Vuam Tshuab Ntawm Titanium Thiab Titanium Alloys
--- Vuam Tshuab Ntawm Titanium Thiab Titanium Alloys ---
Cov khoom siv vuam txuas ntawm titanium thiab titanium alloys muaj ntau yam ntxwv tseem ceeb. Cov yam ntxwv vuam no yog txiav txim siab los ntawm lub cev thiab tshuaj ntawm titanium thiab titanium alloys.
1. Cawv ntawm roj thiab impurity paug ntawm vuam kev ua tau zoo
Ntawm qhov kub thiab txias, titanium thiab titanium alloys yog qhov ruaj khov. Txawm li cas los xij, nyob rau hauv lub rooj ntsuas, thaum lub sijhawm ua haujlwm vuam, cov kua ua kua thiab cov pas dej sib xyaw hlau muaj qhov muaj zog ntawm hydrogen, oxygen, thiab nitrogen, thiab cov roj cua no tau cuam tshuam nrog lawv hauv lub xeev khov kho. Raws li qhov kub nce, qhov peev xwm ntawm titanium thiab titanium alloys kom nqus tau hydrogen, oxygen, thiab nitrogen kuj nce siab. Nws pib nqus cov pa hydrogen txog li 250 ° C, pib nqus oxygen thaum 400 ° C, thiab pib nqus cov pa nitrogen los ntawm 600 ° C. Cov roj cua no tom qab tau nqus, nws yuav ncaj qha ua rau embrittlement ntawm welded sib koom tes, uas yog qhov tseem ceeb heev cuam tshuam rau qhov kev vuam zoo.
(1) Hydrogen yog qhov tseem ceeb tshaj plaws hauv kev muaj peev xwm ntawm cov neeg kho tshuab ntawm titanium hauv hydrogen impurities. Qhov kev hloov ntawm cov ntsiab lus hydrogen hauv lub weld muaj qhov tshwj xeeb zoo tshaj plaws rau qhov kev cuam tshuam ntawm kev ua haujlwm ntawm lub weld. Qhov laj thawj tseem ceeb yog tias vim tias qhov ntau ntawm cov foob pob hydrogen hauv qhov weld nce, qhov ntau ntawm qhov khoob los yog rab koob zoo li TiH 2 precipitated nyob rau hauv lub weld nce. Lub zog ntawm TiH 2 yog qhov tsawg heev, yog li cov nyhuv ntawm daim ntawv zoo li lossis rab koob zoo li HiH 2 tsis raug sau, thiab kev sib xyaw ua ke kev ua tau raug txo qis heev; cov txiaj ntsig ntawm kev hloov pauv ntawm cov ntsiab lus hydrogen ntawm weld ntawm kev txhim kho ntawm lub zog thiab plasticity tsis yog pom tseeb.
(2) Qhov cuam tshuam ntawm cov pa oxygen Oxygen muaj qhov siab dua rau hauv ob theem α theem thiab β theem ntawm titanium, thiab tuaj yeem tsim cov qib theem sib txawv. Cov siv lead ua qhov txhab uas siv txoj cai titanium yog qhov teeb meem loj heev, thiaj li ua rau kom muaj qhov nyuaj ntawm titanium thiab titanium alloys. Thiab lub zog, tab sis plasticity yog ho txo. Txhawm rau kom ntseeg tau tias cov kev ua haujlwm ntawm vuam sib koom tes, ntxiv rau kev tiv thaiv nruj tiv thaiv qhov tseem ceeb oxidation ntawm lub rooj hlau txuas thiab lub vuam tau ua tiav raws li cov tshav kub cuam tshuam thaum lub sijhawm vuam cov txheej txheem, cov ntsiab lus oxygen hauv lub hauv paus hlau thiab vuam hlau yuav tsum txwv.
(3) Qhov cuam tshuam ntawm nitrogen Thaum kub siab tshaj li 700 ° C, nitrogen thiab titanium muaj cov yam ntxwv zoo, ua rau cov nkig thiab tawv titanium nitride (riN) thiab qhov teeb tsa ntawm ntxaij distortion los ntawm nitrogen thiab titanium sib sau ua qhov sib txawv ntawm cov khoom, piv rau Qhov Yuav tshwm sim los ntawm cov pa oxygen yog qhov hnyav dua. Yog li no, nitrogen muaj cov txiaj ntsig zoo dua ntxiv ntawm kev txhim kho lub zog tensile thiab lub zog ntawm kev lag luam ntshiab titanium welds thiab txo cov khoom yas ntawm welds dua li cov pa.
