Cov khoom siv hluav taws xob ntawm cov khoom siv hlau xa mus rau tus cwj pwm ntawm cov khoom siv hlau nyob rau hauv qhov kev txiav txim ntawm kev thauj khoom sab nraud lossis kev sib xyaw ua ke ntawm kev thauj khoom thiab ib puag ncig (kub, nruab nrab thiab thauj tus nqi).
Common mechanical zog ntawm hlau yog qhia nyob rau hauv cov lus hauv qab no:
Hlau Mechanical Properties
Feem ntau siv hlau mechanical properties index
zog
Yield zog, tensile zog, tawg lub zog
Plasticity
Elongation, txo ntawm cheeb tsam, strain hardening index
elasticity
Elastic modulus (ntshav), elastic txwv, proportional txwv
tawv
Brinell hardness, Vickers hardness, Rockwell hardness
tawv
Static toughness, cuam tshuam toughness, tawg toughness
qaug zog
Fatigue lub zog, qaug zog lub neej, qaug zog notch rhiab heev
kev nyuaj siab corrosion
Kev nyuaj siab corrosion tseem ceeb heev kev nyuaj siab teb qhov tseem ceeb, kev nyuaj siab corrosion tawg loj hlob tus nqi
Tensile stress-strain nkhaus ntawm qis carbon steel nyob rau hauv uniaxial static load
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Mild Steel Tensile Force-Elongation Curve
1. Ntu oa: elastic deformation
2. Ntu ab: elastic deformation ntxiv rau cov yas deformation
3. Bcd seem: pom tseeb yas deformation, tshwm sim tshwm sim, thiab qhov nruam elongation ntawm tus qauv nyob rau hauv cov xwm txheej uas cov quab yuam tseem tsis hloov pauv.
4. dB ntu nkhaus: elastic deformation ntxiv rau cov yas deformation
5. Point B: necking phenomenon tshwm sim, lub zos seem ntawm cov qauv yog obviously txo, bearing peev xwm ntawm tus qauv yog txo, lub tensile quab yuam mus txog qhov siab tshaj plaws tus nqi, thiab cov qauv yog hais txog mus ua txhaum.
lub zog index
Lub zog yog hais txog lub peev xwm ntawm cov khoom siv los tiv thaiv cov yas deformation thiab tawg.
1. Yield zog
σs {{0}} Fs/S0
Fs: lub zog tensile (N) uas tus qauv dais thaum nws tawm los; S0: thawj qhov chaw hla ntu ntawm tus qauv (mm).
2. Lub zog tensile
Qhov siab tshaj plaws tensile kev nyuaj siab uas tus qauv dais ua ntej tawg qhia txog qhov siab tshaj plaws ntawm cov khoom deformation tsis kam.
σb {{0}} Fb/S0
σb feem ntau yog siv los ua lub hauv paus rau kev xaiv cov khoom siv thiab tsim cov khoom nkig.
Yas Performance index
Plasticity yog lub peev xwm ntawm cov khoom siv los ua cov yas deformation nyob rau hauv static load yam tsis ua haujlwm.
1. Elongation tom qab so
Qhov feem pua ntawm qhov elongation ntawm qhov ntsuas qhov ntev tom qab tus qauv tawg mus rau qhov qub ntsuas qhov ntev.
δ{{0}}(L1-L0)/L*100 feem pua
L0: ntsuas qhov ntev; L1: ntsuas qhov ntev ntawm cov khoom kuaj tom qab tawg.
2. Txo qhov chaw
Qhov feem pua ntawm qhov kev txo qis tshaj plaws ntawm qhov chaw hla ntu ntawm cov khoom thim rov qab ntawm cov qauv mus rau qhov qub ntu ntu.
Ψ{{0}}(A0-A1)/A0 * 100 feem pua
A0: Thawj qhov chaw hla ntu ntawm cov qauv; A1: Qhov chaw hla ntawm lub caj dab tom qab tawg.
lub zog index
Lub zog yog hais txog lub peev xwm ntawm cov khoom siv los tiv thaiv cov yas deformation thiab tawg.
1. Yield zog
σs {{0}} Fs/S0
Fs: lub zog tensile (N) uas tus qauv dais thaum nws tawm los; S0: thawj qhov chaw hla ntu ntawm tus qauv (mm).
