Cov tshuaj lom neeg muaj pes tsawg leeg ntawm Q345 cuam tshuam nws cov khoom siv neeg kho tshuab?
Raws li qhov qis -} alloy, siab {{{1} {{1 {{{1 {{{{{{{{{1 {{{1 {{{{{{{} Lub zog, ductility, ducability, ductility, thiab lwm yam, thiab lwm yam). Cov ntsiab lus sib txawv ncaj qha tswj cov khoom siv sab hauv (xws li cov khoom siv hluav taws xob, lossis cov khoom siv tsis zoo, thiab cov khoom siv tsis zoo, thiab cov khoom siv tsis taus los ntawm kev sib txawv ntawm cov khoom siv tshuab. Cov ncauj lus ntxaws ntxaws ntxaws ntxaws ntawm cov kev cuam tshuam tshwj xeeb ntawm txhua qhov sib xyaw ntawm cov khoom siv hauv cov khoom siv:
1. Cov tub ntxhais ntxiv dag zog: "lub zog tseem ceeb" txiav txim siab lub zog
Cov ntsiab lus no yog qhov tseem ceeb ntawm Q345's "lub zog siab" (tawm los ntawm lub zog ntau dua lossis sib npaug rau 345 mpa). Lawv txhim kho lub zog los ntawm "impeding cais cov lus tsa suab" thaum tawm ntawm kev txo kev ua haujlwm ntawm kev sib txuas thiab tawv.
1. Manganese (MN, Feem ntau 0.90% -1.60%)
Mechanism ntawm Kev Ua:
MN yog qhov tseem ceeb tshaj plaws ntxiv dag zog hauv Q345, feem ntau ua yeeb yam los ntawm cov khoom siv daws teeb meem zog. Mn atoms yaj hauv ferrite (cov theem matrix) los ua cov kev daws teeb meem ntawm cov hlau thiab cuam tshuam nrog kev tshem tawm ntawm cov hlau). Tsis tas li ntawd, MN txhawb nqa cov kev faib tawm ntawm cov hlawsite
Cuam tshuam rau cov khoom siv kho tshuab:
Tseem ceeb txhim kho zog zog thiab tensile muaj zog zog ntawm MN, Q345 tsis tuaj yeem ncav qhov qis zog zog ntawm 345 MPa. Lub zog txhim kho kev txhim kho rau kwv yees li 40% -50% ntawm tag nrho lub zog.
Ntsuas cov xim sib xyaw thiab muaj zog: tsis zoo li cov pa roj carbon (c), MN tsis cuam tshuam txo cov plasticity. Hloov chaw, nws kho cov hlaws ntawm petpite lamellae, feem ntau loj dua li 21%) thiab chav {2} kev cuam tshuam kub sai ntawm lub zog siab.
Txhim kho Weldability: MN suppresses "kub tawg" thaum lub sij hawm vuam (vim yog kev tsim ntawm qis {} {1} {} {} {} {} {
2. Cov pa roj carbon (c, nruj me ntsis cov ntsiab lus: 0.12% -0.20%)
Mechanism ntawm Kev Ua:
Cov pa roj carbon yog qhov "tseem siv zog siv zog" ntawm cov hlau, los ntawm kev ua kom muaj zog hauv ob qho tib si: Thib ob, los ntawm kev sib xyaw ua ke nrog FE los ua cov hlawsite (FERNC + Ferrite). Cov cementite (fe₃c) hauv Pearlite yog qhov nyuaj heev thiab cuam tshuam cov lus tsa suab.
Cuam tshuam rau cov khoom siv kho tshuab:
Zoo: Tswj lub zog yooj yim - Cov ntsiab lus carbon ntau dhau (<0.12%) will result in insufficient yield strength, failing to meet the standard requirements for Q345.
Negative: The carbon content must be strictly limited-A carbon content too high (>0.20%) yuav ua rau:
① A sharp decrease in toughness: Excessive carbon increases the pearlite content, coarsening the lamellar structure, and promotes stress concentration at grain boundaries, making it prone to brittle fracture at low temperatures.
② Qhov chaw muag hluav taws xob loj heev: Cov pa roj carbon: Cov tshuaj tua hluav taws xob ua rau muaj kev nyuaj rau hauv cov cua sov {}} bein cuam tshuam rau welpeptibility rau weld tawg.
