Nug ib tus kws tsim khoom siv cov khoom siv npe rau ob qho khoom siv austenitic stainless hlau, thiab lawv yuav hais316Lthiab 316H - feem ntau tsis paub tias ob "cov kwv tij" no tau tsim los rau kev ua haujlwm tsis sib haum xeeb . 316L yog cov weldable, corrosion-resistant workhorse ntawm cov nroj tsuag tshuaj, cov khoom siv hauv hiav txwv, thiab kev ua zaub mov. 316H yog qhov siab -kub tus kws tshaj lij, tsim los tiv thaiv creep - thaum muaj kev ntxhov siab nyob rau hauv cov hlau tsis tu ncua kub rau xyoo los yog kaum xyoo.
Tag nrho qhov sib txawv ntawm ob qib los mus rau ob qhov sib txawv: cov ntsiab lus carbon thiab grain loj . 316L caps carbon ntawm 0.03% los tiv thaiv weld rhiab heev. 316H yuav tsum tau carbon ntawm 0.04% thiab 0.10% ntxiv rau coarse grain loj ntawm ASTM Tsis muaj. 7 los yog coarser, ob qho tib si creep zog. Qhov no tsis yog "zoo dua lossis phem dua" kev sib piv - nws yog "qhov cuab yeej zoo rau qhov ntsuas kub zoo" sib piv. Siv 316L siab dua 425℃(800℃F) hauv kev pabcuam siab txaus ntshai tsis ua haujlwm; siv 316H rau lub welded tshuaj tank caw intergranular corrosion. Xaiv qhov tsis ncaj ncees lawm qib nyob rau hauv ob qho kev taw qhia tau ua rau cov nroj tsuag kaw, hlab ntsha tawg, thiab kev puas tsuaj loj.
Txoj cai txiav txim siab hauv ib kab lus: qis dua 425℃(800℃F) thiab welded lossis corrosion- tseem ceeb, xaiv 316L; saum toj no 425℃qhov twg creep zog thiab ASME Code siab - qhov ntsuas kub tseem ceeb, xaiv 316H. Ob qib yog sib ntxiv, tsis hloov pauv tau - thiab ua rau lawv tsis meej pem yog ib qho ntawm cov khoom siv tshaj plaws - kev xaiv yuam kev hauv cov txheej txheem thiab kev lag luam fais fab.
Tshuaj muaj pes tsawg leeg - Cov ntsiab lus Carbon thiab cov qoob loo yuav tsum muaj
316l ua316Hqhia tib cov tub ntxhais chemistry - 16-18% chromium, 10-14% npib tsib xee, thiab 2-3% molybdenum - thiab sib txawv ntawm cov ntsiab lus carbon thiab grain loj. 316L caps carbon ntawm 0.03% (qhov siab tshaj plaws weldability), thaum 316H qhia cov pa roj carbon ntau ntawm 0.04% ntawm cov nplej loj Tsis yog . 7 los yog coarser. Cov molybdenum hauv ob qib yog dab tsi cais tag nrho 316 tsev neeg los ntawm 304: nws muab kev tiv thaiv rau pitting thiab crevice corrosion nyob rau hauv ib puag ncig chloride.
Ob leeg 316L (UNS S31603) thiab 316H (UNS S31609) yog molybdenum-cov kabmob austenitic stainless hlau hauv 300 series. Qhov "L" hauv 316L sawv cev rau "Low Carbon" (Less dua lossis sib npaug li 0.03%). Lub "H" hauv 316H sawv cev rau "High Carbon" (0.04-0.10%), thiab nws muaj qhov yuav tsum tau ua ntxiv uas tsis muaj lwm yam 300-series qib muaj: cov nplej ntxhib loj ntawm ASTM Tsis muaj . 7 lossis coarser. Qhov kev xav tau loj ntawm cov nplej no yog qhov ua rau 316H qhov sib txawv ntawm 316 tiaj tiaj nrog cov pa roj carbon elevated nkaus xwb - cov nplej ntxhib yog qhov tseem ceeb rau kev nkag siab, thiab nws tau txheeb xyuas los ntawm kev tshuaj xyuas microstructural ntawm daim ntawv qhia txog zeb.
|
Khoom / Feature |
316L (UAS S31603) |
316 H (UNS S31609) |
Vim Li Cas Nws Tseem Ceeb |
|
Cov pa roj carbon (C) |
0.03% max |
0.04–0.10% |
LUB core sib txawv - 316L zam kev nkag siab; 316H nce creep zog |
|
Chromium (Cr) |
16.0–18.0% |
16.0–18.0% |
Zoo tib yam - zaj duab xis passive rau oxidation/corrosion kuj |
|
Nickel (Ni) |
10.0–14.0% |
10.0–14.0% |
Zoo tib yam - stabilizes austenitic qauv, toughness |
|
Molybdenum (hli) |
2.00–3.00% |
2.00–3.00% |
Zoo tib yam - pitting/crevice corrosion kuj nyob rau hauv chlorides |
|
Manganese (Mn) |
2.00% max |
2.00% max |
Zoo tib yam - deoxidizer |
|
Silicon (Si) |
0.75% max |
0.75% max |
Zoo tib yam - residual deoxidizer |
|
Phosphorus (P) |
0.045% max |
0.045% max |
Zoo tib yam - impurity |
|
Sulfur (S) |
0.030% max |
0.030% max |
Zoo tib yam - impurity |
|
Nitrogen (N) |
0.10% max |
0.10% max |
Zoo tib yam - residual zog booster |
|
Grain Loj (ASTM) |
Tsis xav tau |
Tsis yog . 7 los yog coarser |
UNIQUE rau 316H - coarse grain=creep resistance |
Vim li cas Cov Ntsiab Lus Carbon taw qhia ob qib hauv cov lus qhia tawm?
