Cov xeev-Kub-Rolled (HR), Normalized (N), thiab Thermo-Mechanical Controlled Processed (TMCP)- sawv cev rau cov txheej txheem sib txawv uas ua rau muaj qhov sib txawv microstructures thiab, yog li ntawd, cov khoom sib txawv rau Q420B steel.
Ntawm no yog ib qho kev sib piv kev tsom xam ntawm qhov sib txawv tseem ceeb:
Summary Table: Core Differences
| Yam | Kub-Rolled (HR) Xeev | Normalized (N) Lub Xeev | TMCP State |
|---|---|---|---|
| Txoj Kev Ua Haujlwm | Rolled ntawm qhov kub tiav (~ 850-950 degree), ces cua txias. | Kub- dov, tom qab ntawd rov ua dua rau ~ 900℃(Ac₃以上) thiab cua- txias. | Precisely tswj dov nyob rau hauv uas tsis yog -recrystallization cheeb tsam (~750-850 degree), ua raws li ceev ceev txias (ACC). |
| Primary Microstructure | Coarse Ferrite -Pearlite. Cov qoob loo loj tsis yog -uniform. | Refined, Uniform Ferrite-Pearlite. Equiaxed nplej. | Ultra-Fine Ferrite + Bainite/Martensite-Austenite (M-A) Cov Txheej Txheem. Complex, nplua multiphase qauv. |
| Loj Loj | Coarsest (ASTM 6-8). | Refined (ASTM 8-10). | Qhov zoo tshaj plaws (ASTM 10-12 lossis finer). |
| Yield zog (ReH) | Ua tau raws li tus qauv yam tsawg kawg nkaus (Ntau dua lossis sib npaug rau 420 MPa). Feem ntau ze rau qhov kawg. | Me ntsis siab dua thiab zoo ib yam li HR. | Siab tshaj. Feem ntau tseem ceeb tshaj qhov tsawg kawg nkaus (piv txwv li, 460-500 MPa) nrog tib chemistry. |
| Toughness (Impact) | qis tshaj. Ua tau raws li tus qauv (Ntau dua lossis sib npaug rau 34J @ 20 degree) tab sis nrog cov npoo tsawg. | Qhov zoo tshaj plaws ntawm peb rau Ferrite-Pearlite steels. Zoo heev thiab uniform toughness. | Zoo heev, tshwj xeeb tshaj yog nyob rau hauv qis kub. Fine grain loj zoo heev txhim kho ductile -nkig hloov kub. |
| Weldability | qis tshaj. Coarse nplej nyob rau hauv HAZ nquag loj hlob. | Zoo. Cov qauv zoo li qub yog ruaj khov, HAZ grain loj hlob yog txwv. | Zoo tshaj. Tsawg carbon sib npaug + ultra- cov nplej nplua nuj ua rau muaj kev nplua, tawv HAZ nrog qis qis rhiab heev. |
| Los ntawm -Thickness Property (Z-kev taw qhia) | Poorer vim kev sib cais centerline. | Txhim kho dua HR vim homogenization. | Zoo tshaj. ACC inhibits kev sib cais, ua rau cov khoom sib xws. |
| Ntsiab Strengthening Mechanisms | Solid solution + grain size (Hall-Petch). | grain refinementyog qhov tseem ceeb mechanism. | Ultra-zoo nplej + dislocation + nag lossis daus + theem transformation. Synergistic nyhuv. |
| Nqi & Daim Ntawv Thov | Tus nqi qis tshaj. Cov qauv dav dav. | Tus nqi siab dua (kev kho cua sov ntxiv). Siv rau cov phaj tuab, cov hlab ntsha siab, qhov chaw sib xws yog qhov tseem ceeb. | Moderate cost (no reheat). Dominant for modern high-performance plates (>40mm) nyob rau hauv choj, offshore, nkoj. |
Cov ncauj lus kom ntxaws
1. Kub-Rolled (HR) Xeev
Microstructure:Cov yam ntxwv los ntawm ntxhib, polygonal ferrite nplej nrog pearlite colonies ntawm cov ciam teb. Qhov kub tiav yog siab, cia cov nplej kom loj hlob thaum cua txias. Microstructure feem ntau yog banded vim kev sib cais.
Khoom:
Lub zog:Basic zog ua tau raws li tus qauv yam tsawg kawg nkaus. Tsawg sib xws los ntawm thickness.
Toughness:Tsawg feem cuam tshuam lub zog thiab siab tshaj plaws ntawm cov khoom siv hluav taws xob-qhov kub hloov pauv hloov (DBTT) vim yog cov nplej ntxhib.
Kev txwv kev thov:Siv rau cov qauv dav dav nrog cov tuab tuab uas siab toughness tsis tseem ceeb.
