Thaum A Qib 12 Titanium Heater Tube Khoov rau 3D Radius Thiab Tom Qab Kev Nyuaj Siab -Relieved ntawm 540 degree, Yuav Ua Li Cas Cov Khoom Siv Hluav Taws Xob Rov Qab Nyob Hauv Lub Radius Sab Nraud Hloov Nws Pitting Peev Xwm Hauv 5% NaCl Ntawm 90 degree?
Tso lus
Qib 12 titanium (Ti-0.3Mo-}0.8Ni) yog siv rau cov kav dej kub hauv cov tshuaj chloride- uas muaj ib puag ncig vim nws txhim kho pitting tsis kam. Thaum lub raj yog khoov mus rau ib lub vojvoog nruj ntawm 3 npaug ntawm txoj kab uas hla (3D), lub vojvoog sab nraud tau txais cov yas tensile ntawm 10-15%. Qhov kev ua haujlwm txias no ua rau muaj kev ntxhov siab ntxiv, ua rau muaj qhov sib txawv ntawm qhov sib txawv, thiab tuaj yeem ua raws cov alpha{17}}theem nplej. Lub peev xwm pitting, uas yog lub peev xwm electrochemical ntawm qhov chaw ruaj khov pib, txo qis nrog kev ua haujlwm txias. Kev ntxhov siab-relief annealing ntawm 540℃rau 30 feeb rov qab tau ib feem ntawm cov kab mob, txo qis kev ntxhov siab, thiab tso cai rau qee qhov rov ua dua tshiab. Lub peev xwm pitting ntawm lub raj khoov thiab kev ntxhov siab rov qab mus rau hauv 50-100 mV ntawm qhov tsis zoo, piv rau 150-250 mV kev nyuaj siab rau lub raj li-bent yam tsis muaj kev ntxhov siab.
Lub Mechanism ntawm Residual Strain Recovery thiab Pitting Potential Restoration
Thaum lub sij hawm khoov yas, dislocations multiply thiab accumulates nyob rau hauv grain ciam teb, tsim siab - zog qhov chaw uas nyiam rau qhov pib pib. Tensile residual stress ntawm lub vojvoog sab nrauv ntxiv destabilizes cov yeeb yaj kiab passive. Kev ntxhov siab-relief annealing ntawm 540℃tso cai rau dislocation nce thiab rhuav tshem, txo qhov dislocation ceev ntawm 60-80%. Cov txheej txheem kuj tseem txo qis tensile kev nyuaj siab ntawm 150-250 MPa rau 30-60 MPa. Molybdenum thiab npib tsib xee hauv Qib 12 redistribute thaum lub sij hawm annealing, enriching nto thiab txhim kho passive zaj duab xis stability. Lub peev xwm pitting tau rov qab los vim tias muaj pes tsawg qhov chaw ua haujlwm rau qhov pib pib raug txo qis, thiab cov yeeb yaj kiab passive yuav zoo ib yam.
Quantitative Pitting Potential raws li kev ua haujlwm ntawm kev khoov thiab kev ntxhov siab
Kev tswj xyuas hauv 5% NaCl ntawm 90℃tau tsim pitting peev xwm rau Qib 12 titanium raj nyob rau hauv ntau yam mob. Rau ib qho kev tsis sib haum xeeb, cov raj annealed (qhov hauv paus), lub peev xwm pitting yog +0.45 rau +0.60 V vs. Ag/AgCl, tsis muaj pitting pom tom qab 1,000 teev. Rau lub raj khoov mus rau 3D vojvoog nyob rau hauv raws li{11}} khoov yam tsis muaj kev ntxhov siab, lub pitting muaj peev xwm poob rau +0.20 rau +0.35 V, thiab pitting pib nyob rau hauv 100-300 teev, ua rau lub qhov tob ntawm 0.1–0.3 hli tom qab 500 teev. Rau lub raj khoov mus rau 3D vojvoog thiab kev ntxhov siab-relieved ntawm 540℃rau 30 feeb, lub pitting muaj peev xwm rov qab los rau +0.35 rau +0.50 V, pitting pib tom qab 500–1,500 teev, thiab qhov tob yog 0.05–0.15 mm. tom qab 500 teev. Rau lub raj khoov mus rau 5D lub vojvoog (ntsuab khoov) nrog rau kev ntxhov siab, lub peev xwm pitting yog +0.40 rau +0.55 V, uas yog ze heev rau lub hauv paus tsis zoo. Rau lub raj khoov mus rau 3D lub vojvoog thiab kev ntxhov siab-relieved ntawm 480℃(tsis txaus), lub pitting peev xwm tsuas yog +0.25 rau +0.40 V, uas qhia ib feem rov qab.