Carbon plays ob lub luag hauj lwm tawm tsam hauv 316-series stainless hlau. Thaum kub siab, carbon ntxiv dag zog rau cov hlau los ntawm kev tsim cov chromium carbide precipitates uas pin lis ciam tiv thaiv creep deformation - qhov no yog vim li cas 316H xav tau 0.04% carbon tsawg kawg nkaus. Tab sis thaum lub sij hawm welding, tib cov pa roj carbon monoxide no nkag mus rau hauv cov ciam teb thiab depletes chromium, ua rau muaj kev cuam tshuam ntawm intergranular (sensitization) - qhov no yog vim li cas 316L caps carbon ntawm 0.03%. Hauv luv luv: carbon yog 316H lub hauv paus ntawm siab - qhov kub thiab txias, thiab 316L qhov tsis muaj carbon yog nws qhov chaw ntawm weld kev ncaj ncees. Koj tsis tuaj yeem muaj ob qho txiaj ntsig hauv ib qho chemistry - yog vim li cas ob qib muaj nyob.
Txhawm rau kom nkag siab qhov kev lag luam no- tawm, duab carbon atoms ua ob txoj haujlwm sib txawv ntawm ob qhov kub sib txawv. Nyob rau hauv 425-870℃(800-1,600℃F) rhiab heev - mus txog rau hauv tshav kub- cuam tshuam cheeb tsam ntawm ib tug weld - carbon reacts nrog chromium los tsim chromium carbides ntawm grain ciam teb, nyiag chromium 'txoj kab uas nyob ib ncig ntawm cov hlau{8} ultra- carbon qis txhais tau tias tsis muaj cov pa roj carbon txaus los ua qhov kev puas tsuaj no, yog li welded 316L nyob twj ywm corrosion-resistant yam tsis muaj kev kho cua sov tom qab vuam.
Tab sis ntawm qhov kub thiab txias (kwv yees li 500-700 degree), zaj dab neeg thim rov qab. Creep - qeeb qeeb ntawm cov hlau nyob rau hauv load - tshwm sim feem ntau yog los ntawm grain ciam teb swb dhau ib leeg thiab los ntawm dislocation txav. Ib qho zoo dispersion ntawm chromium carbide hais ntawm cov ciam teb nplej ua zoo li tus pins uas kaw cov ciam teb nyob rau hauv qhov chaw, ua rau qeeb nkag. Qhov no yog raws nraim cov txheej txheem ntxiv dag zog uas 316H cov pa roj carbon ntau dua muab . 316L, uas yuav luag tsis muaj cov pa roj carbon los ua cov pinning carbides, nkag mus nrawm dua ntawm qhov kub thiab txias. Ntxiv rau qhov kom zoo dua, 316H qhov ntxhib grain loj txhais tau hais tias tsawg dua grain ciam rau ib chav tsev ntim - thiab txij li thaum grain ciam teb yog cov tsis muaj zog txuas nyob rau hauv creep, tsawg ciam teb sib npaug zos zoo creep kuj.
Qhov Yuav Tsum Muaj Qhov Loj Loj - Yuav Ua Li Cas 316H Tiag "H"
Qhov loj npaum li cas ntawm ASTM Tsis yog. 7 lossis coarser yog qhov txhais tau tias cais 316H los ntawm qhov siab siab -carbon 316. Coarse grains txo tag nrho cov nplej- thaj tsam thaj tsam, thiab txij li qhov creep deformation yog concentrated ntawm grain ciam teb, ntxhib -grained khoom} zoo dua li cov khoom zoo tib yam creeping chemistry. Qhov no yog vim li cas ib daim ntawv ntsuam xyuas cov ntaub ntawv rau 316H yuav tsum qhia lub grain loj - ib tug 316 cov ntaub ntawv uas muaj cov pa roj carbon zoo tab sis ib tug nplua nplej tsis yog 316H thiab yuav tsis ua zoo ib yam nyob rau hauv creep kev pab cuam.
Cov qoob loo loj yog ntsuas los ntawm ASTM E112 thiab qhia ua tus lej; cov lej siab dua txhais tau tias cov nplej zoo dua. Ib tug raug annealed 316L muaj ib tug grain loj ntawm ASTM Tsis yog . 5-8, feem ntau nyob rau sab finer tom qab tov annealing . 316H yog txhob txwm ua nrog ib tug grain loj ntawm ASTM Tsis yog . 7 los yog coarser (feem ntau Tsis yog . 3-7 nyob rau hauv xyaum), ua tiav los ntawm kev tswj cov tshuaj -annealing kub thiab txias. Qhov no yog ib qho ntawm ob peb rooj plaub nyob rau hauv stainless hlau qhov "coarser" microstructure yog "zoo dua" - ib tug counterintuitive point uas confuses engineers uas kawm tau hais tias zoo grain loj txhim kho chav tsev - kub lub zog thiab toughness. Qhov tseeb yog tias cov nplej nplua nuj pab nyob rau hauv chav tsev kub, tab sis coarse grain yeej ntawm creep kub.
[Source] ASTM A240/A240M - Txheem Specification rau Chromium thiab Chromium-Nickel Stainless Hlau Phaj, Ntawv, thiab Sawb. ASTM E112 - Standard Test Methods for Defining Average Grain Size.
Mechanical Properties
Nyob rau hauv chav tsev kub nyob rau hauv lub annealed mob, 316H muaj me ntsis siab dua tensile thiab yield zog tshaj 316L (515 MPa vs 485 MPa tensile; 205 MPa vs 170 MPa yield), vim hais tias cov pa roj carbon ntau dua muab me ntsis nag lossis daus. Txawm li cas los xij, qhov no 6-15% qhov sib txawv me me, thiab ob qib yog ductile thiab formable. Chav tsev- qhov kub thiab txias qhov sib txawv tsis yog vim li cas thiaj xaiv ib qib dua lwm tus - qhov sib txawv tiag tiag tshwm sim ntawm qhov kub siab.
