Kev kuaj ultrasonic tuaj yeem pom qhov tsis xws luag xws li shrinkage kab noj hniav, shrinkage porosity, porosity, inclusions, thiab tawg hauv castings nrog cov duab yooj yim thiab tiaj tus, thiab tuaj yeem txiav txim siab qhov loj thiab qhov chaw ntawm qhov tsis xws luag.
Ultrasonic kuaj yog hais txog ib txoj kev txhaj tshuaj ultrasound (siab zaus thiab luv wavelength) rau hauvcasting, thiab tom qab ntawd kuaj xyuas qhov tsis xws luag ntawm cov casting raws li cov yam ntxwv ntawm nws cov refraction thiab waveform transformation ntawm lub interface. Ultrasound muaj cov yam ntxwv ntawm nqaj ncaj qha thiab nthuav tawm kev cuam tshuam.
Muaj peb hom kev kuaj ultrasonic: pulse reflection method, penetration method and resonance method. Feem ntau siv ultrasonic nrhiav kom tau txoj kev yog cov mem tes reflection txoj kev. Nws yog hais txog ib txoj hauv kev txiav txim qhov loj thiab txoj hauj lwm ntawm qhov tsis xws luag raws li lub ncha ntawm qhov tsis xws luag thiab ncha ntawm qhov chaw hauv qab.
Lub hauv paus ntsiab lus ntawm txoj kev xav ntawm mem tes yog tias lub piezoelectric caij hauv kev sojntsuam zoo siab los ntawm high-frequency pulses los tsim ultrasonic pulses. Thaum lub suab yoj propagates nyob rau hauv lub casting thiab ntsib teeb meem, ib feem ntawm nws yog reflected rov qab. Qhov loj ntawm qhov cuam tshuam yoj tuaj yeem cuam tshuam qhov loj me, qhov chaw thiab qhov tob ntawm qhov tsis xws luag ntawm qhov casting. Ultrasonic nthwv dej uas tsis muaj kev cuam tshuam txuas ntxiv mus rau pem hauv ntej kom txog thaum lawv tau rov qab mus rau hauv qab ntawm qhov casting. Lub suab lub zog cuam tshuam los ntawm qhov tsis xws luag thiab hauv qab ntawm lub casting yog ua tiav tau txais los ntawm piezoelectric transducer, thiab tom qab ntawd tso tawm rau ntawm cov zaub ntawm ultrasonic flaw detector nyob rau hauv daim ntawv ntawm amplitude.
Lub rhiab heev ntawm ib qho ultrasonic flaw detector hais txog nws lub peev xwm los nrhiav qhov tsawg tshaj plaws tsis xws luag. Lub rhiab heev ntawm kev kuaj ultrasonic muaj feem xyuam rau yam xws li qhov zaus ntawm ultrasonic nthwv dej, qhov loj ntawm qhov ntsuas qhov tsis haum, lub zog xa mus, kev ua haujlwm ntawm kev sojntsuam, thiab kev ruaj ntseg ntawm lub zog. Txhawm rau kom ntseeg tau tias kev sib kis ntawm ultrasonic nthwv dej mus rau hauv qhov nruab nrab acoustic, yuav tsum tau siv txoj kev sib txuas tsim nyog. Qhov no yuav tsum tau hais tias qhov nto roughness ntawm lub casting yuav tsum yog Ra≤12.5 μm. Nyob rau tib lub sijhawm, txhawm rau kom muaj huab cua nyob hauv qhov sib txawv, cov roj, roj cua, roj cua, thiab lwm yam kom pom tseeb ntawm cov nras.
Cov yam ntxwv ntawm ultrasonic tsis pom kev:
1. Kev tshawb pom siab rhiab heev. Ultrasonic flaw detection tuaj yeem ntes cov teeb liab tsis xws luag nrog lub mem tes rov qab yoj lub suab siab ntawm tsuas yog 0.1% ntawm qhov xwm txheej suab siab.
2. High defect qhov chaw raug thiab siab daws teeb meem
3. Muaj zog siv tau thiab siv ntau yam. Ultrasonic flaw detection tuaj yeem ntes txhua yam ntawm castings tshwj tsis yog austenitic steel castings.
