1. Dab tsi yog cov yam ntxwv ntawm thawj cov qauv siv lead ua ntawm cov vuam?
Teb: Lub crystallization ntawm lub vuam pas dej ua ke kuj ua raws li cov kev cai ntawm cov kua hlau crystallization: kev tsim cov siv lead ua nuclei thiab kev loj hlob ntawm crystal nuclei. Thaum cov kua hlau nyob rau hauv lub vuam pas dej ua ke, lub semi-molten nplej ntawm niam txiv cov ntaub ntawv nyob rau hauv lub fusion zone feem ntau yog siv lead ua nuclei.
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Tom qab ntawd cov crystal nucleus absorbs cov atoms ntawm cov kua ib puag ncig thiab loj hlob. Txij li cov siv lead ua loj hlob nyob rau hauv kev coj rov qab mus rau lub tshav kub conduction kev taw qhia, nws kuj loj hlob nyob rau hauv ob qho tib si kev taw qhia. Txawm li cas los xij, vim raug thaiv los ntawm cov pob zeb uas nyob ib sab, cov ntaub ntawv siv lead ua Crystals nrog columnar morphology hu ua columnar crystals.
Tsis tas li ntawd, nyob rau hauv tej yam kev mob, cov kua hlau nyob rau hauv lub molten pas dej ua ke kuj yuav tsim spontaneous crystal nuclei thaum solidifying. Yog hais tias lub tshav kub dissipation yog nqa tawm nyob rau hauv tag nrho cov lus qhia, cov muaju yuav loj hlob uniformly mus rau hauv grain zoo li crystals nyob rau hauv tag nrho cov lus qhia. Cov Crystal no hu ua Nws yog ib qho siv lead ua equiaxed. Cov kab nrib pleb feem ntau pom nyob rau hauv welds, thiab nyob rau hauv tej yam kev mob, equiaxed crystals kuj yuav tshwm sim nyob rau hauv nruab nrab ntawm lub weld.
2. Dab tsi yog cov yam ntxwv ntawm cov qauv crystallization theem nrab ntawm cov vuam?
Teb: Cov qauv ntawm cov hlau weld. Tom qab thawj crystallization, cov hlau tseem txias hauv qab ntawm theem hloov pauv kub, thiab cov qauv metallographic hloov dua. Piv txwv li, thaum vuam qis carbon steel, cov nplej ntawm thawj crystallization yog tag nrho cov nplej austenite. Thaum txias hauv qab theem kev hloov pauv kub, austenite decomposes rau hauv ferrite thiab pearlite, yog li cov qauv tom qab theem nrab crystallization feem ntau yog ferrite thiab ib qho me me ntawm pearlite.
Txawm li cas los xij, vim qhov ceev ceev ntawm cov vuam, cov ntsiab lus pearlite feem ntau ntau dua cov ntsiab lus hauv cov qauv sib npaug. Qhov ceev ntawm qhov txias txias, qhov siab dua cov ntsiab lus pearlite, thiab tsawg dua ferrite, hardness thiab lub zog kuj tseem txhim kho. , thaum lub plasticity thiab toughness yog txo. Tom qab theem nrab crystallization, qhov tseeb qauv ntawm chav tsev kub yog tau. Cov txheej txheem vuam tau los ntawm cov khoom siv hlau sib txawv hauv cov txheej txheem vuam sib txawv yog txawv.
3. Siv cov pa roj carbon tsawg los ua piv txwv los piav qhia seb cov qauv twg tau txais tom qab theem nrab crystallization ntawm weld hlau?
Teb: Siv cov hlau tsis tshua muaj hlau ua piv txwv, thawj cov qauv crystallization yog austenite, thiab cov txheej txheem kev hloov pauv hauv lub xeev cov txheej txheem ntawm cov hlau vuam yog hu ua theem nrab crystallization ntawm cov hlau weld. Lub microstructure ntawm theem nrab crystallization yog ferrite thiab pearlite.
Nyob rau hauv cov qauv sib npaug ntawm cov pa roj carbon tsawg, cov ntsiab lus ntawm cov hlau vuam yog tsawg heev, thiab nws cov qauv yog ntxhib columnar ferrite ntxiv rau ib qho me me ntawm pearlite. Vim qhov txias txias ntawm cov vuam, cov ferrite tsis tuaj yeem ua tiav tag nrho raws li daim duab kos duab hlau-carbon. Yog li ntawd, cov ntsiab lus ntawm pearlite feem ntau loj dua li ntawm cov qauv du. Lub siab txias txias kuj tseem yuav ua kom cov nplej thiab ua kom lub zog thiab lub zog ntawm cov hlau. Vim qhov txo qis ntawm ferrite thiab qhov nce ntawm pearlite, lub hardness kuj yuav nce, thaum lub plasticity yuav txo.
