Intergranular corrosion tsis ua hauj lwm yog hais txog chromium depletion raws li cov ciam teb ntawm 316 stainless hlau tom qab cua sov nyob rau hauv lub rhiab heev kub ntau yam. Lub corrosion kuj ntawm grain ciam teb poob sharply, thiab corrosive nruab nrab preferentially erodes lub ciam teb cheeb tsam. Cov kab nrib pleb kis tau raws li cov ciam teb rau kev sib koom ua ke-zoo li cov kab nkag mus, ua rau cov kav xa dej embrittlement thiab xau yam tsis muaj qhov pom tseeb macroscopic deformation. Qhov kev ua tsis tiav no feem ntau tshwm sim hauv cov khoom siv welded thiab cov kav dej uas tau rov ua dua siab dua -kub cua sov, uas yog ib qho kev puas tsuaj corrosion tsis ua haujlwm ntawm austenitic stainless hlau.
1. Intergranular Corrosion Evolution Mechanism
Thaum 316 stainless hlau nyob ntawm 450℃thiab 850℃rau qee lub sijhawm, chromium carbides precipitate thiab cais tawm ntawm cov ciam teb. Ntau cov chromium nyob ze ntawm cov ciam teb siv lead ua tau noj, ua rau chromium- thaj chaw tsis zoo uas tsis muaj peev xwm tsim cov yeeb yaj kiab tiv thaiv. Nyob rau hauv nruab nrab corrosive, cov chromium-deficiency grain ciam teb ua tus anode ntawm micro-galvanic cell thiab yaj nyiam dua. Corrosion txuas ntxiv nthuav dav raws li thaj tsam ntawm cov qoob loo los ua qhov sib txawv ntawm qhov sib txawv, ua rau cov khoom poob kev sib raug zoo sib raug zoo. Lub cev yeeb nkab yuav tawg nyob rau hauv me ntsis sab nraud quab yuam los yog sab hauv siab. Tsis zoo li cov phab ntsa sab nrauv corrosion, qhov kev puas tsuaj no tshwm sim hauv cov hlau microstructure uas yuav luag tsis pom xeb ntawm qhov chaw thaum ntxov.
2. Tej hauj lwm uas raug cuam tshuam rau Intergranular Corrosion
Weld tshav kub-cov cheeb tsam cuam tshuam muaj kev vuam thermal voj voog rhiab heev;
Cov kav dej uas muaj qhov ntev - lub sij hawm hauv zos overheating tshaj qhov ntsuas kub ntawm qhov ntsuas kub;
Ntau qhov chaw kho vuam nrog rov qab thermal input thiab superposition ntawm rhiab heev cuam tshuam;
Txias- ua haujlwm khoov cov kav dej nrog kev ntxhov siab sab hauv uas ua rau cov carbide nag lossis daus;
Segments yam tsis muaj kev tshaj tawm -welding tshav kub kho tom qab vuam txoj kev.
3. Cov Ntsiab Tseem Ceeb Ua kom nrawm nrawm ntawm Intergranular Corrosion
Cov txheej txheem vuam yam tsis muaj kev tswj qhov kub thiab txias ua rau lub sijhawm nyob ntev hauv qhov ntsuas kub ntawm lub sijhawm;
Ntev -lub sij hawm ib nrab overtemperature ua hauj lwm ntawm cov kav dej cua sov;
Tsis muaj stabilizing annealing kev kho mob tom qab vuam kom tshem tawm cov qauv rhiab heev;
Nruab nrab uas muaj chloride ions thiab muaj zog oxidizing Cheebtsam aggravating grain ciam sib cais;
Cold forming deformation nce cov khoom siv hauv kev ntxhov siab thiab txhawb nqa carbide nag lossis daus.
4. Tag nrho -Txuas Kev Tiv Thaiv thiab Tswj Kev Ntsuas Kev Ntsuas
① Txhim kho qhov vuam tsis zoo kom luv luv siab -lub sijhawm nyob hauv qhov kub thiab txias
Txais yuav ceev vuam ceev thiab me me cua sov input kom txo rhiab heev℃ntawm tshav kub- cuam tshuam cheeb tsam.
② Ua haujlwm tom qab-weld solution annealing treatment
Ua kom sov lub workpiece kom sov thiab quench sai heev kom redissolve chromium carbides thiab tshem tawm chromium - thaj chaw tsis zoo.
③ nruj me ntsis tswj kev khiav hauj lwm kub kom tsis txhob ntev -kev pab cuam overtemperature
Teem kub interlock los tiv thaiv cov raj xa dej kom tsis txhob nyob hauv qhov ntsuas kub ntawm qhov ntsuas kub.
④ Xaiv qis- carbon qib 316L cov khoom siv rau cov kav dej cua sov uas nquag siv
Txo cov ntsiab lus carbon los tiv thaiv nag lossis daus ntawm chromium carbide hauv paus.
⑤ Tsis tu ncua ua metallographic tshuaj xyuas thiab kev kuaj corrosion ntawm qhov tseem ceeb weld
Screen zais intergranular corrosion tsis xws luag ua ntej.
5. Kev Tiv Thaiv Cov Teeb Meem Sib piv
表格
| Kev Ua Haujlwm & Kev Ua Haujlwm Hom | Intergranular Corrosion Risk | Daim ntawv thov tswv yim |
|---|---|---|
| Ordinary 316 khoom + random vuam + tsis muaj ncej- kho cua sov | Muaj kev pheej hmoo ntawm intergranular cracking nyob rau hauv nruab nrab corrosion | Hloov nrog 316L thiab ua cov tshuaj annealing tam sim ntawd |
| Tsawg- cov khoom siv carbon puag + cov qauv siv hluav taws xob qis qis + kev tshuaj xyuas lub sijhawm | Zoo suppress grain ciam teb rhiab heev thiab corrosion | Standard processing specification rau welded stainless hlau pipelines |
| Kev kho mob tom qab txhua qhov vuam + tiag tiag - ntsuas kub ntsuas lub sijhawm | Tsawg heev intergranular corrosion tsis ua hauj lwm tshwm sim | Cov txheej txheem nyiam rau kev tiv thaiv- cov kav dej cua sov uas muaj kev nyab xeeb nruj |
Xaus
Intergranular corrosion ntawm 316 cua sov raj yog tshwm sim los ntawm grain ciam teb chromium depletion induced los ntawm sensitization cua sov, uas tsim galvanic corrosion hlwb thiab ua rau grain ciam ciam sib cais thiab nkag mus rau kev puas tsuaj. Kev tiv thaiv tseem ceeb txhais tau hais tias suav nrog kev siv qis- carbon stainless hlau, tswj vuam thermal input, tshem tawm cov qauv sensitized los ntawm kev kho cua sov, txwv kev ua haujlwm kub dhau thiab ntxiv dag zog rau kev tshawb pom. Tag nrho- txheej txheem tswj kev xaiv cov khoom siv, vuam tshuab thiab hauv- kev pabcuam kev ua haujlwm tuaj yeem zam kev tawg tawg thiab tawg los ntawm kev sib tsoo ntawm cov kav dej cua sov.
