Lub ntsiab lus thiab lub hom phiaj ntawm quenching
Cov hlau raug cua sov rau qhov kub siab tshaj qhov tseem ceeb Ac3 (hypoeutectoid hlau) lossis Ac1 (hypereutectoid hlau), khaws cia rau ib lub sijhawm kom ua rau nws tag nrho lossis ib nrab austenitized, thiab tom qab ntawd txias ntawm qhov ceev ntau dua li qhov ceev quenching tseem ceeb. Cov txheej txheem kho cua sov uas hloov cov austenite supercooled mus rau hauv martensite lossis qis dua bainite hu ua quenching.
Lub hom phiaj ntawm kev quenching yog hloov cov austenite supercooled mus rau hauv martensite lossis bainite kom tau txais martensite lossis qis dua bainite qauv, uas tom qab ntawd ua ke nrog tempering ntawm ntau qhov kub sib txawv kom txhim kho lub zog, qhov nyuaj, thiab kev tiv thaiv ntawm cov hlau. Kev hnav tau, lub zog qaug zog thiab kev tawv, thiab lwm yam, kom ua tau raws li qhov xav tau siv sib txawv ntawm ntau yam khoom siv kho tshuab thiab cov cuab yeej. Quenching kuj tseem siv tau los ua kom tau raws li cov khoom siv tshwj xeeb thiab tshuaj lom neeg ntawm qee cov hlau tshwj xeeb xws li ferromagnetism thiab kev tiv thaiv corrosion.
Thaum cov khoom hlau raug txias hauv cov khoom siv quenching nrog kev hloov pauv ntawm lub cev, cov txheej txheem txias feem ntau muab faib ua peb theem hauv qab no: theem zaj duab xis vapor, theem boiling, thiab theem convection.
Kev ua kom tawv ntawm cov hlau
Kev ua kom tawv thiab kev ua kom tawv yog ob qho cim qhia txog kev ua tau zoo uas piav qhia txog lub peev xwm ntawm cov hlau kom dhau los ua quenching. Lawv kuj yog lub hauv paus tseem ceeb rau kev xaiv cov khoom siv thiab kev siv.
1. Cov tswv yim ntawm kev ua kom tawv thiab kev ua kom tawv
Kev ua kom tawv yog lub peev xwm ntawm cov hlau kom ua tiav qhov tawv tshaj plaws uas nws tuaj yeem ua tiav thaum quenched thiab hardened nyob rau hauv cov xwm txheej zoo tagnrho. Lub hauv paus tseem ceeb uas txiav txim siab qhov tawv ntawm cov hlau yog cov pa roj carbon ntawm cov hlau. Yuav kom meej dua, nws yog cov pa roj carbon yaj hauv austenite thaum lub sijhawm quenching thiab cua sov. Cov pa roj carbon ntau dua, qhov tawv ntawm cov hlau ntau dua. . Cov khoom sib xyaw hauv cov hlau tsis muaj feem cuam tshuam rau qhov tawv, tab sis lawv muaj feem cuam tshuam loj rau qhov tawv ntawm cov hlau.
Kev ua kom tawv yog hais txog cov yam ntxwv uas txiav txim siab qhov tob ntawm kev tawv thiab kev faib tawm ntawm qhov tawv ntawm cov hlau raws li cov xwm txheej tshwj xeeb. Ntawd yog, lub peev xwm kom tau txais qhov tob ntawm cov txheej tawv thaum cov hlau raug tua. Nws yog ib qho khoom muaj nyob hauv cov hlau. Kev ua kom tawv tiag tiag qhia txog qhov yooj yim uas austenite hloov pauv mus ua martensite thaum cov hlau raug tua. Nws feem ntau yog cuam tshuam nrog kev ruaj khov ntawm supercooled austenite ntawm cov hlau, lossis rau qhov tseem ceeb quenching txias ntawm cov hlau.
Nws kuj tseem yuav tsum tau taw qhia tias qhov ua kom tawv ntawm cov hlau yuav tsum tau sib txawv ntawm qhov tob ntawm qhov tawv ntawm cov khoom hlau hauv qab cov xwm txheej tshwj xeeb. Qhov ua kom tawv ntawm cov hlau yog ib qho khoom muaj nqis ntawm cov hlau nws tus kheej. Nws tsuas yog nyob ntawm nws cov yam ntxwv sab hauv thiab tsis muaj dab tsi ua rau cov yam ntxwv sab nraud. Qhov tob ntawm qhov ua kom tawv ntawm cov hlau tsis yog nyob ntawm qhov ua kom tawv ntawm cov hlau xwb, tab sis kuj nyob ntawm cov khoom siv siv. Nws muaj feem cuam tshuam nrog cov yam ntxwv sab nraud xws li cov khoom siv txias thiab qhov loj ntawm cov khoom ua haujlwm. Piv txwv li, nyob rau hauv tib qho xwm txheej austenitizing, qhov ua kom tawv ntawm cov hlau tib yam yog tib yam, tab sis qhov tob ntawm qhov ua kom tawv ntawm cov dej quenching loj dua li ntawm cov roj quenching, thiab cov khoom me me me dua li ntawm cov roj quenching. Qhov tob ntawm qhov ua kom tawv ntawm cov khoom loj yog loj. Qhov no tsis tuaj yeem hais tias cov dej quenching muaj qhov tawv siab dua li ntawm cov roj quenching. Nws tsis tuaj yeem hais tias cov khoom me me muaj qhov tawv siab dua li cov khoom loj. Nws tuaj yeem pom tias kom ntsuas qhov ua kom tawv ntawm cov hlau, qhov cuam tshuam ntawm cov yam ntxwv sab nraud xws li cov duab ntawm cov khoom ua haujlwm, qhov loj me, cov khoom siv txias, thiab lwm yam yuav tsum tau tshem tawm.
