1. Metallurgical Stability: Dab tsi ua rau Hastelloy B-3 xaim pas nrig zoo tshaj qhov qub Hastelloy B-2 rau vuam daim ntaub ntawv, tshwj xeeb tshaj yog hais txog intermetallic theem nag lossis daus?
Q: Peb tau siv Hastelloy B-2 muab tub lim hlau rau xyoo los txuas cov khoom siv hydrochloric acid. Peb tus neeg muag khoom tam sim no pom zoo B-3. Lawv hais tias nws yog "metallurgically ruaj khov." Qhov no txhais li cas rau cov hlua hlau thaum lub sij hawm vuam, thiab vim li cas peb yuav tsum hloov?
A: Cov evolution ntawm Hastelloy B-2 rau B-3 sawv cev rau kev nce qib tseem ceeb hauv kev tsim metallurgical, tshwj xeeb tshaj yog hais txog qhov tsis muaj zog tseem ceeb hauv B-2 alloy thaum vuam thiab thermal raug.
Qhov Teeb Meem B-2 (Kev Txiav Txim thiab Kev Txiav Txim Siab):
Hastelloy B-2, thaum zoo heev hauv kev tiv thaiv corrosion, raug kev txom nyem los ntawm ob qhov teeb meem loj ntsig txog nws cov ntsiab lus siab molybdenum (kwv yees . 28%):
Luv -Range Ordering: Thaum B-2 raug rau qhov kub thiab txias nyob rau hauv thaj tsam ntawm 550℃F txog 850℃F (290℃rau 455 degree) - uas tuaj yeem tshwm sim tau yooj yim thaum lub sij hawm ntau dhau vuam lossis kev ntxhov siab - cov atoms rov kho lawv tus kheej rau hauv cov qauv lattice. Qhov "ordering" no ua rau cov hlau tsis tshua muaj zog thiab nkig. Ib tug hlau pas nrig los yog ib tug weld deposit uas tau ntsib qhov no yuav ua rau muaj kev puas tsuaj loj tawg nyob rau hauv kev ntxhov siab.
Carbide Precipitation: B-2 yog qhov ua rau nag lossis daus ntawm carbides thiab intermetallic theem (xws li Mu theem) nyob rau hauv cheeb tsam kub-tshuaj, ntxiv txo ductility.
Kev daws teeb meem B-3:
Hastelloy B-3 tau hloov kho tshwj xeeb (nrog kev tswj xyuas ntxiv ntawm cov hlau thiab chromium, thiab kev hloov kho hauv kev ua haujlwm) kom txo qis cov kinetics ntawm qhov kev txiav txim siab no. Nyob rau hauv lub tswv yim:
Rau Hlau Qws: B-3 hlau pas nrig tseem ductile txawm tias nws tau ntsib thermal excursions thaum lub sij hawm cia los yog fabrication. Nws tiv taus qhov embrittlement uas tuaj yeem tshwm sim hauv B-2 yog tias cov hlau tsis raug cua sov.
Rau Weld Deposit: Thaum koj nteg ib lub hlaws nrog B-3 xaim, qhov vuam hlau thiab cov cua sov- thaj tsam cuam tshuam ntau dua rau kev txiav txim. Qhov no txhais tau hais tias cov khoom siv welded khaws nws cov ductility thiab toughness yam tsis tas yuav tsum muaj cov tshuaj tom qab vuam anneal los kho cov khoom.
Qhov tshwm sim: Hloov mus rau B-3 xaim pas nrig muab lub qhov rais ua haujlwm dav dua, txo qhov kev pheej hmoo ntawm tshav kub- cuam tshuam thaj tsam tawg, thiab ua kom muaj kev ncaj ncees ntawm cov welded nyob rau hauv cov xwm txheej zoo li-welded, tshwj xeeb tshaj yog nyob rau hauv cov khoom siv ua haujlwm nyob rau hauv qhov kub thiab txias qhov twg B-2 yuav embrittle.
2. Hydrochloric Acid Service: Nyob rau hauv azeotropic HCl kev pab cuam saum toj no lub boiling point, yog vim li cas yog Hastelloy B-3 hlau pas nrig xaiv rau vuam, thiab yuav ua li cas tiv thaiv corrosion tshwj xeeb mechanism?
