1. Q: Dab tsi yog qhov sib txawv ntawm Kev Lag Luam Pure Titanium (Gr3, Gr4) thiab Alpha-Beta Alloy (Gr5) hauv cov ntawv thov yeeb nkab, thiab cov kev sib txawv no txhais li cas rau lawv cov kev siv hauv kev lag luam?
A: Kev faib tawm ntawm cov kav dej titanium rau hauv Gr3, Gr4, thiab Gr5 sawv cev rau qhov sib faib tseem ceeb ntawm cov qib lag luam ntshiab (CP) thiab alpha-beta alloys, txhua qhov muab cov khoom sib txawv uas haum rau ntau qhov chaw muaj kev lag luam sib txawv.
Gr3 thiab Gr4 yog cov khoom lag luam ntshiab titanium tsev neeg, qhov twg lub zog feem ntau yog muab los ntawm cov ntsiab lus interstitial cov ntsiab lus - feem ntau cov pa. Gr3 (UNS R50550) muaj kwv yees li 0.25% oxygen, muab lub zog tensile nruab nrab ntawm ib ncig ntawm 450-550 MPa nrog rau kev ua kom txias txias. Gr4 (UNS R50700) sawv cev rau lub zog siab tshaj plaws ntawm CP qib, nrog cov pa oxygen mus txog 0.40%, yielding tensile zog ntawm 550-680 MPa. Cov qib CP no muaj qhov tshwj xeeb corrosion kuj nyob rau hauv oxidizing ib puag ncig, tshwj xeeb tshaj yog nyob rau hauv seawater, tshuaj ua, thiab desalination daim ntaub ntawv, vim lawv ruaj khov, passive titanium dioxide (TiO₂) zaj duab xis. Lawv qhov kev txwv tseem ceeb yog nyob rau hauv lawv qhov tsis tshua muaj siab-kub kev ua haujlwm; Lawv feem ntau raug ntsuas rau kev pabcuam txuas ntxiv mus txog kwv yees li 300 degree.
Gr5 (Ti-6Al-4V, UNS R56400), los ntawm qhov sib txawv, yog alpha-beta alloy muaj 6% txhuas (alpha stabilizer) thiab 4% vanadium (beta stabilizer). Qhov no alloying lub tswv yim tsim ib tug duplex microstructure uas yields ntau zog tensile zog (kwv yees 860}-950 MPa nyob rau hauv lub annealed mob) thiab superior qaug zog kuj piv rau CP qib. Txawm li cas los xij, qhov kev ua tau zoo ntawm kev siv tshuab no los nrog kev ua lag luam -offs: Gr5 nthuav tawm qis qis qis qis, yuav tsum tau ua kom kub sib sau lossis tshwj xeeb khoov cov txheej txheem rau kev tsim cov yeeb nkab. Tsis tas li ntawd, thaum Gr5 tuav tau zoo heev corrosion kuj, nws siv nyob rau hauv heev oxidizing ib puag ncig -tshwj xeeb tshaj yog cov uas muaj cov liab fuming nitric acid los yog tej yam kub chloride tov - yuav tsum tau ceev faj saib xyuas vim muaj peev xwm muaj peev xwm corrosion cracking (SCC) susceptibility, ib tug tshwm sim tsis tshua pom nyob rau hauv CP qib. Yog li ntawd, Gr3 thiab Gr4 cov kav dej tswj hwm marine engineering, cov khoom siv hluav taws xob sib hloov, thiab cov kav dej tshuaj lom neeg qhov chaw tsim khoom thiab kev tiv thaiv corrosion yog qhov tseem ceeb, thaum Gr5 cov kav dej tau teev tseg rau aerospace hydraulic systems, siab -kev ua haujlwm ntawm lub tsheb, thiab cov neeg tawm sab nrauv uas muaj zog-rau-hnyav piv thiab qaug zog lub neej nyob rau hauv kev tsim kev tsav tsheb.
2. Q: Dab tsi yog qhov teeb meem tseem ceeb hauv kev tsim cov kav dej titanium seamless hauv Gr3, Gr4, thiab Gr5, thiab cov kev cov nyom no txawv li cas?
