Dab tsi yog niobium (Nb) cov ntsiab lus ntau hauv Inconel 625, thiab nws lub luag haujlwm tseem ceeb yog dab tsi?
1.Niobium cov ntsiab lus ntau (nominal, los ntawm qhov hnyav):
Nb + Ta: 3.15–4.15%
2. Lub luag haujlwm tseem ceeb ntawm niobium hauv Inconel 625:
Solid-kev daws teeb meem (thawj cov nyhuv):
Nb yaj nyob rau hauv npib tsib xee-chromium matrix thiab muab cov khoom tseem ceeb- kev daws teeb meem, ua rau muaj zog tensile siab, creep zog, thiab qaug zog tiv thaiv ntawm ob qho tib si ambient thiab siab kub.
Carbide thiab intermetallic tsim (stabilization & theem nrab ntxiv dag zog):
Nb muaj kev sib raug zoo rau cov pa roj carbon ntau thiab tsim NbC (niobium carbides).
Cov carbides no: pab kom ruaj khov ntawm microstructure los ntawm kev txo cov kev nyiam rau chromium carbides los nag ntawm cov ciam teb;
muab ntxiv dag zog los ntawm dispersion hardening; txhim kho hnav tsis kam nyob rau hauv qee daim ntawv thov.
Nb kuj tseem tuaj yeem ua rau kev tsim cov theem me me (piv txwv li, Laves theem hauv qee qhov microstructural), uas tej zaum yuav muaj qhov cuam tshuam thib ob ntawm ductility thiab toughness nyob ntawm qhov ntim feem thiab morphology.
Txhim kho kev tiv thaiv rau rhiab heev thiab intergranular corrosion:
Los ntawm khi cov pa roj carbon raws li NbC, Nb txo cov pa roj carbon ntau los tsim chromium- nplua nuj carbides (piv txwv li, M₂₃C₆) ntawm cov ciam teb. Qhov no mitigates chromium depletion ntawm grain ciam teb, yog li txhim kho tsis kam mus rau intergranular corrosion thiab rhiab heev, tshwj xeeb tshaj yog nyob rau hauv ib puag ncig uas muaj kev txhawj xeeb.
Txhim kho siab -kub nkag thiab kev ntxhov siab- kev ua haujlwm tawg:
Kev sib xyaw ua ke ntawm cov khoom- kev daws teeb meem ntxiv dag zog thiab carbide nag lossis daus muab Inconel 625 zoo heev creep tsis kam thiab kev ntxhov siab- tawg lub zog ntawm qhov kub txog li 650-700℃(nyob ntawm seb cov khoom siv thiab cov kev pabcuam).
Weldability cov txiaj ntsig (stabilization):
Raws li ib tug muaj zog carbide qub, Nb pab stabilize lub weld tshav kub- cuam tshuam cheeb tsam (HAZ) thiab txo cov kev pheej hmoo ntawm intergranular corrosion nyob rau hauv welded lug, txhawb cov alloy zoo heev weldability nyob rau hauv ntau daim ntawv thov.