Q: Peb tab tom tsim lub reactor los tuav azeotropic hydrochloric acid (kwv yees . 20% HCl) ntawm 150℃. Peb paub B-3 yog lub hauv paus hlau. Tab sis rau vuam, peb tau muab ob qho tib si C-276 thiab B-3 muab tub lim. Vim li cas peb yuav tsum hais rau B-3 hlau pas nrig rau qhov chaw tshwj xeeb no?
A: Hauv azeotropic HCl kev pabcuam ntawm qhov kub siab, kev xaiv cov hlau muab tub lim yog qhov tseem ceeb heev. Siv C-276 muab tub lim rau B-3 lub hauv paus hlau yuav tsim ib qho "sib xyaw hlau" weld cheeb tsam uas tuaj yeem ua tsis tau sai. Ntawm no yog vim li cas B-3 hlau pas nrig yog tsis-negotiable:
Cov txheej txheem Corrosion: Txo Acid vs. Oxidizing Acid
Hastelloy B-3 yog tsim los rau "txo" ib puag ncig, zoo li ntshiab hydrochloric acid. Nws cov ntsiab lus molybdenum siab (28-30%) muab qhov tshwj xeeb tiv thaiv corrosion tsis zoo hauv HCl. Nws txhob txwm tshaj tawm tsis muaj chromium thiab hlau los tiv thaiv kev tawm tsam sai hauv kev txo cov kua qaub.
Hastelloy C-276 yog tsim los rau "oxidizing" ib puag ncig (xws li cov uas muaj ferric lossis cupric ions, lossis chlorine). Nws tso siab rau chromium (15%) rau nws txoj kev tiv thaiv.
Qhov Failure Scenario:
Yog tias koj txuas lub nkoj B-3 nrog C-276 muab tub lim:
Lub Dilution Zone: Lub pas dej welded ua ib qho sib xyaw ntawm B-3 (low Cr, siab Mo) thiab C-276 (siab Cr, siab Mo). Cov txiaj ntsig tso nyiaj muaj cov ntsiab lus nruab nrab chromium.
Electrochemical Cell: Nyob rau hauv ntshiab, kub hydrochloric acid (ib tug txo acid), chromium yog tiag detrimental. Cov chromium hauv C-276 feem ntawm cov vuam sai sai yaj. Qhov no tsim cov galvanic cell uas cov chromium- depleted B-3 puag hlau yog cathodic, thiab cov chromium-muaj weld hlau yog anodic. Lub weld seam dissolves preferentially.
Riam-Kab Tawm Tsam: Koj yuav saib xyuas sai, hnyav corrosion raws nraim li cov vuam seam, uas yuav ua rau kom tawg hauv lub lis piam.
Vim li cas B-3 Wire Wins:
Siv qhov sib txuam B-3 hlau pas nrig kom ntseeg tau tias cov khoom siv vuam muaj qhov qis tib yam -chromium, high-molybdenum chemistry raws li lub hauv paus hlau. Tag nrho cov kev sib koom ua ke nthuav tawm ib qho chaw tsis sib xws rau cov kua qaub, tiv thaiv cov txheej txheem corrosion tsis zoo yam tsis muaj kev qhia galvanic incompatibility.
3. Cold Heading & Formability: Dab tsi yog cov kev cai tshwj xeeb rau kev tsim Hastelloy B-3 hlau qws npaj rau lub taub hau txias fasteners ( txiv ntseej, bolts, ntxhua khaub ncaws) nyob rau hauv ib puag ncig corrosive?
Q: Peb tsim cov fasteners rau kev lag luam tshuaj. Peb yuav tsum tsim bolts los ntawm Hastelloy B-3 hlau pas nrig. Dab tsi tshwj xeeb metallurgical tej yam kev mob thiab nto finishes yuav tsum tau cov hlau qws yuav tsum tau kom ciaj sia lub taub hau txias tsis tawg, muab yuav ua li cas ua hauj lwm-hardening no alloy?