③ txo cov khoom tawg: ntau dhau ntawm cov khoom siv carburized tuaj yeem ua kom cov khoom loj, txo cov khoom siv elongation thiab txias.
Yog li no, cov pa roj carbon ntawm Q345 yuav tsum yog qhov tseeb tswj tau nyob rau hauv cov khoom sib npaug uas ua tiav lub zog uas yuav tsum muaj zog tsis yooj yim.
Thib ob, ib tus kws pab txhawb nqa thiab tawv -}}}}}} kev ua haujlwm "tshuav nyiaj"
Cov ntsiab lus no (microoalloy cov ntsiab, silicon) tsis txhob txhim kho qhov sib npaug ntawm lub zog, tab sis lawv tuaj yeem txhim kho cov nplej "thiab" kho microstructures. " Qhov no yog qhov sib txawv ntawm Q345 thiab cov hlau siv hluav taws xob zoo tib yam (xws li Q235).
1. Microalloy cov ntsiab lus (NB (Niobium), v (vanadium), thiab ti (titanium, nrog cov ntsiab lus theem tsawg dua los yog sib npaug 0.06%))
Mechanism ntawm Kev Ua:
Microalloying Ntsiab yog qhov tseem ceeb ntawm Q345 "kev txhim kho" kev txhim kho "kev txhim kho hauv lub zog thiab tawv," feem ntau los ntawm cov qoob loo zoo thiab daus ntau zog:
① Cov Khoom Siv Hluav Taws Xob: thaum lub siab siab: thaum lub siab - Kub Rolling, NIT / V / Ti sib xyaw ua ke nrog cov tshuaj zoo (xws li NBC, V, thiab Tin). Cov tebchaw "PIN" Austenite gragaries, tiv thaiv qoob loo grain kev loj hlob (ferrite zoo nce lub zog thiab tawv - Nplooj ntawv kev sib raug zoo ").
② Simplium Tsawg, NB / V / TI nyob rau hauv cov lus qhia txog kev tshem tawm, ntxiv dag zog me ntsis.
Cuam tshuam rau cov khoom siv kho tshuab:
Strength Improvement: Through grain refinement, the yield strength can be increased by an additional 30-50 MPa, allowing Q345 to meet standards even in thick plates (>40 hli) lossis ntawm qhov kub tsawg.
Txhim kho kev nruj: tus nplua {- nplej tsim tsim tau zoo txhim kho qis - kub. Piv txwv li, qhov kev cuam tshuam nqus hluav taws xob (AK) ntawm Q345 muaj NB ntawm {}} 10℃tau tshaj li 40-20 J ntawm steel yam tsis muaj microalloy cov ntsiab lus, yog li tiv thaiv tsawg-kub brittle bacitate.
Txhim kho phaj tuab: thaum lub phaj tuab yob, "coarse nplej" yog nws yog tus tsim hauv thaj chaw nruab nrab. Microalloy elemes tau tuaj yeem senomenon no tshwm sim no, txo cov "tuab nyhuv" (qhov twg kev ua tau zoo nthuav nrog tuab) hauv daim hlau tuab.
2. Silicon (Si, 0.20% -0.55%)
Mechanism ntawm Kev Ua:
Si Program ua piv txwv rau cov khoom daws teeb meem zog thiab microstructure tswj. Dissolving nyob rau hauv ferrite, si me ntsis txhim kho cov tshuaj muaj zog dua thaum ua ntej ua ntej {1} utecting nag lossis utiform phoppite tsim. Tsis tas li ntawd, Si txo weld rhiab heev thiab porosity thaum lub sij hawm vuam.
Nyhuv rau cov tshuab khoom siv:
Me zog txhim kho kev txhim kho: Si cov khoom siv dag zog zog ua kom muaj zog dua li ntawm MN, tab sis nws tuaj yeem pab MN hauv kev ua tiav lub hom phiaj.
Ua kom zoo dua cov muaj zog thiab weldability: Si rov qab cov qauv pearlite, tiv thaiv kev tiv thaiv ib qho kev txo qis heev. Nws tseem yuav txo weld tsis xws luag thiab ua kom muaj zog ruaj khov kho cov cuab yeej tom qab vuam.
Note: Excessive Si content (>0.60%) tuaj yeem nce cov hlau txias brittleness thiab me ntsis txo qis qis - kub sab xis yuav tsum tau tswj hwm.