(4) Qhov cuam tshuam ntawm cov pa roj carbon Carbon kuj tseem yog ib qho kev ua kom tsis zoo ntawm cov titanium thiab titanium alloys. Cov kev sim qhia pom tias thaum cov pa roj carbon ntsiab lus yog 0. 13%, cov pa roj yog sib sib zog nqus hauv α titanium, qhov weld lub zog txwv tau nce qee qhov, thiab cov yas plasticity yog qee qhov txo, tab sis tsawg dua oxygen. Cov nyhuv ntawm nitrogen yog muaj zog. Txawm li cas los xij, thaum cov pa roj carbon cov ntsiab lus ntawm qhov txuas tau ntxiv, qhov mesh TiC tshwm sim hauv qhov weld, thiab nws cov nyiaj tau nce nrog qhov nce ntawm cov ntsiab lus carbon, uas ua rau lub plasticity ntawm lub weld txo qis thiab tawg yooj yim tshwm sim nyob rau hauv cov nyhuv ntawm vuam kev ntxhov siab. Yog li no, cov pa roj carbon ntsiab lus ntawm cov khoom siv dag zog ntawm cov khoom siv ntawm titanium thiab titanium alloy tsis yog ntau dua 0. 1%, thiab cov pa roj carbon ntsiab lus ntawm cov hlau txuas tsis pub tshaj cov ntsiab lus carbon ntawm cov khoom siv hauv paus.
2. Weld sib koom ua ke qhov teeb meem
Thaum titanium thiab titanium alloys yog welded, muaj peev xwm ua tau ntawm cov khoom tawg hauv cov hlau sib txuas yog qhov me me heev. Qhov no yog vim hais tias cov ntsiab lus ntawm impurities xws li S, P, thiab C hauv titanium thiab titanium alloys yog me me, thiab qhov chaw qis melting point eutectic tsim los ntawm S thiab P tsis yooj yim tshwm nyob rau hauv thaj chaw muaj qoob loo, ntxiv rau qhov ua rau kub crystallization zoo.
Qhov nqaim, me me ntawm cov titanium thiab titanium alloys thaum lub sijhawm solidification, thiab cov hlau tsis sib haum yuav tsis tsim cov thermal ua kom tawg. Txias vuam ntawm titanium thiab titanium alloys tuaj yeem tshwm sim nyob rau hauv qhov kub-cuam tshuam rau lub sijhawm, uas yog tus cwj pwm los ntawm kev tshwm sim ntawm cov kab nrib pleb ob peb teev lossis ntau dua tom qab vuam, uas yog hu ua kev tawg. Cov kev tshawb fawb pom tias qhov kev tawg no cuam tshuam nrog kev sib txawv ntawm hydrogen pob thaum vuam. Thaum lub sijhawm vuam, hydrogen sib txawv los ntawm kev sib sib zog nqus kub pas mus rau qhov qis-kub kub-cuam tshuam cheeb tsam. Ua kom cov ntsiab lus hydrogen ntau ntxiv qhov ntau ntawm TiH 2 dej nag nyob hauv cheeb tsam no, nce lub brittleness ntawm thaj chaw tshav kub. Tsis tas li ntawd, vim lub ntim nthuav dav thaum lub sijhawm nag lossis daus ntawm hydride, cov ntaub so ntswg loj dua Kev ntxhov siab ntxiv, hydrogen atoms diffuse thiab sib sau nyob rau hauv qhov kev ntxhov siab siab ntawm thaj av, yog li ntawd cov kab nrib pleb tsim. Txoj kev tiv thaiv kev tawg zoo li no feem ntau yog los txo qhov chaw ntawm hydrogen hauv qhov txuas sib txuas. Thaum cov ntaub ntawv xa tawm tseem xa, cov nplaim taws yog suppressed.
3. Lub teeb meem tawg hauv weld
Porosity yog qhov teeb meem ib txwm muaj thaum vuam titanium thiab titanium alloys. Lub hauv paus cag ntawm stomata yog qhov tshwm sim ntawm cov kev cuam tshuam ntawm hydrogen. Qhov tsim ntawm pores nyob rau hauv lub weld hlau tsuas yog cuam tshuam lub zog qaug zog ntawm kev sib koom ua ke. Lub ntsiab thev naus laus zis ntsuas los pab tiv thaiv pores yog:
(1) Qhov kev tiv thaiv ntawm neon roj yuav tsum yog huv, thiab kev coj dawb huv yuav tsum tsis pub tsawg dua 99. 99%
(2) Ua kom huv si tshem tawm cov teeb meem organic xws li roj roj ntawm lub vuam daim thiab qhov chaw vuam hlau.
(3) Siv cov roj zoo tiv thaiv mus rau lub pas dej molten, tswj kev ntws thiab nrawm ntawm cov roj argon, tiv thaiv kev tawm tsam, thiab cuam tshuam rau kev tiv thaiv.
(4) Ua kom raug xaiv cov txheej txheem vuam cov txheej txheem, nce siv kev sib sib zog nqus pas dej nyob lub sijhawm thiab txoj cai siv cov npuas kom khiav tawm, uas tuaj yeem txo lub qhov hws.
