Qee cov hlau ingots thiab nruab nrab billets yuav tsum tau tsim los ntawm qis-ceev deformation thiab chim siab, dov, thiab txawm extrusion.
2) Loj deformation kuj, vim muaj cov complex ntawm superalloy, siab recrystallization kub, qeeb ceev, muaj ib tug siab deformation kuj thiab hardening nyiam ntawm deformation kub, deformation kuj yog feem ntau 4 mus rau 7 npaug ntawm cov qauv zoo tib yam steel.
3) Lub forging kub ntau yog nqaim, lub melting point ntawm superalloy yog tsawg piv nrog steel, thiab cov cua kub kub yog siab dhau los ua overheating thiab overburning. Yog hais tias forging nres kub yog tsawg heev, lub plasticity yog tsawg, lub deformation kuj yog loj, thiab lub txias thiab kub sib tov deformation yog ib qho yooj yim ua rau lub forging los tsim tsis sib xws coarse muaju. Yog li ntawd, qhov kub ntawm superalloy forging yog nqaim heev, feem ntau tsuas yog hais txog 200 degree C. Qhov kub ntawm cov npib tsib xee-raws li kub-resistant alloys yog nqaim, feem ntau ntawm lawv yog 100 ~ 150 ° C, thiab qee qhov tseem tsawg dua. 100 degree C.
4) Cov thermal conductivity tsis zoo, thiab cov thermal conductivity ntawm superalloy ntawm qhov kub tsis tshua muaj qis dua li cov pa roj carbon steel, yog li feem ntau nws yog qhov tsim nyog kom qeeb preheat nyob rau hauv thaj tsam ntawm 700 ~ 800 ° C, txwv tsis pub nws yuav ua rau kub kub. kev ntxhov siab, kom cov cua sov hlau nyob rau hauv lub xeev nkig.
2.Process plasticity ntawm superalloy
1) Vim yog qhov sib ntxiv ntawm ntau cov ntsiab lus alloying, lub tshav kub tsis kam ntawm superalloy tau txhim kho, tab sis cov txheej txheem plasticity tau txo qis heev. High alloying ua rau muaj kev sib cais hnyav thiab coarse columnar crystals. Ntawm qhov tsis muaj zog txuas ntawm thawj dendrite grain ciam teb, cov kab nrib pleb yog yooj yim tshwm sim raws tus ciam teb nplej. Vim dendrite cais, cov ntsiab lus ntawm alloying ntsiab nyob rau hauv thawj crystallized ib feem yog tsawg, thiab cov ntsiab lus ntawm alloying ntsiab nyob rau hauv lub dendrite ntug ib feem yog siab, yog li cov carbides thiab intermetallic tebchaw yog concentrated nyob rau hauv lub dendrite ntug ib feem, uas txo cov malleability. ntawm lub alloy.
2) High alloying ua rau cov yas ntawm lub superalloy bar qis dua li ntawm cov hlau zoo tib yam. Vim hais tias muaj coob tus ntawm cov alloying ntsiab yog enriched nyob rau hauv lub grain ciam teb cheeb tsam, lub grain ciam teb lub zog yog qis dua lub intra-grain lub zog ntawm qhov kub thiab txias, thiab ntau yam ntawm lub zog theem hais tsis yog tag nrho yaj mus rau hauv cov khoom tov nyob rau hauv lub deformation kub. ntau yam, xws li carbide thiab boride, thiab lwm yam, yog li ntawd, ntxiv rau, kuj tseem muaj zog theem cuam tshuam nrog deformation, uas yog, deformation tsis tau ua nyob rau hauv ib theem. xeev. Yog li ntawd, cov txheej txheem plasticity ntawm superalloy dov pas nrig kuj tseem tsawg. Yog li ntawd, nyob rau hauv cov txheej txheem ntawm superalloy forging txheej txheem, cov txheej txheem plasticity ntawm cov hlau yuav tsum tau ntsuas ua ntej.