Tsis tas li ntawd xwb, vim tias qhov nyuaj thiab qhov nyuaj yog ob lub tswv yim sib txawv, cov hlau uas muaj qhov nyuaj siab tom qab quenching tsis tas yuav muaj qhov nyuaj siab; thiab cov hlau uas muaj qhov nyuaj tsawg kuj tseem yuav muaj qhov nyuaj siab.
2. Cov yam ntxwv uas cuam tshuam rau kev ua kom tawv
Qhov ua kom tawv ntawm cov hlau nyob ntawm qhov ruaj khov ntawm austenite. Txhua yam uas tuaj yeem txhim kho qhov ruaj khov ntawm supercooled austenite, hloov C nkhaus mus rau sab xis, thiab yog li txo qhov txias txias tseem ceeb tuaj yeem txhim kho qhov tawv ntawm cov hlau siab. Qhov ruaj khov ntawm austenite feem ntau nyob ntawm nws cov tshuaj lom neeg sib xyaw, qhov loj me ntawm cov noob thiab kev sib xyaw ua ke, uas muaj feem cuam tshuam nrog cov tshuaj lom neeg sib xyaw ntawm cov hlau thiab cov xwm txheej cua sov.
3. Txoj kev ntsuas qhov tawv
Muaj ntau txoj hauv kev los ntsuas qhov tawv ntawm cov hlau, cov uas siv ntau tshaj plaws yog txoj kev ntsuas qhov tseem ceeb thiab txoj kev sim qhov kawg tawv.
(1) Txoj kev ntsuas qhov loj me tseem ceeb
Tom qab cov hlau raug quenched hauv ib qho chaw nruab nrab, qhov siab tshaj plaws thaum lub hauv paus tau txais tag nrho cov martensite lossis 50% martensite qauv hu ua qhov tseem ceeb txoj kab uas hla, sawv cev los ntawm Dc. Txoj kev ntsuas qhov tseem ceeb txoj kab uas hla yog ua ib tug series ntawm cov pas nrig puag ncig nrog ntau txoj kab uas hla, thiab tom qab quenching, ntsuas qhov nyuaj U nkhaus faib raws txoj kab uas hla ntawm txhua qhov piv txwv, thiab nrhiav tus pas nrig nrog cov qauv semi-martensite hauv nruab nrab. Txoj kab uas hla ntawm tus pas nrig puag ncig Qhov ntawd yog txoj kab uas hla tseem ceeb. Qhov loj dua txoj kab uas hla tseem ceeb, qhov siab dua qhov hardenability ntawm cov hlau.
(2) Txoj kev sim quenching kawg
Txoj kev sim ua kom kub thaum kawg siv cov qauv loj uas kub thaum kawg (Ф25mm × 100mm). Tom qab austenitization, dej raug txau rau ntawm ib kawg ntawm cov qauv ntawm cov khoom siv tshwj xeeb kom txias nws. Tom qab txias, qhov nyuaj raug ntsuas raws li qhov kev taw qhia ntawm axis - los ntawm qhov kawg uas txias nrog dej. Txoj kev sim rau qhov nkhaus kev sib raug zoo ntawm qhov deb. Txoj kev sim ua kom kub thaum kawg yog ib txoj hauv kev los txiav txim siab qhov ua kom kub ntawm cov hlau. Nws qhov zoo yog kev ua haujlwm yooj yim thiab ntau yam kev siv.
4. Ua kom muaj kev ntxhov siab, kev hloov pauv thiab kev tawg
(1) Kev ntxhov siab sab hauv ntawm lub workpiece thaum lub sijhawm quenching
Thaum lub workpiece txias sai sai hauv qhov nruab nrab quenching, vim tias lub workpiece muaj qee qhov loj me thiab cov coefficient thermal conductivity kuj yog qee qhov nqi, qee qhov kub thiab txias yuav tshwm sim raws sab hauv ntawm lub workpiece thaum lub sijhawm txias. Qhov kub ntawm qhov chaw qis, qhov kub ntawm lub hauv paus siab, thiab qhov kub ntawm qhov chaw thiab lub hauv paus siab. Muaj qhov sib txawv ntawm qhov kub. Thaum lub sijhawm txias ntawm lub workpiece, kuj muaj ob qho xwm txheej lub cev: ib qho yog thermal expansion, thaum qhov kub poob qis, qhov ntev ntawm lub workpiece yuav ntsws; qhov thib ob yog kev hloov pauv ntawm austenite mus rau martensite thaum qhov kub poob qis mus rau qhov chaw hloov pauv martensite. , uas yuav ua rau qhov ntim tshwj xeeb nce. Vim yog qhov sib txawv ntawm qhov kub thaum lub sijhawm txias, qhov ntau ntawm thermal expansion yuav txawv ntawm ntau qhov chaw raws ntu ntawm lub workpiece, thiab kev ntxhov siab sab hauv yuav tsim nyob rau hauv ntau qhov chaw ntawm lub workpiece. Vim muaj qhov sib txawv ntawm qhov kub hauv lub workpiece, kuj tseem yuav muaj qhov chaw uas qhov kub poob qis dua qhov chaw uas martensite tshwm sim. Kev hloov pauv, qhov ntim nthuav dav, thiab cov khoom uas muaj qhov kub siab tseem siab dua qhov taw tes thiab tseem nyob hauv lub xeev austenite. Cov khoom sib txawv no kuj tseem yuav tsim kev ntxhov siab sab hauv vim muaj qhov sib txawv ntawm kev hloov pauv ntim tshwj xeeb. Yog li ntawd, ob hom kev ntxhov siab sab hauv yuav raug tsim thaum lub sijhawm quenching thiab txias: ib qho yog kev ntxhov siab thermal; qhov tod yog kev ntxhov siab ntawm cov ntaub so ntswg.
