Ntawm qhov tshwj xeeb kev sib xyaw ua ke ntawm Thermal Cycle Frequency thiab Peak Temperature Puas Yog 1.0 millimeter 316 Stainless Steel Sheath tsim Oxide Spallation uas ua kom nrawm nrawm rau cov Phab Ntsa Thinning hauv Cyclic Cua Cua Sov Kev Pabcuam?

Rau cov kws tsim hluav taws xob tsim hluav taws xob tso cua sov rau cov chaw ua lag luam, cov cua kub cua sov, thiab cov cua sov caij tsheb kauj vab, kev tsim khoom thiab kev nthuav dav ntawm oxide nplai nyob rau saum npoo ntawm 316 stainless hlau sheath yog ib qho kev vam meej tab sis kwv yees phab ntsa thinning mechanism. Qhov twg pitting los yog active corrosion induce localized tsis ua hauj lwm, oxide spallation txhawb homogeneous poob ntawm cov khoom nyob rau hauv tag nrho cov rhuab nto. Txhua lub voj voog cua sov nteg ib txheej me me ntawm chromium nplua nuj oxide. Thaum kawg lub oxide txheej yuav tuab heev thiab nws yuav tawg tawm. Qhov no yog vim oxide txheej muaj qhov sib txawv thermal expansion dua li cov hlau, thiab oxide txheej tawg thiab flakes tawm tawm cov hlau tshiab kom oxidized. Cov txheej txheem no tshwj xeeb tshaj yog cuam tshuam rau lub sheath nrog phab ntsa tuab ntawm 1.0 hli, vim tias qhov me me nyias nyias tuaj yeem txo qhov kev ncaj ncees ntawm cov qauv. Daim ntawv no tsim cov xwm txheej meej ntawm lub voj voog thermal zaus thiab qhov siab tshaj qhov kub ntawm qhov uas qhov sib txawv ntawm oxide nrawm mus rau qhov ua rau lub neej poob qis mus rau qib tsis txaus ntseeg rau kev lag luam.

Kinetics ntawm oxide kev loj hlob thiab spallation ntawm stainless hlau 316L
Lub oxidation kinetics ntawm 316 stainless hlau nyob rau hauv cov huab cua ua raws li txoj cai parabolic: lub oxide thickness nce nrog lub square cag ntawm lub sij hawm ntawm kub. Ntawm 600 ° C lub oxide tuab yog li 2 microns tom qab 100 teev thiab txog 5 microns tom qab 1,000 teev. Tib thicknesses tau txais tom qab 20 h thiab 200 h, feem, ntawm 700 ° C. Ntawm 800 ° C, oxide yog 5 microns hauv 50 teev. Qhov tseem ceeb oxide thickness rau spallation thaum lub sij hawm thermal cycling yog ib qho kev ua haujlwm ntawm qhov kub thiab txias sib txawv ntawm ib lub voj voog. Rau qhov kub hloov pauv ntawm 500 ° C (hais 200 ° C rau 700 ° C) spallation pib tshwm sim thaum cov oxide tuab yog li 3-4 micron. Rau lub viav vias ntawm 700 ° C (piv txwv li los ntawm 100 ° C mus rau 800 ° C) spallation pib ntawm 2-3 microns. Txhua qhov kev tshwm sim spallation tshem tawm 1-3 microns ntawm cov hlau los ntawm sheath nto, vim cov oxide txheej muaj hlau los ntawm substrate. Lub 1.0 hli sheath raug rau 100 qhov xwm txheej tshwm sim tuaj yeem poob 0.1-0.3 hli ntawm phab ntsa tuab sib npaug rau 10-30% ntawm nws cov khoom pib. Hauv kev pabcuam cyclic nrog spallation nyob rau hauv 100-500 cycles, 1.0 mm sheath tej zaum yuav muaj tsawg tus yam ntxwv thickness (0.5 mm) tom qab 500-2,000 cycles, piv txwv li . 1-5 xyoo ntawm kev pab cuam ntawm ib lub voj voog ib hnub twg.

Qhov tseem ceeb tshaj plaws rau Accelerated Spallation nyob rau hauv 1.0 Millimeter Sheath Controlled furnace testing ntawm 1.0 mm 316 sheath qauv nyob rau hauv cyclic cua cua sov chaw txheeb xyuas qhov chaw pib ntawm uas spallation accelerates mus rau unacceptable nqi. Qhov tsis txaus ntseeg: cov phab ntsa zoo ib yam> 0.05mm ib 1000 cycles. (Qhov no yuav txo qis 1.0mm sheath rau 0.7mm tom qab 6000 cycles, uas yog nyob ib ncig ntawm 5 xyoo ntawm 3 cycles ib hnub twg).

Peak Cycle Temperature Swing per Cycle Cycles to First Spallation Oxide Thickness at Spallation Wall Thinning per Spallation Event Cycles mus rau 0.7 mm Cov Phab Ntsa Tseem Ceeb (30% poob) 500℃400℃(100℃rau 500 degree) - 1,000 {9 microns - 3,000 microns 15,000 - 30, 000 600℃500℃(100℃txog 600 degree) 500 - 800 4 - 5 microns 2 - 3 microns 3,000 - 6, 000 650℃550℃(100℃rau 650} 2 - 4 microns 1,500 - 3, 000 700℃600℃(100℃txog 700 degree) 100 - 200 3 - 4 microns 3 - 5 microns 800 - 1,500 750℃650℃(100℃txog 750 degree) 6}4 - {0 microns 800 800℃700℃(100℃txog 800 degree) 20 - 50 2 - 3 microns 5 - 8 microns 200 - 400
For 1.0 mm sheath, peak temperature 650°C and 3 cycles per day (approximately 1,000 cycles per year), spallation would result in a wall thickness reduction of 0.02–0.04 mm/year, leaving the sheath at 0.7 mm after 5–8 years. This may be tolerable for many purposes. At 750°C peak, the same cycle frequency accelerates the thinning to 0.05–0.10 mm/year, resulting in a life of 2–4 years. At 800°C peak, life is 1–2 years. The essential threshold for undesirable spallation (wall thinning >0.05 mm per 1000 cycles) is at around 700°C peak temperature with cycles >300℃viav vias. Tshaj li qhov pib no, 1.0 hli sheath poob cov khoom ntawm tus nqi nrawm dua li cov neeg siv khoom lag luam feem ntau xav tau.

