Kev ntxhov siab corrosion cracking tsis ua hauj lwm yog hais txog 316 stainless hlau cua sov kav ib txhij raug rau tensile residual kev nyuaj siab los yog lwm yam mechanical kev nyuaj siab thaum raug chloride - muaj corrosive nruab nrab. Microcracks nucleate sai raws li cov ciam teb los yog transgranular txoj kev nyob rau hauv lub coupling nyhuv ntawm kev nyuaj siab thiab corrosive ions. Cov kab nrib pleb nthuav dav ntawm kev kub ceev yam tsis muaj qhov pom tseeb ntawm cov yas deformation ntawm sab nrauv, nws thiaj li ua rau nkig rupture ntawm cov yeeb nkab phab ntsa thiab nruab nrab to. Qhov tsis ua hauj lwm no muaj zog tam sim ntawd thiab siab zais, thiab yog qhov kev puas tsuaj loj tshaj plaws hauv cheeb tsam corrosion tsis ua haujlwm rau austenitic stainless hlau cua sov cov kav dej hauv cov tshuaj chlorine - muaj cov haujlwm ua haujlwm.
1. Kev Nyuaj Siab Corrosion Crack Pib thiab Propagation Mechanism
Cov ntaub ntawv ntom ntom chromium oxide passive zaj duab xis nyob rau saum npoo ntawm 316 stainless hlau nyob rau hauv cov kev pabcuam ib txwm muaj. Thaum cov chloride ions muaj nyob rau hauv nruab nrab, lawv nyiam adsorb ntawm cov yeeb yaj kiab tsis xws luag thiab ua rau cov txheej txheem tiv thaiv passivation los tsim cov pits me me. Tensile stress concentrates nyob rau hauv qab ntawm pits, tearing qhib lub tshiab regenerated passive zaj duab xis tsis tu ncua. Chloride ions tsis tu ncua nkag mus rau hauv qhov tawg kom tswj tau qhov siab -corrosion occluded ib puag ncig. Qhov tawg propagates rau pem hauv ntej uas tau tsav los ntawm electrochemical corrosion thiab tensile stress. Tsis zoo li niaj hnub thinning corrosion tshwm sim los ntawm tag nrho nruab nrab erosion, SCC tsuas yog txhim kho raws txoj kev tawg, nrog ze li tsis muaj cov khoom poob sab nraum qhov chaw tawg.
2. Tej hauj lwm uas muaj kev puas tsuaj rau SCC
Weld seams thiab cov cua sov uas nyob ib sab- thaj chaw muaj kev cuam tshuam nrog cov welding residual tensile stress;
Txias- khoov lub luj tshib ntu nrog cov txheej txheem kev ntxhov siab tom qab stamping thiab khoov txoj kev;
Flange bolt fastening thaj chaw nrog kev sib koom ua ke tensile kev ntxhov siab;
Kab rov tav cov kav dej qis qis qhov twg chloride ntsev concentrate vim nruab nrab evaporation thiab enrichment;
Pipeline seem nrog sab nraud extrusion deformation bearing ntxiv dabtsi yog khoov tensile kev nyuaj siab.
3. Core Inducing Factors Accelerating SCC Failure
Nruab nrab muaj cov tshuaj chloride ions tsis muaj kev tshem tawm zoo, ua rau qhov tseem ceeb corrosive nruab nrab;
Vuam, kev ua haujlwm txias thiab sib dhos ua rau muaj qhov seem loj tensile kev ntxhov siab hauv lub cev yeeb nkab;
Hauv zos kub ceev ceev ion diffusion thiab electrochemical cov tshuaj tiv thaiv kom luv luv lub sijhawm pib tawg;
Ntev - lub sij hawm kaw ua rau nruab nrab evaporation thiab chloride ion enrichment ntawm cov ces kaum tuag;
Tsis muaj kev tshaj tawm -weld stress relief kev kho mob yog ua los tshem tawm cov kev ntxhov siab hauv vuam.