A: Kev tsim cov fasteners los ntawm Hastelloy B-3 ntawm lub taub hau txias yog qhov nyuaj vim cov hlau ua haujlwm nrawm nrawm. Cov hlua hlau yuav tsum tau muab nkag rau hauv ib qho xwm txheej tshwj xeeb kom muaj sia nyob ntawm cov txheej txheem.
Ntawm no yog cov kev xav tau tseem ceeb rau lub taub hau txias xaim pas nrig:
Qhov xwm txheej: "Txhim kho qhov zoo" thiab cov tshuaj Annealed:
Cov pas nrig hlau yuav tsum tau muab nkag rau hauv qhov kev daws teeb meem annealed- lub xeev softest tau. Qhov no txhais tau hais tias nws tau ua kom sov siab tshaj 1060℃thiab sai sai kom yaj tag nrho cov precipitates thiab ua tiav tag nrho recrystallized, equiaxed grain qauv.
Nws yuav tsum tau muab qhab nia tshwj xeeb raws li "txoj hau kev zoo," uas txhais tau hais tias kev tswj hwm nruj ntawm lub suab sab hauv (tsis muaj subsurface inclusions lossis yeeb nkab) uas tuaj yeem ua rau muaj kev ntxhov siab thaum ntxhov siab.
Surface Condition: Qhov "Scalped" lossis "Peeled" Finish:
Qhov no yog qhov tseem ceeb tshaj plaws. Txhua qhov chaw tsis xws luag ntawm tus pas hlau- seams, laps, tuag marks, los yog decarburization (txawm hais tias decarb tsis tshua muaj feem xyuam rau cov nickel alloys)-yuav qhib zoo li lub zipper thaum lub caij txias.
Rau fasteners, cov hlau pas nrig yuav tsum muaj ib tug tev los yog hauv av nto. Qhov kev tshem tawm ntawm cov txheej txheem txheej txheej no tshem tawm tag nrho cov kev tsis zoo ntawm qhov chaw, muab lub ntsej muag pristine uas tuaj yeem tiv taus qhov tensile hoop stresses ntawm nqe lus.
Lubrication thiab Coatings:
Cov hlua hlau feem ntau yog muab los ntawm cov khoom siv roj nplua nyeem tshwj xeeb (feem ntau oxalate lossis polymer tshwj xeeb) uas pab kos cov hlau los ntawm kev tuag thiab txhawb cov hlau thaum lub sij hawm siab - kev nyuaj siab.
Grain Size Control:
Cov qoob loo loj yuav tsum tau tswj hwm (feem ntau ASTM 5 lossis finer). Ib qho kev ntxhib los mos ntau dhau tuaj yeem ua rau "txiv kab ntxwv tev" cuam tshuam rau ntawm lub taub hau taub hau lossis txawm tawg ntawm cov ciam teb hauv qab lub taub hau.
Tshaj tawm -Kev txiav txim siab:
Txawm hais tias npaj tau zoo kawg nkaus xaim pas nrig, cov txheej txheem txias taub hau yuav ua haujlwm- tawv taub hau thiab shank. Rau cov fasteners uas yuav tsum tau ductility los yog cov khoom siv tshwj xeeb, ib qho kev tshaj tawm - tsim cov tshuaj anneal ntawm cov ntsia liaj qhov rooj tiav yuav tsum tau ua kom nws soften ua ntej threading los yog zaum kawg siv.
4. Cov txheej txheem kos duab hlau: Yuav ua li cas cov ntsiab lus siab molybdenum ntawm Hastelloy B-3 cuam tshuam rau cov txheej txheem kos duab hlau, thiab cov txheej txheem tshwj xeeb twg yog siv los tsim cov hlua hlau zoo?
Q: Peb tab tom sim kos Hastelloy B-3 xaim mus rau 0.5mm txoj kab uas hla siv los ua thermocouple sheathing hlau. Peb pheej tau tawg. Peb cov txheej txheem kos duab stainless hlau tsis ua haujlwm. Dab tsi yog qhov tshwj xeeb ntawm kev kos cov hlau no?
