1. Tus yeej "Wet Process": Dab tsi ua rau Hastelloy G-30 nyiam cov khoom siv rau kev pabcuam phosphoric acid, thiab nws txawv ntawm lwm cov alloys li cas?
Q:Hauv peb cov nroj tsuag chiv, peb tswj cov dej ntau ntawm cov ntub dej - txheej txheem phosphoric acid, uas muaj cov fluoride thiab chloride ions ntau heev. Peb tau siv Hastelloy G-3, tab sis peb tus kws tshaj lij corrosion pom zoo kom hloov kho G-30 rau lub tsheb ciav hlau tshiab evaporation. G-30 muaj dab tsi uas ua rau kev hloov kho tshiab?
A:Koj tau txheeb xyuas ib daim ntawv thov tseem ceeb tshaj plaws rau Hastelloy G-30 (UNS N06030). Nws tau tsim tshwj xeeb los daws cov kev txwv ntawm cov alloys ua ntej hauv kev pabcuam tshuaj lom neeg hauv kev lag luam chiv:ntub - txheej txheem phosphoric acid (WPA) .
Yuav kom nkag siab tias vim li cas G-30 yog tus yeej, koj yuav tsum nkag siab txog qhov sib txawv ntawm WPA. Tsis zoo li cov ntshiab phosphoric acid, ntub-txheej txheem acid yog complex, txhoj puab heev cocktail. Nws muaj:
Phosphoric Acid (H₃PO₄):Thawj corrosive nruab nrab.
Fluorides (F⁻) thiab Fluorosilicic Acid:Originating los ntawm phosphate pob zeb.
Chlorides (Cl⁻):Kuj tseem muaj nyob hauv pob zeb.
Sulfuric Acid Residuals:Los ntawm cov txheej txheem digestion.
Abrasive khoom:Gypsum thiab lwm yam insoluble hais.
Qhov kev sib xyaw ua ke no tsim ib puag ncig uas pitting, crevice corrosion, thiab dav dav thinning yog hnyav. Nov yog li cas G-30 txawv ntawm nws cov thawj coj (G-3) thiab vim li cas nws ua tau zoo dua:
1. Qhov zoo ntawm Chromium:
G-3 (UNS N06985):Muaj kwv yees li 22% Chromium.
G-30 (UNS N06030):Muaj cov qib chromium ntau dua ntawm28.0-31.5%.
Hauv oxidizing / txo qhov sib xyaw ua ke ntawm WPA (vim muaj cov ferric ions thiab yaj oxygen), chromium yog lub ntsiab tseem ceeb rau kev ua haujlwm. Kev dhia mus rau ze li ntawm 30% chromium muab G-30 ntau ruaj khov thiab tiv thaiv zaj duab xis passive. Nws tiv taus ntau dua rau kev tawg los ntawm chlorides thiab fluorides dua li G-3.
2. Molybdenum thiab tooj liab sib npaug:
G-30 muaj molybdenum (4-6%) thiab tooj liab (1.0-2.4%). Molybdenum muab kev tiv thaiv los txo cov xwm txheej (xws li non-oxidizing acids), thaum tooj liab tshwj xeeb txhim khu kev tiv thaiv rau sulfuric acid. Qhov sib npaug ntawm chemistry no tso cai rau G-30 los tswj qhov sib txawv oxidation muaj peev xwm nyob rau hauv phosphoric acid evaporator.
3. Niobium Stabilization:
G-30 muaj niobium (columbium) uas ua haujlwm ua kom ruaj khov. Nws ua ke nrog cov pa roj carbon monoxide los tsim niobium carbides, tiv thaiv nag lossis daus ntawm chromium carbides ntawm grain ciam teb thaum vuam. Qhov no ua kom ntseeg tau tias qhov vuam cua sov- thaj tsam cuam tshuam khaws nws cov ntsiab lus chromium tag nrho thiab, yog li ntawd, nws qhov kev tiv thaiv corrosion tsis tas yuav tsum tau kho cua sov tom qab vuam.
