Nyob rau hauv lub welding seam los yog nyob ze seam cheeb tsam, vim muaj kev cuam tshuam ntawm vuam, atomic ua ke ntawm cov khoom raug puas tsuaj, thiab lub seam tsim los ntawm kev tsim ib tug tshiab interface yog hu ua ib tug vuam tawg, uas yog yus muaj los ntawm ib tug ntse sib txawv. thiab loj nam piv.
Cov kab nrib pleb tuaj yeem muab faib ua cov kab nrib pleb kub, cov kab nrib pleb txias, kev ntxhov siab corrosion thiab lamellar tearing raws li qhov kub thiab txias thiab lub sijhawm tshwm sim. Hauv vuam ntau lawm, muaj ntau qhov chaw uas muaj cov kab nrib pleb tshwm sim. Qee cov kab nrib pleb tshwm rau ntawm qhov chaw ntawm qhov vuam thiab tuaj yeem pom ntawm qhov muag liab qab; qee qhov tau muab zais rau hauv qhov vuam thiab tsuas tuaj yeem pom los ntawm kev kuaj pom qhov tsis zoo; qee qhov tshwm sim ntawm qhov vuam; thiab qee qhov tshwm sim hauv thaj chaw muaj kev kub ntxhov. Nws yog ib qho tsim nyog yuav tsum nco ntsoov tias qee zaum cov kab nrib pleb tshwm sim thaum lub sijhawm vuam, thiab qee zaum tshwm sim tom qab vuam tau muab tso rau lossis ua haujlwm rau lub sijhawm tom qab vuam. Cov tom kawg yog hu ua ncua kev tawg, uas ua rau muaj kev phom sij ntau dua. Qhov chaw thiab hom kab nrib pleb yog qhia hauv daim duab hauv qab no.
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Qhov chaw thiab hom kab nrib pleb
2. Cov phom sij ntawm vuam tawg
Vuam tawg yog qhov teeb meem loj tshaj plaws. Ntxiv nrog rau kev txo cov kabmob muaj peev xwm ntawm qhov sib koom ua ke, qhov sib txawv ntawm qhov kawg ntawm qhov tawg yuav ua rau muaj kev ntxhov siab loj, txhawb kev nthuav dav ntawm qhov tawg, thiab nws thiaj li ua rau kev puas tsuaj ntawm cov qauv welded, thiab cov khoom yuav yog. muab pov tseg. ua rau muaj xwm txheej loj. Feem ntau, cov kab nrib pleb yog ib qho impermissible defect nyob rau hauv welded pob qij txha. Thaum pom, nws yuav tsum tau muab tshem tawm tag thiab kho thiab welded.
3. Ua rau thiab tiv thaiv kev ntsuas ntawm vuam tawg
Vim yog qhov sib txawv ua rau thiab tsim cov txheej txheem ntawm cov kab nrib pleb sib txawv, peb hom kub tawg, cov kab nrib pleb txias thiab cov kab nrib pleb reheated yuav sib tham hauv qab no.
3.1, kub crack
Cov kab nrib pleb feem ntau xa mus rau cov kab nrib pleb uas tsim los ntawm qhov kub thiab txias (los ntawm ze rau qhov kub thiab txias ntau mus rau saum A3 kab ntawm daim duab hlau-carbon tshuav nyiaj li cas) raws li qhia hauv daim duab hauv qab no, tseem hu ua cov kab nrib pleb kub lossis crystallization tawg.
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Cov kab tawg kub feem ntau tshwm sim hauv qhov vuam, thiab qee zaum kuj tuaj yeem tshwm sim hauv thaj chaw kub ntxhov, raws li qhia hauv daim duab.
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vim li cas:
Vim qhov tshwm sim ntawm kev sib cais nyob rau hauv lub vuam molten pas dej ua ke thaum lub sij hawm crystallization txheej txheem, qhov tsawg melting point eutectic thiab impurities tsim segregation nyob rau hauv cov kua interlayer thaum lub sij hawm crystallization txheej txheem, thiab lub zog tom qab solidification kuj tsawg. Thaum lub vuam kev nyuaj siab loj txaus, cov kua interlayer yuav raug tso tawm. Cov txheej los yog cov hlau uas tau ua tiav tshiab rub tawm los ua cov kab nrib pleb.
