Yuav Ua Li Cas Ua Ntej Txias Ua Haujlwm Feem Xyuam los ntawm Tube Drawing ntawm 316L Heater Sheath Tswj tus nqi ntawm Recrystallization thiab Grain Loj hlob Thaum Kev Pabcuam ntawm 600 degree

Microstructural Evolution Parameter rau Kub Kub. Kev tuav ruaj khov

Qhov feem pua ​​​​ntawm kev ua haujlwm txias ua ntej los ntawm kev kos duab ntawm lub raj dictates tus nqi ntawm recrystallisation thiab cov qoob loo tom qab kev loj hlob tshwm sim thaum lub sij hawm siab -kub raug rau 316L stainless hlau qhwv hluav taws xob cua sov raj khiav ntawm 600 degree, uas yog lub sab saum toj txwv ntawm kev pab cuam mus tas li siv rau no alloy. Raws li -raws raj tau khaws lub zog los ntawm cov yas deformation (dislocation ceev sib xws rau % ua haujlwm txias). Lub zog khaws cia no ua rau recrystallisation ntawm 600 degree: kev tsim cov nplej tshiab, tsis muaj kab mob hloov pauv cov deformed microstructure. Lub sijhawm pib ntawm recrystallisation poob qis heev nrog kev ua haujlwm txias: ntawm 10% ua haujlwm txias, nws yog 1,000-2,000 teev; ntawm 20% ua haujlwm txias, 200-500 teev; ntawm 30% ua haujlwm txias, 50-150 teev. Recrystallisation ua rau cov qoob loo tsim. Qhov no coarsens lub microstructure thiab txo cov creep zog . 10,000 teev kev pab @ 600℃qhov zoo tshaj plaws txias ua hauj lwm ntau yam yog 10-15% (sib npaug: ncua recrystallisation txaus kom ciaj sia 10,000 teev tab sis tsis sai li sai tau raws li cov ntxhib nplej). Daim ntawv no ntsuas qhov sib txuas ntawm kev ua haujlwm txias ua ntej, recrystallisation kinetics, kev loj hlob ntawm cov qoob loo thiab lub neej creep ntawm 600 degree.

Mechanism ntawm Recrystallisation thiab Grain Loj hlob hauv 316L Txias Ua Haujlwm

Recrystallisation yog txheej txheem thermally stimulated. Cov nplej tshiab nucleate ntawm qhov chaw ntawm qhov siab dislocation ceev (txheej txheem cej luam, deformation bands, inclusions) thiab txhim kho rau hauv cov matrix distorted. Lub zog tsav tsheb yog proportional rau lub zog khaws cia ntawm kev ua haujlwm txias, uas yog proportional rau square of flow stress (li linear with cold work feem pua ​​mus txog 30-40%). Kev ua haujlwm txias ua rau muaj qhov nce ntxiv ntawm nucleation tus nqi. Tom qab recrystallisation tiav, grain expansion tshwm sim los ntawm ciam teb tsiv teb tsaws tsav los ntawm ib tug txo nyob rau hauv lub grain ciam teb cheeb tsam. Cov nplej loj loj hlob ntawm qhov siv nyiaj me me (Ostwald ripening). Zoo, khov kho grain loj (ASTM 6-8) muab qhov zoo tshaj plaws creep tsis kam ntawm 600 deg C. Zoo heev grained (ASTM 10+) thiab coarse grained (ASTM 3-5) nplej tau pom tias yuav shorten creep life, los ntawm grain ciam swb, raws li.

Kev sib raug zoo ntawm Kev Ua Haujlwm Txias, Lub Sijhawm Recrystallisation thiab Grain Loj ntawm 600 degree.

Tswj isothermal aging ntawm 600℃nrog lub sij hawm kuaj metallographic tau siv los txiav txim cov nqi ntawm recrystallisation thiab grain loj hlob nyob rau hauv txias -kos 316L tubing:

Previous Cold Work (%) Time to Recrystallise 50% at 600°C (hours) Recrystallised Grain Size After Completion (ASTM, µm) Time to Grain Growth to ASTM 5 (>70 µm, hours) Creep Rupture Life at 80 MPa, 600°C (hours) Recommended for 10,000 hour Service at 600°C 0 (annealed) N/A (no cold work) 8-9 (20-30 µm) initial >20,000 (stable) 2,500-3,500 Yog (yog tias twb zoo lawm)
5 5,000-10, 000 8-9 (20-30 µm) 15,000-20, 000 3,000-4,000 Yog
10 1,500-3,000 7-8 (25-35 µm) 8,000-12,000 3,500-5,000 Yog (zoo tshaj)
12 1,000-2,000 7-8 (25-35 µm) 6,000-9,000 3,500-5,000 Yog
15 500-1,000 6-7 (35-50 µm) 4,000-7, 000 3,000-4,500 Txais
20 200-500 5-6 (50-70 µm) 2,000-4,000 2,000-3,500 Marginal 25 100-200 4-5 (70-90 µm) 1,000-2,{11}},500-2,500 Tsis pom zoo 30 50-150 3-4 (90-120μm) 500-1,500 1,000-2,000 Tsis pom zoo 35 30-80 3 (100-130 µm) 300-800 800-1,500 Tsis yog 40 20-50 2-3 (120-150 µm) 200-500 600-1,000 Tsis yog
Kev cuam tshuam ntawm thawj zaug grain loj ntawm recrystallisation kinetics

Tus nqi recrystallisation nyob ntawm seb qhov loj me me ua ntej yuav txias txias. Yog li cov khoom zoo dua, qhov nrawm dua nws yuav rov ua dua -crystalize. Muaj ntau qhov chaw nucleation.