Raws li lub sijhawm muaj nyob ntawm kev ntxhov siab sab hauv, nws kuj tseem tuaj yeem muab faib ua kev ntxhov siab tam sim ntawd thiab kev ntxhov siab seem. Kev ntxhov siab sab hauv uas tsim los ntawm cov khoom ua haujlwm thaum lub sijhawm txias hu ua kev ntxhov siab tam sim ntawd; tom qab cov khoom ua haujlwm txias, kev ntxhov siab uas tseem nyob hauv cov khoom ua haujlwm hu ua kev ntxhov siab seem.
Kev ntxhov siab thermal yog hais txog kev ntxhov siab los ntawm kev nthuav dav thermal tsis sib xws (lossis kev cog lus txias) vim qhov sib txawv ntawm qhov kub thiab txias hauv ntau qhov ntawm cov khoom ua haujlwm thaum nws raug cua sov (lossis txias).
Tam sim no siv ib lub tog raj kheej khov kho ua piv txwv los piav qhia txog kev tsim thiab hloov cov cai ntawm kev ntxhov siab sab hauv thaum nws cov txheej txheem txias. Tsuas yog kev ntxhov siab axial xwb thiaj li tau tham txog ntawm no. Thaum pib txias, vim tias qhov chaw txias sai, qhov kub qis, thiab ntsws ntau, thaum lub hauv paus txias, qhov kub siab, thiab qhov ntsws me me. Yog li ntawd, qhov chaw thiab sab hauv raug txwv tsis pub sib cais, ua rau muaj kev ntxhov siab tensile ntawm qhov chaw, thaum lub hauv paus nyob hauv qab kev nyuaj siab. kev ntxhov siab. Thaum txias mus ntxiv, qhov sib txawv ntawm qhov kub ntawm sab hauv thiab sab nraud nce ntxiv, thiab kev ntxhov siab sab hauv kuj nce ntxiv raws li. Thaum kev ntxhov siab nce ntxiv kom dhau qhov muaj zog ntawm qhov kub no, kev hloov pauv yas tshwm sim. Txij li thaum lub plawv tuab dua li ntawm qhov chaw, lub plawv ib txwm cog lus axially ua ntej. Vim yog kev hloov pauv yas, kev ntxhov siab sab hauv tsis nce ntxiv lawm. Tom qab txias mus rau ib lub sijhawm, qhov txo qis ntawm qhov kub ntawm qhov chaw yuav maj mam qeeb, thiab nws qhov ntsws kuj yuav maj mam txo qis. Lub sijhawm no, lub hauv paus tseem tab tom ntsws, yog li qhov kev ntxhov siab tensile ntawm qhov chaw thiab kev ntxhov siab compressive ntawm lub hauv paus yuav maj mam txo qis kom txog thaum lawv ploj mus. Txawm li cas los xij, thaum txias mus ntxiv, qhov av noo ntawm qhov chaw yuav qis dua thiab qis dua, thiab qhov ntau ntawm kev ntsws yuav tsawg dua thiab tsawg dua, lossis txawm tias tsis txhob ntsws. Vim tias qhov kub hauv lub plawv tseem siab, nws yuav txuas ntxiv ntsws, thiab thaum kawg kev ntxhov siab compressive yuav tsim rau ntawm qhov chaw ntawm qhov workpiece, thaum lub plawv yuav muaj kev ntxhov siab tensile. Txawm li cas los xij, vim tias qhov kub qis, kev hloov pauv yas tsis yooj yim tshwm sim, yog li qhov kev ntxhov siab no yuav nce ntxiv thaum txias mus ntxiv. Nws txuas ntxiv nce thiab thaum kawg tseem nyob hauv qhov workpiece ua kev ntxhov siab seem.
Nws tuaj yeem pom tias qhov kev ntxhov siab thermal thaum lub sijhawm txias ua rau txheej txheej saum npoo raug ncab thiab lub hauv paus raug nias, thiab qhov kev ntxhov siab seem seem yog txheej txheej saum npoo raug nias thiab lub hauv paus raug ncab.
Hauv kev xaus lus, qhov kev ntxhov siab thermal uas tsim thaum lub sijhawm txias quenching yog tshwm sim los ntawm qhov sib txawv ntawm qhov kub thiab txias thaum lub sijhawm txias. Qhov txias ntau dua thiab qhov sib txawv ntawm qhov kub thiab txias ntau dua, qhov kev ntxhov siab thermal ntau dua. Nyob rau hauv tib lub chaw txias txias, qhov kub ntawm qhov workpiece siab dua, qhov loj dua, qhov thermal conductivity ntawm cov hlau me dua, qhov sib txawv ntawm qhov kub thiab txias hauv qhov workpiece ntau dua, thiab qhov kev ntxhov siab thermal ntau dua. Yog tias qhov workpiece txias tsis sib xws ntawm qhov kub siab, nws yuav raug distorted thiab deformed. Yog tias qhov kev ntxhov siab tensile tam sim ntawd tsim thaum lub sijhawm txias ntawm qhov workpiece ntau dua li lub zog tensile ntawm cov khoom, quenching tawg yuav tshwm sim.
Kev ntxhov siab hloov pauv theem yog hais txog kev ntxhov siab los ntawm lub sijhawm sib txawv ntawm kev hloov pauv theem hauv ntau qhov ntawm cov khoom ua haujlwm thaum lub sijhawm kho cua sov, tseem hu ua kev ntxhov siab ntawm cov ntaub so ntswg.