A: Kos duab Hastelloy B-3 rau cov kab uas hla zoo yog qhov ua pov thawj rau qhov tseeb metallurgy. Cov ntsiab lus molybdenum siab (kwv yees . 28%) uas muab B-3 nws zoo heev corrosion kuj tseem ua rau nws npau suav phem los kos yog tias tsis kho kom raug. Tej zaum koj yuav tau ntsib "centerline bursting" los yog "khob-thiab-cone" pob txha vim yog cov hlau ua haujlwm ceev ceev.
Nov yog cov txheej txheem tshwj xeeb uas yuav tsum tau ua:
Qhov "Annealing Frequency" Challenge: B-3 ua hauj lwm-hardens sai dua stainless hlau. Koj tsis tuaj yeem tsuas spool tawm ntev ntev thiab kos nws mus txog 10 tuag hauv ib qho dhau los. Koj yuav tsum ntiav cov txheej txheem nrog cov kev daws teeb meem nruab nrab annealing cov kauj ruam.
Txheej txheem:Kos qhov txo me me, anneal, kos dua, anneal. Rau cov hlau zoo, koj tuaj yeem mus txog 5-10 lub voj voog annealing. Cov hlau yuav tsum tau muab tso rau hauv qhov chaw tiv thaiv (ci annealing) kom tiv thaiv oxidation, vim oxide nplai yuav rhuav tshem cov nplua tuag.
Die Geometry (Qhov "K" Factor): Cov qauv stainless hlau tuag muaj qhov tshwj xeeb txo lub kaum sab xis ("lub kaum sab xis tuag"). Rau siab -molybdenum alloys zoo li B-3, lub kaum sab xis tuag yuav tsum tau ua kom zoo dua. Yog hais tias lub kaum sab xis siab dhau lawm, cov zaj duab xis lubrication tawg thiab cov hlau welds mus rau qhov tuag (galling). Yog tias nws ntiav heev, koj tau txais kev ua haujlwm tsis tu ncua thiab ua kom kub ntau dhau. Lub kaum sab xis me me feem ntau yog siv los faib cov deformation ntau tusyees thiab txo qhov nruab nrab tawg.
Lubrication yog qhov tseem ceeb: Cov roj txheem txheem-raws li cov roj nplua nyeem tuaj yeem tawg nyob rau hauv lub siab dhau los ntawm kev kos duab B-3. Koj xav tau hnyav-lub luag haujlwm, tsis muaj chlorine-free huab siab (EP) lubricants los yog cov xab npum qhuav tshwj xeeb uas tsim cov zinc stearate lossis molybdenum disulfide zaj duab xis.
Kev Tswj Kev Nyuaj Siab: B-3 muaj lub qhov rai nqaim ntawm qhov tawm los thiab lub zog tensile ib zaug ua haujlwm-hardened. Lub nraub qaum thiab qhov nro pem hauv ntej ntawm lub rooj zaum rub yuav tsum tau tswj kom meej. Nrhav ntau dhau, thiab koj yield cov hlau, ua rau caj dab thiab tawg.
Kev Ntsuas Ultrasonic (rau kev kuaj pom tawg): Hauv kev kos duab zoo, hauv - kab eddy tam sim no los yog ultrasonic testers yog siv los kuaj xyuas qhov me me laps los yog seams tam sim ntawd, nres txoj kab ua ntej kev tawg tag.
Kev vam meej hauv kev kos duab B-3 xaim yuav tsum muaj kev koom tes nrog lub zeb uas nkag siab txog cov nuances no thiab muaj lub qhov cub tawg thiab tuag engineering tshwj xeeb rau cov nickel-molybdenum alloys.
5. Pickling thiab Descaling: Tom qab annealing Hastelloy B-3 hlau qws, dab tsi yog qhov tseeb pickling chemistry kom tshem tawm cov oxide nplai yam tsis tau tawm tsam lub hauv paus hlau los yog ua rau intergranular nres?
Q: Peb anneal Hastelloy B-3 hlau qws nyob rau hauv lub cua sov cua sov (peb tsis muaj ib tug kaj annealer). Qhov ntsuas yog tenacious. Peb tus qauv nitric-hydrofluoric acid pickle rau stainless hlau tsis ua haujlwm zoo, thiab peb txhawj xeeb txog kev xaiv ntau dhau. Dab tsi yog qhov sib xyaw acid rau B-3?