2. Lub zog tensile
Qhov siab tshaj plaws tensile kev nyuaj siab uas tus qauv dais ua ntej tawg qhia txog qhov siab tshaj plaws ntawm cov khoom deformation tsis kam.
σb {{0}} Fb/S0
σb feem ntau yog siv los ua lub hauv paus rau kev xaiv cov khoom siv thiab tsim cov khoom nkig.
Yas Performance index
Plasticity yog lub peev xwm ntawm cov khoom siv los ua cov yas deformation nyob rau hauv static load yam tsis ua haujlwm.
1. Elongation tom qab so
Qhov feem pua ntawm qhov elongation ntawm qhov ntsuas qhov ntev tom qab tus qauv tawg mus rau qhov qub ntsuas qhov ntev.
δ{{0}}(L1-L0)/L*100 feem pua
L0: ntsuas qhov ntev; L1: ntsuas qhov ntev ntawm cov khoom kuaj tom qab tawg.
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2. Txo qhov chaw
Qhov feem pua ntawm qhov kev txo qis tshaj plaws ntawm qhov chaw hla ntu ntawm cov khoom thim rov qab ntawm cov qauv mus rau qhov qub ntu ntu.
Ψ{{0}}(A0-A1)/A0 * 100 feem pua
A0: Thawj qhov chaw hla ntu ntawm cov qauv; A1: Qhov chaw hla ntawm lub caj dab tom qab tawg.
Elasticity Index
Stiffness: Lub peev xwm ntawm cov khoom siv los tiv thaiv elastic deformation thaum muaj kev ntxhov siab.
E=σ/ε
σ: tensile kev nyuaj siab; ε: lub zog tensile
Lub microstructure tsis rhiab rau lub tshuab ua haujlwm Performance index, thiab alloying, kho cua sov, thiab txias yas deformation tsis tshua muaj kev cuam tshuam rau nws.
Mechanical Performance index tseem ceeb rau kev xaiv cov khoom siv ntawm cov tshuab thiab cov khoom siv:
► Lub nqaj tsav tsheb yuav tsum muaj qhov nruj txaus, txwv tsis pub nws yuav ua rau muaj kev vibration vim muaj ntau dhau deflection thaum nqa cov khoom hnyav.
► Tshuab cuab yeej thiab xovxwm spindle, txaj thiab workbench muaj qhov yuav tsum tau rau rigidity los xyuas kom meej machining raug.
►Main Cheebtsam xws li combustion engine, centrifuges thiab compressors yuav tsum muaj rigidity txaus los tiv thaiv kev co.
tawv
Lub peev xwm ntawm qhov chaw hauv cheeb tsam ntawm cov khoom siv los tiv thaiv cov yas deformation thiab tsis ua haujlwm.
Nws yog qhov ntsuas los ntsuas qhov softness thiab hardness ntawm cov khoom, thiab nws lub ntsiab lus ntawm lub cev muaj feem xyuam rau txoj kev xeem.
Txoj kev kuaj Hardness: Brinell hardness, Rockwell hardness, Vickers hardness, Shore hardness, Leeb hardness, Mohs hardness
(1) Brinell hardness
Qhov nruab nrab kev ntxhov siab ib cheeb tsam, uas yog, qhov quotient ntawm qhov kev sim quab yuam p thiab lub ntsej muag kheej kheej ntawm qhov indentation.
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< 450HB: The test indenter is a quenched steel ball, the hardness symbol is HBS;
<650HB: The test indenter is cemented carbide, and the hardness symbol is HBW.
Empirical formula:
Cov pa roj carbon tsawg: σb≈3.6HBS;
High carbon steel: σb≈3.4HBS.
Scope ntawm daim ntawv thov: siv los ntsuas grey cam khwb cia hlau, structural steel, non-ferrous hlau thiab non-metallic cov ntaub ntawv, thiab lwm yam.
Qhov zoo thiab qhov tsis zoo:
Tus nqi ntsuas yog qhov tseeb dua thiab rov ua dua;
Ntsuas cov ntaub so ntswg inhomogeneous;
Tsis haum rau kev soj ntsuam cov khoom tiav thiab cov khoom nyias;
Kev ntsuas yog siv sijhawm thiab tsis muaj txiaj ntsig.
(2) Rockwell hardness
Tus nqi hardness ntawm cov khoom yog qhia los ntawm kev ntsuas qhov tob indentation, thiab txhua txhua 0.002mm yog sib npaug rau 1 Rockwell hardness unit.