Yog li ntawd, cov qauv kawg ntawm cov vuam yog txiav txim siab los ntawm cov khoom sib xyaw ntawm cov hlau thiab cov cua txias. Vim yog cov yam ntxwv ntawm cov txheej txheem vuam, cov qauv hlau vuam yog qhov zoo dua, yog li cov hlau vuam muaj cov yam ntxwv zoo dua li lub xeev cam khwb cia.
4. Dab tsi yog cov yam ntxwv ntawm qhov sib txawv ntawm cov hlau vuam?
Teb: 1) Cov yam ntxwv ntawm qhov sib txawv ntawm cov hlau vuam feem ntau yog nyob rau hauv qhov sib txawv ntawm qhov sib txawv ntawm cov hlau alloy ntawm cov hlau tso thiab cov vuam. Nrog rau cov duab ntawm lub vuam, lub thickness ntawm lub hauv paus hlau, lub electrode txheej los yog flux, thiab hom kev tiv thaiv roj, lub vuam yaj yuav hloov. Kev coj cwj pwm hauv pas dej kuj tsis sib haum,
Yog li ntawd, tus nqi ntawm melting ntawm lub hauv paus hlau kuj txawv, thiab kev sib nrig sib dilution nyhuv ntawm cov concentration ntawm cov tshuaj Cheebtsam ntawm deposited hlau thiab lub melting cheeb tsam ntawm lub hauv paus hlau kuj yuav hloov. Nws tuaj yeem pom tias qhov sib txawv ntawm cov hlau welded pob qij txha sib txawv nrog cov tshuaj tsis sib xws ntawm thaj chaw. Qhov degree tsis tsuas yog nyob ntawm qhov tseem ceeb ntawm cov khoom siv vuam thiab muab tub lim, tab sis kuj txawv nrog cov txheej txheem vuam sib txawv.
2) Inhomogeneity ntawm cov qauv. Tom qab tau ntsib lub voj voog thermal, cov txheej txheem metallographic sib txawv yuav tshwm sim nyob rau hauv txhua qhov chaw ntawm qhov sib koom ua ke, uas muaj feem xyuam rau cov tshuaj muaj pes tsawg leeg ntawm lub hauv paus hlau thiab cov ntaub ntawv muab tub lim, vuam txoj kev, vuam theem, vuam txheej txheem thiab kev kho cua sov.
3) Kev tsis sib xws ntawm kev ua haujlwm. Vim qhov sib txawv tshuaj muaj pes tsawg leeg thiab cov qauv hlau ntawm kev sib koom ua ke, cov khoom siv kho tshuab ntawm kev sib koom ua ke sib txawv. Lub zog, hardness, plasticity, toughness, thiab lwm yam ntawm txhua cheeb tsam raws li kev sib koom tes sib txawv heev. Nyob rau hauv lub weld Qhov kev cuam tshuam qhov tseem ceeb ntawm cov tshav kub cuam tshuam rau ob sab yog txawm ntau zaus sib txawv, thiab qhov kev txwv tsis pub nkag thiab lub zog ntev ntawm qhov kub thiab txias kuj yuav txawv heev nyob ntawm seb muaj pes tsawg leeg thiab cov qauv.
4) Non-uniformity ntawm kev ntxhov siab teb kev faib tawm. Qhov seem ntawm kev ntxhov siab nyob rau hauv cov hlau sib txawv yog cov tsis sib xws. Qhov no feem ntau yog txiav txim siab los ntawm qhov sib txawv plasticity ntawm txhua cheeb tsam ntawm kev sib koom tes. Tsis tas li ntawd, qhov sib txawv ntawm thermal conductivity ntawm cov ntaub ntawv yuav ua rau cov kev hloov nyob rau hauv qhov kub thiab txias ntawm lub vuam thermal voj voog. Cov yam ntxwv xws li qhov sib txawv ntawm qhov sib txawv ntawm cov kab sib txuas hauv ntau thaj tsam yog vim li cas rau qhov tsis sib xws ntawm qhov kev ntxhov siab.