4. Tag nrho -Txuas Kev Tiv Thaiv thiab Tswj Kev Ntsuas Kev Ntsuas
① Kho cov khoom siv nruab nrab dechlorination pom ntawm qhov system pem hauv ntej kawg
Txo cov tshuaj chloride ion concentration los ntawm qhov chaw los txiav tawm qhov nruab nrab ntawm corrosion.
② Ua ib qho tseem ceeb ntawm kev ntxhov siab annealing rau welded thiab txias - cov txheej txheem cov yeeb nkab tseem ceeb
Tshem tawm cov residual tensile kev nyuaj siab uas tsav tawg expansion.
③ Txhim kho cov kav dej kom zoo kom tsis txhob muaj qhov nruab nrab stagnation thiab hauv zos concentration ntawm ntsev deposits
Teem cov dej ntws los tiv thaiv cov chloride enrichment hauv cov ceg tuag.
④ nruj me ntsis tswj qhov siab tshaj plaws kev pab cuam kub kom suppress lub acceleration nyhuv ntawm kub siab ntawm SCC
Txwv qhov kub thiab txias ua haujlwm nyob rau hauv cov khoom siv los tiv thaiv -SCC lub caij nyab xeeb.
⑤ Ua raws li niaj zaus eddy tam sim no thiab ultrasonic flaw nrhiav kom tau vuam thiab khoov yeeb nkab txoj haujlwm
Tshawb xyuas microcracks nyob rau theem pib ua ntej nkag mus tawg.
5. Kev Tiv Thaiv Cov Teeb Meem Sib piv
表格
| Kev Ua Haujlwm & Kev Ua Haujlwm Hom | SCC Brittle Fracture Risk | Daim ntawv thov tswv yim |
|---|---|---|
| Cov tshuaj chloride siab nruab nrab + tsis kho cov vuam seem kev ntxhov siab + hauv zos overtemperature | Sudden yeeb nkab rupture leakage tshwm sim nyob rau hauv nruab nrab - lub sij hawm ua hauj lwm | Ntxiv dechlorination chav tsev thiab ua kev ntxhov siab kho cua sov |
| Medium chloride tswj + ncej-kev tshem tawm kev ntxhov siab + tiv thaiv- txhim kho layout tsim | Muaj txiaj ntsig txwv kev tawg nucleation thiab nthuav tawm sai | Cov qauv tsim tshwj xeeb rau cov tshuaj chlorine- muaj cov kav dej nruab nrab stainless hlau cua sov |
| Tsawg-carbon siab-molybdenum stainless hlau kho dua tshiab + kev tshuaj xyuas online chloride + peb lub hlis twg tsis yog- kuaj kev puas tsuaj | Tsis tshua muaj kev ntxhov siab corrosion cracking kev nyab xeeb kev nyab xeeb | Cov txheej txheem zoo tshaj plaws rau cov txheej txheem tshuaj tua kab hluav taws xob cua sov nrog cov tshuaj chloride tsis tu ncua |
Xaus
Kev ntxhov siab corrosion tawg ntawm 316 stainless hlau cua sov raj tshwm sim los ntawm kev sib koom ua ke ntawm kev ntxhov siab tensile thiab chloride ion corrosion, inducing ceev nrooj tawg thiab sai li sai tau nkig tawg. Cov tswv yim tiv thaiv tseem ceeb suav nrog txo cov ntsiab lus chloride nruab nrab, tshem tawm cov kev ntxhov siab uas nyob ntawm kev kho cua sov thiab kev ua kom zoo dua qub, zam kom tsis txhob muaj cov khoom siv corrosive hauv zos, tswj kev khiav hauj lwm kub thiab ntxiv dag zog rau lub sij hawm uas tsis yog - kev soj ntsuam kev puas tsuaj. Tag nrho- txheej txheem kaw- txoj kev tswj xyuas cov khoom xa tuaj, kev tsim cov kav dej thiab kev saib xyuas nruab nrab txhua hnub tuaj yeem tiv thaiv kev tsim khoom thiab kev nyab xeeb xwm txheej tshwm sim los ntawm kev ntxhov siab corrosion ntawm cov kav dej cua sov.