Cov txiaj ntsig zoo:
Hauv phosphoric acid evaporator, hloov los ntawm G-3 mus rau G-30 feem ntau ua rau txo qis hauv cov nqi corrosion thiab, qhov tseem ceeb tshaj, kev tshem tawm virtual ntawm lub zos pitting thiab crevice nres, tshwj xeeb tshaj yog nyob rau hauv cov cheeb tsam uas cov khib nyiab tuaj yeem daws tau. Thaum cov khoom siv ua ntej tus nqi siab dua, cov cuab yeej siv txuas ntxiv lub neej thiab txo qis kev saib xyuas ua rau G-30 qhov kev xaiv zoo tshaj plaws rau kev pabcuam WPA tseem ceeb. Nws tau dhau los ua tus qauv de facto rau phosphoric acid evaporator raj thiab kav dej.
2. Chemistry Balancing Act: Lub siab chromium cov ntsiab lus ntawm G-30 cuam tshuam nws cov yam ntxwv vuam piv rau qis-chromium alloys xws li C-276?
Q:Peb pab pawg vuam tau paub zoo nrog Hastelloy C-276. Tam sim no peb tab tom ntsib peb thawj qhov project nrog Hastelloy G-30 welded yeeb nkab. Chemistry qhia ze li ntawm 30% Chromium. Cov qib chromium siab no puas yuav hloov peb cov kev ntsuas vuam lossis kev xaiv hlau muab tub lim? Peb puas muaj kev pheej hmoo siab ntawm kub tawg?
A:Koj qhov kev xav los nug txog qhov cuam tshuam ntawm high chromium yog qhov tseeb. Qhov kev hloov mus rau "30% Chromium" alloy zoo li G-30 qhia txog qhov sib txawv ntawm kev txiav txim siab piv rau C-276 (uas muaj ~ 16% Cr). Thaum C-276 yog nickel{11}}molybdenum alloy optimized rau txo cov acids, G-30 yog nickel-chromium-hlau-molybdenum alloy optimized rau tov acids thiab oxidizing tej yam kev mob. Qhov no hloov qhov vuam metallurgy.
Nov yog yam koj pab neeg yuav tsum paub:
1. Qhov Kub Cracking Risk (thiab Mitigation):
Siab -chromium, tag nrho cov austenitic alloys tuaj yeem raug cuam tshuam rau vuam hlau kub cracking (solidification cracking) dua li qis dua -chromium qib yog tias tsis raug kho kom raug. G-30, nrog nws cov Cr siab thiab muaj niobium, yuav tsum tau saib xyuas kom meej.
Mechanism:Kub tawg tshwm sim thaum lub sij hawm kawg ntawm solidification thaum ua kua zaj duab xis yog daig ntawm solidifying nplej. Cov ntsiab lus chromium siab, ua ke nrog cov kab ke, tuaj yeem nthuav dav qhov kub thiab txias ntau yam.
Lub Mitigation:Qhov no feem ntau yog tswj los ntawm kev muab tub lim hlau xaiv thiab cov txheej txheem. Tus qauv muab tub lim hlau rau G-30 yogERNiCrMo-11. Qhov muab tub lim no yog tshuaj sib npaug los muab "kev zam txim" tus cwj pwm ua kom muaj zog. Koj cov welders tseem yuav tsum:
Tsis txhob tso cua sov ntau dhau, uas ua rau thaj tsam mushy.
Khaws ib qho me ntsis convex hlaws profile (cov hlaws tiaj tus lossis concave hlaws muaj ntau dua kev tawg yooj yim nyob rau hauv tag nrho austenitic welds).
Xyuas kom huv huv kom tshem tawm cov kab mob (sulfur, phosphorus) los ntawm qhov chaw.
2. Kev tshem tawm Oxide (Qhov "Chromium Oxide" Factor):
Nyob rau ntawm 30% chromium, cov alloy tsim ib tenacious, nruj adherent chromium oxide txheej. Qhov no zoo heev rau corrosion kuj tab sis muaj teeb meem rau vuam.
Qhov teeb meem:Chromium oxide muaj qhov melting siab heev thiab tsis yooj yim tawg thaum vuam. Yog tias tsis tshem tawm, nws tuaj yeem ua rau tsis muaj fusion, slag entrapment, thiab porosity.
