Kev Tshav Kub Kub 4: Ntxawm, Kub, Txiav, Kev Tuag

Txoj kev kho cua sov 4: quenching, tempering, normalizing, annealing

Ua ntej, quenching

1. Dab tsi yog quenching?

Hlau quenching yog ib yam ntawm cov hlau yog rhaub rau ib qho tseem ceeb kub Ac3 (hypoeutectoid steel) los yog Ac1 (hypereutectoid steel) saum toj no, kev txuag hluav taws kub rau ib lub sijhawm, ua kom tag nrho lossis ib feem ntawm cov khoom siv, tom qab ntawd ntau tshaj qhov tseem ceeb txias rate ntawm txias txias txias hauv qab Ms mus rau martensite isothermal nyob ze (los yog Ms) los yog bainite transformation ntawm cov txheej txheem kub txheej txheem. Feem ntau, txoj kev kho tshuaj muaj txhuas cias hlau, tooj hlau hlau, titanium alloy, tempered iav thiab lwm yam khoom los yog kev kho cua sov thaum muaj kev txias txias yog hu ua quenching.

2. Lub hom phiaj ntawm quenching:

1) txhim kho cov khoom siv dag zog ntawm cov khoom hlau lossis cov khoom. Piv txwv: txhim kho txoj kev hnyav thiab hnav tsis zoo ntawm cov cuab yeej, bearings, thiab lwm yam ntxiv, ua kom zoo tshaj plaws ntawm lub caij nplooj ntoos hlav, txhim kho cov khoom sib luag ntawm cov qhov sib luag, thiab lwm yam.
2) txhim kho cov khoom lossis cov khoom siv tshuaj ntawm qee cov hlau tshwj xeeb. Xws li kev txhim kho qhov kev xeb ntawm cov hlau tsis huv, ua kom muaj kev sib txawv ntawm hlau nplaum, thiab lwm yam

Kev haus dej txias, ntxiv nrog rau qhov kev xav tau ntawm kev tsim nyog ua kom tsis haum, tab sis kuj yog txoj kev quenching, hom kev quenching, feem ntau yog ib qho kua quenching, ob zaug kua quenching, quenching, isothermal quenching, lub zos quenching.

3. Lub tshuab ua haujlwm hlau muaj cov yam ntxwv nram qab no tom qab quenching:

(1) martensite, bainite, residual austenite thiab lwm yam kauj (uas yog, tsis ruaj tsis khov) cov khoom tau txais.
(2) muaj kev ntxhov siab loj heev.
(3) Cov khoom siv dag zog ua tsis tau raws li cov cai. Yog li ntawd, cov hlau ua hauj lwm tom qab quenching yog feem ntau los ntawm tempering

Thib ob, qhov kub

1. Dab tsi yog qhov kub ntxhov?

Kub tom qab quenching hlau ntoo los yog tej qhov cua kub rau ib qho kub, sov txuag, tom qab ib lub sij hawm nyob rau hauv ib txoj kev txoj kev txias ntawm kev kho cua sov txheej txheem thiab tempering yog tom qab los ntawm ib lub lag luam, tom qab quenching kuj feem ntau workpiece kub kho nyob rau hauv lub kawg ntawm tus txheej txheem, thiab yog li muaj ua ke ntawm quenching thiab tempering txheej txheem hu ua qhov kawg ua.

2. Lub ntsiab tseem ceeb ntawm kev quenching thiab tempering yog:

1) txo cov kev ntxhov siab thiab txo tus txiv neej, muaj ntau txoj kev ntxhov siab thiab brittleness rau hauv kev quenching, xws li tsis timely tempering ntau tsim deformation los yog txawm cracking.
2) Kho cov khoom ua haujlwm ntawm cov khoom ua haujlwm, lub chaw ua haujlwm tom qab quenching, siab tawv, brittleness, kom ua tau raws li ntau yam workpiece txawv kev kawm, yuav raug kho los ntawm tempering, hardness, lub zog, plasticity thiab toughness.
3) tswj kom cov khoom siv me me. Lub cev metallographic tuaj yeem ruaj ntseg los ntawm kev kub siab kom paub meej tias kev lag luam tsis tsim nyob rau yav tom ntej siv.
4) txhawm rau txhim kho kev ua tiav ntawm qee cov hlau txhuam.

3. Cov nyhuv kub:

(1) txhim kho kom ruaj khov ntawm lub koom haum, yog li ntawd cov haujlwm workpiece nyob rau hauv kev siv cov txheej txheem tsis muaj kev hloov ua lub koom txoos, kom lub chaw ua haujlwm geometric loj thiab kev ua haujlwm nyob ruaj khov.
(2) tshem tawm kev ntxhov siab, kom txhawm rau txhim kho kev ua hauj lwm thiab kev ruaj ntseg ntawm cov hauj lwm tiav geometry me me.
(3) kho cov khoom siv hlau ntawm cov hlau kom ua tau raws li kev siv ntawm kev siv.