5. Dab tsi yog cov ntsiab cai ntawm kev xaiv cov khoom siv vuam thaum vuam sib txawv?
Teb: Cov ntsiab cai xaiv rau cov khoom siv sib txawv ntawm cov hlau tsis sib xws feem ntau suav nrog plaub lub ntsiab lus hauv qab no:
1) Nyob rau hauv qhov tseeb hais tias lub welded sib koom ua ke tsis tsim cov kab nrib pleb thiab lwm yam tsis xws luag, yog hais tias lub zog thiab plasticity ntawm cov hlau weld tsis tuaj yeem muab rau hauv tus account, cov khoom siv vuam nrog cov yas zoo dua yuav tsum raug xaiv.
2) Yog tias cov khoom siv hlau sib txawv ntawm cov khoom siv hlau sib txawv tsuas yog ua tau raws li ib qho ntawm ob lub hauv paus ntaub ntawv, nws raug txiav txim siab kom ua tau raws li cov kev cai.
3) Cov khoom siv vuam yuav tsum muaj cov txheej txheem zoo thiab cov vuam vuam yuav tsum zoo nkauj zoo nkauj. Cov khoom siv vuam yog kev lag luam thiab yooj yim mus yuav.
6. Dab tsi yog qhov weldability ntawm pearlitic hlau thiab austenitic hlau?
Teb: Pearlitic steel thiab austenitic steel yog ob hom hlau nrog cov qauv sib txawv thiab cov khoom sib xyaw. Yog li ntawd, thaum ob hom hlau no tau welded ua ke, cov hlau vuam yog tsim los ntawm kev sib xyaw ntawm ob hom sib txawv ntawm cov hlau thiab cov khoom muab tub lim. Qhov no tsa cov lus nug hauv qab no rau kev weldability ntawm ob hom steel:
1) Dilution ntawm vuam. Txij li cov hlau pearlitic muaj cov ntsiab lus kub qis, nws muaj cov nyhuv diluting ntawm cov hlau ntawm tag nrho cov hlau weld. Vim qhov no dilution nyhuv ntawm pearlitic hlau, cov ntsiab lus ntawm austenite-forming ntsiab nyob rau hauv lub weld yog txo. Yog li ntawd, nyob rau hauv lub weld, Ib tug martensite qauv yuav tshwm sim, yog li deteriorating qhov zoo ntawm cov welded sib koom tes thiab txawm ua rau tawg.
2) Tsim cov txheej txheem ntau dhau. Nyob rau hauv qhov kev txiav txim ntawm vuam kub lub voj voog, qhov degree ntawm kev sib xyaw ntawm cov hlau molten thiab muab tub lim hlau sib txawv ntawm ntug ntawm lub pas dej molten. Nyob ntawm ntug ntawm lub pas dej molten, qhov kub ntawm cov kua hlau yog qis dua, lub fluidity tsis zoo, thiab lub sij hawm nyob hauv lub xeev cov kua yog luv dua. Vim muaj qhov sib txawv loj hauv cov tshuaj muaj pes tsawg leeg ntawm pearlitic steel thiab austenitic steel, molten puag hlau thiab muab tub lim hlau tsis tuaj yeem ua kom zoo fused ntawm ntug ntawm lub pas dej molten nyob rau sab pearlitic. Yog li ntawd, nyob rau hauv lub weld ntawm pearlitic steel sab, pearlitic puag hlau Qhov kev faib ua feem loj dua, thiab ze rau cov kab fusion, ntau dua qhov kev faib ua feem ntawm cov khoom siv hauv paus. Qhov no tsim cov txheej txheem kev hloov pauv nrog cov sib txawv sab hauv ntawm cov hlau weld.
3) Tsim ib txheej diffusion hauv thaj tsam fusion. Nyob rau hauv cov hlau weld tsim los ntawm ob hom steels, txij li pearlitic steel muaj cov ntsiab lus siab dua cov pa roj carbon ntau dua tab sis cov ntsiab lus alloying tsawg dua, thaum cov hlau austenitic muaj qhov sib txawv, yog li ntawm ob sab ntawm pearlitic steel sab ntawm fusion zone A. Qhov sib txawv ntawm qhov sib txawv ntawm carbon thiab carbide-forming ntsiab yog tsim. Thaum qhov sib koom ua haujlwm ntawm qhov kub siab tshaj 350-400 degrees rau lub sijhawm ntev, yuav muaj qhov pom tseeb ntawm cov pa roj carbon diffusion hauv thaj tsam fusion, uas yog, los ntawm pearlite steel sab los ntawm thaj tsam fusion mus rau austenite vuam tsam. seams kis tau. Yog li ntawd, ib txheej decarburized softening yog tsim nyob rau hauv pearlitic steel puag hlau ze rau ntawm fusion zone, thiab ib txheej carburized coj mus rau decarburization yog tsim nyob rau hauv austenitic weld sab.