|
Khoom |
316L (ntxiv) |
316H (ntxiv) |
Qhov txawv |
|
Tensile zog (min) |
485 MPa (70 ksi) |
515 MPa (75 ksi) |
316H ~ 6% siab dua |
|
Yield zog 0.2% (min) |
170 MPa (25 ksi) |
205 MPa (30 ksi) |
316H ~ 20% siab dua yam tsawg kawg nkaus |
|
Yield Strength (zoo) |
205-260 MPa |
240-300 MPa |
316H me ntsis siab dua |
|
Elongation hauv 50mm (min) |
40% |
40% |
Yam tsawg kawg nkaus |
|
Hardness (max) |
217 HWB / 95 HRB |
217 HWB / 95 HRB |
Zoo tib yam siab kawg |
|
Modulus ntawm Elasticity |
193 gp ua |
193 gp ua |
Zoo ib yam |
|
Qhov ntom |
8.00 g / cm³ |
8.00 g / cm³ |
Zoo ib yam |
|
Thermal conductivity |
16.3 W / m·K (100 degree) |
16.3 W / m·K (100 degree) |
Zoo ib yam |
Ua kom siab -Tsub Muaj Zog thiab ASME Tso Cai Stress Sib faib
Qhov kev txiav txim siab ntawm qhov sib txawv ntawm qhov tshwm sim saum toj no txog 425℃(800℃F). ASME Boiler thiab Pressure Vessel Code Tshooj II, Tshooj D teev cov txiaj ntsig kev ntxhov siab rau 316L tsuas yog mus txog 800℃F (427 degree) - dhau li ntawd, 316L tsis muaj Code- teev tso cai rau kev ntxhov siab vim tias nws lub zog creep tsis muaj kev lav phib xaub . 316H, los ntawm kev sib piv ntawm 10, 8 ° F. Qhov tseeb ib leeg no yog txoj cai siv tau uas tswj hwm tag nrho 316L vs 316H xaiv kev txiav txim siab hauv siab- lub nkoj thiab cov kav dej tsim.
Yog vim li cas rau 800℃F (427 degree) qab nthab ntawm 316L yog creep. Ntawm qhov kub siab tshaj li 0.4 npaug ntawm qhov melting point (qhia hauv Kelvin), hlau pib deform mus tas li nyob rau hauv loads zoo hauv qab lawv chav -kub yield zog. Rau austenitic stainless hlau, qhov kev nkag siab no pib ntawm 500℃(930℃F), thiab los ntawm 600℃(1,112℃F) nws dominates tsim. Vim tias 316L tsis muaj cov pa roj carbon monoxide lossis cov nplej ntxhib los tiv thaiv kev nkag mus, ASME tsuas yog tsis tshaj tawm kev ntxhov siab rau nws siab tshaj 800℃F - tus tsim qauv siv tsis tau 316L rau Code-stamped siab tivthaiv ntawm 600℃. 316H, engineered tshwj xeeb rau kev creep} txhua txoj kev nyuaj siab 1,500℃F (816 degree).
|
Kub |
316L Tso Cai Stress |
316H Tso Cai Stress |
Sau ntawv |
|
Chav tsev kub (tsawg dua lossis sib npaug li 100 degree) |
~ 138 MPa (20.0 ksi) |
~ 138 MPa (20.0 ksi) |
Qhov tseem ceeb sib npaug |
|
200℃(392℃F) |
~ 124 MPa (18.0 ksi) |
~ 124 MPa (18.0 ksi) |
Sib npaug |
|
400℃(752℃F) |
~ 103 MPa (15.0 ksi) |
~ 105 MPa (15.2 ksi) |
Ze li sib npaug |
|
427℃(800℃F) |
~ 97 MPa (14.1 ksi) - kawg teev |
~ 99 MPa (14.3 ksi) |
316L qab nthab mus txog |
|
500℃(932℃F) |
TSIS MUAJ |
~ 95 MPa (13.8 ksi) |
316L tsis tuaj yeem siv rau hauv kev pabcuam ASME |
|
600℃(1,112℃F) |
TSIS MUAJ |
~ 77 MPa (11.2 ksi) |
316H tseem Code-usable |
|
700℃(1,292℃F) |
TSIS MUAJ |
~ 46 MPa (6.7 ksi) |
Creep tag nrho dominates; 316H tseem teev |
|
816℃(1,500℃F) |
TSIS MUAJ |
~ 14 MPa (2.0 ksi) - kawg teev |
Upper txwv ntawm 316H |
[Source] ASME Boiler thiab Pressure Vessel Code, Tshooj II, Ntu D - Cov Khoom (Metric). Tus nqi qhia yog tus sawv cev; sab laj nrog tsab cai tam sim no rau kev tsim.
Creep zog
Creep yog qhov qeeb, mus tas li deformation ntawm cov hlau tuav nyob rau hauv kev ntxhov siab ntawm qhov kub siab - txawm tias nyob rau ntawm qhov kev ntxhov siab nyob deb ntawm nws chav tsev - qhov kub thiab txias yield zog. Cov yeeb nkab uas yooj yim tuav 100 bar ntawm 20℃tuaj yeem, ntawm 600 degree, maj mam o, nyias, thiab tawg ntau lub hlis lossis xyoo nyob rau hauv tib lub siab. Creep yog qhov tseem ceeb tsis ua hauj lwm mechanism nyob rau hauv siab - cov khoom kub xws li boiler raj, superheater headers, refinery furnace raj, thiab chav piping - thiab nws yog precisely lub tsis ua hauj lwm hom uas 316H yog engineered los tiv thaiv thiab 316L tsis yog.
Txhawm rau nkag siab nkag siab, xav txog kev ncab ib qho ntawm cov caramel sov lossis cov cheese muag. Rub maj mam thiab nws stretches maj mam thiab mus tas li - nws tsis snap rov qab. Cov hlau ua tib yam ntawm qhov kub thiab txias: cov atoms hauv cov hlau tau txais lub zog thermal txaus kom txav mus los thiab rov kho dua hauv qab load. Nyob rau tib lub sij hawm, qhov no atomic zog accumulates raws li mus tas li deformation. Nyob rau hauv chav tsev kub, qhov kev txav no qeeb heev nws tsis cuam tshuam rau tib neeg lub neej. Ntawm 600 degree, nws tshwm sim sai txaus rau rupture lub siab hlab ntsha nyob rau hauv ob peb xyoos - uas yog vim li cas creep, tsis yield zog, kav siab - kub tsim.