2. Normalized (N) Xeev
Microstructure:Lub re-austenitization (normalizing) kev kho cua sov rov pib dua lub microstructure. Nws tsim ib qho zoo, sib xws, thiab equiaxed ferrite-pearliteqauv. Cov txheej txheem no tshem tawm cov banding thiab coarse nplej los ntawm kub - dov.
Khoom:
Lub zog:Zoo thiab zoo heev. Yield zog yog txhim khu kev qha.
Toughness:Kev txhim kho tseem ceeb tshaj HR xeev. Cov qauv zoo, zoo ib yam lis muab kev cuam tshuam zoo heev ntawm chav tsev thiab qhov kub thiab txias. Qhov no yog txoj kev classic rau kev txhim khu kev qha zoo.
Qhov tsis zoo:Zog- mob hnyav (reheating tag nrho cov phaj), ua rau tus nqi siab dua thiab muaj peev xwm cuam tshuam.
3. Thermo-Mechanical Controlled Processed (TMCP) Xeev
Microstructure:Qhov no yog lub cev metallurgy triumph. Nws suav nrog:
Tswj Rolling:Hnyav deformation nyob rau hauv qis - kub, tsis yog -recrystallization cheeb tsam ntawm austenite, tsim ib "pancaked" austenite nplej tag nrho ntawm deformation bands.
Accelerated Cooling (ACC):Tam sim ntawd tom qab dov, lub phaj yog txias txias nrog cov dav hlau dej. Qhov no hloov cov deformed austenite mus rau hauv ib qho ultra- zoo ferrite grain qauv, feem ntau nrog rau theem ob ntawm acicular ferrite, bainite, los yog zoo pearlite.
Khoom:
Lub zog: Siab tshaj.Kev sib xyaw ua ke ntawm ultra-zoo grain ntxiv dag zog rau (Hall-Petch), dislocation strengthening (los ntawm deformation), thiab theem transformation ntxiv dag zog rau TMCP Q420B kom ua tiav lub zog siab dua nrog qis carbon thiab alloy cov ntsiab lus tshaj HR los yog N xeev.
Toughness: Tshwj xeeb.Lub ultra-loj loj loj ua rau txo qis DBTT, muab qhov zoo tshaj qhov qis- qhov kub thiab txias cuam tshuam, feem ntau tshaj qhov yuav tsum tau ua rau Q420D lossis E qib.
Weldability: Superior.Qis Ceq (vim kev cia siab tsawg dua ntawm cov pa roj carbon rau lub zog) thiab nplua ua ntej austenite nplej txwv kev loj hlob ntawm HAZ nplej, ua rau muaj kev sib zog, tawg ntau dua - thaj tsam weld.
Homogeneity:Zoo heev los ntawm - cov khoom tuab vim muaj kev sib cais los ntawm ACC.
Engineering Implication & Selection Guide
Xaiv Kub-Rolled Q420B rau:Tus nqi -rhiab heev, tsis yog- tseem ceeb, cov qauv zoo li qub nrog cov tuab tuab hauv ib puag ncig zoo.
Xaiv Normalized Q420B rau:Cov ntawv thov tseem ceeb uas yuav tsum tau muaj kev sib txig sib luag thiab muaj pov thawj kev ntseeg siab hauv cov ntu tuab (piv txwv li, cov hlab ntsha siab, cov qauv qub qub), tshwj xeeb tshaj yog thaum tsim cov cai tswj hwm cov hlau tsis muaj zog.
Xaiv TMCP Q420B rau:Niaj hnub nimno, siab -cov qauv kev ua tau zoo uas muaj zog siab, zoo heev qis- qhov kub thiab txias, thiab qhov zoo tshaj plaws weldability yog qhov tseem ceeb (xws li, offshore platforms, siab-nce vaj tse nyob rau hauv seismic zones, niaj hnub ntev -span choj, dej khov-chav kawm nkoj). Nws yog qhov kev siv thev naus laus zis thiab feem ntau kev xaiv pheej yig tshaj plaws rau tuab, siab - qib phaj.
Hauv cov ntsiab lus, qhov kev nce qib ntawm HR mus rau N rau TMCP sawv cev rau kev hloov pauv los ntawm cov txheej txheem yooj yim, kev lag luam mus rau lub tswv yim zoo ntawm cov hlau uas ua rau cov khoom siv microstructure ntawm qib atomic kom ua tiav qhov sib npaug zoo ntawm cov khoom uas tsis tuaj yeem ua tiav los ntawm kev sib xyaw ib leeg. Rau Q420B thiab qib siab dua, TMCP tau dhau los ua kev lag luam -xav tau lub xeev rau cov ntawv thov.