Yog vim li cas vim li cas chiming cov teebmeem no yog thaum qhov kub hlob, qhov kev ua ntawm atoms yog kho kom zoo, thiab qhov atoms ntawm hlau, cov carbon thiab lwm yam alloying cov ntsiab lus hauv steel yuav diffused sai dua rau ntawm qhov kev hloov thiab ua ke ntawm atoms, yog li kom maj mam txav cov tsis ruaj khov qauv rau hauv ib qho kev ruaj ntseg equilibrium qauv.Qhov kev tshem tawm ntawm kev ntxhov siab yog tseem cuam tshuam rau txo cov hlau zog thaum kub nce. General steel npau, kev ua tsis muaj zog thiab muaj zog, poob zoo dua qub. Qhov kub dua qhov kub, qhov loj dua qhov kev hloov ntawm cov khoom siv no. Qee cov hlau alloy nrog ntau dua cov ntsiab lus ntawm cov hlau, thaum tempered nyob rau hauv tej qhov kub, ntau tshaj plaws precipitate tej co zoo hlau tebchaw, ua lub zog thiab hardness nce. Qhov tshwm sim no yog hu ua theem ob sab.

Tempering yuav tsum: cov workpieces nrog ntau lub hom phiaj yuav tsum tau raug tempered ntawm txawv kub kom tau raws li qhov yuav tsum tau siv.

(1) txiav cov cuab yeej, kev coj, kev sib hlav thiab quenching qhov chaw, qhov chaw quenching feem ntau nyob rau hauv 250 ℃ kub tsawg tempering. Tom qab kub siab thaum qis dua, qhov nyuaj yuav hloov me ntsis, kev ntxhov siab zuj zus thiab cov toughness nce me ntsis.
(2) caij nplooj ntoos hlav nyob rau hauv 350 ~ 500 ℃ nyob rau hauv qhov kub thiab txias, siab elasticity thiab qhov tsim nyog toughness tau.
(3) nyob rau hauv cov pa sib xyaw hlau qhov feem ntau yog ua hauv 500 ~ 600 ℃ high kub tempering, thiaj li yuav tau txais qhov tsim nyog uas muaj zog zoo thiab muaj zog.

Hlau ntawm 300 ℃ tempering, feem ntau ua rau nws brittleness nce, qhov no phenomenon yog hu ua thawj hom kev mob brittleness. Lub cev yuav tsum tsis txhob nquag siv hauv qhov kub thiab txias. Qee cov qaub qaub qaub hlau qis qis dua kuj yuav ua rau nkig yog tias lawv maj mam txias mus rau qhov chaw kub tom qab kub kub. Qhov tshwm sim no yog hu ua ob hom kev txhawj xeeb txog kev chim. Ntxiv molybdenum rau hlau los yog txias hauv cov roj los yog dej thaum lub sij hawm kub ntxhov tuaj yeem tiv thaiv kom txhob muaj ob hom kev mob siab ntxhov siab. Qhov no brittleness yuav tshem tawm los ntawm reheating qhov thib ob hom temper frittle hlau mus rau thawj kub tempering.

Hauv kev tsim, feem ntau raws li kev ua haujlwm ntawm kev ua haujlwm. Raws li qhov sib txawv cua sov kub, lub tempering tau muab faib ua tsawg tempering, medium tempering thiab high tempering. Txoj kev kho thaum tshav kub kub sib txuas ua ke thaum tshem tawm thiab tom qab kub siab kub yog hu ua quenching thiab tempering, uas yog, nws muaj zog thiab zoo tib lub sij hawm.

1) tsawg tempering: 150-250 ℃, M rov qab, txo cov kev ntxhov siab thiab brittleness, zoo dua qub toughness, hnyav dua thiab hnav tsis taus. Siv los ua cov cuab yeej ntsuas, txiav cov cuab yeej thiab dov bearings, thiab lwm yam.
Kub kub nyob rau hauv 2): 350-500 ℃, T rov qab, muaj qhov siab elasticity, muaj qee cov yas thiab qhov nruj. Siv rau cov kwj deg, forging koos, thiab lwm yam.
3) high temperature tempering: 500-650 ℃, S rov qab, muaj qhov sib xyaw zoo txhua yam khoom. Siv rau kev txiav txim siab, crankshafts, thiab lwm yam.