Creep feem ntau yog tus cwj pwm los ntawm lub zog creep rupture: qhov kev ntxhov siab uas ua rau tawg tom qab lub sijhawm teev ntawm qhov ntsuas kub, feem ntau tshaj tawm ntawm 100,000 teev (txog 11.4 xyoo). Piv txwv li, cov khoom siv yuav muaj 100,000-teev creep rupture zog ntawm 100 MPa ntawm 600 degree, txhais tau hais tias cov khoom thauj mus rau 100 MPa yuav, qhov nruab nrab, muaj sia nyob 100,000 teev ua ntej tawg. Cov qauv tsim qauv siv cov txiaj ntsig kev sib tsoo no, muab faib los ntawm qhov muaj kev nyab xeeb, los teeb tsa qhov kev cia siab ntawm qhov kub siab - uas yog vim li cas 316L tsis pub muaj kev ntxhov siab tshaj 800℃F.
Vim li cas 316H Resistant Creep Zoo dua 316L
316H resists creep los ntawm ob qho kev txhawb zog uas 316L tsis muaj: (1) cov pa roj carbon ntau dua (0.04-0.10%) tsim cov chromium carbide precipitates ntawm cov ciam teb, uas pin cov ciam teb thiab tiv thaiv lawv los ntawm zawv zawg; (2) ntxhib grain loj (ASTM Tsis yog. 7 los yog coarser) txhais tau hais tias tsawg dua grain ciam rau ib chav tsev ntim, thiab txij li thaum grain ciam teb yog cov tsis muaj zog txuas nyob rau hauv creep, tsawg ciam teb sib npaug zos tsawg creep. 316L tsis muaj mechanism, yog li nws creeps sai heev nyob rau hauv kub kub.
Mechanism 1 - carbide pinning. Nyob rau hauv 316H, cov pa roj carbon monoxide ua ib qho kev tawg ntawm chromium- nplua nuj M₂₃C₆ carbides ntawm thaj tsam lis. Cov carbides ua zoo li cov pins uas tau tsav los ntawm cov ciam teb nplej, xauv cov nplej uas nyob ib sab ua ke thiab tiv thaiv cov ciam teb zawv zawg uas ua rau nkag mus deformation . 316L, uas yuav luag tsis muaj cov pa roj carbon monoxide, ua rau tsawg dua ntawm cov pinning carbides, yog li nws cov ciam teb cov nplej swb ntau dua ywj pheej nyob rau hauv qhov kub thiab txias.
Mechanism 2 - coarse grain. Creep deformation concentrates ntawm grain ciam teb vim ciam teb yog qhov twg cov qauv atomic tsis meej. Ib qho zoo - cov khoom muaj txiaj ntsig muaj ntau thaj tsam (ntau qhov txuas tsis muaj zog); ib co ntxhib- cov khoom nplej muaj tsawg. Los ntawm kev xav tau ASTM grain loj No. 7 los yog coarser, 316H txo tus naj npawb ntawm cov tsis muaj zog txuas, ncaj qha txo tus nqi nkag. Qhov no yog qhov tsis tshua muaj tshwm sim hauv metallurgy qhov twg coarser zoo dua - qhov sib txawv ntawm qhov zoo -grain nyiam rau chav- kub lub zog thiab toughness.
Cov nyhuv ua ke yog qhov tseem ceeb. Ntawm 600℃(1,112℃F), 100,000-teev creep rupture lub zog ntawm 316H yog kwv yees li 30-60% siab dua li ntawm 316L ntawm qhov sib npaug puag chemistry. Hauv cov ntsiab lus ua tau zoo, 316H boiler raj tuaj yeem nqa tib lub nkev load ntawm 600℃rau ob mus rau peb zaug ntev dua li 316L raj - lossis nqa ntau dua rau tib lub neej tsim. Rau cov khoom siv nrog 20-30 xyoo tsim lub neej, qhov sib txawv no yog qhov sib txawv ntawm kev ua tiav thiab tsis ua tiav ntxov.
Creep Applications - Qhov twg 316H Khwv Tau Nws
316H yog cov khoom siv rau kev ua kom siab- qhov kub thiab txias hauv 500-700℃(930-1,290℃F) ntau yam, tshwj xeeb tshaj yog nyob rau hauv kev tsim hluav taws xob thiab kev ua kom zoo: boiler superheater thiab reheater tubes, steam headers thiab steam piping, refinery furnace, thiab transformertemperatures{8} heat-exchanger tubing. Nws raug xaiv tshwj xeeb uas qhov ntev - lub sij hawm nkag siab lub zog - tsis yog lub sij hawm luv luv kub lub zog - yog tus qauv tsim qauv.
|
Daim ntawv thov |
Yam Temp |
Vim li cas 316H (tsis yog 316L) |
Ntsiab Standard |
|
Boiler superheater / reheater raj |
540-650 degree |
Creep rupture zog nyob rau hauv chav siab |
ASME SA-213 TP316H |
|
Steam headers & main steam piping |
540-600 degree |
Ntev - lub neej nkag mus rau hauv lub siab sab hauv |
ASME SA-312 TP316H / SA-358 |
|
Refinery rauv /reformer tubes |
550-700 degree |
Creep + carburization kuj |
ASTM A312 TP 316H Cov Lus Qhia |
|
Siab -temp reactor nkoj plhaub |
450-650 degree |
ASME tso cai kev ntxhov siab tshaj 800℃F |
ASME SA-240 316H |
|
Thaum tshav kub kub-exchanger tubing (kub sab) |
450-600 degree |
Creep zog + chloride pitting kuj |
ASTM A213 TP 316H Cov Lus Qhia |
|
Tshuaj cog kub piping |
450-550 degree |
Nkag mus qhov twg 316L tsis Code- teev |
ASME B31.3 / SA-312 TP316H |
Siab -Kev xaiv kub
Tus lej tseem ceeb tshaj plaws hauv 316L vs 316H kev txiav txim siab yog 425℃(800℃F). Hauv qab no qhov kub thiab txias, 316L tau txais tag nrho thiab feem ntau yog qhov kev xaiv zoo dua vim tias nws cov weldability zoo dua thiab tsis kam mus rau intergranular corrosion. Saum toj no qhov kub thiab txias, nyob rau hauv ib qho Code- tswj kev siv siab, 316L tsis tso cai thiab 316H (los yog lwm yam creep-rated alloy) yuav tsum tau. Nco txog qhov pib no: nws daws qhov feem ntau ntawm 316L vs 316H cov lus nug.