4) Txij li thaum lub cev lub cev ntawm pearlitic steel thiab austenitic steel sib txawv heev, thiab cov ntsiab lus ntawm cov welds kuj sib txawv heev, hom kev sib koom tes no tsis tuaj yeem tshem tawm cov kev ntxhov siab los ntawm kev kho cua sov, thiab tsuas yog tuaj yeem ua rau muaj kev ntxhov siab. Nws txawv heev ntawm vuam ntawm tib lub hlau.
5) ncua kev tawg. Thaum lub sij hawm crystallization txheej txheem ntawm vuam molten pas dej ua ke ntawm no hom ntawm dissimilar steel, muaj ob qho tib si austenite qauv thiab ferrite qauv. Ob qho tib si nyob ze rau ib leeg, thiab cov roj tuaj yeem sib txawv, kom cov diffused hydrogen tuaj yeem sib sau ua ke thiab ua rau ncua kev tawg.
25. Dab tsi yuav tsum tau xav txog thaum xaiv ib txoj kev kho cov hlau cam khwb cia?
Teb: Thaum xaiv ib txoj kev grey cam khwb cia hlau vuam, cov hauv qab no yuav tsum tau xav txog:
1) Cov xwm txheej ntawm cov casting yuav tsum tau welded, xws li cov tshuaj muaj pes tsawg leeg, qauv thiab txhua yam khoom ntawm lub casting, qhov loj, thickness thiab structural complexity ntawm lub casting.
2) Qhov tsis xws luag ntawm cov khoom cam khwb cia. Ua ntej vuam, koj yuav tsum nkag siab txog yam tsis xws luag (kev tawg, tsis muaj nqaij, hnav, pores, hlwv, dej tsis txaus, thiab lwm yam), qhov loj ntawm qhov tsis xws luag, qhov tawv nqaij ntawm qhov chaw, qhov ua rau ntawm qhov tsis xws luag, thiab lwm yam.
3) Cov kev xav tau zoo tom qab vuam xws li cov khoom siv kho tshuab thiab cov khoom ua haujlwm ntawm kev sib txuas tom qab vuam. Nkag siab txog qhov yuav tsum tau muaj xws li xim xim thiab kev sib khi.
4) Cov khoom siv hauv tsev thiab kev lag luam. Raws li kev ua kom ntseeg tau cov kev xav tau zoo tom qab vuam, lub hom phiaj tseem ceeb tshaj plaws ntawm kev kho vuam ntawm cov castings yog siv txoj kev yooj yim tshaj plaws, cov cuab yeej siv vuam thiab cov txheej txheem feem ntau, thiab tus nqi qis tshaj kom tau txais txiaj ntsig kev lag luam ntau dua.
7. Dab tsi yog kev ntsuas los tiv thaiv kev tawg thaum kho vuam ntawm cam khwb cia hlau?
Teb: (1) Preheat ua ntej vuam thiab maj mam txias tom qab vuam. Preheating lub weldment nyob rau hauv tag nrho los yog ib feem ua ntej welding thiab qeeb txias tom qab welding tsis tau tsuas yog txo cov nyiam ntawm cov weld los ua dawb, tab sis kuj txo cov vuam kev nyuaj siab thiab tiv thaiv cov tawg ntawm weldment. .
(2) Siv arc txias vuam los txo cov kev ntxhov siab welding, thiab xaiv cov khoom siv vuam nrog cov yas zoo, xws li npib tsib xee, tooj liab, npib tsib xee-tooj liab, siab vanadium hlau, thiab lwm yam. deformation thiab tiv thaiv cov kab nrib pleb. , siv txoj kab uas hla me me welding rods, me me tam sim no, sib quas ntus vuam (nruab nrab vuam), dispersed welding (dhia vuam) txoj kev tuaj yeem txo qhov kub ntawm qhov sib txawv ntawm cov vuam thiab lub hauv paus hlau thiab txo cov vuam kev nyuab siab, uas tuaj yeem raug tshem tawm los ntawm hammering lub vuam. . kev ntxhov siab thiab tiv thaiv kev tawg.