Muaj ob hom indenters:
1. Pob zeb diamond cone nrog lub khob hliav qab =120 degree ,
2. Ib qho me me quenched steel pob nrog txoj kab uas hla ntawm Φ1.588mm.
Rockwell hardness xam cov mis:
HR{{0}}(kh)/0.002
Indenter 1: k=0.2 hli; Indenter 2: k=0.26mm.
tus kav
hardness cim
Hom taub hau
Tag nrho kev xeem quab yuam F / N
Ntsuas hardness ntau yam
Daim ntawv thov piv txwv
C
HRC
Pob zeb diamond
1471
20-70
Hardened steel, siab hardness cam khwb cia hlau, pearlitic malleable cam khwb cia hlau
B
HRB
Φ1.588mm steel pob
980.7
20-100
Me me hlau, tooj liab alloy, ferritic malleable hlau
A
HRA
Pob zeb diamond
588.4
20-88
Carbide, Hardened Sheet Steel, Case Hardened Steel
Qhov zoo thiab qhov tsis zoo:
Qhov kev xeem yog yooj yim, yooj yim thiab ceev;
Lub indentation yog me me, thiab cov khoom tiav thiab nyias nyias tuaj yeem ntsuas tau;
Cov ntaub ntawv tsis raug txaus, peb lub ntsiab lus yuav tsum tau ntsuas kom coj tus nqi nruab nrab;
Inhomogeneous cov ntaub ntawv xws li cam khwb cia hlau yuav tsum tsis txhob raug kuaj.
(3) Vickers hardness
Tus nqi hardness yog xam raws li qhov ntsuas quab yuam ib cheeb tsam ntawm indentation.
Lub indenter yog pob zeb diamond quadrangular pyramid nrog lub kaum sab xis ntawm 136 degree ntawm ob qhov chaw sib txawv.
Kev ntsuas ntau:
Nws yog feem ntau siv los ntsuas qhov nyias nyias, txheej txheej, txheej txheej tom qab kev kho cua sov, thiab lwm yam.
Qhov zoo thiab qhov tsis zoo:
Kev ntsuas qhov tseeb thiab ntau yam kev siv (hardness los ntawm mos heev mus rau qhov nyuaj heev);
Ntsuas cov khoom tiav thiab cov khoom nyias;
Cov kev xav tau saum npoo ntawm cov qauv yog siab thiab siv zog ua haujlwm.
Impact toughness
Lub peev xwm ntawm cov khoom siv los tiv thaiv kev puas tsuaj nyob rau hauv kev cuam tshuam loads.
Lub zog cuam tshuam Ak noj thaum tus qauv tawg yog:
Ak=mgH – mgh (J)
Qhov cuam tshuam toughness tus nqi ak yog qhov cuam tshuam lub zog siv rau ib chav tsev hla ntu ntawm qhov ntsuas ntawm tus qauv.
ak {{0}} Ak / S0 (J/cm²)
Tsawg tus nqi - cov khoom siv brittle:
Tsis pom tseeb deformation thaum tawg, nws yog xim hlau luster, crystalline.
High ak nqi - cov khoom tawv:
Pom tseeb yas hloov, qhov tawg yog grey thiab fibrous, npub.
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Fracture toughness
Fracture Mechanics: Nyob rau ntawm qhov chaw lees paub qhov muaj nyob ntawm cov kab nrib pleb hauv lub tshuab, ntau yam tshiab ntawm cov tshuab tawg tau tsim, thiab cov txheej txheem tawg thiab cov khoom tawg yooj yim ntawm lub cev tawg yog npaj.
duab
qaug zog
Fatigue phenomenon:
Qhov tshwm sim tawg tshwm sim los ntawm kev puas tsuaj ntawm cov hlau lossis cov khoom siv nyob rau hauv lub sijhawm ntev ntawm kev hloov pauv ntawm kev ntxhov siab thiab kev nyuaj siab.
Fatigue Features:
(1) Kev qaug zog yog lub voj voog uas tsis tshua muaj kev ntxhov siab ncua sij hawm ncua kev puas tsuaj, thiab kev nyuaj siab puas feem ntau qis dua lub zog tensile ntawm cov khoom, lossis txawm tias lub zog tawm los;
(2) Kev qaug zog yog ib qho nkig thiab tam sim ntawd tawg, thiab yuav tsis muaj qhov pom tseeb ntawm deformation ua ntej qhov tawg, uas yog qhov txaus ntshai heev;
(3) Kev qaug zog yog rhiab heev rau qhov tsis zoo, cov kab nrib pleb thiab cov yam ntxwv tsis xws luag, thiab xaiv tau zoo heev.