Thaum lub sijhawm quenching thiab txias sai, thaum txheej saum npoo txias mus rau Ms point, kev hloov pauv martensitic tshwm sim thiab ua rau nthuav dav. Txawm li cas los xij, vim yog qhov thaiv ntawm lub hauv paus uas tseem tsis tau hloov pauv, txheej saum npoo tsim kev ntxhov siab compressive, thaum lub hauv paus muaj kev ntxhov siab tensile. Thaum kev ntxhov siab loj txaus, nws yuav ua rau deformation. Thaum lub hauv paus txias mus rau Ms point, nws kuj tseem yuav dhau los ntawm kev hloov pauv martensitic thiab nthuav dav hauv ntim. Txawm li cas los xij, vim yog qhov kev txwv ntawm txheej saum npoo hloov pauv nrog qis plasticity thiab lub zog siab, nws qhov kev ntxhov siab kawg yuav nyob rau hauv daim ntawv ntawm kev ntxhov siab nto, thiab lub hauv paus yuav Nyob rau hauv siab. Nws tuaj yeem pom tias qhov kev hloov pauv thiab qhov xwm txheej kawg ntawm kev ntxhov siab hloov pauv theem yog qhov sib txawv kiag li rau kev ntxhov siab thermal. Ntxiv mus, txij li thaum kev ntxhov siab hloov pauv theem tshwm sim ntawm qhov kub qis nrog qis plasticity, deformation nyuaj rau lub sijhawm no, yog li kev ntxhov siab hloov pauv theem yuav ua rau tawg ntawm qhov workpiece.
Muaj ntau yam uas cuam tshuam rau qhov loj ntawm kev ntxhov siab hloov pauv theem. Qhov ceev ntawm cov hlau txias hauv qhov kub hloov pauv martensite, qhov loj dua ntawm cov hlau, qhov thermal conductivity ntawm cov hlau phem dua, qhov ntim tshwj xeeb ntawm martensite loj dua, qhov kev ntxhov siab hloov pauv theem ntau dua. Nws loj dua. Tsis tas li ntawd, kev ntxhov siab hloov pauv theem kuj tseem cuam tshuam nrog cov khoom sib xyaw ntawm cov hlau thiab qhov tawv ntawm cov hlau. Piv txwv li, cov hlau carbon siab siab ua rau qhov ntim tshwj xeeb ntawm martensite nce vim nws cov ntsiab lus carbon siab, uas yuav tsum ua rau kev ntxhov siab hloov pauv theem ntawm cov hlau nce. Txawm li cas los xij, thaum cov ntsiab lus carbon nce, Ms point txo qis, thiab muaj ntau ntawm austenite khaws cia tom qab quenching. Nws qhov ntim nthuav dav txo qis thiab kev ntxhov siab seem qis.
(2) Kev puas tsuaj ntawm cov khoom ua haujlwm thaum lub sijhawm quenching
Thaum lub sijhawm quenching, muaj ob hom kev hloov pauv tseem ceeb hauv qhov workpiece: ib qho yog qhov kev hloov pauv ntawm cov duab geometric ntawm qhov workpiece, uas yog qhia ua qhov kev hloov pauv ntawm qhov loj me thiab cov duab, feem ntau hu ua warping deformation, uas yog tshwm sim los ntawm kev ntxhov siab quenching; qhov tod yog ntim deformation. , uas qhia nws tus kheej ua qhov kev nthuav dav lossis kev cog lus ntawm qhov ntim ntawm qhov workpiece, uas yog tshwm sim los ntawm kev hloov pauv ntawm qhov ntim tshwj xeeb thaum lub sijhawm hloov pauv theem.
Kev hloov pauv ntawm cov khoom kuj suav nrog kev hloov pauv ntawm cov duab thiab kev hloov pauv ntawm cov khoom. Kev hloov pauv ntawm cov khoom feem ntau yog los ntawm kev tso cov khoom ua haujlwm tsis raug hauv lub cub tawg thaum lub sijhawm cua sov, lossis tsis muaj kev kho cov duab tom qab kho cov khoom ua ntej quenching, lossis txias tsis sib xws ntawm ntau qhov ntawm cov khoom ua haujlwm thaum cov khoom ua haujlwm txias. Qhov kev hloov pauv no tuaj yeem tshuaj xyuas thiab daws tau rau cov xwm txheej tshwj xeeb. Cov hauv qab no feem ntau tham txog kev hloov pauv ntawm qhov ntim thiab kev hloov pauv ntawm cov duab.
1) Ua rau muaj kev hloov pauv ntawm cov qauv thiab nws cov cai hloov pauv
Qhov ntim deformation los ntawm kev hloov pauv ntawm cov qauv Lub xeev ntawm cov khoom ua haujlwm ua ntej quenching feem ntau yog pearlite, uas yog, cov qauv sib xyaw ntawm ferrite thiab cementite, thiab tom qab quenching nws yog cov qauv martensitic. Cov ntim tshwj xeeb sib txawv ntawm cov ntaub so ntswg no yuav ua rau muaj kev hloov pauv ntim ua ntej thiab tom qab quenching, ua rau deformation. Txawm li cas los xij, qhov kev hloov pauv no tsuas yog ua rau cov khoom ua haujlwm nthuav dav thiab cog lus sib npaug, yog li nws tsis hloov pauv cov duab ntawm cov khoom ua haujlwm.
Ntxiv mus, qhov ntau martensite hauv cov qauv tom qab kev kho cua sov, lossis qhov siab dua cov pa roj carbon hauv martensite, qhov ntau dua nws qhov ntim nthuav dav, thiab qhov ntau dua ntawm cov austenite khaws cia, qhov tsawg dua qhov ntim nthuav dav. Yog li ntawd, qhov kev hloov pauv ntim tuaj yeem tswj tau los ntawm kev tswj cov ntsiab lus sib piv ntawm martensite thiab cov martensite seem thaum lub sijhawm kho cua sov. Yog tias tswj tau zoo, qhov ntim yuav tsis nthuav dav lossis ntsws.