A: Koj tau txheeb xyuas qhov teeb meem tseem ceeb. Cov nplai oxide ntawm Hastelloy B-3 yog cov tshuaj sib txawv ntawm cov hlau tsis muaj hlau, thiab siv cov khoom siv tsis zoo tuaj yeem ua tsis tiav los ntxuav cov hlau los yog, qhov phem dua, ua rau cov ciam teb, ua rau nws cov khoom puas.
Qhov xwm ntawm B-3 Scale:
Vim tias B-3 yog npib tsib xee- molybdenum alloy nrog chromium tsawg heev, cov nplai tsim thaum lub sij hawm cua annealing yog nplua nuj nyob rau hauv nickel oxides thiab molybdenum oxides. Cov oxides no tawv dua thiab muaj zog dua li cov chromium oxides ntawm stainless hlau. Cov txheej txheem nitric-HF sib xyaw siv rau cov hlau tsis huv yog me me heev los ua kom cov molybdenum oxides zoo.
Cov txheej txheem Pickling pom zoo:
Kauj Ruam 1: Lub Oxidizing Salt Bath (Cuaj Khov):
Ua ntej acid pickling, B-3 hlau pas nrig feem ntau yuav tsum tau fused ntsev da dej (feem ntau muaj sodium hydride los yog oxidizing ntsev). Cov hlau yog immersed nyob rau hauv molten ntsev ntawm ib ncig ntawm 400-500 degree.
Lub hom phiaj:Qhov no tshuaj hloov cov refractory nickel-molybdenum oxides rau hauv qis oxides uas yog soluble ntau nyob rau hauv acid. Nws "cov xwm txheej" lossis "lov" cov nplai.
Kauj Ruam 2: Acid Pickle:
Tom qab da dej ntsev thiab dej quench (uas thermally shocks lub teev), cov hlau yog immersed nyob rau hauv ib tug tshwj xeeb acid sib tov.
Cov Formula: Ib qho kev daws ntawm Sulfuric Acid (H2SO4) feem ntau zoo dua li nitric -HF rau B-3. Feem ntau, 10-20% sulfuric acid tov rhuab mus rau 60-80℃yog siv.
Vim li cas ho tsis Nitric -HF? Nitric acid yog oxidizing acid. Nco ntsoov, B-3 yog tsim rautxoib puag ncig. Kev nthuav tawm qhov liab qab B-3 nto kom muaj zog oxidizing nitric acid tuaj yeem ua rau muaj kev cuam tshuam ntawm intergranular los yog passivate saum npoo ntawm txoj kev uas cuam tshuam kev tu ntxiv. Hydrofluoric acid tawm tsam molybdenum, tab sis yog tias qhov sib piv tsis raug, koj yuav raug etching cov ciam teb.
Inhibitors:
Kev lag luam pickling inhibitors feem ntau ntxiv rau sulfuric acid kom ntseeg tau tias tsuas yog cov nplai raug tawm tsam, thiab lub hauv paus hlau tiv thaiv.
Qhov pheej hmoo ntawm "Hnub-Pickling":
Yog tias koj tawm B-3 nyob rau hauv ib qho kev txhoj puab heev ntev heev, lossis yog tias cov kua qaub kub dhau, koj yuav nyiam tawm tsam cov cheeb tsam molybdenum-depleted (zoo li cov ciam teb). Qhov no ua rau muaj qhov ntxhib, "fuzzy" nto thiab muaj peev xwm ua kom tawg ntawm intergranular thaum lub sij hawm xaim txuas ntxiv.
Kev pom zoo:
Yog tias koj tsis tuaj yeem nruab cov kab dej ntsev da dej, koj yuav tsum tau muab koj cov B-3 hlau pas nrig los ntawm lub zeb uas ua kom ci ntsa iab (hauv qhov chaw tswj qhov cub nrog hydrogen lossis argon). Qhov no ua kom huv si, oxide-dawb nto uas yuav tsum tsis muaj pickling, tshem tawm txoj kev pheej hmoo tag nrho thiab khaws cia cov hlau qhov chaw ncaj ncees rau cov dej ntws.