(3) Lwm yam kev ntsuas suav nrog kev kho cov tshuaj muaj pes tsawg leeg ntawm cov hlau vuam kom txo nws cov brittleness kub ntau; ntxiv cov ntsiab lus tsis tshua muaj hauv ntiaj teb los txhim kho cov desulfurization thiab dephosphorization metallurgical cov tshuaj tiv thaiv ntawm cov vuam; thiab ntxiv cov khoom muaj zog nplej-refining kom cov weld crystallized. grain refinement.
Qee zaum, cua sov yog siv los txo qhov kev ntxhov siab ntawm qhov chaw kho vuam, uas tuaj yeem tiv thaiv qhov tshwm sim ntawm cov kab nrib pleb.
8. Kev ntxhov siab yog dab tsi? Dab tsi yog qhov ua rau muaj kev ntxhov siab ntau ntxiv?
Teb: Vim yog cov duab ntawm cov weld thiab cov yam ntxwv ntawm cov weld, discontinuity nyob rau hauv lub collective duab tshwm. Thaum thauj khoom, nws ua rau tsis sib npaug ntawm kev ua haujlwm ntawm kev ntxhov siab hauv cov welded sib koom ua ke, ua rau lub zog siab tshaj plaws hauv zos σmax siab dua qhov nruab nrab kev ntxhov siab σm. Ntxiv mus, qhov no yog kev ntxhov siab concentration. Muaj ntau qhov laj thawj rau kev ntxhov siab hauv cov pob qij txha welded, qhov tseem ceeb tshaj plaws yog:
(1) Cov txheej txheem tsis xws luag tsim nyob rau hauv lub vuam, xws li cua inlets, slag inclusions, tawg thiab tsis tiav kev nkag mus, thiab lwm yam. Ntawm lawv, cov kev ntxhov siab concentration tshwm sim los ntawm vuam cov kab nrib pleb thiab tsis tiav kev nkag mus yog qhov loj tshaj plaws.
(2) Tsis tsim nyog weld zoo li, xws li qhov cuab lub zog ntawm lub pob tw weld loj heev, cov ntiv taw weld ntawm fillet weld siab dhau lawm, thiab lwm yam.
Txoj kev tsim tsis tsim nyog. Piv txwv li, txoj kev sib tshuam tau hloov pauv sai sai, thiab siv cov vaj huam sib luag npog los txuas rau txoj kev. Cov txheej txheem vuam tsis tsim nyog kuj tuaj yeem ua rau muaj kev ntxhov siab, xws li T-zoo li cov pob qij txha nrog tsuas yog cov khw muag khoom welds.
9. Kev puas tsuaj yas yog dab tsi thiab nws muaj kev phom sij dab tsi?
Teb: Yas puas muaj xws li yas instability (yield los yog loj yas deformation) thiab yas puas (ntug puas los yog ductile puas). Cov txheej txheem yog tias cov qauv welded ua ntej dhau los ntawm elastic deformation → tawm los → yas deformation (yas tsis ruaj khov) nyob rau hauv qhov kev txiav txim ntawm load. ) → tsim micro tawg los yog micro voids → daim ntawv macro tawg → undergo unstable expansion → tawg.
Piv nrog cov pob txha tawg, cov yas puas yog qhov tsis zoo, tshwj xeeb yog cov hauv qab no:
(1) Irrecoverable yas deformation tshwm sim tom qab yielding, ua rau welded lug nrog siab loj yuav tsum tau scrapped.
(2) Kev tsis ua haujlwm ntawm cov hlab ntsha uas ua los ntawm cov khoom siv siab, cov khoom siv tsis muaj zog tsis yog tswj los ntawm cov khoom tawg, tab sis yog tshwm sim los ntawm cov yas tsis ruaj khov vim tsis muaj zog txaus.
Qhov kawg tshwm sim ntawm kev puas tsuaj yas yog tias cov qauv welded tsis ua haujlwm lossis muaj kev puas tsuaj loj tshwm sim, uas cuam tshuam rau kev tsim khoom lag luam, ua rau tsis tsim nyog raug mob, thiab cuam tshuam rau kev loj hlob ntawm lub teb chaws kev lag luam.