Kev hloov pauv ntawm cov duab los ntawm kev ntxhov siab thermal Kev hloov pauv los ntawm kev ntxhov siab thermal tshwm sim hauv thaj chaw kub siab uas lub zog ntawm cov khoom hlau qis, qhov plasticity siab, qhov chaw txias sai, thiab qhov kub sib txawv ntawm sab hauv thiab sab nraud ntawm qhov workpiece yog qhov loj tshaj plaws. Lub sijhawm no, kev ntxhov siab thermal tam sim ntawd yog kev ntxhov siab tensile ntawm qhov chaw thiab kev ntxhov siab compressive ntawm lub hauv paus. Txij li thaum qhov kub ntawm lub hauv paus siab thaum lub sijhawm no, lub zog tso zis qis dua qhov chaw, yog li nws qhia tau tias yog kev hloov pauv nyob rau hauv qhov kev ua ntawm ntau qhov kev ntxhov siab compressive, uas yog, lub voos xwmfab yog spherical hauv kev coj. Ntau yam. Qhov tshwm sim yog tias qhov loj dua shrinks, thaum qhov me dua nthuav dav. Piv txwv li, lub tog raj kheej ntev luv luv hauv qhov ntev thiab nthuav dav hauv qhov txoj kab uas hla.
Kev hloov pauv ntawm cov duab los ntawm kev ntxhov siab ntawm cov ntaub so ntswg Kev hloov pauv ntawm cov ntaub so ntswg los ntawm kev ntxhov siab ntawm cov ntaub so ntswg kuj tshwm sim thaum ntxov thaum kev ntxhov siab ntawm cov ntaub so ntswg siab tshaj plaws. Lub sijhawm no, qhov sib txawv ntawm qhov kub thiab txias ntawm qhov chaw txiav yog loj, qhov kub ntawm lub hauv paus yog siab dua, nws tseem nyob hauv lub xeev austenite, qhov plasticity zoo, thiab lub zog tso zis qis. Kev ntxhov siab ntawm cov ntaub so ntswg tam sim ntawd yog kev ntxhov siab ntawm qhov chaw thiab kev ntxhov siab ntawm lub hauv paus. Yog li ntawd, qhov kev hloov pauv yog pom tseeb tias yog kev nthuav dav ntawm lub hauv paus nyob rau hauv kev ua ntawm kev ntxhov siab ntawm ntau txoj kev. Qhov tshwm sim yog tias nyob rau hauv kev ua ntawm kev ntxhov siab ntawm cov ntaub so ntswg, sab loj dua ntawm qhov workpiece ntev dua, thaum sab me dua luv dua. Piv txwv li, kev hloov pauv ntawm kev ntxhov siab ntawm cov ntaub so ntswg hauv lub tog raj kheej ntev yog kev nthuav dav hauv qhov ntev thiab txo qis hauv txoj kab uas hla.
Rooj 5.3 qhia txog cov cai ntawm kev quenching deformation ntawm ntau yam khoom siv hlau.
2) Cov yam ntxwv uas cuam tshuam rau kev quenching deformation
Cov yam tseem ceeb uas cuam tshuam rau qhov kev hloov pauv quenching yog feem ntau yog cov tshuaj lom neeg ntawm cov hlau, cov qauv qub, cov qauv ntawm cov khoom thiab cov txheej txheem kho cua sov.
3) Tua cov kab nrib pleb
Cov kab nrib pleb hauv cov khoom feem ntau tshwm sim thaum kawg ntawm kev quenching thiab txias, uas yog, tom qab kev hloov pauv martensitic tiav lawm lossis tom qab txias tag, kev ua tsis tiav brittle tshwm sim vim tias qhov kev ntxhov siab tensile hauv cov khoom ntau dua li lub zog tawg ntawm cov hlau. Cov kab nrib pleb feem ntau yog perpendicular rau qhov kev taw qhia ntawm qhov siab tshaj plaws tensile deformation, yog li ntau hom kab nrib pleb hauv cov khoom feem ntau nyob ntawm lub xeev faib kev ntxhov siab.
Cov hom kab nrib pleb uas nquag siv: Cov kab nrib pleb ntev (axial) feem ntau yog tsim thaum lub zog tensile tangential siab tshaj qhov tawg ntawm cov khoom siv; cov kab nrib pleb transverse yog tsim thaum lub zog tensile axial loj tsim rau sab hauv ntawm qhov chaw ntau dua qhov tawg ntawm cov khoom siv. Cov kab nrib pleb; cov kab nrib pleb network yog tsim nyob rau hauv qhov kev ua ntawm ob-seem tensile kev nyuaj siab ntawm qhov chaw; cov kab nrib pleb peeling tshwm sim hauv ib txheej nyias heev, uas yuav tshwm sim thaum lub zog hloov pauv sai thiab kev ntxhov siab tensile ntau dhau ua rau hauv qhov kev taw qhia radial. Hom kab nrib pleb.
Cov kab nrib pleb ntev kuj hu ua cov kab nrib pleb axial. Cov kab nrib pleb tshwm sim ntawm qhov siab tshaj plaws tensile ze ntawm qhov chaw ntawm qhov, thiab muaj qee qhov tob mus rau hauv nruab nrab. Cov kev taw qhia ntawm cov kab nrib pleb feem ntau yog sib luag rau lub axis, tab sis cov kev taw qhia kuj tseem yuav hloov pauv thaum muaj kev ntxhov siab hauv qhov lossis thaum muaj cov qauv sab hauv.
Tom qab ua tiav qhov workpiece quenched, cov kab nrib pleb ntev yuav tshwm sim. Qhov no yog txuam nrog rau qhov loj tangential tensile kev nyuaj siab ntawm qhov chaw ntawm quenched workpiece. Raws li cov pa roj carbon ntawm cov hlau nce ntxiv, qhov kev nyiam los tsim cov kab nrib pleb ntev nce ntxiv. Cov hlau carbon qis muaj qhov me me ntawm martensite thiab muaj zog thermal kev nyuaj siab. Muaj qhov loj ntawm cov compressive kev nyuaj siab ntawm qhov chaw, yog li nws tsis yooj yim rau quenched. Raws li cov pa roj carbon nce ntxiv, qhov kev nyuaj siab ntawm qhov chaw txo qis thiab qhov kev nyuaj siab ntawm cov qauv nce ntxiv. Tib lub sijhawm, qhov siab tshaj plaws tensile kev nyuaj siab txav mus rau txheej saum npoo. Yog li ntawd, cov hlau carbon siab yuav muaj cov kab nrib pleb ntev quenching thaum overheated.