Thib peb, normalizing

1. Dab tsi yog qhov qub?

Normalizing yog ib txoj kev kho cua sov uas pab kho tus toughness ntawm hlau. Tshav hlau cov hlau rau Ac3 tom qab ntau tshaj 30 ~ 50 ℃ , kub txuag rau lub sijhawm ntawm huab cua txias. Tus cwj pwm tseem ceeb yog tias qhov txias ceev ceev dua qhov kev txhawj xeeb tab sis qis tshaj qhov kev sib ntxub. Thaum twg normalizing, cov pob txha crystallized hlau tau ua kom zoo zoo dua qub txias, uas tsis tsuas yog tau txais kev txaus siab, tab sis kuj tuaj yeem txhim kho qhov toughness (AKV tus nqi) thiab txo qhov tawg paj ntawm cov khoom. Tom qab normalizing qee cov hlau qes hlau uas muaj low-alloy kub, cov hlau forging thiab casting qhov chaw, txhua yam khoom siv sib luag ntawm cov ntaub ntawv tuaj yeem zoo tuaj, thiab cov khoom txua tau zoo tuaj.

2. Kev ua tiav yog cov hom phiaj nram qab no thiab SIV:

(1) rau cov hlau hypoeutectoid hlau, normalizing mus tua cov casting, forging, vuam qhov chaw ntawm cov txheej txheem nplaum ntxhib siv thiab cov qauv wechsler, dov hauv cov qauv kab; Txhim kho qoob; Thiab yuav siv tau ua ntej ua kom sov sov ua ntej yuav tau quenching.
(2) rau cov kab mob hypereutectoid steel, normalizing yuav tshem tawm lub network secondary cementite, thiab ua kom pearlite refining, tsis tsuas yog txhim kho cov cuab yeej mechanical, tab sis kuj conducive rau lub neej yav tom ntej spheroidization.
(3) rau cov pa qis sib sib zog nqus hlau phaj, normalizing yuav tua tau cov ciam teb tsis pub cementite, kom nws ua kom tob tob kev ua tau zoo.

(4) rau cov uas tsis muaj carbon tsawg thiab tsis tshua muaj carbon alloy hlau, siv normalizing, tuaj yeem txais nplua nplaum pearlite qauv, ua rau qhov kev ua kom muaj zog ntxiv rau hb140-190, tsis txhob muaj "riam riam" phenomenon thaum txiav, txhim kho kev ua. Rau cov pa nruab nrab, normalizing yog kev yoojyim thiab yoojyim thaum muaj kev ua haujlwm thiab kev ua haujlwm zoo.
(5) rau theem nrab cov qauv carbon steel, nyob rau hauv cov khoom siv dag zog ntawm lub ntees yog tsis siab, yuav siv tsis txhob siv quenching thiab kub kub tempering, tsis tsuas yog yooj yim mus ua hauj lwm, thiab ua hlau qauv thiab loj stability.
( 6 ) high temperature normalizing (150 ~ 200 ℃ saum Ac3) vim tias qhov kub siab tshaj diffusion tshaj tawm yog siab dua, tuaj yeem txo qhov kev sib xyaw cais ntawm castings thiab kev zam txim. Cov co co nplej tom qab kub kub normalizing tau refined los ntawm lub thib ob tom qab normalizing ntawm qis kub.

(7) Tag nrho cov tswv av rau qee yam siv rau kev ua haujlwm ua kom muaj zog thiab cov cua kub ntawm cov qes thiab nruab nrab carbon, cov normalizing feem ntau yog siv kom tau bainite cov qauv, ces los ntawm kev kub siab, thaum siv 400 ~ 550 ℃ muaj peev xwm tiv taus nws .
(8) Ntxiv rau cov hlau thiab hlau, normalizing kuj yog siv dav hauv kev kho cua sov ntawm nodular cam khwb cia hlau, kom nws muaj pearlite matrix, ua kom lub zog ntawm nodular cam khwb cia hlau.

Vim tias normalizing yog huab cua txias, ambient kub, stacking hom, airflow thiab workpiece loj muaj feem rau cov qauv thiab kev kawm tom qab normalizing. Normalizing microstructure kuj tseem siv tau ua ib txoj kev faib tawm rau cov hlau alloy. Feem ntau yog ua raws li cov qauv coj mus rau 900 ℃ rau 25 millimeters inch, huab cua txias ntawm lub koom haum, hlau hlau yuav muab faib ua pearlite, bainite steel, steel martensitic hlau thiab austenitic hlau.

