1.Puas qhov hloov pauv ntawm npib tsib xee- tooj liab piv hauv Monel 400 cuam tshuam rau nws qhov kev tiv thaiv corrosion?
Monel 400 yog ib zaug xwb -theem khoom- daws nickel- tooj liab alloy nrog tus qauv nominal muaj pes tsawg leeg ntawm kwv yees li 65% Ni, 33% Cu, thiab lwm yam khoom me me. Cov npib tsib xee- tooj liab piv yog qhov tseem ceeb hauv kev txiav txim siab nws qhov tseem ceeb corrosion kuj, yog li ib qho kev sib txawv ntawm qhov ntau yam yuav cuam tshuam ncaj qha rau nws txoj kev ua haujlwm corrosion.
Hauv kev txo cov acidic ib puag ncig(xws li tsis yog -oxidizing hydrochloric acid, sulfuric acid, thiab hydrofluoric acid), npib tsib xee yog lub ntsiab tseem ceeb uas endows lub alloy nrog corrosion kuj. Nws tuaj yeem tsim cov yeeb yaj kiab ruaj khov thiab tiv thaiv kev yaig ntawm hydrogen ions. Thaum cov ntsiab lus npib tsib xee tsawg dhau thiab cov tooj liab feem ntau yog siab heev, cov hlau alloy muaj peev xwm tiv taus cov kua qaub txo qis heev. The passive film becomes less dense and more prone to local breakdown, leading to accelerated general corrosion and intergranular corrosion.
Hauv oxidizing ib puag ncig thiab nruab nrab ntsev daws(nrog rau cov dej hiav txwv, uas yog qhov zoo tshaj plaws daim ntawv thov scenario ntawm Monel 400), tooj liab synergizes nrog npib tsib xee los txhim kho cov hlau tsis kam rau pitting corrosion, crevice corrosion thiab chloride ion yaig. Yog tias cov ntsiab lus tooj liab tsawg dhau thiab npib tsib xee dominates ntau dhau, cov hlau tsis kam rau cov tshuaj chloride-induced localized corrosion yuav poob qis, ua rau nws muaj peev xwm tsim pitting qhov thiab crevice corrosion nyob rau hauv marine thiab brackish dej ib puag ncig.
Monel 400 tuav lub ntsej muag -centered cubic solid- kev daws teeb meem nyob rau hauv nws cov qauv muaj pes tsawg leeg. Kev hloov pauv loj hauv cov npib tsib xee- tooj liab piv yuav ua rau nag lossis daus ntawm theem ob lossis tsim cov qauv sib txawv. Cov yam ntxwv tsis xws li no ua qhov chaw nyiam rau kev pib corrosion, ntxiv impairing tag nrho thiab hauv zos corrosion kuj. Rau cov ntawv thov kev lag luam, cov npib tsib xee- tooj liab piv yuav tsum nruj me ntsis tswj nyob rau hauv tus txheej txheem specification ntau yam kom ntseeg tau zoo thiab txhim khu kev qha corrosion kuj.
2. Puas yog phosphorus thiab sulfur muaj teeb meem impurities hauv Monel 400?
Phosphorus (P) thiab sulfur (S) yog universally lees paub tias yog teeb meem residual impurities nyob rau hauv Monel 400, thiab lawv cov ntsiab lus yuav tsum nruj me ntsis txwv nyob rau hauv tus qauv specifications.
Sulfur (S)
Sulfur muaj cov khoom solubility tsawg heev hauv cov npib tsib xee- tooj liab matrix ntawm Monel 400. Txawm tias ib qho me me ntawm leej faj yuav ua ke nrog npib tsib xee thiab lwm yam khoom los ua kom qis - melting - cov ntsiab lus eutectic compounds, feem ntau yog npib tsib xee sulfide, uas feem ntau yog muab faib rau ntawm cov qoob loo.
Thaum cov txheej txheem kub ua haujlwm xws li forging thiab kub dov, cov nplej no - ciam teb sulfide theem yuav yaj ua ntej ntxov, ua rau kub luv- cov hlau yog nquag tawg thiab tawg nyob rau hauv thermal stress, txo qhov kub workability thiab manufacturing yield.
Sulfur segregation ntawm grain ciam teb kuj rhuav tshem cov continuation ntawm passive zaj duab xis thiab kev ncaj ncees ntawm grain ciam qauv. Nws tsub kom lub rhiab heev ntawm intergranular corrosion thiab txo cov neeg kho tshuab stability ntawm cov hlau nyob rau hauv corrosive ib puag ncig, yog li cov sulfur ntsiab lus feem ntau yog tswj mus rau ib tug heev tsawg theem nyob rau hauv ntau lawm.
Phosphorus (P)
Phosphorus kuj muaj kev txwv tsis pub solubility hauv Monel 400. Cov phosphorus ntau dhau yuav sib cais ntawm cov ciam teb nplej thiab tsim cov phosphide theem, txo cov plasticity thiab toughness ntawm cov hlau, tshwj xeeb tshaj yog cuam tshuam toughness ntawm chav tsev thiab qhov kub thiab txias.
Phosphorus segregation tuaj yeem ua rau muaj kev cuam tshuam ntawm intergranular corrosion thiab kev ntxhov siab corrosion tawg. Nws rhuav tshem qhov sib xws ntawm cov zaj duab xis saum npoo av, tsim cov khoom siv hluav taws xob muaj peev xwm sib txawv ntawm cov ciam teb, thiab ua kom lub zog corrosion hauv zos.
Txawm hais tias qhov kev puas tsuaj ntawm phosphorus yog qhov mob me dua li cov leej faj, nws tseem ua rau cov khoom siv dag zog thiab corrosion tsis kam ntawm cov hlau. Yog li ntawd, ob qho tib si phosphorus thiab sulfur raug suav tias yog qhov tsis muaj kev phom sij tsis zoo, thiab lawv cov kev txwv sab saud tau teev meej meej hauv cov qauv siv los lav kev ua haujlwm thiab kev pabcuam ntawm Monel 400.