Kev daws:Koj qhov kev npaj vuam yuav tsum nruj dua. Qhov chaw vuam (ob lub yeeb nkab thiab cov xaim muab tub lim) yuav tsum tau ua kom huv si (stainless steel hlau txhuam los yog sib tsoo) tam sim ua ntej vuam. Cov kuab tshuaj ntxuav ib leeg yuav tsis tshem cov oxide. Koj yuav tsum tau siv 100% argon shielding gas (thiab cov roj thaub qab rau cov hauv paus hniav) los tiv thaiv oxidation thaum vuam. Ib qho "sugaring" (oxidation) ntawm lub hauv paus hla yuav nyuaj heev kom tshem tawm thiab yuav cuam tshuam kev tiv thaiv corrosion.
3. Filler Hlau yog Tsis yog-Tshaj tawm:
Tsis txhob sim hloov ERNiCrMo-3 (rau Alloy 625) lossis ERNiCrMo-4 (rau C-276) thaum vuam G-30. Thaum lawv yog tag nrho cov nickel alloys, lawv cov chemistry yog mismatched rau lub hauv paus hlau txoj cai corrosion. Kev siv cov muab tub lim tsis raug yuav tsim kom muaj galvanic cell los yog ib cheeb tsam ntawm inferior corrosion kuj nyob rau hauv weld.ERNiCrMo-11 yog qhov kev xaiv tsuas yog rau kev tswj hwm G-30 qhov kev ua tau zoo hauv phosphoric thiab cov kua qaub sib xyaw.
Hauv cov ntsiab lus, koj pab neeg tuaj yeem ua tiav vuam G-30, tab sis lawv yuav tsum hwm nws cov ntsiab lus chromium siab. Ua kom pom tseeb ntawm kev huv huv, cov hlau muab tub lim kom zoo (ERNiCrMo-11), tswj cov cua sov, thiab tswj cov hlaws zoo.
3. Tus Nqi -Kev Tshawb Fawb Cov txiaj ntsig: Thaum twg yog qhov qhia meej Hastelloy G-30 welded yeeb nkab ua kev lag luam ncaj ncees tshaj cov hlau tsis zoo xws li 904L lossis 254 SMO?
Q:Peb tab tom tsim cov sulfuric acid dilution txias system. Lub acid concentration yuav txawv ntawm 98% mus rau 10%, thiab kub yuav ncav cuag 90 degree. Peb tab tom xav txog Hastelloy G-30, tab sis 904L stainless hlau yog pheej yig dua. Thaum twg tus nqi ntxiv ntawm G-30 ua kom ncaj ncees?
A:Qhov no yog cov lus nug tseem ceeb hauv kev lag luam hauv kev xaiv cov ntaub ntawv rau cov txheej txheem tshuaj lom neeg. Cov lus teb tsis yog nyob rau hauv cov khoom siv ua ntej, tab sis nyob rau hauvlifecycle nqithiab, tshwj xeeb tshaj yog, hauv kev txheeb xyuas qhov "cliff edge" qhov twg qis dua - cov ntaub ntawv qib poob ntawm qhov kev ua tau zoo.
Koj daim ntawv thov -sulfuric acid dilution system nrog ntau qhov sib txawv thiab qhov kub thiab txias- yog qhov xwm txheej qub uas "cliff edge" muaj.
Stainless Hlau Cliff (904L thiab 254 SMO):
Alloys zoo li 904L thiab 254 SMO (6% Mo super austenitics) ua tau zoo nyob rau hauv nruab nrab sulfuric acid tej yam kev mob. Txawm li cas los xij, lawv muaj qhov txwv:
Concentration / Kub Curve: Sulfuric acid has a well-known corrosion peak in the mid-concentration range (around 20-80%) at elevated temperatures. At 90°C, 904L may show acceptable corrosion rates (>0.1 hli / xyoo) ntawm 10% thiab 98% acid, tab sis nyob rau hauv nruab nrab ntawm 40-60% ntau, tus nqi tuaj yeem nce siab heev.
