Bars nrog cov ntsiab lus siab carbon tau tawg ntau zaus, xws li shafts ua los ntawm 45 # steel, uas yuav tawg tom qab siv sijhawm luv luv. Kev coj mus kuaj los ntawm cov khoom tawg thiab ua cov kev ntsuas metallographic, feem ntau tsis tuaj yeem nrhiav qhov laj thawj, txawm tias nws nyob deb mus nrhiav qee qhov laj thawj, nws tsis yog vim li cas tiag.
Txhawm rau kom muaj zog dua, carbon yuav tsum tau ntxiv rau cov hlau, uas cov hlau carbides precipitate. Los ntawm qhov pom ntawm electrochemical, hlau carbide ua raws li cathode, ua kom cov anodic dissolution cov tshuaj tiv thaiv nyob ib ncig ntawm lub substrate. Qhov nce hauv qhov ntim feem ntawm cov hlau carbides nyob rau hauv microstructure kuj yog vim qhov qis hydrogen overvoltage zog ntawm cov carbides.
Qhov saum npoo ntawm cov hlau yog yooj yim los tsim thiab nqus hydrogen. Thaum cov hydrogen atoms nkag mus rau hauv cov hlau, qhov ntim feem ntawm hydrogen tuaj yeem nce ntxiv, thiab thaum kawg qhov kev tiv thaiv rau hydrogen embrittlement ntawm cov khoom yog txo qis.
Qhov tseem ceeb txo qis hauv kev tiv thaiv corrosion thiab hydrogen embrittlement tsis kam ntawm high-strength steels tsis tsuas yog ua phem rau cov khoom ntawm cov hlau, tab sis kuj zoo heev txwv rau daim ntawv thov ntawm cov hlau.
Piv txwv li, thaum lub tsheb hlau raug rau ntau yam corrosive ib puag ncig xws li chloride, nyob rau hauv qhov kev txiav txim ntawm kev ntxhov siab, qhov tshwm sim ntawm kev nyuaj siab corrosion cracking (SCC) uas yuav tshwm sim yuav ua rau muaj kev hem thawj rau kev nyab xeeb ntawm lub tsheb lub cev.
Qhov siab dua cov ntsiab lus carbon, qhov qis dua hydrogen diffusion coefficient thiab siab dua hydrogen solubility. Scholar Chan ib zaug tau npaj siab tias ntau yam lattice defects xws li precipitates (raws li qhov chaw ntxiab rau hydrogen atoms), muaj peev xwm, thiab pores yog proportional rau carbon cov ntsiab lus. Qhov nce ntawm cov ntsiab lus carbon yuav inhibit hydrogen diffusion, yog li cov hydrogen diffusion coefficient kuj tsawg.
Txij li thaum cov ntsiab lus carbon yog proportional rau hydrogen solubility, qhov ntau dua qhov ntim feem ntawm carbides li hydrogen atom ntxiab, qhov me me ntawm hydrogen diffusion coefficient hauv cov hlau, qhov ntau dua hydrogen solubility, thiab hydrogen solubility kuj muaj cov ntaub ntawv hais txog diffusible hydrogen, yog li Hydrogen embrittlement susceptibility yog siab tshaj. Nrog rau qhov nce ntawm cov ntsiab lus carbon, qhov diffusion coefficient ntawm hydrogen atoms txo qis thiab qhov chaw hydrogen concentration nce, uas yog tshwm sim los ntawm qhov txo qis ntawm hydrogen overvoltage ntawm steel nto.