Qhov 800℃F txwv rau L- qib tsis yog qhov kev txiav txim siab - nws tau sau rau hauv ASME BPVC Tshooj II, Ntu D, uas tsuas yog tsis sau cov kev ntxhov siab rau 316L siab dua 800℃F. Vim ASME Tshooj VIII (cov hlab ntsha siab) thiab ASME B31.3 (txheej txheem piping) yuav tsum muaj cov qauv tsim los siv cov kev ntxhov siab tsis tuaj yeem raug cai siv 316L siab tshaj 800℃F. Qhov no muaj tseeb txawm tias tus neeg muag khoom qhia rau koj 316L "yuav tsum tuav" ntawm 600℃- cov khoom siv lub cev muaj sia nyob ib ntus, tab sis nws tsis muaj Code- pom zoo rau kev ntxhov siab, thiab nws lub neej creep tsis tau lav.
Kub xaiv ntaiv
|
Qhov kub thiab txias |
Pom zoo Qib |
Kev xav |
|
Hauv qab 425℃(800℃F) - welded / corrosion- tseem ceeb |
316L |
Weldability + intergranular corrosion kuj; creep tsis yog qhov tseem ceeb |
|
Hauv qab 425℃(800℃F) - chloride raug |
316L (los yog 317L / duplex rau hnyav Cl⁻) |
Molybdenum resists pitting; tsis muaj siab -kev txhawj xeeb |
|
425-540℃(800-1,000℃F) - kev pabcuam siab |
316H |
316L tsis Code- teev; 316H ua rau muaj kev ntxhov siab |
|
540-700℃(1,000-1,290℃F) - creep-critical |
316H |
Creep zog yog qhov kev cai tswj |
|
700-816℃(1,290-1,500℃F) - cuam tshuam / lub teeb load |
316H (xyuas oxidation) |
Sab saum toj 316H ntau yam; oxidation ua limiting |
|
Saum toj no ~ 870℃(1,600℃F) - nruam |
Nickel alloy (Inconel 625 / 601) los yog cua sov- qib resistant |
316H oxidation - txwv; hloov mus rau Ni-raws li alloy |
Oxidation - Lwm Qhov Siab Tshaj -Tsuas Kub Txwv
Txawm tias 316H muaj qhov kub thiab txias. Tshaj li ntawm 870℃(1,600℃F) hauv huab cua, kev tiv thaiv chromium oxide nplai ntawm 316H pib tawg, thiab kev pabcuam txuas mus ntxiv ua rau muaj kev loj hlob oxidation (scaling) thiab poob ntawm seem. Rau kev pabcuam txuas ntxiv saum toj li 870 degree, hloov mus rau qib cua sov- tiv taus qib (xws li 310S lossis 253MA) lossis nickel alloy (xws li Inconel 625 lossis 601). Nyob nruab nrab ntawm 816℃thiab 870 degree, 316H yuav siv tsis tu ncua los yog nyob rau hauv lub teeb load, tab sis oxidation lub neej yuav tsum raug soj ntsuam los ntawm rooj plaub.
High-kub corrosion yog qhov sib txawv ntawm aqueous corrosion uas dominates ntawm qhov kub thiab txias. Thaum tsis tshua muaj kub, corrosion yog electrochemical - nws xav tau cov kua electrolyte. Thaum kub siab, corrosion yog oxidation - hlau reacts ncaj qha nrog oxygen, sulfur, los yog carbon nyob rau hauv cov pa. Cov chromium hauv 316H tsim kev tiv thaiv Cr₂O₃ nplai uas tiv thaiv oxidation txog li 870 degree. Nyob rau hauv tas li ntawd, lub scale yuav tsis tshua muaj kev tiv thaiv, thiab lub hauv paus hlau yog nce noj.
Qhov no yog vim li cas "siab kub" xaiv cov khoom muaj ob lo lus nug ywj pheej: "Puas yog lub zog creep txaus?" thiab "Yuav ua li cas cov hlau puas oxidize?" - thiab ob qho tib si yuav tsum tau teb ua ntej xaiv qib.
Welding thiab Sensitization
Ntawm no yog cov ntsiab lus tseem ceeb ntawm 316 tsev neeg: cov pa roj carbon ntau uas muab 316H nws qhov siab -kub creep zog yog tib cov pa roj carbon uas ua rau 316H yooj yim rau vuam sensitization. Thaum 316H yog welded thiab cua sov- thaj tsam cuam tshuam dhau los ntawm 425-870 degree, nws cov pa roj carbon precipitates li chromium carbides ntawm cov ciam teb nplej, depleting chromium thiab tsim kom muaj kev cuam tshuam rau intergranular corrosion yog tias cov tshuaj tiv thaiv tom qab raug rau cov corrosive aqueous} ib puag ncig, yuav luag tsis muaj cov pa roj carbon monoxide, {{8}. - yog vim li cas 316L yog tus qauv xaiv rau welded, tsis tshua muaj kub, corrosive kev pab cuam.