A: Seamless titanium yeeb nkab ntau lawm sawv cev rau ib qho ntawm cov kev xav tau tshaj plaws hauv kev ua metallurgical, nrog rau cov kev sib tw uas ua rau muaj zog heev thaum ib qho txav ntawm CP qib mus rau alpha-beta Gr5 alloy.
Txoj kev tsim khoom feem ntau pib nrog kev tho los yog extrusion ntawm billet Tshuag ntawm qhov kub siab. Rau Gr3 thiab Gr4, lub qhov rais ua haujlwm yog qhov dav, nrog kev ua haujlwm kub feem ntau ua ntawm 650℃thiab 850 degree. Cov qhab nia no qhia txog kev ua haujlwm tau zoo thiab tuaj yeem raug rau kev kos duab txias lossis pilgering nrog cov voj voog nruab nrab ntawm kev sib tw kom txo tau cov kev ntxhov siab. Txawm li cas los xij, titanium qhov kev nyiam ua rau lub plab thiab qaug dab peg yuav tsum tau tshwj xeeb lubricants thiab carbide tooling nrog optimized geometries kom muaj kev ncaj ncees saum npoo. Tsis tas li ntawd, cov khoom siv qis qis ntawm elasticity (kwv yees li 105-110 GPa) yuav tsum muaj kev tswj xyuas mandrel meej thaum kos duab los tiv thaiv ovality lossis phab ntsa thickness sib txawv uas yuav ua txhaum txoj cai nruj ASTM B338 lossis B861 specifications.
Gr5 nthuav qhia ntau qhov kev tsim khoom nyuaj. Nws alpha-beta microstructure nthuav tawm cov kev ntxhov siab txog li 30-40% siab dua li qib CP ntawm qhov sib npaug, yuav tsum hnyav dua - cov khoom siv zeb ua haujlwm. Qhov kev sib tw tseem ceeb nyob rau hauv kev tswj qhov kub thiab txias thaum ua haujlwm kub: qhov kev ua haujlwm zoo tshaj plaws rau Gr5 yog nqaim (feem ntau 900℃-950 degree), raws li qhov kub siab tshaj qhov beta transus (kwv yees li 995 degree) yuav ua rau muaj cov qauv acicular Widmanstätten uas degrades ductility thiab qaug zog ua haujlwm, thaum tsis txaus qhov chaw ntawm qhov kub thiab txias. Tshaj tawm- kev kho cua sov yog qhov yuav tsum tau ua rau Gr5 kav dej kom ua tiav qhov xav tau cov txheej txheem annealed microstructure, whereas Gr3 thiab Gr4 yuav siv tau raws li - kos rau ntau daim ntawv thov. Tsis tas li ntawd, Gr5 lub zog siab dua ua rau nws muaj kev cuam tshuam rau hydrogen embrittlement thaum lub sij hawm pickling lossis tshuaj milling ua haujlwm, yuav tsum muaj cov txheej txheem nruj tswj hwm kom muaj cov ntsiab lus hydrogen qis dua 150 ppm ib ASTM specifications. Cov kev tsim khoom nyuaj no ua rau Gr5 cov kav dej tswj hwm tus nqi hwm tus nqi-feem ntau 2-3 npaug ntawm cov qib CP sib npaug-tab sis qhov kev nqis peev tau tsim nyog los ntawm lawv lub zog zoo tshaj - rau - qhov hnyav piv rau qhov xav tau kev pab cuam.
3. Q: Yuav ua li cas corrosion kuj profiles txawv ntawm Gr3, Gr4, thiab Gr5 titanium kav nyob rau hauv aggression tshuaj thiab marine ib puag ncig?
A: Thaum tag nrho cov qib titanium muaj qhov tshwj xeeb corrosion tsis kam vim lawv txoj kev ua haujlwm tsis tu ncua, ua raws TiO₂ zaj duab xis tsis zoo, cov nuances hauv kev ua tau zoo thoob plaws Gr3, Gr4, thiab Gr5 ua qhov tseem ceeb hauv cov kev pabcuam nruj heev.