Chloride Sensitivity:Yog tias koj cov dej dilution muaj cov tshuaj chlorides, cov hlau tsis muaj stainless no muaj kev cuam tshuam rau pitting thiab crevice corrosion, tshwj xeeb tshaj yog nyob rau hauv qhov kub, tsis yog -oxidizing tej yam kev mob ntawm nruab nrab- concentration ntau.
Velocity Effects:Cov hlau tsis muaj steel tuaj yeem raug kev puas tsuaj los ntawm kev yaig-corrosion yog tias cov nqi ntws siab, vim lawv cov yeeb yaj kiab tsis zoo yog thinner.
G-30 Kev Ncaj Ncees "Zones":
G-30 dhau los ua kev lag luam ncaj ncees hauv peb qhov xwm txheej tshwj xeeb:
Zone 1: Qhov Sib xyaw Acid / Contaminated Acid Zone.
Yog tias koj cov kua qaub muaj cov tshuaj chlorides, fluorides, lossis oxidizing ions (xws li Fe³⁺, Cu²⁺), stainless hlau yuav pit. G-30's siab chromium thiab molybdenum cov ntsiab lus muab ib zaj duab xis passive uas yog nyob deb npaum li cas resistant rau hauv zos tawg. Nyob rau hauv ib qho "dub" system, 904L yuav kav 1-2 xyoo; G-30 yuav kav ntev 10+. Tus nqi hloov pauv ua kom pom tseeb qhov hloov tshiab.
Zone 2: Lub Variable Concentration/Dead Zone.
Nyob rau hauv ib tug dilution system, yuav muaj tej thaj chaw uas cov acid concentration yog raws nraim nyob rau hauv lub "tshem tawm tsam" (xws li, 40-60% H₂SO₄ ntawm 90℃). Ntawm no, 904L yuav corrode uniformly ntawm 0.5-1.0 hli / xyoo, yuav tsum tau cov phab ntsa tuab thiab nquag hloov. G-30 yuav zoo li corrode ntawm<0.1 mm/year, allowing for thinner walls and longer life. The material savings from using a thinner wall can offset some of the cost premium.
Zone 3: Txoj Kev Tseem Ceeb / Tsis Txaus Siab Tus Nqi Zej Zog.
Yog tias qhov kev sib cais no yog ib qho - taw tes tsis ua haujlwm rau koj cov nroj tsuag tag nrho (piv txwv li, yog tias nws tsis ua haujlwm, tag nrho cov nroj tsuag kaw), tus nqi ntawm qhov tsis tau npaj tseg rau ib hnub twg tuaj yeem dwarf cov nqi khoom sib txawv ntawm 904L thiab G-30. Nyob rau hauv cov ntaub ntawv no, koj tsis muas corrosion kuj; koj yuavkev pov hwm kev ntseeg. G-30 muab qhov kev nyab xeeb loj heev uas 904L tsis tuaj yeem sib tw.
Kev xam:
Ua ib qho kev txheeb xyuas tus nqi lifecycle siv cov qauv hauv qab no:
(Nqi ntawm G-30 Pipe - Tus Nqi ntawm 904L Yeeb Nkab) vs. (Nyiaj ntawm 904L Hloov + Tus Nqi Them Nqi Rau Ib Qhov Tsis Ua Haujlwm + Kev Ua Haujlwm Saib Xyuas)
Hauv kev ua phem, sib txawv, lossis cov kev pabcuam tseem ceeb, qhov sib npaug yuav luag ib txwm nyiam G-30. Rau ib qho yooj yim, huv si, tsis tu ncua-kev pabcuam (piv txwv li, 93% H₂SO₄ ntawm 40 degree), 904L yog qhov txaus.
4. Txoj Kev Sib Tw: Dab tsi yog qhov kev xav tau rau kev khoov thiab coiling G-30 welded yeeb nkab hauv kev tsim cov khoom siv hluav taws xob?