4. Tsawg tus nqi, kev kub ceev thiab loj nrhiav kom pom thickness.
Cov yam ntxwv ntawm cov mem tes thiab cov duab piav qhia ntawm qhov sib txawv sab hauv tsis xws luag ntawm castings ntawm lub vijtsam zaub:
1. Ncua tseg
Casting tawg yog ib hom hlau tawg, uas muaj roj, muaj ib qho kev taw qhia, thiab yog linearly faib. Thaum cov teeb meem no tau pom los ntawm kev tshuaj xyuas ultrasonic, yog tias lawv nyob ib sab ntawm lub suab beam, cov pulses pom tau pom tseeb, ntse thiab muaj zog. Tab sis thaum nws qhov kev faib tawm yog sib npaug rau lub suab beam, nws tsis yooj yim pom. Yog li ntawd, thaum kuaj, nws yuav tsum tau kwv yees los ntawm ntau cov lus qhia, kom qhov tsis xws luag yog perpendicular mus rau lub suab beam mus rau qhov loj tshaj plaws, thiab nws muaj peev xwm mus nrhiav tau cov kab nrib pleb nyob rau hauv tag nrho cov lus qhia.
2. Tshuab tshuab
Zoo li cov kab nrib pleb, blowholes hauv castings muaj roj. Qhov kev cuam tshuam ntawm lub qhov cua ntawm lub qhov yog tsis tu ncua thiab du, yog li thaum lub suab beam yog kiag li perpendicular rau nws reflection interface, cov yam ntxwv thiab cov duab ntawm lub reflected mem tes yog zoo li cov tawg, thiab nws kuj yog pom tseeb, ntse thiab muaj zog. Txawm li cas los xij, vim tias feem ntau ntawm cov tshuab raj yog ncig los yog elliptical, thaum qhov kev sojntsuam txav me ntsis, cov mem tes ploj tam sim ntawd. Thaum qhov kev sojntsuam kuaj pom los ntawm txhua qhov kev taw qhia, tshuab lub qhov tuaj yeem pom, thiab cov yam ntxwv ntawm cov mem tes pom tau me me. Qhov no tsis yog cov ntaub ntawv nrog cov kab nrib pleb. Vim hais tias cov kab nrib pleb yog linearly faib nrog muaj zog directionality, lawv cov pulses reflected tsis ploj tam sim ntawd thaum lub sij hawm txav ntawm kev sojntsuam, thiab tib lub sijhawm, tsis yog txhua tus tuaj yeem pom thaum kuaj xyuas los ntawm txhua qhov kev qhia. Raws li cov yam ntxwv no, peb tuaj yeem paub qhov txawv ntawm qhov pores thiab kab nrib pleb.
3. Kev poob qis
Lub shrinkage kab noj hniav muaj cov pa roj, thiab thaum nws qhov zoo ntawm qhov kev xav ntawm qhov chaw loj dua lub suab nrov ntawm lub suab nrov nrov, lub suab ntawm txoj kev tau cuam tshuam tag nrho, thiab qhov kev xav ntawm lub plawv hauv qab yog tshem tawm. Cov yam ntxwv ntawm cov mem tes reflected ntawm lub shrinkage kab noj hniav kuj pom tseeb, ntse thiab muaj zog. Txawm li cas los xij, ntxiv rau txoj kev txiav txim siab saum toj no, kev txiav txim siab ntawm cov kab noj hniav tsis zoo yuav tsum tau siv ntau txoj kev npaj dav hlau.
4. Sand Inclusion thiab Slag Inclusion
Sand inclusion thiab slag inclusion xa mus rau cov hlau castings uas muaj ib tug me me ntawm cov pa roj thiab non-metallic inclusions. Cov impurities no muaj cov nyhuv ntawm absorbing suab zog, thiab vim hais tias lub reflecting nto yog ib qho yooj yim thiab du, cov yam ntxwv ntawm nws cov mem tes reflection nyob nruab nrab ntawm pom tseeb, ntse, muaj zog thiab dull, qeeb thiab luv. Qhov xwm txheej kawg no tshwm sim thaum qhov sib cuam tshuam ntawm cov khoom sib txuas thiab cov hlau tsis sib xws thiab nruj nruj rau cov hlau.
5. Shrrinkage Porotity
Lub pulse reflection yam ntxwv ntawm shrinkage porosity yog tias tsis muaj ib qho hauv qab ntawm lub ntsej muag pulse los yog ib qho tsis xws luag ntawm lub plawv dhia, tab sis ib qho tshwm sim creeping ntawm kab cheb ntawm lub vijtsam.
Post lub sij hawm: Sep-24-2022