Qhov kev lag luam tawm no -tawm yog vim li cas ob qib sib ntxiv ntau dua li kev sib tw . 316H cov khoom (boiler tubes, steam headers) ua haujlwm siab tshaj 500℃hauv chav los yog combustion gas - ib puag ncig uas aqueous intergranular corrosion tsis tshwm sim, yog li rhiab heev tsis yog ib qho kev txhawj xeeb . 316L cov khoom siv hauv qab no, cov khoom siv 2 qib marpi aqueous los yog me ntsis acidic ib puag ncig uas intergranular corrosion yog ib qho kev hem thawj tiag tiag, yog li qhov qis - carbon kom zoo dua yog qhov tseem ceeb. Xaiv qhov tsis ncaj ncees lawm qib inverts no logic thiab caw tsis ua hauj lwm.
Vuam xyaum rau 316L vs 316H
|
Parameter |
316L |
316H |
Sau ntawv |
|
Filler Hlau |
ER316L (GTAW) / E316L (SMAW) |
ER316H lossis ER316L (code-nyob ntawm) |
Match muab tub lim rau kev pabcuam temp; 316H weld hlau xav tau cov pa roj carbon monoxide rau creep |
|
Preheat |
Tsis xav tau |
Tsis xav tau |
Austenitic SS feem ntau xav tau tsis muaj preheat |
|
Max Interpass Temp |
175 ° F (350 ° F) |
175 ° F (350 ° F) |
Siab temps ua rau rhiab heev |
|
PWHT (Solution Anneal) |
Tsis xav tau rau corrosion |
Feem ntau yuav tsum tau txo qis kev ntxhov siab / tswj kev cuam tshuam |
316H tuab seem yuav xav tau kev ntxhov siab |
|
Sensitization Risk (HAZ) |
QEEJ |
HIGH |
316H HAZ sensitizes; txais tau yog tias kev pabcuam siab -temp / non-aqueous |
|
Ncej -Weld hauv Corrosive Service |
Raws li -welded OK |
TSIS pom zoo - HAZ yuav corrode |
Tsis txhob siv welded 316H nyob rau hauv qis -temp corrosive kev pab cuam yam tsis muaj anneal |
Koj puas tuaj yeem Weld 316L rau 316H?
Yog - 316L thiab 316H yog metallurgically sib xws thiab tuaj yeem welded ua ke, tab sis cov hlau muab tub lim thiab kev pabcuam kub yuav tsum tau txiav txim siab ua ke. Rau qhov qis- qhov kub thiab txias sib koom, siv ER316L muab tub lim kom lub vuam hlau tiv taus rhiab heev. Rau qhov siab -kub creep sib koom ua ke, cov hlau vuam yuav tsum muaj cov pa roj carbon zoo sib xws thiab tib lub zog creep zoo li 316H puag hlau - siv qis- cov pa roj carbon muab tso rau hauv qhov sib koom ua ke tsim qhov sib txuas tsis muaj zog uas yuav nkag mus tau ua ntej. Nrog rau txoj cai siv tau (ASME B31.3, Tshooj VIII) rau qhov tshwj xeeb muab tub lim hlau uas yuav tsum tau muaj siab -kub 316H pob qij txha.
Qhov no yog qhov hloov maj mam tab sis qhov tseem ceeb uas cov engineers feem ntau nco. Nyob rau hauv ib tug welded sib koom nyob rau hauv chav tsev kub, lub weld hlau feem ntau muaj zog tshaj lub hauv paus hlau, yog li ib tug me ntsis weaker weld yog tseem tau. Tab sis nyob rau hauv creep kev pab cuam, qhov vuam hlau thiab tshav kub- thaj tsam cuam tshuam tuaj yeem yog qhov nkag tau - qhov tsis muaj zog ntawm qhov sib koom ua ke. Lub 316L muab tso rau hauv 316H creep sib koom ua ke muaj cov pa roj carbon tsawg thiab cov nplej zoo dua li 316H lub hauv paus hlau, yog li nws yuav nkag thiab tawg ua ntej - ib qho tshwm sim hu ua "txo lub neej txo ntawm welds." Rau qhov tseem ceeb heev - qhov kub thiab txias welds, cov chemistry muab tub lim, cov qauv nplej, thiab txawm tias qhov kev kho cua sov yuav tsum tau ua tib zoo sib xyaw kom ruaj khov lub neej.
Corrosion Resistance - Aqueous vs High-Tsub
Rau kev txhim kho corrosion, pitting, thiab crevice corrosion kuj nyob rau hauv ib puag ncig aqueous, 316L thiab 316H yog qhov tseem ceeb sib npaug, vim tias cov khoom no tau tswj hwm los ntawm chromium, npib tsib xee, thiab molybdenum - uas zoo tib yam hauv ob qib. Ob leeg muaj PREN (Pitting Resistance Equivalent Number) ntawm kwv yees li 24-25, ua rau ob qho tib si haum rau cov tshuaj chloride me me tab sis tsis yog rau cov dej hiav txwv loj. Qhov sib txawv corrosion ntawm cov qib tshwm tsuas yog tom qab vuam (sensitization) thiab kub (oxidation).
Cov ntsiab lus molybdenum (2-3%) yog dab tsi ua rau tag nrho 316 tsev neeg nws qhov zoo dua 304. Molybdenum ua kom muaj zog tiv thaiv pitting thiab crevice corrosion nyob rau hauv ib puag ncig chloride. Qhov no yog vim li cas 316/316L/316H yog tus qauv "marine-qib" thiab "chemical{10}}qib" stainless hlau, hos 304 yog tus qauv "general{14}} hom phiaj" qib. Txij li thaum 316L thiab 316H sib koom tib cov ntsiab lus molybdenum, lawv cov tshuaj tiv thaiv chloride pitting zoo ib yam - qhov "L" lossis "H" tsis muaj qhov cuam tshuam ntawm cov khoom no.
Intergranular Corrosion - Qhov twg Qib Diverge Tom qab Vuam
Tom qab vuam, tus cwj pwm corrosion ntawm 316L thiab 316H diverges sharply . 316L resists intergranular corrosion nyob rau hauv raws li-welded mob vim nws cov pa roj carbon tsawg tiv thaiv chromium carbide nag lossis daus nyob rau hauv lub tshav kub- cuam tshuam cheeb tsam. 316H, nrog 0.04{1{9% welded, thaum nyeem ntawv, welded 0.04{0. ib qho welded 316H tivthaiv raug corrosive aqueous ib puag ncig hauv qab li 400℃yuav raug kev cuam tshuam intergranular ntawm qhov vuam tshav kub- thaj tsam cuam tshuam. Qhov no yog vim li cas welded 316H yog tshwj tseg rau siab - qhov kub thiab txias, tsis muaj dej.