Q:Peb yuav tsum tau tsim ib co coil -hom kub exchanger siv Hastelloy G-30 welded yeeb nkab. Cov yeeb nkab yuav txias khoov rau hauv nruj radii. Muab nws lub zog thiab kev ua haujlwm siab - hardening npaum li cas, peb yuav tsum tau ceev faj dab tsi kom tsis txhob tawg los yog dhau lub caij nplooj ntoos hlav-rov qab?
A:Fabricating coils los ntawm G-30 welded yeeb nkab yog qhov xav tau ua haujlwm. G-30, nrog nws cov ntsiab lus chromium thiab molybdenum siab, muaj qhov ua haujlwm hnyav-txhais tau tias nws tau muaj zog dua thiab tsis tshua muaj ductile sai heev vim nws deformed. Qhov no nthuav tawm cov kev sib tw tshwj xeeb rau kev khoov txias.
Ntawm no yog ib daim ntawv qhia ua tau zoo bending G-30 welded yeeb nkab:
1. Cov ntsiab lus "Starting Point": Mill Condition.
Ua ntej koj txawm muab cov yeeb nkab rau hauv bender, koj yuav tsum paub nws lub xeev metallurgical.
Kev daws Annealed:Qhov no yog qhov pib zoo tagnrho. Cov yeeb nkab yog nyob rau hauv nws softest, feem ntau ductile xeev. Koj daim ntawv xaj yuav tsum qhia meej tias G-30 welded yeeb nkab yog nyob rau hauv qhov kev daws teeb meem.
Txias ua hauj lwm/Stress Relieved:Yog tias cov yeeb nkab tau ua haujlwm txias dhau los (piv txwv li, rau qhov loj me) thiab tsuas yog kev ntxhov siab xwb, nws yuav muaj qhov qis dua thiab yuav nyuaj rau khoov.
Kev txheeb xyuas:Tshawb xyuas Mill Test Report rau tensile thiab yield zog. Tsawg tawm los lub zog qhia tau hais tias tag nrho annealed, formable mob.
2. Tooling yog txhua yam.
Koj tsis tuaj yeem khoov G-30 nrog cov cuab yeej tsim los rau carbon steel lossis txawm tias 304 stainless.
Mandrel thiab Wiper Tuag:Rau lub vojvoog nruj nruj (piv txwv li, 2D lossis 3D vojvoog), koj yuav tsum siv lub mandrel (los txhawb tus ID thiab tiv thaiv ovality / wrinkling) thiab wiper tuag (kom tiv thaiv buckling ntawm sab compression). Cov cuab yeej yuav tsum nyob rau hauv qhov zoo heev, tsis muaj khawb lossis burrs uas tuaj yeem ua raws li kev ntxhov siab.
Lubrication:Siv lub siab -zoo, chlorine- tsis muaj roj nplua nyeem. Chlorinated lubrication tuaj yeem tawg hauv qab cua sov thiab siab ntawm kev khoov thiab tawm cov khoom seem uas tuaj yeem ua rau pitting corrosion yog tias tsis huv huv tom qab- khoov.
3. Khoov Radius thiab Caij nplooj ntoos hlav-Rov qab.
Dav dav dav:Tsim rau qhov loj tshaj plaws khoov vojvoog uas koj lub tshav kub exchanger geometry yuav tso cai. Lub vojvoog nruj dua, qhov siab dua ntawm cov phab ntsa sab nrauv thiab qhov kev pheej hmoo ntawm kev tawg, tshwj xeeb tshaj yog nyob rau ntawm qhov ntev ntawm weld seam.
Caij nplooj ntoos hlav-Rov qab:G-30 muaj lub zog tawm los ntau dua li austenitic stainless hlau. Nws yuav nthuav tawm ntau lub caij nplooj ntoos hlav- rov qab. Koj tus neeg teb xov tooj bender yuav tsum suav rau qhov no los ntawm kev khoov me ntsis kom ua tiav lub kaum sab xis kawg. Nws yog qhov zoo los ua qhov kev sim khoov ntawm cov qauv coj los ntsuas lub tshuab rau cov khoom siv cua sov no.