Initial ASTM Grain Size Ua ntej kos cov txheeb ze Recrystallisation Rate (10% CW) Raws li Kev Ua Haujlwm Txias Txias 10,000-hour Cold Work Recommended Life 10 (zoo heev, 10 µm) 1.5 × (ceev) 8% 8 (fine, 20 µ10% (1%)
6 (nruab nrab, 45 µm) 0.7 × (slower) 12%
4 (coarse, 80 µm) 0.4 × (deb qeeb) 15% Cov lus pom zoo rau 316L rhaub tube ntau lawm

Rau 316L sheaths rau 600℃kev pabcuam nrog lub neej tsim ntawm 10,000 teev cov haujlwm txias hauv qab no thiab ua ntej-kev pabcuam kev kho cua sov tsis tau thov.

Kev Pabcuam Lub Neej (teev) 600℃Pom Zoo Ua Haujlwm Txias Ua Ntej Kev Pabcuam (%) Grain Loj Tom Qab Ua Ntej-Kev Pabcuam Thaum Kub Kub Tom Qab 10,000 h ntawm 600℃(ASTM)Tsev Muaj Peev Xwm Ua Ntej Lub Neej (teev) 5,000 15-20 Tsis muaj (raws li kos) 5-70µm (5µ0) 3,000-4,500 10,000 10-12 Tsis muaj (raws li kos) 6-7 (35-50 µm) 3,500-5,000 10,000 0-5 Puv anneal + fine grain 7-8 (25-35 µm) 3,000-5},{2000-4},{2000-5} (850 degree, 2 h) 7 (30-40 µm) 5,000-7, 000 20, 000 + corrosion resistance 0 Tag nrho cov tshuaj anneal + stabilization 7-8 4,000-6,000
Kev Tshawb Fawb Hauv Xeev ntawm Recrystallisation

Ob txoj kev pov thawj muaj rau cov neeg yuav khoom uas xav tau qee yam kev ruaj ntseg microstructural. Thawj yog kev sim hardness. Lub hardness ntawm li -kos 316L yog 180-320 HV nyob ntawm kev ua haujlwm txias. Recrystallisation ua rau lub hardness poob mus rau 140-160 HV (muab kiag li). Yog tias qhov hardness tom qab 1,000 h ntawm 600℃siab dua 200 HV, recrystallisation tseem tsis tau tshwm sim. Qhov thib ob yog kev kuaj xyuas metallographic tom qab etching (glyceregia lossis electrolytic oxalic acid). Qhov tsim ntawm "necklace" cov qauv (kab ntawm cov nplej tshiab zoo raws li cov ciam teb qub) qhia txog qhov pib ntawm recrystallisation.

Xaus Txias Ua Haujlwm Txhim Kho rau 600℃Kev Pabcuam Lub Neej

Lub recrystallisation kinetics thiab cov qoob loo tom ntej ntawm 316L stainless hlau rhaub sheaths ntawm 600℃yog cuam tshuam los ntawm kev ua haujlwm txias ua ntej %. Recrystallisation tau txais tom qab ua haujlwm txias ntawm 10-12% thiab 1,500-3,000 xuab moos, ua rau raug nplua (ASTM 7-8) recrystallised grain qauv uas khaws zoo creep zog rau 10,000+ teev. Kev ua haujlwm txias dua (20-30%) ua rau rov ua dua tshiab sai sai (200-500 teev) thiab cov nplej ntxhib (ASTM 4-5) uas txo qis lub neej ntawm 40-60%. Lub microstructure twb recrystallised thiab ruaj khov ntawm tsawg dua 5% kev ua haujlwm txias (annealed) tab sis qhov tsis muaj kev ua haujlwm hardening txo qis li tsim lub zog. Rau 10,000 teev kev pabcuam ntawm 600 degree, engineers qhia 316L sheaths tuaj yeem cia siab tias 10-15% ua haujlwm txias los ntawm kev kos duab raj. Tom qab kos duab, kev kho cua sov stabilization (850 degree, 2 teev) yog siv los ua kom zoo dua cov microstructure rau lub sij hawm ntev grain-loj stability rau kev pab ntau tshaj 10,000 teev. Lub moj khaum uas tau hais los ntawm no tso cai rau cov neeg yuav khoom los piav qhia txog kev txo qis uas ua kom lub neej nkag siab los ntawm kev tswj hwm microstructural evolution los ntawm kev cuam tshuam txog kev ua haujlwm txias % rau recrystallisation kinetics thiab kev loj hlob nplej ntawm 600 degree.