Qhov loj ntawm cov khoom cuam tshuam ncaj qha rau qhov loj thiab kev faib tawm ntawm kev ntxhov siab seem, thiab nws qhov kev tawg quenching kuj txawv. Cov kab nrib pleb ntev kuj yooj yim tsim los ntawm kev quenching hauv qhov txaus ntshai hla-section loj ntau yam. Tsis tas li ntawd, kev thaiv ntawm cov khoom siv hlau feem ntau ua rau muaj kab nrib pleb ntev. Txij li thaum feem ntau cov khoom hlau yog ua los ntawm kev dov, cov khoom tsis yog kub, carbides, thiab lwm yam hauv cov hlau raug faib raws qhov kev taw qhia deformation, ua rau cov hlau yog anisotropic. Piv txwv li, yog tias cov cuab yeej hlau muaj cov qauv zoo li band, nws lub zog tawg transverse tom qab quenching yog 30% txog 50% me dua li lub zog tawg longitudinal. Yog tias muaj cov yam xws li cov khoom tsis yog kub hauv cov hlau uas ua rau muaj kev ntxhov siab, txawm tias qhov kev ntxhov siab tangential ntau dua li qhov kev ntxhov siab axial, cov kab nrib pleb ntev yooj yim tsim nyob rau hauv cov xwm txheej qis kev ntxhov siab. Vim li no, kev tswj hwm nruj ntawm qib ntawm cov khoom tsis yog hlau thiab qab zib hauv cov hlau yog qhov tseem ceeb hauv kev tiv thaiv cov kab nrib pleb quenching.
Cov yam ntxwv ntawm kev faib tawm ntawm kev ntxhov siab sab hauv ntawm cov kab nrib pleb transverse thiab cov kab nrib pleb arc yog: qhov chaw raug kev ntxhov siab compressive. Tom qab tawm ntawm qhov chaw rau qee qhov deb, kev ntxhov siab compressive hloov mus rau kev ntxhov siab tensile loj. Qhov tawg tshwm sim hauv thaj chaw ntawm kev ntxhov siab tensile, thiab tom qab ntawd thaum kev ntxhov siab sab hauv Nws nthuav dav mus rau qhov chaw ntawm qhov tsuas yog tias nws tau rov faib tawm lossis qhov brittleness ntawm cov hlau ntxiv nce ntxiv.
Cov kab nrib pleb transverse feem ntau tshwm sim hauv cov qhov loj ntawm lub qhov, xws li cov menyuam, cov turbine rotors lossis lwm qhov ntawm lub qhov. Cov yam ntxwv ntawm cov kab nrib pleb yog tias lawv yog perpendicular rau qhov kev taw qhia ntawm axis thiab tawg los ntawm sab hauv mus rau sab nraud. Lawv feem ntau tsim ua ntej raug tawv thiab yog tshwm sim los ntawm kev ntxhov siab thermal. Cov forgings loj feem ntau muaj cov qhov tsis zoo ntawm cov hlau xws li cov qhov hws, cov khoom suav nrog, cov kab nrib pleb forging thiab cov pob dawb. Cov qhov tsis zoo no ua haujlwm ua qhov pib ntawm kev tawg thiab tawg nyob rau hauv qhov kev ua ntawm axial tensile kev ntxhov siab. Arc kab nrib pleb yog tshwm sim los ntawm kev ntxhov siab thermal thiab feem ntau yog faib ua ib daim duab arc ntawm cov qhov uas cov duab ntawm qhov hloov pauv. Nws feem ntau tshwm sim sab hauv lub workpiece lossis ze ntawm cov npoo ntse, grooves thiab qhov, thiab yog faib ua ib daim duab arc. Thaum cov hlau carbon siab nrog lub cheeb tsam lossis tuab ntawm 80 txog 100 hli lossis ntau dua tsis raug quenched, qhov chaw yuav qhia txog kev ntxhov siab compressive thiab qhov chaw yuav qhia txog kev ntxhov siab tensile. Kev ntxhov siab, qhov siab tshaj plaws tensile kev ntxhov siab tshwm sim hauv thaj chaw hloov pauv los ntawm txheej tawv mus rau txheej tsis tawv, thiab arc kab nrib pleb tshwm sim hauv cov chaw no. Tsis tas li ntawd xwb, qhov txias ntawm cov npoo ntse thiab cov ces kaum yog ceev thiab txhua yam raug tua. Thaum hloov mus rau qhov chaw mos mos, uas yog, mus rau thaj chaw tsis tau tawv, qhov siab tshaj plaws ntawm thaj chaw ntxhov siab tshwm sim ntawm no, yog li cov kab nrib pleb arc feem ntau tshwm sim. Qhov txias ntawm qhov ze ntawm lub qhov pin, groove lossis qhov chaw nruab nrab ntawm qhov workpiece qeeb, cov txheej tawv sib xws yog nyias, thiab qhov kev ntxhov siab tensile ze ntawm thaj chaw hloov pauv tawv tuaj yeem ua rau cov kab nrib pleb arc yooj yim.
Cov kab nrib pleb reticular, tseem hu ua cov kab nrib pleb saum npoo av, yog cov kab nrib pleb saum npoo av. Qhov tob ntawm qhov kab nrib pleb yog qhov ntiav, feem ntau nyob ib puag ncig 0.01 ~ 1.5 hli. Lub ntsiab lus tseem ceeb ntawm hom kab nrib pleb no yog tias qhov kev taw qhia ntawm qhov kab nrib pleb tsis muaj feem cuam tshuam rau cov duab ntawm qhov khoom. Ntau cov kab nrib pleb txuas nrog ib leeg los tsim ib lub network thiab tau faib dav dav. Thaum qhov tob ntawm qhov kab nrib pleb loj dua, xws li ntau dua 1 hli, cov yam ntxwv ntawm lub network ploj mus thiab dhau los ua cov kab nrib pleb random lossis faib ntev. Cov kab nrib pleb network muaj feem cuam tshuam rau lub xeev ntawm ob-seem tensile kev ntxhov siab ntawm qhov chaw.