10. Cov pob txha tawg yog dab tsi thiab nws muaj kev phom sij dab tsi?
Teb: Feem ntau brittle fracture yog hais txog kev sib cais dissociation fracture (xws li quasi-dissociation fracture) raws li ib lub dav hlau siv lead ua thiab grain ciam teb (intergranular) tawg.
Cleavage fracture yog ib qho kev puas tsuaj uas tsim los ntawm kev sib cais raws ib lub dav hlau crystallographic nyob rau hauv cov siv lead ua. Nws yog ib qho intragranular puas. Nyob rau hauv tej yam kev mob, xws li tsis tshua muaj kub, siab strain npaum li cas thiab siab concentration concentration, cleavage thiab puas yuav tshwm sim nyob rau hauv cov ntaub ntawv hlau thaum qhov kev nyuaj siab mus txog ib tug tej yam nqi.
Muaj ntau ntau cov qauv rau tiam ntawm cleavage fractures, feem ntau muaj feem xyuam rau txoj kev xav dislocation. Nws feem ntau ntseeg tau tias thaum cov txheej txheem yas deformation ntawm cov khoom raug cuam tshuam loj heev, cov khoom siv tsis tuaj yeem hloov mus rau qhov kev ntxhov siab sab nraud los ntawm kev deformation tab sis los ntawm kev sib cais, ua rau tawg tawg.
Inclusions, brittle precipitates thiab lwm yam tsis xws luag nyob rau hauv cov hlau kuj muaj ib tug tseem ceeb cuam tshuam rau qhov tshwm sim ntawm cleavage tawg.
Cov pob txha tawg feem ntau tshwm sim thaum qhov kev ntxhov siab tsis siab tshaj qhov tsim qauv tso cai rau kev ntxhov siab ntawm cov qauv thiab tsis muaj qhov tseem ceeb ntawm cov yas deformation, thiab tam sim ntawd txuas mus rau tag nrho cov qauv. Nws muaj qhov xwm txheej ntawm kev puas tsuaj tam sim ntawd thiab nyuaj rau kev kuaj xyuas thiab tiv thaiv ua ntej, yog li nws feem ntau ua rau tus kheej raug mob. thiab kev puas tsuaj loj heev rau vaj tse.
11. Lub luag haujlwm ntawm cov vuam tawg ua haujlwm li cas hauv cov txheej txheem brittle fracture?
Teb: Ntawm txhua qhov tsis xws luag, cov kab nrib pleb yog qhov txaus ntshai tshaj plaws. Nyob rau hauv qhov kev txiav txim ntawm sab nraud load, ib tug me me ntawm cov yas deformation yuav tshwm sim nyob ze ntawm lub tawg pem hauv ntej, thiab nyob rau tib lub sij hawm yuav muaj ib tug tej yam nqi ntawm qhib kev khiav hauj lwm nyob rau hauv lub ntsis, ua rau lub tawg yuav maj mam;
Thaum lub load sab nraud nce mus rau qee qhov tseem ceeb, qhov tawg yuav nthuav dav ntawm kev kub ceev. Lub sijhawm no, yog tias qhov tawg nyob rau hauv qhov chaw siab tensile siab, nws yuav ua rau tawg tawg ntawm tag nrho cov qauv. Yog hais tias qhov nthuav dav nkag mus rau thaj chaw uas tsis tshua muaj kev ntxhov siab, lub koob npe nrov muaj lub zog txaus los txhawb nqa qhov kev nthuav dav ntxiv ntawm kev tawg, los yog cov kab nrib pleb nkag mus rau cov khoom siv nrog cov khoom zoo dua qub (los yog cov khoom siv tib yam tab sis nrog kub thiab nce toughness) thiab tau txais kev tiv thaiv ntau dua thiab tsis tuaj yeem txuas ntxiv. Nyob rau lub sijhawm no, qhov txaus ntshai ntawm qhov tawg yuav txo qis raws li.
12. Dab tsi yog vim li cas vim li cas cov khoom siv welded tuaj yeem ua rau tawg tawg?
Teb: Cov laj thawj rau pob txha tuaj yeem muab sau ua peb yam:
(1) Tib neeg tsis txaus ntawm cov khoom siv
Tshwj xeeb tshaj yog nyob rau ntawm qhov kawg ntawm lub thais, lub microscopic deformation peev xwm ntawm cov khoom yog tsis zoo. Tsawg-stress brittle tsis ua hauj lwm feem ntau tshwm sim nyob rau hauv qis kub, thiab raws li qhov kub thiab txias, lub toughness ntawm cov khoom yuav txo sharply. Tsis tas li ntawd, nrog rau txoj kev loj hlob ntawm cov hlau tsis tshua muaj alloy siab zog, lub zog Performance index tseem nce ntxiv, thaum lub plasticity thiab toughness tau txo. Feem ntau, brittle fracture pib los ntawm qhov vuam cheeb tsam, yog li tsis txaus toughness ntawm weld thiab tshav kub cuam tshuam cheeb tsam feem ntau yog lub ntsiab ua rau tsawg-stress brittle puas.