4. Lub Weld Seam Orientation.
Qhov no yog qhov tseem ceeb. Lub longitudinal weld seam ntawm cov yeeb nkab yog ib cheeb tsam metallurgically txawv.
Txoj Cai:Weld seam yuav tsum tau positioned ntawm lubnruab nrab axisntawm khoov. Qhov no yog txoj kab nyob rau sab ntawm cov yeeb nkab uas tsis muaj qhov nro (stretching) lossis compression (squashing) thaum khoov.
Vim li cas?Muab cov seam rau ntawm extrados (sab nraum ntawm qhov khoov) txaus ntshai tawg nws nyob rau hauv nro. Muab tso rau ntawm qhov intrados (sab hauv ntawm qhov khoov) muaj kev pheej hmoo buckling lossis wrinkling nws. Qhov nruab nrab axis yog "Zoo ruaj ntseg" qhov twg deformation tsawg heev.
5. Inter-theem Annealing.
Yog tias koj lub coil xav tau ntau qhov khoov los yog lub vojvoog nruj heev, koj tuaj yeem tshaj lub peev xwm ua haujlwm txias. Ib txoj cai dav dav ntawm tus ntiv tes xoo yog tias yog tias tag nrho cov elongation xav tau tshaj li ~ 15-20%, koj yuav muaj kev tawg.
Kev daws:Yog hais tias qhov khoov ib theem zuj zus, tej zaum koj yuav tau ua qhov dabtsi yog khoov nyob rau hauv cov theem, nrog ib tug tag nrho cov tshuaj annealing kev kho mob (nyob ib ncig ntawm 1175℃tom qab quenching ceev) nyob rau hauv nruab nrab ntawm recrystallize txoj hauj lwm - hardened qauv thiab restore ductility. Qhov no yog kim tab sis qee zaum tsim nyog rau txoj kev geometry.
Los ntawm kev hwm cov khoom ntawm cov khoom- pib annealed, siv cov cuab yeej tsim nyog, tiv thaiv cov vuam seam, thiab kev npaj rau lub caij nplooj ntoos hlav- rov qab- koj tuaj yeem ua tiav cov khoom siab - zoo G-30 tshav kub exchanger coils.
5. Cov Lus Qhia Txog Kev Muag Khoom: Cov ntsiab lus tseem ceeb dab tsi yuav tsum muaj nyob rau hauv daim ntawv xaj khoom rau G-30 welded yeeb nkab kom ntseeg tau tias muaj kev nyab xeeb rau kev pabcuam phosphoric acid?
Q:Peb tab tom yuav tshaj tawm qhov kev sib tw rau Hastelloy G-30 welded yeeb nkab rau cov phosphoric acid evaporator tshiab. Tshaj li tus qauv ASTM yooj yim, peb yuav tsum ua dab tsi ntxiv rau kev lav phib xaub kev ua tau zoo nyob rau hauv qhov hnyav, kub, muaj cov tshuaj chloride?
A:Rau cov phosphoric acid evaporator, koj tab tom xaj cov yeeb nkab rau ib qho ntawm cov kev ua phem tshaj plaws hauv kev lag luam tshuaj. Txuj kev lag luam- qib yeeb nkab tsis txaus. Koj yuav tsum sau cov lus qhia txog kev yuav khoom uas hais txog cov kev pheej hmoo tshwj xeeb ntawm cov kev pabcuam no: pitting, crevice corrosion, thiab weld kev ncaj ncees. Weld seam yog qhov chaw tseem ceeb tshaj plaws.
Nov yog daim ntawv teev npe ntawm cov kev xav tau ntxiv uas koj yuav tsum suav nrog hauv koj daim ntawv xaj khoom rau G-30 welded yeeb nkab rau qhov kev pabcuam tseem ceeb no:
1. Txoj Cai Tswjfwm:
Pib nrogASTM B619 Cov khoom lag luam(Standard Specification rau Welded Nickel Alloy Yeeb Nkab). Tab sis tam sim ntawd ntxiv cov kev cai ntxiv.
2. Chemistry Verification (Positive Material Identification):
Yuav tsum tau:Mandate qhov ntawdPositive Material Identification (PMI)yuav ua tau rau 100% ntawm cov yeeb nkab ntev.