3.Kev txiav txim siab deformation kub ntawm superalloy
1) Lub hauv paus ntsiab lus ntawm kev txiav txim siab deformation kub ntawm superalloy, vim qhov nyuaj ntawm cov alloying degree ntawm superalloy, qhov pib melting kub ntawm cov hlau yuav txo qis, thiab cov kub dissolution ntawm recrystallization thiab ntxiv dag zog rau theem nce, uas ua rau lub deformation kub yog nqaim. thiab nqaim. Yog li ntawd, thaum txiav txim siab qhov deformation kub, ntxiv rau kev ua kom cov txheej txheem plasticity thiab ua tau raws li kev tsim, nws kuj yuav tsum ua kom tau raws li qhov xav tau kom tau txais lub koom haum zoo thiab cov khoom. Txhawm rau kom cov cellular dislocation network nyob rau hauv microstructure ntawm superalloy forgings thiab tau txais cov hmoov nplej zoo thiab cov khoom zoo, lub forging deformation kub yuav tsum qis dua cov qoob loo loj hlob kub, thiab qhov kawg forging kub yuav tsum nyob ze rau (me ntsis siab dua) qhov kub ntawm theem ob particle dissolution rau hauv cov khoom tov thiab recrystallization kub.
Uncovering qhov paub tsis meej ntawm superalloy forging: tsim cov khoom siv superhero ntawm kev lag luam
2) Cov cua kub specification ntawm superalloy, superalloy cua sov muab faib ua preheating thiab cua sov ob theem. Txhawm rau kom txo lub sijhawm tuav ntawm superalloy ntawm forging cua sov, tsis txhob overcoarsening thiab alloying caij depletion; Nyob rau tib lub sijhawm, txhawm rau txo cov thermal kev ntxhov siab los ntawm cov thermal conductivity tsis zoo thiab siab thermal expansion coefficient ntawm superalloy, qhov khoob yuav tsum tau preheated ua ntej forging. Lub preheating kub yog 750 ~ 800 degree, thiab lub sij hawm tuav yog xam li 0.6 ~ 0.8min/mm. Cov cua kub feem ntau yog 1100 ~ 1180 ° C, thiab lub sijhawm tuav yog 0.4 ~ 0.8min / hli. Cov cuab yeej siv cua sov tuaj yeem siv lub qhov cub ua kom tsis muaj zog, nruab nrog lub ntsuas kub thiab lub ntsuas kub tsis siv neeg hloov khoom siv rau kev tswj kom raug. Thaum cov nplaim taws raug xaiv, cov ntsiab lus ntawm sulfur nyob rau hauv cov roj yuav tsum nruj me ntsis tswj: cov ntsiab lus ntawm sulfur nyob rau hauv diesel los yog hnyav roj yuav tsum tsawg tshaj li 0.5%; Cov ntsiab lus sulfur ntawm cov pa yuav tsum tsawg dua 0.7g / m3. Cov ntsiab lus sulfur ntau dhau hauv cov roj yuav tsim Ni-Ni3S3 eutectic nrog cov ntsiab lus melting tsawg (≈650 degree) thaum nws nkag mus rau hauv qhov chaw ntawm lub billet, ua rau cov hlau kub nkig. Nws yog ib qho tsim nyog yuav tsum tau siv tsawg dua thiab tsis muaj oxidation cua sov ntsuas kom tsis txhob depletion ntawm chromium, aluminium, titanium thiab lwm yam khoom nyob rau saum npoo ntawm qhov khoob, thiab txo qhov qaug zog thiab kub siab lub zog ntawm cov hlau. Hauv zos induction cua sov tuaj yeem siv rau hauv preforging ntawm qhov khoob. Ua ntej cua sov, qhov khoob yuav tsum tau ntxuav kom tshem tawm cov av thiab tsis txhob muaj qhov tsis xws luag vim corrosion. Thaum forging nrog ntau qhov hluav taws kub, lub forging cua sov kub yuav tsum tau txo nrog rau ncua sij hawm ncua sij hawm ntawm ob qhov hluav taws kub kom tsis txhob muaj cov nplej loj hlob uas tau tshwm sim zoo li qub recrystallization, nyob rau tib lub sij hawm, lub reheating kub yuav tsum tau qis dua nrog lub ze zog. mus rau cov khoom tiav forging, qhov me dua qhov deformation.