Cov khoom siv hlau uas muaj carbon ntau lossis carburized nrog cov txheej decarburized ntawm qhov chaw yuav ua rau muaj cov kab nrib pleb thaum lub sijhawm quenching. Qhov no yog vim tias cov txheej saum npoo muaj cov pa roj carbon tsawg dua thiab cov ntim tshwj xeeb me dua li cov txheej sab hauv ntawm martensite. Thaum lub sijhawm quenching, cov txheej saum npoo ntawm carbide raug kev nyuaj siab tensile. Cov khoom uas cov txheej dephosphorization tsis tau raug tshem tawm tag nrho thaum lub sijhawm ua haujlwm kho tshuab kuj tseem yuav ua rau muaj cov kab nrib pleb thaum lub sijhawm siab lossis nplaim taws quenching. Txhawm rau kom tsis txhob muaj cov kab nrib pleb zoo li no, qhov zoo ntawm qhov chaw ntawm cov khoom yuav tsum tau tswj hwm nruj me ntsis, thiab yuav tsum tiv thaiv kev vuam oxidation thaum lub sijhawm kho cua sov. Tsis tas li ntawd, tom qab siv lub forging tuag rau ib lub sijhawm, cov kab nrib pleb thermal qaug zog uas tshwm sim hauv cov strips lossis networks hauv qhov thiab cov kab nrib pleb hauv cov txheej txheem sib tsoo ntawm cov khoom quenched txhua tus koom nrog daim ntawv no.
Cov kab nrib pleb tshwm sim hauv thaj chaw nqaim heev ntawm txheej saum npoo. Kev ntxhov siab compressive ua haujlwm hauv axial thiab tangential kev taw qhia, thiab kev ntxhov siab tensile tshwm sim hauv radial kev taw qhia. Cov kab nrib pleb yog sib luag rau qhov chaw ntawm qhov. Kev tev tawm ntawm txheej tawv tom qab qhov chaw quenching thiab carburizing qhov chaw txias yog koom nrog cov kab nrib pleb zoo li no. Nws qhov tshwm sim yog cuam tshuam nrog cov qauv tsis sib xws hauv txheej tawv. Piv txwv li, tom qab alloy carburized hlau txias ntawm qee qhov ceev, cov qauv hauv txheej carburized yog: txheej sab nraud ntawm pearlite zoo heev + carbide, thiab cov txheej hauv qab yog martensite + seem Austenite, txheej sab hauv yog pearlite zoo lossis cov qauv pearlite zoo heev. Txij li thaum qhov ntim tshwj xeeb ntawm cov txheej hauv qab martensite yog qhov loj tshaj plaws, qhov tshwm sim ntawm kev nthuav dav ntim yog tias kev ntxhov siab compressive ua rau txheej saum npoo hauv axial thiab tangential kev taw qhia, thiab kev ntxhov siab tensile tshwm sim hauv radial kev taw qhia, thiab kev hloov pauv kev ntxhov siab tshwm sim rau sab hauv, hloov mus rau lub xeev kev ntxhov siab compressive, thiab cov kab nrib pleb tshwm sim hauv thaj chaw nyias heev uas kev ntxhov siab hloov pauv sai. Feem ntau, cov kab nrib pleb nyob sab hauv uas sib luag rau ntawm qhov chaw, thiab nyob rau hauv cov xwm txheej hnyav yuav ua rau qhov chaw tev tawm. Yog tias qhov txias ntawm cov khoom carburized raug nrawm lossis txo qis, cov qauv martensite sib xws lossis cov qauv pearlite zoo heev tuaj yeem tau txais hauv cov txheej carburized, uas tuaj yeem tiv thaiv qhov tshwm sim ntawm cov kab nrib pleb zoo li no. Tsis tas li ntawd, thaum lub sijhawm siab lossis nplaim taws quenching, qhov chaw feem ntau overheated thiab cov qauv tsis sib xws raws li cov txheej tawv tuaj yeem yooj yim tsim cov kab nrib pleb zoo li no.
Cov kab nrib pleb me me txawv ntawm plaub qhov kab nrib pleb uas tau hais los saum toj no vim tias lawv yog los ntawm kev ntxhov siab me me. Cov kab nrib pleb intergranular uas tshwm sim tom qab quenching, overheating thiab sib tsoo ntawm cov hlau cuab yeej carbon siab lossis cov khoom ua haujlwm carburized, nrog rau cov kab nrib pleb uas tshwm sim los ntawm kev tsis tempering cov khoom quenched raws sijhawm, txhua yam yog cuam tshuam nrog qhov muaj thiab tom qab ntawd nthuav dav ntawm cov kab nrib pleb me me hauv cov hlau.
Yuav tsum tau kuaj xyuas cov kab nrib pleb me me hauv qab lub tshuab microscope. Feem ntau lawv tshwm sim ntawm cov ciam teb austenite qub lossis ntawm qhov sib tshuam ntawm cov ntawv martensite. Qee qhov kab nrib pleb nkag mus rau hauv cov ntawv martensite. Kev tshawb fawb qhia tau hais tias cov kab nrib pleb me me feem ntau tshwm sim hauv cov martensite flaky twinned. Qhov laj thawj yog tias cov martensite flaky sib tsoo nrog ib leeg thaum loj hlob ntawm qhov ceev ceev thiab tsim kev ntxhov siab siab. Txawm li cas los xij, cov martensite twinned nws tus kheej yog brittle thiab tsis tuaj yeem tsim cov yas deformation so kev ntxhov siab, yog li yooj yim ua rau cov kab nrib pleb me me. Cov noob austenite yog coarse thiab qhov cuam tshuam rau cov kab nrib pleb me me nce ntxiv. Qhov muaj cov kab nrib pleb me me hauv cov hlau yuav txo qhov muaj zog thiab plasticity ntawm cov khoom quenched, ua rau muaj kev puas tsuaj ntxov (fracture) ntawm cov khoom.