Influence ntawm Khoov Radius thiab Stress Relief Temperature ntawm Pitting Potential
Kev rov qab los ntawm pitting muaj peev xwm nyob ntawm ob qho tib si lub vojvoog khoov thiab qhov kub ntawm qhov kev ntxhov siab. Rau 3D khoov, raws li -bent pitting muaj peev xwm kev nyuaj siab yog 150-250 mV hauv qab tus nqi unbent. Kev ntxhov siab ntawm 480℃rov qab 30-50 mV, tawm hauv 120-200 mV kev nyuaj siab. Kev ntxhov siab ntawm 540℃rov 100-150 mV, tawm hauv 50-100 mV kev nyuaj siab. Kev ntxhov siab ntawm 600℃rov qab tau 150-200 mV, tawm hauv 20-50 mV kev nyuaj siab, tab sis muaj kev pheej hmoo alpha-cov ntaub ntawv tsim yog tias tsis ua rau hauv qhov chaw tsis zoo. Rau 5D khoov, qhov zoo li -kev nyuaj siab khoov tsuas yog 50–100 mV, thiab kev ntxhov siab ntawm 540℃rov zoo tag nrho mus rau qib unbent. Rau 2D khoov (nruj dua 3D), qhov zoo li - kev nyuaj siab khoov yog 200–350 mV, thiab txawm tias kev ntxhov siab ntawm 540℃tsuas yog rov qab 80–120 mV, tawm hauv kev nyuaj siab loj.
Khoov Radius thiab Stress Relief Phau Ntawv Qhia rau Qib 12 hauv Kev Pabcuam Kub Chloride
Cov lus hauv qab no muab cov lus pom zoo rau khoov Qib 12 titanium rhaub raj rau kev pabcuam hauv 5% NaCl ntawm 90 degree, raws li khoov lub vojvoog, kho kev ntxhov siab, thiab xav tau pitting kuj.
| Khoov Radius (R/D) | Raws li -Bent Pitting Potential (V vs. Ag/AgCl) | Stress Relief Temperature (degree) | Tshaj tawm -Kev Pab Cuam Tshuam Muaj Peev Xwm (V vs. Ag/AgCl) | Pom zoo daim ntawv thov |
|---|---|---|---|---|
| 5D | +0.30 rau +0.45 | 540 degree | +0.45 rau +0.60 | Siab -kev pab cuam |
| 5D | +0.30 rau +0.45 | Tsis muaj | +0.30 to +0.45 | Kev pabcuam nruab nrab |
| 3D | +0.20 rau +0.35 | 540 degree | +0.35 rau +0.50 | Txais nrog kev tshuaj xyuas |
| 3D | +0.20 rau +0.35 | Tsis muaj | +0.20 rau +0.35 | Tsis pom zoo rau kub chloride |
| 2D | +0.05 rau +0.20 | 540 degree | +0.15 rau +0.30 | Zam yog tias ua tau |
| 2D | +0.05 rau +0.20 | 600℃(argon) | +0.25 rau +0.40 | Marginal nrog Qib 7 |
Engineering Beyond Stress Relief Treatment
Qib titanium cuam tshuam rau qhov pib pitting muaj peev xwm thiab rov qab los tom qab kev ntxhov siab. Qib 7 muaj lub hauv paus pitting muaj peev xwm 100–200 mV siab dua Qib 12, yog li txawm tias 3D li -bent Qib 7 raj (+0.30 rau +0.45 V) tej zaum yuav siv tau rau ntau daim ntawv thov. Phab ntsa thickness tsis cuam tshuam rau lub peev xwm pitting tab sis cuam tshuam rau lub sijhawm nthuav tawm hauv av; phab ntsa 2.0 hli nrog lub qhov tob 0.1 hli muaj 95% ntawm nws phab ntsa. Qhov kev ntxhov siab ntawm kev ntxhov siab yog qhov tseem ceeb; annealing nyob rau hauv huab cua ntawm 540℃ua ib tug nyias oxide uas tsis ua mob pitting kuj, tab sis annealing nyob rau hauv argon los yog nqus tsev vacuum yog nyiam. Tus nqi txias tom qab kev ntxhov siab tsis muaj qhov cuam tshuam loj rau pitting peev xwm.
Ua ib qho kev qhia tshwj xeeb
Rau Qib 12 titanium rhaub raj xav tau 3D khoov rau kev pabcuam hauv 5% NaCl ntawm 90 degree, qhia kev ntxhov siab- nyem annealing ntawm 540℃rau 30 feeb hauv qhov chaw argon tom qab khoov. Yuav tsum tau ua pov thawj ntawm qhov muaj peev xwm pitting los ntawm kev sim cyclic polarization ntawm tus qauv ntawm khoov thiab kev ntxhov siab-relieved raj; lub peev xwm pitting yuav tsum nyob rau hauv 100 mV ntawm tus nqi qis ntawm tus nqi ntawm +0.45 rau +0.60 V. Rau qhov khoov nruj dua 3D, xav txog kev siv Qib 7 titanium los yog nce qhov khoov vojvoog rau 5D. Yog tias tsis muaj kev ntxhov siab tsis tuaj yeem ua tau, lees txais lub neej ua haujlwm luv dua thiab tshuaj xyuas thaj tsam khoov peb lub hlis twg rau pitting. Thaum lub sijhawm ua haujlwm, saib xyuas qhov qhib - lub peev xwm ntawm lub tshuab cua sov; qhov poob qis dua +0.20 V vs. Ag/AgCl qhia tias muaj kev pheej hmoo siab pitting. Los ntawm kev ntxhov siab-reliving ntawm 540℃tom qab khoov, tus kws kho tsheb rov qab lub peev xwm ntawm Qib 12 titanium kom nyob rau hauv 50-100 mV ntawm qhov tsis zoo, kom ntseeg tau tias kev ua tau zoo hauv kev pabcuam kub chloride.