4.Kev txiav txim siab ntawm deformation degree ntawm superalloy
1) Lub hauv paus ntsiab lus ntawm kev txiav txim siab qhov degree ntawm deformation ntawm superalloys
Vim qhov siab ntawm alloying, qhov deformation kub ntau ntawm superalloy yog nqaim, thiab tsis muaj qhov hloov pauv ntau. Tsis tas li ntawd, lub superalloy tsis muaj kev hloov pauv isomerization, thiab cov nplej loj ntawm cov hlau feem ntau yog tswj los ntawm forging deformation. Yog li ntawd, tom qab lub deformation kub yog txiav txim siab, kev xaiv ntawm deformation degree yog ib qho tseem ceeb heev. Ntawm qhov ntsuas kub ntawm forging, qhov deformation ntawm txhua qhov cua sov yuav tsum siab tshaj qhov tseem ceeb ntawm deformation degree thiab me dua qhov sib thooj deformation degree ntawm thaj tsam kev loj hlob thib ob. Raws li lub hauv paus ntsiab lus ntawm kev ua tau zoo ntawm cov txheej txheem plasticity thiab txheej txheem txheej txheem (pre-forging), txhua qhov deformation yuav tsum sib sib zog nqus thiab zoo ib yam, thiab sim kom tsis txhob deformation tsis sib xws, txwv tsis pub nws yuav tsim cov pob zeb ntxhib thiab cov pob zeb ntxhib hauv zos. Cov pob zeb ntxhib ntawm superalloys muaj qee yam caj ces tawv tawv, thiab nws yog qhov nyuaj los hloov cov pob zeb ntxhib uas tsim los ntawm ib qho tsis sib xws ntawm deformation thaum lub deformation degree tsis loj txaus nyob rau hauv tam sim ntawd deformation. Txhawm rau kom tau txais kev txaus siab microstructure thiab cov khoom, cov cua kub qis dua, qhov loj dua deformation degree, nag lossis daus theem yuav tsum tau siv los tswj microstructure, txhim kho cov qoob loo loj thiab cov ciam teb ntawm lub xeev thaum kawg forging deformation.
Ntxiv nrog rau qhov loj me me, lub xeev ciam teb tseem yog qhov tseem ceeb ntawm microstructure. Los ntawm qhov kev pom ntawm grain ciam teb ntxiv dag zog thiab toughening, kev tswj ntawm grain ciam teb lub koom haum muaj cov cai hauv qab no:
(1) Qhov tsis muaj nag lossis daus theem ntawm cov ciam teb yog ib qho yooj yim los ua cov kab tawg.
(2) Cov coarse 'theem thiab carbide yog sib npaug faib rau ntawm thaj tsam ntawm cov nplej, uas yuav ntxiv dag zog thiab ua kom tawv nqaij ntawm cov qoob loo.
(3) Muaj cov kev ntxhov siab nyob rau hauv thaj tsam ntawm thaj tsam ntawm cov qoob loo depleted, uas tuaj yeem txo qis kev cuam tshuam thiab nthuav dav thaj tsam ntawm cov strain concentration. Yog li ntawd, thaum lub grain ciam zog siab dhau lawm, lub depleted cheeb tsam plays lub luag hauj lwm pab.
(4) Kev tsim cov yeeb yaj kiab tsis tu ncua carbide theem ntawm cov ciam teb ua rau cov hlau tsis zoo.
(5) Kev tsim cov cellular carbides ntawm cov ciam teb nplej muaj qhov cuam tshuam tsis zoo rau lub zog thiab toughening ntawm alloy grain ciam teb.
Yog li ntawd, nyob rau hauv tas li ntawd mus rau ib tug tsim nyog kev kho cua sov system, nyob rau hauv lub forging txheej txheem, los ntawm ib tug tsim nyog tis ntawm deformation, tshwj xeeb tshaj yog yuav tsum tau nce lub degree ntawm forging zaum kawg deformation ntawm lub xeem hluav taws, los txhim kho lub grain ciam teb, grain thiab grain ciam teb lub zog sib piv. , kom tau txais cov koom haum zoo, yog qhov tseem ceeb heev.
2)Feem ntau deformed superalloys yog rhiab heev rau qhov tseem ceeb deformation, thiab qhov tseem ceeb deformation degree feem ntau txawv nyob rau hauv ib tug ntau yam ({{0}}.5% ~ 20%), tus nqi tshwj xeeb txawv nrog cov alloy, thiab qhov tseem ceeb deformation degree ntawm cov tib alloy yog sib txawv ntawm cov cua kub sib txawv. Piv txwv li, tag nrho qhov tseem ceeb deformation degree ntawm GH4049 alloy yog 0.1% ~ 7%. Tag nrho qhov tseem ceeb deformation degree ntawm GH4220 alloy yog 0.6% -4.7% ntawm 1150 degree thiab 0.1% -3% ntawm 1180 degree, tab sis qhov tseem ceeb deformation degree ntawm qhov sib txawv forging kub, deformation degree ntawm lub qhov siab tshaj plaws thiab qhov siab tshaj plaws deformation txoj kab uas hla tsis zoo ib yam. Txoj kab uas hla ntawm qhov tseem ceeb deformation coarse siv lead ua yog ntau qhov kev txiav txim siab loj dua li ntawm cov nplej ib txwm, nrog qhov loj tshaj plaws yog 10mm thiab qhov tsawg tshaj plaws yog 1mm.