Fatigue limit σ-1:
Tus nqi siab tshaj plaws ntawm cov khoom siv tau dhau los ntawm ntau lub voj voog kev ntxhov siab yam tsis muaj kev qaug zog tawg.
Cov xwm txheej qaug zog txwv:
Tus nqi siab tshaj plaws uas tuaj yeem tiv taus 107 lub voj voog kev ntxhov siab yam tsis muaj kev tawg.
Empirical formula ntawm steel qaug zog lub zog:
σ-1= (0.45-0.55)σb
los yog σ-1= 0.27(σs plus σb)
σ-1p= 0.23(σs plus σb)
02
Kev kho cua sov txheej txheem
Txhais: Cov txheej txheem ntawm kev hloov cov qauv sab hauv ntawm cov khoom hlau lossis hlau los ntawm cov cua sov, kev txuag hluav taws xob thiab cua txias kom tau txais cov khoom tsim nyog.
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Lub hom phiaj: Ib qho yog txhawm rau txhim kho cov txheej txheem kev ua tau zoo ntawm cov ntaub ntawv thiab xyuas kom meej qhov kev vam meej ntawm kev ua haujlwm tom ntej. Qhov kev kho cua sov no yog hu ua kev kho cua sov ua ntej; lwm qhov yog txhawm rau txhim kho kev ua haujlwm ntawm cov khoom siv thiab ua kom lub neej ua haujlwm ntev ntawm cov khoom. Qhov kev kho cua sov no yog hu ua kev kho cua sov zaum kawg.
Kev faib tawm ntawm kev kho cua sov:
Kev kho cua sov zoo tib yam (plaub qhov hluav taws kub: annealing, normalizing, quenching, tempering)
Kev kho cua sov saum npoo (nto quenching, tshuaj kho cua sov)
Lwm yam kev kho cua sov (kev kho cua sov, kev kho cua sov deformation, thiab lwm yam)
Microstructural transformation ntawm eutectoid hlau thaum cua sov
Plaub kauj ruam hauv kev hloov pauv ntawm pearlite rau austenite:
(1) Austenite nucleation;
(2) Austenite kev loj hlob;
(3) Qhov seem Fe3C yaj;
(4) Homogenization ntawm austenite.
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Cov qauv kev hloov pauv ntawm cov hlau thaum txias
Txias transformation ntawm austenite: Austenite yog ib theem ruaj khov tshaj qhov tseem ceeb ntawm A1, thiab nws yuav dhau los ua ib theem tsis ruaj khov thaum nws txias hauv qab A1, thiab cov qauv hloov pauv yuav tshwm sim.
Qhov tseem ceeb: Txiav txim siab cov qauv thiab cov khoom ntawm cov hlau tom qab kev kho cua sov. Rau tib cov hlau, qhov kub thiab txias ntawm lub sijhawm tuav yog tib yam, tab sis cov txheej txheem txias yog txawv, thiab cov khoom tom qab kev kho cua sov yog txawv kiag li.
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Mechanical zog ntawm 45 steel rhuab mus rau 840 degree thiab txias nyob rau hauv txawv txias txias
txoj kev ua kom txias
σb/Mpa
σs/Mpa
d / feem pua
ψ/ feem pua
HRC
Txias nrog lub qhov cub
519
272
32.5
49
15~18
cua txias
657~706
333
15~18
45~50
18~24
txias hauv roj
882
608
18~20
48
40~50
dej txias
1078
706
7~8
12~14
52~60
Tsim kom muaj isothermal transformation nkhaus ntawm supercooled austenite hauv eutectoid steel (metallographic hardness method)
Kuj hu ua "TTT nkhaus" (Lub Sijhawm-Temperature-Transformation Curve), vim tias cov duab zoo ib yam li "C", feem ntau hu ua "C nkhaus".
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Nrog kev pab los ntawm "C nkhaus", nws muaj peev xwm nkag siab tias hom qauv austenite hloov mus rau hauv cov cua txias sib txawv thiab cov khoom ntawm cov khoom hloov pauv, muab lub hauv paus theoretical rau kev tsim kom raug thiab xaiv cov txheej txheem kho cua sov.