Intergranular corrosion (IGC) yog hom tsis ua haujlwm uas cov qib "L" tau tsim los tiv thaiv. Nws tshwm sim thaum chromium carbides tsim ntawm cov ciam teb thaum lub sij hawm vuam, depleting cov hlau nyob ib sab ntawm chromium hauv qab ntawm ~ 12% passive- zaj duab xis pib. Cov ciam teb depleted ces corrode nyiam, ua rau cov hlau poob lub zog thiab nws thiaj li poob raws li ib thaj tsam ntawm grain . 316H yog txhob txwm siab siab nyob rau hauv carbon, yog li nws yog inherently rhiab heev- nquag. Rau cov khoom siv welded uas yuav pom dej, txheej txheem tshuaj, lossis txawm tias huab cua ntub ntawm qhov kub thiab txias, 316L - tsis yog 316H - yog qhov kev xaiv raug. Piv txwv li, rau lub boiler raj ntawm 600℃nyob rau hauv qhuav chav, rhiab heev yog tsis tsim nyog, thiab 316H yog lawm.
Siab -Tub kub Oxidation thiab Carburization
Thaum qhov kub thiab txias, qhov cuam tshuam corrosion mechanisms hloov ntawm aqueous nres rau oxidation, sulfidation, thiab carburization. Ntawm no, 316H ua tau zoo li (los yog me ntsis zoo dua) 316L, vim oxidation tsis kam yog tswj hwm los ntawm chromium - zoo tib yam hauv ob qib - thiab cov pa roj carbon ntau dua ntawm 316H tuaj yeem txhim kho kev tiv thaiv carburization los ntawm ua ntej - saturating nto nrog carbon. Ob qib tsim muaj kev tiv thaiv Cr₂O₃ nplai txog li 870 degree, saum toj no uas yuav tsum tau muaj cua sov- tiv taus lossis npib tsib xee{10}}raws li alloy.
Hauv qhov cub hluav taws xob thiab cov kev pabcuam hloov kho, carburization - nqus cov pa roj carbon monoxide rau hauv cov hlau - yog ib qho kev degradation mechanism uas ua rau cov hlau. Vim tias 316H twb muaj cov pa roj carbon ntau dua, nws muaj cov pa roj carbon ntau dua "muaj peev xwm" ua ntej carburization yuav ua teeb meem, muab nws me ntsis ntug dua 316L hauv carburizing cua. Qhov no yog lwm qhov laj thawj 316H yog qib nyiam hauv kev ua kom zoo dua thiab kev pabcuam petrochemical furnace. Rau sulfidizing (siab-H₂S) cov huab cua ntawm qhov kub siab, txawm li cas los xij, tsis yog qib zoo tagnrho, thiab siab dua -nickel alloy xws li Incoloy 825 lossis Inconel 625 yuav tsum raug txiav txim siab.
Nqi thiab Muaj
316L thiab 316H yog tus nqi tseem ceeb zoo ib yam - tus nqi sib txawv yog qhov tsis txaus ntseeg (feem ntau nyob rau hauv 2-5%, thiab feem ntau xoom) vim tias ob qib yog tsim los ntawm tib txoj kev AOD refining thiab qhov sib txawv tsuas yog ib qho kev hloov kho carbon me ntsis ntxiv rau cov kauj ruam tswj qhov loj. Qhov no txhais tau tias tus nqi yuav tsum tsis txhob tsav qhov kev txiav txim siab 316L vs 316H; qhov kev xaiv yuav tsum tau ua tag nrho raws li kev khiav hauj lwm kub, vuam, thiab corrosion yuav tsum tau.
Tsis zoo li 304L vs 304 - qhov twg L- qib nqa tus nqi me me tshaj tus qauv 304 - qhov sib piv 316L vs 316H yog kwv yees tus nqi- nruab nrab. Ob qib hais kom tib lub hauv paus alloy nqi (tsav los ntawm 2-3% molybdenum cov ntsiab lus, uas yog cov khoom siv kim), thiab tus nqi nce ntxiv ntawm kev ua tiav 316H cov pa roj carbon ntau thiab cov nplej ntxhib yog me. Qhov no yog hmoov zoo, vim hais tias nws tshem tawm tus nqi ntawm qhov sib npaug tag nrho: engineers muaj peev xwm xaiv tau los ntawm kev ua tau zoo, uas yog raws nraim li kev txiav txim siab txog kev nyab xeeb yuav tsum tau ua.
Muaj
316L yog cov khoom siv dav dav thiab muaj cov hlau tsis muaj hlau nyob hauv lub ntiaj teb, muaj nyob rau hauv txhua daim ntawv (daim ntawv, phaj, bar, yeeb nkab, raj, fittings, flanges) los ntawm qhov tseem ceeb ntawm txhua tus stainless hlau distributor thiab zeb. 316H tsis tshua muaj tab sis tseem muaj nyob rau hauv, tshwj xeeb tshaj yog nyob rau hauv cov khoom siv tubular cov ntaub ntawv (ASTM A213/A312) thiab TP3 (ASTM A213/A312) {1} ASTM A213/A312 ASTM 5 thiab refining daim ntawv thov. Rau siab - qhov kub thiab txias daim ntawv thov, 316H muaj yog zoo tsim los ntawm mills ua hauj lwm rau boiler thiab petrochemical industries.