Hauv marine thiab chloride-muaj ib puag ncig-xws li seawater cooling systems, brine tuav, thiab offshore platforms-tag nrho peb qib qhia kev tiv thaiv zoo rau pitting, crevice corrosion, thiab chloride stress corrosion cracking. Cov zaj duab xis passive tseem nyob ruaj khov ntawm pH ntau ntawm 3-12 hauv cov tshuaj chloride, txawm tias qhov kub siab tshaj mus txog qhov kub. Rau cov ntawv thov zoo li no, Gr3 thiab Gr4 cov kav dej feem ntau nyiam tsis yog vim kev txhim kho corrosion, tab sis vim tias lawv cov nqi qis dua thiab cov qauv zoo dua ua kom haum rau cov kav dej geometries yam tsis muaj kev cuam tshuam corrosion. Seawater piping systems nyob rau hauv desalination nroj tsuag thiab offshore platforms niaj hnub qhia Gr3 los yog Gr4 rau cov kev pab cuam lub neej tshaj 30 xyoo nrog tsawg tsawg corrosion nyiaj.
Qhov sib txawv tshwm sim nyob rau hauv chemically txo ib puag ncig los yog nyob rau hauv lub xub ntiag ntawm tshwj xeeb oxidizing agents. Gr5 (Ti-6Al-4V) tau pom tias muaj kev cuam tshuam rau kev ntxhov siab corrosion cracking (SCC) hauv qee qhov chaw uas CP qib tseem tiv thaiv. Cov piv txwv tseem ceeb muaj xws li:
Liab fuming nitric acid (RFNA): Gr5 tuaj yeem pom SCC nyob rau hauv siab -lub zog, txwv tsis pub nws siv hauv aerospace propellant tuav cov tshuab uas CP nyiam dua.
Kev sib xyaw methanol / halide: Hauv cov xwm txheej tshwj xeeb, Gr5 qhia tau tias muaj kev cuam tshuam ntau ntxiv rau SCC piv rau CP qib.
High-temperature chloride solutions (>70 degree) nrog acidic pH: Txawm hais tias ob qho tib si CP thiab Gr5 feem ntau ua tau zoo, cov qauv tsim feem ntau derate Gr5 qhov kev cia siab rau hauv qhov chaw zoo li no.
Hloov pauv, hauv cov ntawv thov uas yuav tsum tau yaig- corrosion resistance- xws li siab - dej hiav txwv ceev los yog slurries uas muaj cov abrasive particulates -Gr5 lub superior hardness (kwv yees li 340 HV piv rau 180-220 HV muab kev cuam tshuam rau cov khoom siv hluav taws xob.) Qhov no ua rau Gr5 cov kav dej tshwj xeeb yog tsim rau cov neeg tawm sab nrauv, tsim cov kab dej, thiab cov tshuab hluav taws xob hauv qhov chaw uas cov dej tshaj tawm tuaj yeem tshaj 10 m / s. Tsis tas li ntawd, nyob rau hauv oxidizing acid ib puag ncig (xws li, nitric acid, ntub chlorine gas, thiab qee cov organic acids), txhua qib ua tau zoo heev, txawm tias CP qib feem ntau tau teev tseg vim lawv cov ntaub ntawv pov thawj thiab kev lag luam zoo. Qhov kev xaiv kawg yog nyob ntawm kev ntsuas qhov xav tau ntawm cov khoom siv nrog cov kev ntxhov siab ib puag ncig, nrog cov kws tshaj lij corrosion feem ntau pom zoo CP qib rau kev pabcuam tshuaj lom neeg thiab dej hiav txwv tshwj tsis yog lub zog lossis kev qaug zog dictate Gr5.
4. Q: Dab tsi vuam kev txiav txim siab thiab tshaj tawm -weld kev kho yuav tsum paub qhov txawv Gr3/Gr4 los ntawm Gr5 titanium yeeb nkab fabrication?
A: Titanium yeeb nkab vuam xav tau kev saib xyuas zoo rau kev tiv thaiv cov pa roj thiab kev tswj xyuas cov cua sov, nrog rau cov kev xav tau ua kom nruj dua rau Gr5 piv rau CP qib vim nws lub zog ntau dua thiab cov ntsiab lus alloying.