(2) Muaj qhov tsis xws luag xws li micro tawg
Kev puas tsuaj ib txwm pib los ntawm qhov tsis xws luag, thiab cov kab nrib pleb yog qhov tsis zoo tshaj plaws. Vuam yog lub ntsiab ua rau tawg. Txawm hais tias cov kab nrib pleb tuaj yeem tswj tau nrog kev txhim kho ntawm vuam tshuab, nws tseem nyuaj kom tsis txhob tawg tag.
(3) Qee qhov kev ntxhov siab
Kev tsim tsis raug thiab cov txheej txheem tsim khoom tsis zoo yog qhov ua rau lub ntsiab ntawm cov vuam seem ntawm kev ntxhov siab. Yog li ntawd, rau cov txheej txheem welded, ntxiv rau kev ntxhov siab ua haujlwm, vuam qhov seem ntawm kev ntxhov siab thiab kev ntxhov siab, nrog rau kev ntxhov siab ntxiv los ntawm kev sib dhos tsis zoo, yuav tsum tau txiav txim siab.
13. Dab tsi yog qhov tseem ceeb uas yuav tsum tau xav txog thaum tsim cov qauv welded?
Teb: Cov ntsiab lus tseem ceeb uas yuav tsum xav txog yog raws li hauv qab no:
1) Lub welded sib koom ua ke yuav tsum ua kom muaj kev ntxhov siab txaus thiab nruj kom ntseeg tau tias lub neej ua haujlwm ntev txaus;
2) Xav txog kev ua haujlwm nruab nrab thiab kev ua haujlwm ntawm kev sib koom ua ke, xws li kub, corrosion, vibration, qaug zog, thiab lwm yam.;
3) Rau cov txheej txheem loj, qhov ua haujlwm ntawm preheating ua ntej vuam thiab tom qab vuam kev kho cua sov yuav tsum raug txo kom ntau li ntau tau;
4) Cov welded qhov chaw tsis tas yuav tsum tau lossis tsuas yog siv me me ntawm kev siv tshuab;
5) Lub vuam ua haujlwm tuaj yeem raug txo kom tsawg;
6) Txo qhov deformation thiab kev ntxhov siab ntawm cov qauv welded;
7) Ib qho yooj yim rau kev tsim thiab tsim kev ua haujlwm zoo rau kev tsim kho;
8) Siv cov thev naus laus zis tshiab thiab siv tshuab thiab siv vuam tshuab kom ntau li ntau tau los txhim kho kev ua haujlwm; 9) Welds yog ib qho yooj yim los soj ntsuam xyuas kom muaj kev sib koom tes zoo.
14. Thov piav qhia txog cov xwm txheej hauv paus rau kev txiav roj. Puas tuaj yeem siv cov pa oxygen-acetylene nplaim taws txiav rau tooj liab? Vim li cas?
Teb: Cov xwm txheej hauv paus rau kev txiav roj yog:
(1) Lub ignition point ntawm hlau yuav tsum qis dua lub melting point ntawm hlau.
(2) Lub melting point ntawm cov hlau oxide yuav tsum qis dua lub melting point ntawm cov hlau nws tus kheej.
(3) Thaum cov hlau hlawv hauv cov pa oxygen, nws yuav tsum muaj peev xwm tso tawm cov cua kub ntau.
(4) Lub thermal conductivity ntawm hlau yuav tsum me me.
Cov pa roj carbon dioxide-acetylene nplaim taws txiav tsis tuaj yeem siv rau ntawm tooj liab liab, vim tias tooj liab oxide (CuO) tsim cov cua sov me me, thiab nws cov thermal conductivity zoo heev (lub tshav kub tsis tuaj yeem nyob ze ntawm qhov kev txiav), yog li cov roj txiav tsis tuaj yeem ua tau.
Post lub sij hawm: Nov-06-2023