Tsis tas li ntawd, yog hais tias muaj tsawg-melting eutectics thiab impurities nyob rau hauv lub grain ciam teb ntawm lub hauv paus hlau, cov uas tsis muaj-melting tebchaw yuav yaj los ua ib tug ua kua interlayer nyob rau hauv lub tshav kub-cuam tshuam cheeb tsam uas cov cua kub kub tshaj nws melting point. Thaum lub vuam tensile kev nyuaj siab loj txaus, kuj yuav raug rub tawm los ua liquefaction tawg nyob rau hauv lub tshav kub-cuam tshuam cheeb tsam.
Hauv luv luv, qhov tshwm sim ntawm thermal tawg yog qhov tshwm sim ntawm kev sib xyaw ua ke ntawm metallurgical thiab mechanical yam.
Kev Tiv Thaiv:
Kev ntsuas los tiv thaiv thermal tawg tuaj yeem pib los ntawm ob yam ntawm metallurgical yam thiab mechanical yam.
Tswj cov ntsiab lus ntawm cov teeb meem thiab impurities nyob rau hauv lub hauv paus hlau thiab vuam consumables
Txwv cov ntsiab lus ntawm cov khoom sib cais yooj yim thiab cov khoom tsis zoo hauv cov hlau thiab cov khoom siv vuam (xws li vuam pas nrig, vuam hlau, flux thiab shielding gas). Hauv particular, cov ntsiab lus ntawm impurity ntsiab xws li sulfur thiab phosphorus yuav tsum tau tswj thiab cov ntsiab lus carbon yuav tsum tau txo.
Sulfur yog xyaum insoluble nyob rau hauv steel, thiab nws tsim hlau sulfide (FeS), uas muaj ib tug tsawg melting point, nrog hlau. Thaum lub sij hawm vuam, lub xub ntiag ntawm hlau sulfide yuav ua rau kub tawg ntawm lub vuam thiab liquefaction tawg nyob rau hauv lub tshav kub-cuam tshuam cheeb tsam, uas yuav deteriorate lub vuam kev ua tau zoo; tib yam sulfur muaj nyob rau hauv lub grain ciam nyob rau hauv daim ntawv ntawm ib tug zaj duab xis, uas yuav txo tau cov plasticity thiab toughness ntawm cov hlau. Feem ntau, cov ntsiab lus sulfur hauv cov hlau siv rau vuam yuav tsum tsis pub tshaj 0.045 feem pua. Qee zaum kev tswj nruj dua yuav tsum tau ua.
Phosphorus yuav txo tau cov plasticity thiab toughness ntawm hlau, ua rau kom lub nkig hloov kub ntawm hlau, thiab ua rau tawg nyob rau hauv welds thiab tshav kub-kho cheeb tsam. Cov ntsiab lus phosphorus yuav tsum tsis pub tshaj 0.055 feem pua . Qee zaum kev tswj nruj dua yuav tsum tau ua.
Lub vuam kev ua tau zoo ntawm cov ntaub ntawv yog ze ze rau cov ntsiab lus carbon. Qhov siab dua cov ntsiab lus carbon ntawm cov hlau, qhov tsis zoo ntawm weldability. Nws feem ntau ntseeg tau tias cov ntsiab lus ntawm cov pa roj carbon monoxide yog tswj hauv qab no 0.10 feem pua, thiab cov thermal tawg rhiab heev tuaj yeem txo qis heev.
Kho cov tshuaj muaj pes tsawg leeg ntawm cov hlau weld, txhim kho cov qauv ntawm cov weld, ua kom cov nplej ntawm cov weld los txhim kho nws cov plasticity, txo lossis cuam tshuam cov degree ntawm kev sib cais, thiab tswj cov teeb meem cuam tshuam ntawm qis melting point eutectic.