Rau tag nrho cov qib titanium, lub hauv paus ntsiab lus tseem ceeb yog kev cais tawm ntawm huab cua paug. Oxygen, nitrogen, thiab hydrogen absorption thaum lub sij hawm vuam tuaj yeem ua rau cov cua sov- cuam tshuam thaj chaw (HAZ), ua rau tus yam ntxwv xiav lossis straw- cov xim tsis muaj xim qhia txog kev cuam tshuam ductility. Gas tungsten arc welding (GTAW) yog cov txheej txheem tseem ceeb, siv cov ntaub thaiv npog thiab cov txheej txheem thaub qab kom tswj tau argon lossis helium kev pab them nqi kom txog thaum thaj chaw weld txias hauv qab li ntawm 400 degree. Rau cov kav dej Gr3 thiab Gr4, qhov kev lees paub ntawm weld tsis zoo yog qhov zam txim: cov khoom siv hluav taws xob zoo li ntawm 0.5 txog 2.0 kJ / mm, thiab tom qab-weld heat treatment (PWHT) feem ntau tsis tas yuav tsum tau rau cov phab ntsa thickness hauv qab 12 hli, raws li cov khoom khaws cia txaus {12.} raws li cov khoom siv ductility nyob rau hauv cov xwm txheej.
Gr5 vuam qhia qhov nyuaj ntxiv. Lub alloy lub zog ntau dua thiab txo cov thermal conductivity (kwv yees li 6.7 W / m·K piv rau 16–20 W / m·K rau steel) mloog zoo rau cov cua sov hauv thaj tsam weld, ua rau muaj kev pheej hmoo ntawm cov nplej coarsening thiab tsim cov alpha brittle - cov ntaub ntawv txheej. Cov kev xav tseem ceeb rau Gr5 yeeb nkab vuam muaj xws li:
Filler hlau xaiv: Gr5 kav yog feem ntau welded siv txuam Ti-6Al-4V muab tub lim (AWS A5.16 ERTi-5) rau lub zog sib npaug, tab sis cov khoom lag luam ntshiab tuaj yeem siv rau cov khoom siv tsis-load-bearing los txo kev tawg yooj yim.
Preheating thiab interpass kub: Feem ntau khaws cia qis dua 150℃los tiv thaiv kev loj hlob ntawm beta ntau dhau hauv HAZ.
Tshaj tawm -weld kub kho: Rau Gr5 cov kav dej hauv cov txheej txheem lossis siab- khaws cov ntawv thov, kev ntxhov siab- nyem annealing ntawm 650℃-700℃rau 1-2 teev feem ntau raug yuam kom rov qab ductility thiab txo cov kev ntxhov siab uas tuaj yeem txhawb SCC hauv kev pabcuam.
Volumetric soj ntsuam: Vim tias muaj kev pheej hmoo siab dua ntawm hydrogen-induced cracking thiab tsis muaj fusion defects, Gr5 welds feem ntau yuav tsum tau 100% radiographic los yog ultrasonic kuaj, whereas Gr3/Gr4 welds nyob rau hauv uas tsis yog- cov kev pab cuam tseem ceeb yuav txais yuav txo cov tshuaj ntsuam xyuas.
Kev cuam tshuam kev lag luam yog qhov tseem ceeb: Gr5 yeeb nkab weld xav tau PWHT tag nrho, cov tshuab tiv thaiv, thiab qib NDT tuaj yeem raug nqi 3-5 npaug ntawm qhov sib npaug Gr4 weld. Yog li ntawd, cov nqi tsim khoom feem ntau cuam tshuam rau qib kev xaiv hauv cov kav dej sib txuas, nrog rau qib CP nyiam qhov twg vuam - kev teeb tsa hnyav dua qhov zoo ntawm Gr5.
5. Q: Yuav ua li cas yog Gr3, Gr4, thiab Gr5 titanium kav tau teev thiab tau ntawv pov thawj raws li ASTM thiab ASME cov qauv rau kev lag luam?