Yuav kom tsis txhob muaj cov kab nrib pleb me me hauv cov hlau uas muaj cov pa roj carbon ntau, kev ntsuas xws li txo qhov kub thiab txias ntawm cov hlau quenching, tau txais cov qauv martensite zoo, thiab txo cov pa roj carbon hauv martensite tuaj yeem siv tau. Tsis tas li ntawd, kev tempering raws sijhawm tom qab quenching yog ib txoj hauv kev zoo los txo qhov kev ntxhov siab sab hauv. Kev sim tau ua pov thawj tias tom qab tempering txaus saum 200 ° C, cov carbides uas tau precipitated ntawm cov kab nrib pleb muaj cov nyhuv ntawm "welding" cov kab nrib pleb, uas tuaj yeem txo qhov txaus ntshai ntawm cov kab nrib pleb me me.
Qhov saum toj no yog kev sib tham txog cov ua rau thiab cov txheej txheem tiv thaiv ntawm cov kab nrib pleb raws li tus qauv faib cov kab nrib pleb. Hauv kev tsim khoom tiag tiag, qhov faib ntawm cov kab nrib pleb sib txawv vim yog cov yam xws li qhov zoo ntawm cov hlau, cov duab ntawm ib feem, thiab cov txheej txheem ua kub thiab txias. Qee zaum cov kab nrib pleb twb muaj ua ntej kev kho cua sov thiab nthuav dav ntxiv thaum lub sijhawm quenching; qee zaum ntau hom kab nrib pleb yuav tshwm sim hauv tib qho tib lub sijhawm. Hauv qhov no, raws li cov yam ntxwv morphological ntawm cov kab nrib pleb, kev tshuaj xyuas macroscopic ntawm qhov chaw tawg, kev kuaj metallographic, thiab thaum tsim nyog, kev tshuaj xyuas tshuaj lom neeg thiab lwm txoj hauv kev yuav tsum tau siv los ua kev tshuaj xyuas tag nrho los ntawm cov khoom zoo, cov qauv kev teeb tsa mus rau qhov ua rau ntawm kev ntxhov siab kho cua sov kom pom qhov kab nrib pleb. cov ua rau tseem ceeb thiab tom qab ntawd txiav txim siab cov kev ntsuas tiv thaiv zoo.
Kev tshuaj xyuas qhov tawg ntawm cov kab nrib pleb yog ib txoj hauv kev tseem ceeb los tshuaj xyuas qhov ua rau muaj kab nrib pleb. Txhua qhov tawg muaj qhov pib rau kab nrib pleb. Cov kab nrib pleb uas ua kom kub feem ntau pib los ntawm qhov sib sau ua ke ntawm cov kab nrib pleb radial.
Yog tias qhov tawg ntawm qhov chaw muaj nyob rau ntawm qhov chaw ntawm qhov, nws txhais tau tias qhov tawg yog tshwm sim los ntawm kev ntxhov siab ntau dhau ntawm qhov chaw. Yog tias tsis muaj qhov tsis zoo ntawm cov qauv xws li kev suav nrog ntawm qhov chaw, tab sis muaj cov yam ntxwv ntawm kev ntxhov siab xws li cov cim riam loj, cov nplai oxide, cov ces kaum ntse ntawm cov hlau, lossis cov khoom hloov pauv ntawm cov qauv, cov kab nrib pleb tuaj yeem tshwm sim.
Yog tias keeb kwm ntawm qhov tawg yog sab hauv qhov, nws muaj feem cuam tshuam nrog cov khoom tsis zoo lossis kev ntxhov siab sab hauv ntau dhau. Qhov chaw tawg ntawm kev quenching ib txwm yog grey thiab porcelain zoo. Yog tias qhov chaw tawg yog grey tsaus thiab ntxhib, nws yog tshwm sim los ntawm overheating lossis cov ntaub so ntswg qub yog tuab.
Feem ntau hais lus, yuav tsum tsis muaj xim oxidation rau ntawm qhov iav ntawm qhov tawg quenching, thiab yuav tsum tsis muaj decarburization nyob ib puag ncig qhov tawg. Yog tias muaj decarburization nyob ib puag ncig qhov tawg lossis xim oxidized ntawm qhov tawg, nws qhia tau hais tias qhov chaw twb muaj qhov tawg ua ntej quenching, thiab cov kab nrib pleb qub yuav nthuav dav nyob rau hauv kev cuam tshuam ntawm kev ntxhov siab kho cua sov. Yog tias pom cov carbides sib cais thiab cov khoom suav nrog ze ntawm cov kab nrib pleb ntawm qhov, nws txhais tau hais tias cov kab nrib pleb muaj feem cuam tshuam nrog kev sib cais hnyav ntawm carbides hauv cov khoom siv raw lossis muaj cov khoom suav nrog. Yog tias cov kab nrib pleb tsuas yog tshwm sim ntawm cov ces kaum ntse lossis cov duab hloov pauv ntawm qhov chaw tsis muaj qhov xwm txheej saum toj no, nws txhais tau hais tias qhov tawg yog tshwm sim los ntawm kev tsim qauv tsis tsim nyog ntawm qhov chaw lossis kev ntsuas tsis raug los tiv thaiv cov kab nrib pleb, lossis kev ntxhov siab kho cua sov ntau dhau.
Tsis tas li ntawd xwb, cov kab nrib pleb hauv kev kho cua sov thiab cov khoom siv tua nplaim feem ntau tshwm sim ze ntawm txheej tawv. Kev txhim kho cov qauv ntawm txheej tawv thiab txo kev ntxhov siab ntawm kev kho cua sov yog cov hauv kev tseem ceeb kom tsis txhob muaj kab nrib pleb ntawm qhov chaw.
Lub sijhawm tshaj tawm: Tsib Hlis-22-2024