Plaub, pob ntseg

1. Kev mob siab yog dabtsi?

Kev txhim kho yog txoj kev kho cua sov thaum uas cov hlau maj mam rhais mus rau ib qho kub, khaws cia rau ib lub sijhawm txaus, thiab tom qab ntawd txias rau ntawm tus nqi tsim nyog. Kev kho cov cua kub rau lub cev yog muab faib ua kom tiav, tsis muaj kev txhawj thiab tsis muaj kev ntxhov siab. Cov khoom sib txuas ntawm cov khoom siv khib nyiab tuaj yeem soj ntsuam los ntawm kev kuaj qis los yog kev sim siab tawv. Ntau cov phom qhwv hauv lub xeev ntawm kev kho kom sov sov. Rockwell hardness tester yuav siv tau los ntsuam xyuas HRB nyuaj rau kev sib tw steel. Rau cov thinner steel daim hlau, cov tawv steel thiab cov hlua khi hlau, tawv rockwell hardness tester tuaj yeem siv los kuaj HRT nyuaj.

2. Lub hom phiaj ntawm kev ntuav yog:

(1) txhim kho lossis tshem tawm cov hlau hauv casting, forging, rolling thiab welding cov txheej txheem los ntawm ntau hom ntaub so ntswg thiab kev ntxhov siab, kom tiv thaiv kev ua hauj lwm deformation, tawg.
(2) kom mos txoj haujlwm ua haujlwm kom txiav.
(3) ua kom zoo dua qub, txhawm rau txhim kho lub koom haum los txhim kho cov cuab yeej ntawm cov khoom ua haujlwm.
(4) rau qhov kev kho mob kawg thaum kub ntxhov (quenching, tempering) los npaj rau lub koom haum.

3. Cov txheej txheem kev tawm tsam muaj xws li:

(1) Ua kom tiav. Siv cov nplua rau nruab nrab thiab qis carbon steel casting, forging thiab vuam tom qab cov khoom siv dag zog ntawm cov neeg pluag coarse overheating qauv. Tag nrho rau hauv qhov workpiece heated mus rau ferrite austenite kub ntau dua 30 ~ 50 ℃ , qhov kub txuag rau lub sijhawm, thiab tom qab ntawd nrog lub cua txias cua sov, austenite thaum lub caij cua txias dua, hloov ua lub koom haum ntawm cov hlau.

(2) Spheroidizing kev ntuag. Yuav kom txo cov kev kub ntxhov ntawm cov cuab yeej hlau thiab cov kabmob hlau tom qab forging. Lub workpiece heated yuav pib rau austenitic steel kub saum 20 ~ 40 ℃ , txias txias tom qab thaum txuag ntoo, nyob rau hauv tus txheej txheem ntawm txias ntawm pearlite lamellar cementite rau hauv ib lub pob, txo cov hardness.

(3) Isothermal kev ntuag. Yuav kom txo cov kev kub ntxhov ntawm qee qhov sib txawv hlau cov hlau uas muaj cov ntsiab lus nickel thiab chromium rau kev txiav. Feem ntau, cov austenite txias rau qhov kub tsis txaus ntawm lub austenite ntawm ib qho ceev ceev ua ntej, thiab cov kev ua kom tawv nqaij yuav raug txo thaum cov austenite yuav hloov mus rau cov dej thooj av los yog sorbite tom qab cov cua sov txuag kom zoo.

(4) Recrystallization kev ntuag. Yuav kom tshem tawm cov hlau hlau, nyias phaj nyob rau hauv tus txheej txheem ntawm txias daim duab, txias rolling hardening phenomenon (hardness nce, yas poob). Cov cua sov kub feem ntau yog pib ua cov cua txias hauv qab 50 ~ 150 ℃ , tsuas yog nyob rau hauv txoj kev no thiaj tshem tau cov tawv tsis sib haum los kho cov hlau.

(5) Kev thaij duab sib luag. Nws yog siv los hloov cov hlau nrig uas muaj ib qho loj ntawm cementite rau hauv cov pa iron nrog cov yas zoo. Cov ntaub ntawv pov tseg yog cua sov rau 950 ℃ los yog li ntawd, tsim nyog txias tom qab thaum cov sij hawm sov txuag, ua cov qauv cementite decocposition form flocculent mass graphite.

(6) Diffusion kev ntuag. Nws yog siv los homogenize tshuaj lom neeg muaj pes tsawg leeg ntawm alloy casting thiab txhim kho nws txoj kev ua haujlwm. Cov txheej txheem yog ua kom sov lub rhaub kom kub tshaj plaws uas tsis muaj kev kub ntxhov thiab ua kom sov so ntev, thiab tom qab ntawd ces maj mam tom qab tag nrho cov ntsiab lus nyob hauv cov alloy yog diffused thiab tusyees faib.

(7) Kev nyuaj siab pab tiv thaiv kev nyuab siab. Yuav kom tshem tawm cov kev ntxhov siab ntawm hlau castings thiab qhov chaw welding. Rau pib tom qab tsim ntawm austenitic hlau cua kub kub hauv 100 ~ 200 ℃ , tuav hauv huab cua tom qab txias, muaj peev xwm tshem tawm kev ntxhov siab.