A: Cov kev qhia tshwj xeeb thiab daim ntawv pov thawj rau cov kav dej titanium yog tswj hwm los ntawm cov txheej txheem dav dav ntawm ASTM cov qauv, nrog rau cov kev xav tau ntxiv los ntawm ASME Boiler thiab Pressure Vessel Code (BPVC) rau siab - muaj cov ntawv thov.
Primary Material Specifications:
| Qib | ASTM Seamless | ASTM Welded muaj | ASME Section II | Tej kev siv |
|---|---|---|---|---|
| Gr3 (CP-3) | B861 | B862 | SWB-861/SB-862 | Kev ua tshuaj lom neeg, cov khoom siv hluav taws xob, cov tshuab dej hiav txwv |
| Gr4 (CP-4) | B861 | B862 | SWB-861/SB-862 | Siab - zog marine piping, hydraulic kab |
| Gr5 (Ti-6Al-4V) | B861 | B862 | SWB-861/SB-862 | Aerospace hydraulics, offshore risers, siab -kev ua tau zoo tso pa tawm |
Cov cai yuav tsum tau ntawv pov thawj raws li cov qauv no:
Tshuaj ntsuam xyuasASTM E2371, nrog kev txwv nruj ntawm oxygen (Gr3: 0.20–0.30%; Gr4: 0.30–0.40%; Gr5: 0.20% max), hlau, thiab hydrogen (125-150 ppm max nyob ntawm qib).
Tensile zog: Txheeb xyuas qhov ntsuas kub hauv chav nrog qhov xav tau yam tsawg kawg nkaus sib txawv raws qib; Gr5 annealed mob yuav tsum tau 860–965 MPa qhov kawg tensile zog nrog 10–15% elongation.
Kev ntsuam xyuas hydrostatic: Txhua lub yeeb nkab yuav tsum tiv taus qhov ntsuas siab ntsuas ntawm ASME B31.3, feem ntau 1.5 × tsim siab, tsis muaj qhov to.
Tsis yog -kev kuaj xyuas kev puas tsuaj: Ultrasonic kuaj ib ASTM E213 los yog E2375 rau seamless kav; radiographic soj ntsuam ntawm longitudinal welds rau welded yeeb nkab.
Rau ASME BPVC cov ntaub ntawv, cov kav dej titanium yuav tsum tau ua raws li Tshooj VIII, Division 1 (cov hlab ntsha siab) los yog Tshooj III (nuclear Cheebtsam) uas muaj feem xyuam, nrog rau kev tsim cov kev ntxhov siab uas tau txais los ntawm ASME Tshooj II, Ntu D. Gr5 qhov siab dua qhov tso cai rau kev ntxhov siab (kwv yees li 138 MPa rau cov thickness ntawm 3515 reefs) rau cov phab ntsa ntawm 315 MPa siab piping, txawm tias qhov no yuav tsum sib npaug tiv thaiv kev tsim thiab tshuaj xyuas cov cai.
Cov ntaub ntawv pov thawj zoo yuav tsum muaj tag nrho cov ntaub ntawv taug qab los ntawm zeb mus rau qhov kawg -tus neeg siv, nrog cov ntawv pov thawj zeb xeem ntawv (MTRs) qhia txog cov xov tooj cua sov, cov txiaj ntsig kev ntsuas tshuab, thiab cov lus qhia ua raws. Rau cov ntawv thov tseem ceeb-xws li offshore platforms, nuclear chaw, lossis kev tsim tshuaj lag luam- thib peb- cov koom haum soj ntsuam (piv txwv li, DNV, ABS, TÜV) feem ntau tsim cov kev xav tau ntxiv, suav nrog kev sim ua pov thawj ntawm cov cuab yeej siv tshuab, tshuaj xyuas cov txheej txheem vuam tshwj xeeb (WPS), thiab tom qab- qauv tsim. Kev ua raws li cov ntawv pov thawj nruj me ntsis kom ntseeg tau tias titanium yeeb nkab tshuab -txawm yog Gr3, Gr4, lossis Gr5-xa lub neej tshwj xeeb thiab kev ntseeg siab uas ua pov thawj rau lawv cov nqi khoom kim heev hauv kev xav tau ib puag ncig kev lag luam.