5.Influence ntawm forging txheej txheem tsis ntawm microstructure thiab cov khoom ntawm superalloy
Kev xaiv kom zoo ntawm forging thiab tom qab kev kho cua sov txheej txheem tsis ncaj qha cuam tshuam rau cov khoom siv ntawm forgings. Cov txiaj ntsig ntawm ntau yam alloys tau teev tseg hauv qab no rau kev siv hauv kev xaiv cov txheej txheem ua cua sov.
1) Cov nyhuv ntawm cov cua kub kub ntawm microstructure thiab cov khoom ntawm GH2036 alloy
Qhov tso cai cua sov ntawm GH2036 alloy turbine disk ua ntej tuag forging yog 1190 degree. Yog hais tias lub alloy yog rhuab ntawm 1220 degree rau 2h, lub tensile thiab cuam tshuam kuaj hloov los ntawm transgranular puas mus rau intergranular puas, uas yog, lub alloy overheats. Yog hais tias lub alloy yog rhuab rau 2h ntawm 1250 degree thiab 1280 degree, lub grain ciam teb ntawm cov hlau ua rau lub zos pib melting, uas yog, lub alloy yog overburned. Intergranular fracture tshwm sim nyob rau hauv ob qho tib si tensile thiab cuam tshuam cov qauv, thiab tag nrho cov khoom ntawm cov alloy txo. Kev cuam tshuam ntawm cov cua kub kub ntawm cov khoom ntawm GH2036 alloy, qhov cuam tshuam, tensile thiab ruaj khov khoom ntawm alloy deteriorate nrog qhov nce ntawm cov cua sov.
2) Cov nyhuv ntawm qhov kawg deformation kub ntawm cov khoom ntawm GH4169 alloy
Thaum qhov kawg deformation degree yog 25%, qhov rhiab heev rhiab heev tuaj yeem raug tshem tawm los ntawm kev tswj qhov kawg deformation kub ntawm 900 ~ 955 degree, thiab qhov nce ntawm qhov kawg deformation kub yuav ua rau cov nplej ntawm cov hlau tsis sib xws thiab txo nws cov plasticity, uas ua rau muaj qhov sib txawv ntawm qhov kawg deformation degree. nyob rau hauv notch rhiab heev. 3) Kev cuam tshuam ntawm grain loj ntawm kev ua haujlwm
3) Cov txiaj ntsig ntawm grain loj ntawm cov khoom
Cov nplej coarser tuaj yeem ua rau kom lub zog ntev thiab nkag mus rau lub zog, thaum cov nplej zoo tuaj yeem ua rau kom muaj zog thiab qaug zog. Uniform grain loj yog qhov zoo rau cov khoom ntawm cov hlau. Lub neej tawg ntawm cov pob zeb ntxhib yog luv dua li cov pob zeb zoo nkauj. Cov txiaj ntsig zoo ntawm cov qoob loo loj ntawm cov khoom ntawm GH4169 alloy qhia tau hais tias lub zog tawm los thiab qaug zog ntawm GH4169 alloy yog pom tseeb los ntawm cov nplej ua kom zoo dua qub, tab sis lub zog qaug zog ntawm qhov kub siab tshaj 600 degree yog txo. Kev cuam tshuam ntawm lub zog ruaj khov ntawm cov hlau yog nyob ntawm daim ntawv pob txha (transgranular lossis intergranular fracture), uas yog, qhov kub thiab txias ntawm cov hlau yog cuam tshuam.
4) Kev cuam tshuam ntawm cov txheej txheem thermal tsis ua haujlwm ntawm dynamic recrystallization
Thaum lub deformation degree ntau dua 30%, thaum GH4169 alloy yog forged rau rauj los yog hydraulic xovxwm, dynamic recrystallization pib kub yog roughly ntawm 930 ~ 960 degree, thiab thaum isothermal forging, nws yog roughly 930 ~ 940 degree.
Lub dynamic recrystallization ntawm GH4169 alloy yog yooj yim los ntawm kev nce forging kub, nce deformation degree, txais yuav siab dua lossis qis dua tus nqi thiab siv ntau yam deformation.