Piv txwv li, thaum vuam austenitic stainless hlau, kev siv austenite ntxiv rau ferrite dual-theem qauv vuam tuaj yeem txhim kho nws cov thermal cracking tsis kam. Ib-theem austenitic weld seam yog ua rau kub tawg.
Siv cov welding pas nrig lossis flux los txo cov ntsiab lus impurity hauv cov vuam thiab txhim kho qib ntawm kev sib cais thaum lub sij hawm crystallization.
Tswj cov txheej txheem vuam, tsim nyog ua kom zoo dua qhov zoo ntawm cov vuam, txais yuav ntau txheej txheej txheej txheej txheej vuam, zam kev sib cais ntawm qhov nruab nrab, thiab tiv thaiv cov kab nrib pleb. Thaum vuam, qhov sib piv ntawm qhov dav dav rau qhov vuam tuab ntawm qhov sib txuas ntawm ib leeg yog hu ua Cov duab zoo, lossis qhov zoo tshaj plaws weld, ntawm qhov vuam. Thaum qhov zoo tshaj plaws ntawm weld seam me me dhau lawm, weld seam yog nqaim thiab sib sib zog nqus, thiab impurities nrog qis melting point yuav sib sau ua ke nyob rau hauv nruab nrab ntawm weld seam, uas ua rau kom muaj peev xwm ntawm thermal tawg. Thaum qhov zoo tshaj plaws ntawm cov weld seam loj, weld seam yog dav thiab ntiav, Tsawg-melting eutectics thiab impurities sau nyob rau hauv ze-ntog cheeb tsam ntawm weld, zoo heev txo lub propensity rau centerline cracking.
Siv cov kev ntsuas los txo cov kev ntxhov siab welding
Siv ntau yam kev ntsuas los txo cov kev ntxhov siab ntawm vuam, xws li kev siv cov txheej txheem vuam tsim nyog thiab cov txheej txheem, siv lub zog vuam me me, tag nrho cov txheej txheem preheating thiab rauj, thiab lwm yam.
Sau lub arc crater thaum lub sij hawm arc kaw tuaj yeem zam qhov arc crater tawg.
3.2, txias crack
Cov kab mob khaub thuas feem ntau yog hais txog cov kab nrib pleb uas tsim los ntawm cov vuam hauv qab A3 qhov kub thiab txias thaum lub sij hawm txias. Qhov kub ntawm qhov tawg yog feem ntau qis dua 300 ~ 200 degree, uas yog nyob rau hauv thaj tsam ntawm martensitic transformation kub, yog li nws yog hu ua txias tawg.
Cov kab nrib pleb txias tuaj yeem tshwm sim tam sim tom qab vuam, lossis tom qab lub sijhawm ntev tom qab vuam, yog li lawv kuj tseem hu ua ncua kev tawg. Txij li thaum cov kab mob khaub thuas yog txuam nrog hydrogen, nws tseem hu ua hydrogen-induced cracks. Lub cim ntawm cov kab nrib pleb txias muaj qhov ncua sij hawm, uas tuaj yeem ua rau muaj kev sib tsoo loj heev. Yog li ntawd, nws yog qhov txaus ntshai dua thiab yuav tsum tau saib xyuas tag nrho.
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Ua rau mob khaub thuas
Cov txheej txheem yooj yim rau kev tsim cov kab nrib pleb txias yog: kev tsim cov qauv tawv tawv hauv cov pob qij txha welded; lub hav zoov thiab concentration ntawm diffusible hydrogen; thiab lub hav zoov ntawm loj vuam tensile kev nyuaj siab. Peb yam xwm txheej no cuam tshuam ib leeg thiab txhawb ib leeg. Nyob rau hauv cov xwm txheej sib txawv, ib qho ntawm peb yam yuav ua rau muaj qhov tshwm sim ntawm cov kab mob khaub thuas, cov uas diffusible hydrogen yog qhov tseem ceeb tshaj plaws ua rau cov kab mob khaub thuas.
