1. Pitting Corrosion Resistance
Seawater thiab Marine Environments
Monel K500 nthuav tawm zoo heev pitting tsis kam nyob rau hauv zoo li qub los yog ntws dej hiav txwv ntawm chav tsev kub. Cov tshuaj chloride ion concentration hauv dej hiav txwv (kwv yees li 3.5%) tsis txaus los rhuav tshem nws cov zaj duab xis saum npoo av, thiab pitting corrosion yog tsawg dua 0.01 hli / xyoo. Txawm tias nyob rau hauv dej hiav txwv nrog yaj oxygen los yog muaj kuab paug me ntsis, lub alloy nto tsuas yog ua rau ib tug me me qhov ntiav pits, uas yuav tsis tsim rau hauv nkag mus rau hauv corrosion. Txawm li cas los xij, thaum dej hiav txwv kub siab tshaj 60℃los yog muaj cov oxidizing ions siab (xws li Fe³⁺, Cu²⁺), cov zaj duab xis passivation yuav raug puas tsuaj hauv zos, thiab pitting rhiab heev yuav nce ntxiv.
Chloride- muaj cov Media
Hauv nruab nrab lossis tsis muaj zog alkaline chloride cov kev daws teeb meem (xws li brine, dej txias), Monel K500 muaj qhov tsis zoo pitting. Nws tuaj yeem tiv taus chloride ion concentrations txog 10,000 ppm ntawm chav tsev kub yam tsis muaj qhov pom tseeb pitting. Tab sis nyob rau hauv acidic chloride media (xws li hydrochloric acid uas muaj chloride ions), cov zaj duab xis passivation tsis ruaj khov, thiab pitting corrosion yog ib qho yooj yim tshwm sim txawm nyob rau hauv tsawg chloride ion concentrations, nrog rau hydrogen evolution.
Critical Pitting Kub (CPT)
Qhov tseem ceeb pitting kub ntawm Monel K500 nyob rau hauv 6% ferric chloride tov (tus qauv nruab nrab rau kev kuaj pitting kuj) yogsiab tshaj 40 degree, uas siab tshaj qhov zoo tib yam 304 stainless hlau (kwv yees 10 degree) thiab ze rau ntawm 316L stainless hlau. Qhov no txhais tau hais tias Monel K500 tuaj yeem tswj cov pitting zoo nyob rau hauv qhov kub thiab txias chloride ib puag ncig.
2. Crevice Corrosion Resistance
Mechanism ntawm Crevice Corrosion Resistance
Hauv qhov nqaim crevices, cov pa oxygen concentration qis dua qhov chaw sab nraud, tsim kom muaj oxygen concentration cell. Cov hlau nyob rau hauv qhov crevice ua tus anode thiab undergoes corrosion. Cov npib tsib xee - tooj liab passivation zaj duab xis ntawm Monel K500 muaj zog tus kheej - kho muaj peev xwm. Txawm hais tias cov pa oxygen hauv qhov crevice depleted, cov yeeb yaj kiab passivation tseem tuaj yeem tswj tau qee qhov kev ruaj ntseg, tiv thaiv qhov tshwm sim ntawm acidification hauv qhov crevice thiab inhibiting kev txhim kho corrosion.
Kev ua tau zoo nyob rau hauv Hom Crevice Ib puag ncig
Marine flange kev sib txuas: Thaum Monel K500 siv rau flange fasteners lossis sealing nto nyob rau hauv marine ib puag ncig, txawm tias muaj qhov khoob los ntawm gasket compression los yog nto roughness, crevice corrosion yuav tsis tshwm sim tom qab ntev - kev pab cuam. Qhov no yog qhov zoo tshaj plaws rau cov hlau tsis zoo thiab cov hlau tsis zoo tib yam, uas ua rau xeb thiab xeb hauv cov xwm txheej zoo sib xws.
Cov cuab yeej muaj qhov khoob: Hauv cov khoom siv hluav taws xob, lub rooj zaum valve thiab lwm yam khoom siv uas qhov khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob khoob. Txawm li cas los xij, nyob rau hauv acidic chloride media lossis siab - qhov kub thiab txias (siab dua 80 degree), qhov crevice corrosion kuj yuav txo qis, thiab nws yuav tsum tau siv los tiv thaiv- kev ntsuas corrosion xws li sealing nrog corrosion- gaskets resistant los yog filling nrog anti-corrosion compounds.
Critical Crevice Temperature (CCT)
Qhov ntsuas kub tseem ceeb ntawm Monel K500 hauv 6% ferric chloride tov yogtxog 35 degree, uas yog siab dua li ntawm 316L stainless hlau nyob rau hauv qee kis. Qhov kev ntsuas no qhia tau hais tias Monel K500 tuaj yeem tiv thaiv kev xeb hauv qhov kub thiab txias.
3. Cov ntsiab lus tseem ceeb cuam tshuam rau Pitting thiab Crevice Corrosion Resistance
Chloride Ion Concentration: Chloride ions yog lub ntsiab inducement ntawm pitting thiab crevice corrosion. Thaum cov tshuaj chloride ion concentration ntau tshaj 10,000 ppm thiab qhov kub thiab txias, qhov corrosion kuj ntawm Monel K500 yuav txo qis heev.
Kub: Kub nce yuav ceev cov tshuaj tiv thaiv electrochemical ntawm corrosion. Rau txhua txhua 20℃qhov kub thiab txias, pitting thiab crevice corrosion rhiab heev ntawm Monel K500 yuav ob npaug.
pH Tus nqi nruab nrab: Hauv nruab nrab lossis tsis muaj zog alkaline media (pH 6–9), cov yeeb yaj kiab passivation ntawm Monel K500 yog qhov ruaj khov; nyob rau hauv acidic media (pH <5), cov zaj duab xis passivation yog ib qho yooj yim rau yaj, thiab kev pheej hmoo ntawm pitting thiab crevice corrosion nce sharply.
Surface State: Lub nto ntawm Monel K500 tom qab pickling, passivation los yog polishing muaj zoo corrosion kuj; thaum nto nrog khawb, weld defects los yog muaj kuab paug yog nquag pitting corrosion.