1.0 hli Sheath Safe Operating Envelope nyob rau hauv Cyclic Air Service
Lub hnab ntawv ua haujlwm nyab xeeb rau 1.0 mm 316 sheath rau cyclic cua cua sov lub luag haujlwm tau muab rau hauv cov lus hauv qab no. Lub hauv paus yog tolerable phab ntsa thinning tsawg dua 0.03 hli ib 1,000 cycles (0.1 hli txhua 3,000 cycles los yog ib ncig ntawm 10% poob tshaj 5 xyoo ntawm 2 cycles ib hnub twg).

Peak Sheath Surface Temperature Max. Pom zoo Cycles ib hnub Max. Pom Zoo Tag Nrho Cov voj voog hla kev pabcuam Lub Neej Cia Siab Phab Ntsa Thinning Tom Qab Max. CyclesRecommended Action Beyond these limits
Txog 500 ° C 10 50,000 Hauv qab 0.05 hli 316 tau; txhua lub voj voog zaus 500 - 550 ° C 5 25, 000 0.05 - 0.10 mm Tau txais kev pabcuam feem ntau
550 - 600 ° C 3 15, 000 0.10 - 0.15 mm Saib xyuas phab ntsa thickness ib ntus 600 - 650 ° C 2 10, 000 0.15 - 0.25 mm Xav txog Incoloy 800H rau lub neej ntev 650 - 700 °C {{114}, {{134}}, marginal; upgrade pom zoo 700 – 750°C 0.5 2, 500 0.30 – 0.50 mm 316 tsis pom zoo
>750 ° C Tsis pom zoo Tsis siv Rapid spallationCeramic rhaub lossis Incoloy 800H
Incoloy 800H muaj kev tiv thaiv oxidation ntau dua qhov twg cov ntawv thov yuav tsum tau kub siab tshaj 650 ° C thiab ntau dua 2 lub voj voog ib hnub. Cov alloy tsim ib qho kev txhim kho qeeb, ntau adherent oxide uas spalls ntawm ntau dua thicknesses (10-15 microns) thiab kub (dhau 850 ° C). Piv txwv li, 1.0 hli Incoloy 800H sheath ntawm 750 ° C nrog 5 cycles / hnub yuav undergo phab ntsa thinning<0.05 mm over 10,000 cycles - five to ten times better than 316.

Tsim cov kev hloov pauv kom txo qis kev sib tsoo hauv nyias nyias -Walled Sheaths
Peb qhov kev hloov pauv tsim tuaj yeem txo qis qhov sib txawv thaum lub 1.0 hli 316 sheath yuav tsum tau khiav hauv kev pabcuam huab cua ze rau lossis dhau qhov kev txwv. Thawj yog siv cov kev kho ua ntej - oxidation. Kev ua haujlwm ntawm lub rhaub dej kub ntawm qhov kub siab tshaj plaws rau 100-200 h ua ntej kev ua haujlwm cyclic ua rau lub thicker, ntau nplaum oxide uas tsis tshua muaj spill dua li nyias oxide uas tsim thaum ntxov mus. Qhov thib ob kev hloov pauv yog ua kom qeeb ntawm qhov txias txias. Kev txias txias los ntawm 700℃mus rau chav tsev kub ua rau thermal shock thiab spallation. Tsis txhob siv cua txias txias. Spallation yog txo los ntawm 30-50% nrog ntuj txias nyob rau hauv tseem huab cua. Qhov kev hloov pauv zaum kawg yog txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau daim iav ci ntawm tsawg dua 0.2 microns Ra. Smooder deg ua rau finer-grain oxides uas yog adherent ntau tshaj oxides tsim nyob rau hauv ntxhib, raws li zoo raws li -swaged nto. Tus nqi spallation ntawm electropolished 316 sheaths yog 40-60% qis dua li ntawm as-swaged sheaths nyob rau hauv tib lub voj voog. Rau feem ntau cov kev lag luam cua cua sov hauv qab 650 ° C ncov ib 1.0 hli 316 sheath nthuav tawm lub neej ua haujlwm txaus siab ntawm 5-10 xyoo nrog rau lub voj voog ntev. Tshaj 650 ° C, txo lub neej yuav tsum raug lees txais, lossis lub voj voog zaus yuav tsum raug txo, lossis siv cov hlau oxidation ntau dua. Thaum qhia txog cov cua sov rau kev pabcuam huab cua, ib txwm hais txog qhov ntsuas qhov ntsuas kub ntawm qhov ntsuas kub, lub voj voog zaus thiab lub neej kev pabcuam. Ib lub chaw tsim khoom uas qhia 316 rau 750C kev pabcuam yam tsis tau hais txog kev sib kis thiab cov phab ntsa thinning yog tsis muab cov lus qhia tiav engineering. Kev poob ntawm cov phab ntsa tuab vim yog oxide spallation yog kwv yees thiab tswj tau, tab sis yuav tsum tau txiav txim siab hauv kev kwv yees lub neej, tshwj xeeb tshaj yog rau cov phab ntsa nyias nyias qhov twg txhua micron ntawm cov khoom ploj suav.