Eutectoid steel C nkhaus thiab transformation khoom
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1) Pearlite hom transformation (tseem hu ua kub hloov pauv)
Kev hloov pauv kub: A1 ~ 550 degree; Transformation khoom: pearlite
A1 ~ 6500 degree: daim ntawv pearlite yog tuab, P (pearlite-pearlite)
6500 degree ~ 6000 degree: Pearlite txheej yog nyias, S (Sorbite-sorbite)
6000 degree ~ 5500 degree: pearlite txheej zoo heev, T (troolstite)
duab
Lub thickness ntawm ferrite thiab cementite lamellar txheej ntawm pearlite muaj feem xyuam rau kev hloov pauv kub. Qhov kub thiab txias, qhov zoo dua cov pearlite lamellae. Cov khaubncaws sab nraud povtseg ua thinner, lub zog thiab hardness nce, thiab cov yas toughness nce.
2) Bainitic transformation (tseem hu ua qhov nruab nrab kub hloov pauv)
Kev hloov pauv kub: 550-Ms (230 degree)
Cov khoom hloov pauv: Bainite B (bainite) - kev sib xyaw ntawm supersaturated F thiab cementite.
duab
550 ~ 350 degree: sab sauv bainite (saum B) feathery qauv, tsis tshua muaj zog thiab yas, siab brittleness.
350 degree ~ Ms: qis bainite (qis B) koob zoo li qauv, kev ua haujlwm zoo.
duab
3) Martensitic transformation (tseem hu ua low temperature transformation)
Kev hloov pauv kub: Ms (230 degree) ~ Mf
Cov khoom hloov pauv: martensite (martensite) ntxiv rau A'(residual austenite)
Martensite: Ib qho kev daws teeb meem supersaturated carbon tsim hauv -Fe, sawv cev los ntawm M.
Kev faib tawm:
Tsawg carbon martensite (tsawg carbon martensite): Lath-zoo li, muaj zog thiab ductility. Kuj tseem hu ua lath M (lath martensite).
High carbon martensite (high carbon martensite): lenticular, zoo li daim ntawv, nrog ridges nyob rau hauv nruab nrab. Nws muaj lub zog siab, tab sis tsis zoo ductility thiab siab brittleness.
Image] [duab
C nkhaus ntawm hypoeutecoid steel
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C nkhaus ntawm hypereutecoid steel
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Supercooled austenite nruam transformation txias nkhaus (CCT nkhaus) (Continuous Cooling Transformation)
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annealing
Lus Txhais: Cua sov hlau mus rau qhov kub thiab txias, tswj nws rau lub sijhawm txaus, thiab tom qab ntawd txias nws ntawm tus nqi tsim nyog
Lub hom phiaj:
ua kom cov nplej;
Txo qhov hardness thiab txhim kho kev tsim thiab txiav kev ua haujlwm ntawm cov hlau;
Tshem tawm kev ntxhov siab sab hauv.
Kev faib tawm: Raws li lub hom phiaj thiab txheej txheem cov yam ntxwv ntawm annealing, nws tuaj yeem muab faib ua tiav annealing, tsis tiav annealing, isothermal annealing, spheroidizing annealing, kev nyuaj siab annealing, thiab lwm yam.
tag nrho annealing
l Scope ntawm daim ntawv thov: hypoeutecoid steel
lHeating kub: Ac3 ntxiv rau 30-50 degree
l Lub hom phiaj: txhawm rau txhim kho cov qauv, txo qhov hardness, txhim kho machinability,
Tshem tawm kev ntxhov siab sab hauv
l Cov ntaub so ntswg kub: F ntxiv rau P
duab
Spheroidizing annealing
Scope ntawm daim ntawv thov: eutectoid steel thiab hypereutectoid steel
Kub kub: Ac1 ntxiv rau 20 ~ 30 degree
Lub hom phiaj: kom spheroidize reticular los yog flake Fe3CⅡ
Lub koom haum: spherical pearlite
duab
isothermal annealing
Cov txheej txheem: Cua sov rau Ac1 ntxiv rau 30 ~ 50 degree lossis Ac3 ntxiv rau 30 ~ 50 degree, tom qab ua kom sov, txias sai rau qhov kub hauv qab Ar1, thaum A tau hloov mus rau P-hom ntaub so ntswg, tshem tawm ntawm lub qhov cub thiab cua txias. .