Kev tiv thaiv kab mob khaub thuas
1) Siv cov electrodes yooj yim lossis fluxes los txo cov ntsiab lus hydrogen diffusible hauv cov hlau vuam. Alkaline electrodes tseem hu ua low-hydrogen electrodes, uas tuaj yeem txo cov ntsiab lus hydrogen hauv cov hlau vuam.
2) Electrodes thiab flux yuav tsum tau qhuav kom nruj raws li qhov yuav tsum tau ua ua ntej siv. Tsis tas li ntawd, qhov zawj thiab vuam hlau yuav tsum tau ua tib zoo ntxuav kom tshem tawm cov roj, dej thiab xeb me ntsis kom txo tau qhov chaw ntawm hydrogen.
3) Xaiv qhov tsim nyog welding specifications thiab cua sov input, xws li preheating ua ntej vuam, tswj interlayer kub, qeeb txias tom qab vuam, thiab lwm yam.
4) Ua kev kho cua sov hauv lub sijhawm tom qab vuam. Ib qho yog ua tiav kev kho annealing kom tshem tawm cov kev ntxhov siab sab hauv, temper lub quenched qauv thiab txhim kho nws toughness; lwm qhov yog ua kom tshem tawm cov kev kho hydrogen kom dim hydrogen los ntawm kev sib koom ua ke.
5) Txhim kho cov hlau zoo, txo cov txheej txheej hauv cov hlau, thiab ntsuas los ntawm cov txheej txheem tsim thiab vuam txheej txheem kom txo tau qhov vuam tensile kev nyuaj siab nyob rau hauv cov kev taw qhia ntawm lub thickness ntawm lub phaj, uas yuav tiv thaiv cov txheej txheem tearing.
6) Siv ntau yam kev ntsuas thev naus laus zis los txo qhov kev ntxhov siab ntawm vuam (saib thermal tawg, kev tiv thaiv kev ntsuas kom paub meej)
3.3, reheat crack
Reheat cov kab nrib pleb tshwm sim los ntawm thaj chaw coarse-grained nyob rau hauv thaj chaw kub-tshuaj cuam tshuam ntawm vuam, uas yog tus cwj pwm los ntawm cov pob zeb tawg. Feem ntau ntawm cov kab nrib pleb tshwm sim nyob rau hauv qhov kev ntxhov siab concentration. Feem ntau, nws yog tsim thaum lub weld cheeb tsam yog rhuab dua, yog li nws yog hu ua reheat crack.
Ua rau reheat tawg
Yog vim li cas rau reheating tawg yog feem ntau ntseeg tau hais tias thaum lub sij hawm reheating, supersaturated solid-solution carbides (feem ntau carbides ntawm vanadium thiab molybdenum) precipitate dua nyob rau hauv thawj txheej txheem kub, uas ua rau intragranular ntxiv dag zog thiab slippage. Cov kab mob concentrates rau yav dhau los austenite grain ciam teb. Reheat cov kab nrib pleb thaum lub peev xwm ntawm cov yas ntawm cov ciam teb tsis txaus los tiv thaiv cov kab mob vim thaum lub sij hawm kev ntxhov siab.
Reheat kev tiv thaiv kab mob
1) Txo qhov seem ntawm kev ntxhov siab thiab kev ntxhov siab, xws li nce qhov kub thiab txias, txias txias tom qab vuam, thiab kev hloov pauv ntawm cov vuam thiab lub hauv paus hlau.
2) Raws li qhov ua tau raws li cov qauv tsim, xaiv cov khoom siv vuam tsim nyog kom lub zog kub ntawm cov hlau vuam yog me ntsis qis dua li ntawm cov hlau hauv paus, tso cai rau kev ntxhov siab los so hauv qhov vuam thiab tsis txhob muaj kab nrib pleb. tshav kub cuam tshuam.
3) Nyob rau hauv cov ntaub ntawv ntawm kev ua kom lub zog sib koom ua ke nyob rau hauv chav tsev kub, nce qhov kub ntawm annealing rau kev ntxhov siab, ua rau cov nag lossis daus ntawm coarse carbide hais los txhim kho qhov kub thiab txias ductility.