Yog vim li cas:Koj yuav tsum xyuas kom meej tias cov ntsiab lus chromium nyob rau sab saud (28-31%) thiab molybdenum thiab tooj liab muaj nyob. Qhov no yog koj thawj kab ntawm kev tiv thaiv ib lub zeb sib tov-txog uas tuaj yeem qhia qis-chromium alloy rau hauv koj lub evaporator.
3. Weld Seam Nondestructive Examination (Qhov "Tsis yog-Fail" Zone):
Yuav tsum muaj 1: 100% Radiography (RT) rau ASTM B619, S1.Qhia meej txog kev lees txais ibASME Section VIII, Division 1, UW-51. Qhov no ua kom cov weld tsis muaj qhov tsis zoo hauv qhov ntim.
Yuav Tsum Tau 2: 100% Dye Penetrant Examination (PT)ntawm sab hauv txoj kab uas hla (ID) weld nto tom qab kawg kev kho cua sov thiab sizing.
Vim li cas (rau PT):Hauv kev pabcuam phosphoric acid, tus ID ntawm cov yeeb nkab yog raug rau cov kua corrosive. Txhua qhov chaw- tawg qhov tsis zoo ntawm daim ID weld-txawm tias lub qhov me me lossis microfissure- yuav dhau los ua qhov chaw nyiam rau pitting thiab crevice corrosion. PT ntawm tus ID tsis yog - sib tham tau rau qhov kev pabcuam no. Nws xyuas kom meej qhov weld nto yog flawless.
4. Ferrite Number Control:
Yuav tsum tau:Qhia meej tias qhov vuam hlau thiab cua sov- thaj tsam cuam tshuam yuav tsum muajtsis muaj ferrite(Ferrite Number=0).
Yog vim li cas:Ferrite yog sib nqus thiab muaj cov yam ntxwv sib txawv ntawm qhov sib txawv ntawm austenitic matrix. Hauv ib puag ncig chloridic zoo li WPA, ferrite tuaj yeem nyiam corrode. Lub weld yuav tsum yog tag nrho austenitic.
5. Kev kuaj Corrosion (Qhov kawg pov thawj):
Yuav tsum tau:Qhia kom meej tias cov qauv piv txwv ntawm cov yeeb nkab welded (xws li lub vuam seam) tau txais kev kuaj corrosion, xws liASTM G-28 Txoj Kev A(Boiling 50% Sulfuric Acid with Ferric Sulfate) test.
Yog vim li cas:Qhov no yog qhov kev xeem "kev tsim nyog". Nws txheeb xyuas tias tag nrho cov txheej txheem tsim khoom-chemistry, vuam, kho cua sov- tau tsim cov khoom siv nrog qhov kev cia siab corrosion. Tus nqi qis corrosion (xws li,<0.5 mm/year) in the G-28 test indicates that the material is properly solution annealed and free of detrimental precipitates. You can request that the test be performed with the weld seam included and the corrosion rate reported separately for the weld and base metal.
6. Nto tiav thiab huv:
Yuav tsum tau:Qhia kom meej qhov siab tshaj qhov roughness (piv txwv li,63r ualos yog zoo dua) ntawm qhov chaw ID. Tsis tas li ntawd, qhia tias cov yeeb nkab yuav tsum tau muabpickled thiab passivatedtshem tawm cov cua sov los yog oxide nplai los ntawm kev tsim khoom.
Yog vim li cas:Qhov chaw du, huv si txo qhov chaw rau cov khib nyiab kom ua raws thiab pib hauv qab - tso nyiaj corrosion. Pickling restores tag nrho chromium-nplua nuj passive txheej.
Los ntawm kev qhia txog cov kev cai no-PMI, 100% RT, 100% ID PT, xoom ferrite, kuaj corrosion, thiab qhov chaw huv si tiav - koj tsis yog yuav cov yeeb nkab xwb. Koj tab tom yuav cov khoom siv hluav taws xob uas tau tsim nyog rau cov kev pabcuam phosphoric acid uas xav tau tshaj plaws.