Daim ntawv ceeb toom: vim tias 316L yog qhov tseem ceeb hauv kev ua lag luam, ntau tus neeg xa khoom thiab cov neeg tsim khoom ua haujlwm rau nws - txawm rau cov ntawv thov uas yuav tsum siv 316H. Thaum xaj kom siab - qhov kev pabcuam kub, qhia meej meej "316H" thiab txheeb xyuas ntawm cov ntaub ntawv xeem cov ntaub ntawv uas (1) carbon yog 0.04-0.10%, thiab (2) grain loj yog ASTM Tsis muaj. 7 lossis coarser. Cov khoom uas ua tau raws li 316 chemistry nkaus xwb (nrog 0.08% max carbon) tab sis tsis muaj qhov xav tau ntawm cov qoob loo loj tsis yog 316H thiab yuav tsis xa cov kev ua haujlwm creep xav tau.
Cov lus nug nquag
Q: Dab tsi yog "H" hauv 316H sawv rau?
A: "H" sawv cev rau "High Carbon." 316H qhia txog cov ntsiab lus carbon ntawm 0.04-0.10% (siab dua 316L's 0.03% max) ntxiv rau cov nplej ntxhib loj ntawm ASTM No. 7 lossis coarser. Ua ke, ob qho no ua kom lub zog nkag siab siab rau siab - qhov kev pabcuam kub. Lub npe "H" tau qhia kom paub qhov txawv txav - ntsuas 316 los ntawm qhov qub 316 thiab los ntawm cov pa roj carbon tsawg 316L.
Q: Puas yog 316H muaj zog dua 316L?
A: Nyob rau hauv chav tsev kub, 316H muaj zog tsawg dua me ntsis (515 MPa vs 485 MPa tensile; 205 MPa vs 170 MPa yield). Tab sis lub ntsiab lus sib txawv yog qhov kub thiab txias: siab tshaj 425℃(800℃F), 316H khaws cia siab dua creep zog tshaj 316L, thiab 316H tsuas yog ib qho ntawm ob qho nrog Code- teev tso cai rau kev ntxhov siab siab tshaj 800℃F. Rau chav - qhov kub thiab txias kev siv, qhov sib txawv yog qhov sib txawv heev.
Q: Kuv puas tuaj yeem siv 316L hloov 316H ntawm qhov kub thiab txias?
A: Tsis yog rau ASME Code kev pabcuam siab tshaj 425℃(800℃F) . 316L tsis muaj Code- tau teev cia kev ntxhov siab tshaj qhov ntsuas kub no vim tias nws cov pa roj carbon tsawg thiab cov nplej zoo tsis tuaj yeem lav kev nkag siab. Rau qhov kub siab tshaj 425℃hauv kev siv siab, siv 316H. Rau cov ntawv uas tsis yog - siab lossis me me, 316L qee zaum siv txog li 450 degree, tab sis qhov no yog sab nraud Code xyaum thiab yuav tsum tau ua nrog engineering ceev faj.
Q: Puas yog 316H weldable?
A: Yog, 316H yog weldable, tab sis nws cov pa roj carbon ntau dua ua rau cov cua sov- cuam tshuam thaj chaw muaj kev cuam tshuam rau kev nkag siab (chromium carbide nag lossis daus) thaum vuam. Qhov no siv tau rau siab - kub, tsis yog - aqueous kev pab cuam, qhov twg aqueous intergranular corrosion tsis tshwm sim. Tsis txhob siv welded 316H hauv qis-kub corrosive aqueous kev pabcuam - siv 316L hloov.
Q: Qhov kev pabcuam siab tshaj plaws ntawm 316H yog dab tsi?
A: 316H muaj ASME Code tso cai rau kev ntxhov siab txog 816℃(1,500℃F). Txawm li cas los xij, rau kev pabcuam txuas ntxiv hauv huab cua, oxidation yuav txwv tsis pub tshaj 870℃(1,600℃F). Hauv kev xyaum, 316H feem ntau yog siv nyob rau hauv 500-700℃(930-1,290℃F) creep range. Tshaj li 870℃txuas ntxiv, hloov mus rau qib kub-resistant lossis npib tsib xee alloy.
Q: Qhov kev pabcuam siab tshaj plaws ntawm 316L yog dab tsi?
A: Rau ASME Code siab kev pabcuam, 316L yog txwv rau 425℃(800℃F). Qhov no tsis yog qhov txwv tsis pub xeb tab sis creep- lub zog txwv: siab dua 800℃F, 316L's creep kuj tsis tau lees paub, yog li tsis muaj kev ntxhov siab tso cai tau tshaj tawm. Rau txhua qhov siab- khaws cov khoom siv siab tshaj 800℃F, siv 316H.
Q: 316L vs 316H vs 316 - Kuv yuav xaiv li cas?
A: Siv 316L rau welded, corrosion- tseem ceeb, qis- kub (qis dua 425 degree) kev pab cuam - chemical tanks, marine piping, khoom noj khoom haus. Siv 316H rau siab - kub (425-816 degree) creep service - boiler raj, chav piping, rauv tubes. Siv cov pa 316 (0.08% max carbon) feem ntau yog cov hom phiaj dav dav thaum tsis siv qhov hnyav, txawm hais tias hauv kev xyaum 316L tau hloov pauv ntau rau 316 rau kev siv welded.
Q: Kuv yuav ua li cas thiaj paub tseeb tias kuv tau txais 316H thiab tsis yog 316 lossis 316L?
A: Tshawb xyuas cov ntaub ntawv xeem cov ntaub ntawv (MTR). Rau 316H, MTR yuav tsum qhia: (1) carbon 0.04-0.10%, thiab (2) grain loj ASTM No. 7 los yog coarser. Handheld XRF (PMI) tsis tuaj yeem paub qhov txawv ntawm 316/316L / 316H vim nws tsis tuaj yeem ntsuas cov pa roj carbon lossis cov nplej loj. Cov pa roj carbon yuav tsum raug kuaj xyuas los ntawm OES lossis kuaj tshuaj ntsuam xyuas, thiab cov nplej loj los ntawm kev kuaj xyuas metallographic ib ASTM E112. Thov daim ntawv pov thawj EN 10204 Hom 3.1 kom paub meej tias cov khoom muaj tseeb 316H.
