Kev ntxhov siab corrosion cracking (SCC) ntawm titanium cua sov raj yog hais txog nkig cracking tsis ua hauj lwm tshwm sim los ntawm kev sib xyaw ua ke ntawm tensile kev nyuaj siab thiab cov xov xwm corrosive tshwj xeeb. Residual stress los ntawm txias dabtsi yog khoov, vuam thiab yuam los ua ke superimposes rau corrosive ib puag ncig uas muaj chloride, fluoride, concentrated acid los yog organic solvents. Cov kab nrib pleb me me tshwm rau ntawm lub raj nplaim thiab nthuav dav sai raws li cov khoom siv sab hauv yam tsis muaj qhov pom tseeb ntawm corrosion thinning, nws thiaj li ua rau kev nkag mus sai sai hauv kev ua haujlwm siab. Qhov kev ua tsis tiav no nta muaj zog tam sim ntawd thiab zais, uas yog qhov tseem ceeb zais kev pheej hmoo rau titanium cov khoom siv hluav taws xob hloov pauv.
1. Coupled Stress-Corrosion Crack Initiation Mechanism
Titanium nto cia siab rau lub compact TiO₂ passivation zaj duab xis los tiv thaiv- tiv thaiv corrosion. Tensile kev ntxhov siab ua rau me me slips thiab microdefects ntawm cov txheej txheem passivation, rhuav tshem cov yeeb yaj kiab txuas ntxiv hauv zos. Corrosive anions xws li fluorine thiab chlorine ions ntxeem tau lub substrate raws cov ntsiab lus puas thiab tsim thawj qhov chaw corrosion. Kev ntxhov siab concentrates nyob rau hauv lub hauv paus ntawm pits thiab tas li kua muag lub tshiab regenerated passivation zaj duab xis, ua kom lub tawg ntsoog nyob rau hauv ib tug active dissolution xeev. Cracks propagate transgranularly los yog intergranularly ntawm kev kub ceev nyob rau hauv kev sib koom tes ntawm mechanical tensile force thiab electrochemical corrosion. Txawm tias kev ntxhov siab nyob deb ntawm qhov kev tawm dag zog ntawm titanium tuaj yeem ua rau los ntawm - phab ntsa tawg tom qab ntev - lub sij hawm tsub zuj zuj.
2. Tej thaj chaw uas muaj kev nyuaj siab Corrosion Cracking
Weld seams thiab tshav kub- thaj chaw cuam tshuam nrog vuam shrinkage tensile residual stress;
U-zoo li tus bent seem khaws cia loj residual stress tom qab txias txias;
Flange fastening thiab yeeb nkab clamping txoj hauj lwm nrog ntau tshaj bolts ua ntej-tightening quab yuam;
Ua kua theem alternation thaj chaw uas corrosive ntsev evaporate thiab mloog zoo tsis tu ncua;
Rigid tsau kav ntu uas tsis tuaj yeem nthuav dav thiab cog lus raws li qhov kub thiab txias.
3. Tej yam tseem ceeb ua kom SCC puas tsuaj
Nruab nrab nrog siab concentration ntawm fluoride, chloride ions thiab siab ua hauj lwm kub;
Unrelieved residual kev nyuaj siab los ntawm dabtsi yog khoov, vuam thiab machining txheej txheem;
Tshaj -tightened fasteners qhia ntxiv rau sab nraud tensile stress;
Lub zos evaporation ua rau ntsev los nag thiab ion enrichment ntawm titanium nto;
Nto khawb khawb thiab indentations ua hauj lwm raws li qhov chaw pib tawg kom tawg cov zaj duab xis passivation.
4. Tag nrho -Txuas Kev Tiv Thaiv thiab Tswj Cov Kev Ntsuas Kev Ntsuas
① Tshem tawm cov kev ntxhov siab uas seem ntawm kev tshaj tawm - txheej txheem annealing
Ua kom muaj kev ntxhov siab rau kev kho cua sov tom qab khoov thiab vuam kom txo qis hauv tensile kev nyuaj siab ntawm workpieces.
② Standardize los ua ke thiab kho hom
Txais torque wrenches kom txwv ceev ceev; siv zawv zawg kev txhawb nqa los khaws cov nyiaj thermal nthuav dav thiab tsis txhob muaj kev txwv nruj.
③ Purify nruab nrab ua hauj lwm thiab huv si teev
Nruab cov khoom pom thiab desalination kom txo cov ntsiab lus halogen ion; yaug sediment thiab crystalline ntsev tsis tu ncua.
④ Ua kom zoo xaiv cov khoom siv rau kev pabcuam hnyav
Xaiv cov titanium alloys nrog kev txhim kho los tiv thaiv -SCC kev ua tau zoo rau siab - kub thiab siab - halogen ib puag ncig.
⑤ Tshem tawm kev puas tsuaj saum npoo thiab ntxiv dag zog rau passivation
Polish khawb thiab burrs; siv anodic oxidation kom tuab cov zaj duab xis passivation thiab txhim kho nws txoj kev ncaj ncees.
5. Kev Tiv Thaiv Cov Teeb Meem Sib piv
表格
| Kev Ua Haujlwm & Kev Pabcuam Hom | SCC Risk Level | Pom zoo Plan Optimization Plan |
|---|---|---|
| Txias txoj kev tsis muaj kev ntxhov siab + siab fluorine / chloride nruab nrab | Tsis tshua muaj kev pheej hmoo ntawm kev tawg sai sai | Ua kom muaj kev ntxhov siab lossis txhim kho qib khoom siv |
| Kev kho kev ntxhov siab + kev teeb tsa tus qauv + nruab nrab purification | Zoo suppress kev ntxhov siab corrosion cracking | Standard ntau lawm thiab kev ua haujlwm specification |
| Nto anodic passivation + hloov pauv kev txhawb nqa | Yam tsawg kawg cracking nyiam nyob rau hauv hnyav tej yam kev mob | Siab -kev pheej hmoo corrosive ua hauj lwm tej yam kev mob nyiam lub tswv yim |
Xaus
Kev ntxhov siab corrosion tawg ntawm titanium cua sov raj yog sib koom ua ke los ntawm tensile kev nyuaj siab puas tsuaj rau cov zaj duab xis passivation thiab xaiv electrochemical corrosion ntawm cov lus qhia tawg. Cov tswv yim tiv thaiv tseem ceeb yog tshem tawm cov kev ntxhov siab sab hauv thiab sab nraud, tswj kev txhim kho ntawm corrosive ions ntawm cov khoom siv saum npoo, tshem tawm cov teeb meem ntawm qhov chaw pib thiab txhim kho kev ruaj ntseg ntawm cov yeeb yaj kiab oxide tiv thaiv. Kev tswj hwm nruj ntawm kev ua cov thev naus laus zis, kev tsim kho kev tsim kho thiab kev saib xyuas txhua hnub tuaj yeem ua kom tsis txhob muaj kev sib tsoo tam sim ntawd los ntawm kev ntxhov siab corrosion cracking.