Lub koom haum: Chav Kawm P
Qhov zoo: lub sijhawm luv annealing, cov qauv zoo ib yam
duab
Relief annealing
Lub hom phiaj: tshem tawm cov kev ntxhov siab seem
cua sov
Kub: T cua sov Daim ntawv thov: Tshem tawm cov kev ntxhov siab sab hauv ntawm castings, forgings, weldments, thiab lwm yam. duab Homogenization annealing (diffusion annealing) Hom phiaj: Tshem tawm kev cais tawm; uniform composition, koom haum Qhov kub thiab txias: AC3 + 150-250 degree Lub koom haum: hypoeutectoid steel yog P ntxiv F. Daim ntawv thov: Feem ntau yog siv rau alloy steel ingots, castings thiab forgings nrog cov kev xav tau zoo. Recrystallization annealing Cov txheej txheem: Cua sov rau 50-150 degree hauv qab Ac1, lossis T ntxiv rau 30-50 degree, ua kom sov thiab txias maj mam. Lub hom phiaj: Tshem tawm kev ua haujlwm hardening thiab rov ua kom cov plasticity thiab toughness ntawm cov hlau. Daim ntawv thov: Tshem tawm kev ua haujlwm hardening ntawm workpieces tom qab ua haujlwm txias. Xws li lub annealing nyob rau hauv nruab nrab ntawm cov hlau hlau kos duab txheej txheem. Txhais: Cov txheej txheem kho cua sov uas cov khoom ua haujlwm tau ua kom sov rau 30-50 degree saum toj no Ac3 lossis Accm, tshem tawm ntawm lub qhov cub tom qab kev txuag hluav taws xob, thiab txias hauv huab cua. Lub hom phiaj: Tsawg carbon steel: nce hardness thiab pab txiav. Hypereutectoid steel: Tshem tawm cov reticular secondary cementite, uas yog qhov zoo rau P spheroidization. Nruab nrab-carbon steel thiab nruab nrab-carbon low-alloy steel: qhov kev ntxhov siab tsis loj, thiab cov kev xav tau ntawm kev ua haujlwm tsis siab, uas tuaj yeem siv los ua kev kho cua sov zaum kawg. duab duab Lub hom phiaj: kom tau txais cov qauv hauv qab M lossis B, thiab txhim kho hardness thiab hnav tsis kam ntawm cov hlau. Kev xaiv ntawm quenching kub Hypoeutectoid steel: AC3 ntxiv rau 30-50 degree ; Eutectoid steel thiab hypereutectoid steel: AC1 ntxiv rau 30-50 degree . duab quenching cua txias yog tus yuam sij rau kev txiav txim siab qhov zoo ntawm quenching, thiab qhov zoo tshaj plaws cua txias yuav tsum yog raws li qhia hauv daim duab. Tshaj 650 degree, qeeb, txo thermal stress 650-400 degree, ceev, zam C nkhaus Hauv qab 400 degree, qeeb, txo cov theem hloov kev ntxhov siab duab Feem ntau siv quenching nruab nrab Tam sim no, cov khoom siv cua txias tshaj plaws hauv kev tsim khoom yog roj, dej, thiab brine, thiab lawv lub peev xwm txias tau nce zuj zus. Dej: muaj peev xwm quenching muaj zog, tab sis muaj qhov muag muag ntawm qhov chaw ua haujlwm, uas yooj yim rau deform thiab tawg. Cov dej ntsev: lub peev xwm quenching muaj zog dua, qhov chaw ntawm lub workpiece yog du thiab huv, tsis muaj qhov muag muag, tab sis nws yooj yim dua rau deform thiab tawg; Roj: Lub peev xwm quenching tsis muaj zog, tab sis lub workpiece tsis yooj yim rau deform thiab tawg Common quenching txias method (quench cooling method) duab Txhais: duab Lub hom phiaj tseem ceeb ntawm tempering Tshem tawm sab hauv kev ntxhov siab thiab txo qhov brittleness Cov ntaub so ntswg ruaj khov thiab workpiece qhov ntev Txo hardness, txhim kho plasticity Hloov cov qauv thiab cov khoom ntawm tempering Cov txheej txheem hloov pauv ntawm quenched steel thaum tempering mas tshwm sim nyob rau hauv lub cua sov theem. Raws li cov cua kub kub nce, cov qauv ntawm quenched steel undergoes plaub theem ntawm kev hloov. 1. Decomposition ntawm martensite Tempering: Thaum tempering ntawm<100°C, the structure does not change; when heating at 100~200°C, martensite will decompose. Tau txais lub koom haum: tempered martensite M times (supersaturated solid solution). Kev hloov pauv kev ua haujlwm: qhov kev ntxhov siab sab hauv maj mam txo qis, thiab qhov kev ua tau zoo tseem zoo li qub. 2. Decomposition ntawm khaws cia austenite Tempering kub: 200-300 degree . A 'decomposes thiab transforms rau hauv B. Tau txais lub koom haum: M (Tempered Martensite) qhia Kev hloov pauv kev ua haujlwm: Cov kev ntxhov siab ntxiv yog txo, thiab lub zog thiab hardness yog me ntsis txo. 3. Lub decomposition ntawm martensite tiav thiab tsim cov cementite Tempering kub: 300-400 degree . ε carbides hloov mus rau hauv cov cementite ruaj khov. Tau txais lub koom haum: Tempered Troostite, sawv cev los ntawm T (Tempered Troostite). Kev hloov pauv kev ua haujlwm: qhov kev ntxhov siab sab hauv yog qhov yooj yim tshem tawm, hardness txo, thiab cov yas toughness nce. 4. Fe3C aggregate kev loj hlob thiab rov qab thiab recrystallization ntawm cov khoom tov Tempering: siab tshaj 400 degree. Cov theem pib rov zoo, thiab recrystallization tshwm sim saum 500 degree; Tau txais lub koom haum: Tempered Sorbite, sawv cev los ntawm S (Tempered Sorbite). Kev hloov pauv kev ua tau zoo: kev ua tau zoo tag nrho tau txais. Microstructure thiab mechanical zog ntawm tempered steel khoom siv tes ua tempering kub (degree) Cov ntaub so ntswg tom qab tempering Hardness tom qab tempering (HRC) Nta siv tsis kub tempering 150-250 M rov 58-64 High hardness, hnav tsis kam; brittleness, txo kev ntxhov siab sab hauv cov cuab yeej steel, Rolling bearings, carburized qhov chaw, thiab lwm yam. Nruab nrab kub tempering 250-500 T rov 35-50 Ntau dua elastic txwv thiab tawm los txwv, nrog qee yam plasticity thiab toughness caij nplooj ntoos hlav steel, Kub ua hauj lwm pwm kub tempering 500-600 S rov qab 25-35 zoo tag nrho kev ua tau zoo cov yam ntxwv tseem ceeb Kev sib hloov ntawm cov khoom siv kho tshuab hloov pauv thaum lub sij hawm tempering: Nrog rau qhov kub ntawm tempering, lub zog thiab hardness ntawm steel txo, thiab plasticity thiab toughness nce. Surface Heat Treatment (Kev kho cua sov saum npoo) Kev kho cua sov saum npoo: txheej txheem kev kho cua sov uas tsuas yog ua kom sov ntawm qhov chaw ua haujlwm kom hloov nws cov qauv thiab cov khoom. Classification: nto quenching thiab tshuaj kho cua sov. Hauv kev tsim khoom, muaj ntau qhov chaw uas xav tau qhov chaw thiab cov tub ntxhais kom muaj cov khoom sib txawv. Feem ntau, qhov saum npoo muaj siab hardness, hnav tsis kam thiab qaug zog; thaum cov tub ntxhais xav tau zoo dua plasticity thiab toughness. Hauv qhov no, pib los ntawm kev xaiv cov khoom siv ib leeg lossis siv cov kev kho cua sov zoo tib yam tsis tuaj yeem ua tau raws li qhov xav tau. Txoj hauv kev los daws qhov teeb meem no yog kev kho cua sov saum npoo. nto quenching Txhais: Cov txheej txheem kev kho cua sov uas tsuas yog quenches (ntxiv rau tempers) saum npoo ntawm lub workpiece Lub hom phiaj: Ua kom lub ntsej muag ntawm lub workpiece nyuaj thiab tawv. Hlau rau saum npoo hardening: nruab nrab carbon structural steel (0.4 feem pua -0.5 feem pua carbon ntsiab lus) Txoj kev: nto hardening los ntawm induction cua sov thiab nto hardening los ntawm nplaim hluav taws kub. Induction nto quenching Lub hauv paus ntsiab lus: Lub kauj induction yog pub nrog alternating tam sim no → ua ib qho eddy tam sim no (cov nyhuv ntawm daim tawv nqaij) → tau txais A ntawm qhov chaw → tau txais M los ntawm dej txias. Kev faib tawm: High zaus induction cua sov: 2 00 ~ 300kHz, 0.5 ~ 2.5mm; Nruab nrab zaus induction cua sov: 0.5 ~ 10kHz, 2 ~ 10mm; Lub zog zaus induction cua sov: 50Hz, 10-20 hli. nplaim hluav taws kub nto quenching Lus Txhais: Cov nplaim hluav taws kub kub quenching yog daim ntawv thov ntawm oxy-acetylene (los yog lwm yam combustible gas) nplaim taws kom sov rau saum npoo ntawm qhov chaw thiab ces quench lawv sai. Qhov tob ntawm txheej hardened feem ntau yog 2 mus rau 6 hli. Daim ntawv thov: haum rau ib thooj thiab me me batch ntau lawm. Kev kho cua sov ntawm cov hlau Txhais: Cov txheej txheem kev kho cua sov uas ib feem ntawm cov hlau tau khaws cia hauv qhov nruab nrab ntawm qhov kub thiab txias kom tso cai rau ib lossis ob peb lub ntsiab lus nkag mus rau hauv nws qhov chaw los hloov nws cov tshuaj muaj pes tsawg leeg, qauv thiab kev ua haujlwm. Kev faib tawm: Raws li cov khoom sib txawv infiltrated, tshuaj kho cua sov tuaj yeem muab faib ua carburizing, nitriding, carbonitriding, boronizing, aluminizing, thiab lwm yam. Basic txheej txheem: ① Decomposition: Ua kom cov tshuaj nruab nrab decompose cov active atoms uas nkag mus rau hauv cov ntsiab lus thaum lub sij hawm cua sov thiab kub preservation txheej txheem; ② Absorption: Active atoms yog adsorbed los ntawm qhov chaw ntawm lub workpiece los tsim cov kev daws teeb meem los yog cov sib txuas tshwj xeeb; ③ Diffusion: Cov infiltrated atoms diffuse inwardly los ntawm qhov chaw ntawm lub workpiece los tsim ib tug diffusion txheej nrog ib tug tej yam tob, uas yog, infiltrated txheej. Carburizing ntawm steel (Carburize ntawm steel) duab Lub hom phiaj: txhawm rau txhim kho hardness thiab hnav tsis kam ntawm workpiece nto Hlau rau carburizing: qis carbon steel lossis qis carbon alloy steel Nruab Nrab: feem ntau siv cov pa roj (kerosene, benzene, thiab lwm yam), nrog rau cov pa roj carbon activated. Kub: hauv thaj tsam austenite, 900-950 degree Sijhawm: Nyob ntawm qhov tob ntawm txheej seepage, txog 10 teev. Lwm txoj kev kho cua sov Nitriding: Cov txheej txheem kho cua sov uas nkag mus rau cov khoom siv nitrogen atoms rau hauv qhov chaw ntawm qhov chaw ua haujlwm ntawm qhov kub thiab txias. Txhim kho qhov tawv tawv, hnav tsis kam, qaug zog lub zog, thermal hardness thiab corrosion kuj ntawm qhov chaw. Carbonitriding (carbonitriding): Cov pa roj carbon thiab nitrogen nkag mus rau hauv qhov chaw ntawm lub workpiece tib lub sijhawm. Txhim kho deg hardness, qaug zog tiv thaiv thiab hnav tsis kam, thiab muab cov txiaj ntsig zoo ntawm carburizing thiab nitriding. Chromizing: Nws muaj kev tiv thaiv corrosion zoo thiab zoo heev oxidation tsis kam, hardness thiab hnav tsis kam, thiab tuaj yeem hloov cov hlau tsis muaj steel thiab kub-resistant steel rau cov cuab yeej tsim khoom. Boronizing: zoo heev hnav tsis kam, corrosion kuj thiab av nkos hnav tsis kam, hnav tsis kam yog pom tseeb zoo dua li nitriding, carbon thiab carbonitriding txheej, tab sis tsis resistant rau atmospheric thiab dej corrosion. Feem ntau siv rau cov av nkos twj tso kua mis, kub ua hauj lwm tuag thiab workpiece fixtures.
normalizing
Quenching
Kub
Txoj Cai: Qhov ntau dua qhov zaus tam sim no, qhov tob tob ntawm txheej txheej hardened.
