304 vs 321 Stainless Steel: General Purpose vs. Stabilized for High Temp

 

Dab tsi yog cov ntsiab lus tseem ceeb thiab kev siv qhov sib txawv ntawm 304 thiab 321 stainless hlau?
Ob qib yog ua raws li 18-8 chromium-nickel austenitic qauv. Lub ntsiab lus txawv yog tias 321 (UNS S32100) muaj titanium tsawg kawg yog 5 npaug ntawm cov ntsiab lus carbon. Qhov no titanium stabilizes cov hlau los ntawm kev tsim titanium carbides, tiv thaiv cov teeb meem chromium carbides uas ua rau intergranular corrosion . 304 (UNS S30400) tsis muaj qhov ruaj khov no . 304 yog qhov kev xaiv universal rau kev ua zaub mov, chav ua noj, thiab architecture. 321 yog tshwj xeeb hauv kev ua haujlwm kub thiab txias. xws li aircraft tso tshuab, rauv qhov chaw, thiab expansion tshuab.

Vim li cas qhov stabilization hauv 321 tseem ceeb heev rau welded lossis siab -kev siv kub?
Thaum tus qauv 304 yog cua sov nyob rau hauv thaj tsam ntawm 450-850℃-txawm thaum vuam lossis hauv kev pabcuam-carbon migrate mus rau thaj tsam nplej thiab ua rau cov chromium. Qhov no depletes cov chromium, tsim txoj hauv kev rau corrosive nres hu ua "weld decay." titanium nyob rau hauv 321 muaj ib tug muaj zog affinity rau carbon. Nws tsim ruaj khov titanium carbides ua ntej, kaw cov pa roj carbon monoxide thiab tawm hauv tag nrho cov chromium nyob rau hauv kev daws teeb meem kom muaj ib qho teeb meem, corrosion-resistant barrier. Qhov no ua kom cov welded sib koom los yog rhuab seem tseem resistant li lub hauv paus hlau.

Nyob rau hauv cov xwm txheej twg yog qhov qhia txog 321 tshaj 304 tsis yog- sib tham tau?
Kev qhia txog 321 tsis yog-kev sib tham tau rau ib qho kev sib txuas uas yuav raug welded thiab tsis tuaj yeem tshaj tawm -weld heat- kho, thiab tom qab ntawd yuav ua haujlwm nyob rau hauv qhov kub thiab txias. Qhov no suav nrog: cov khoom siv hluav taws xob tso tawm, cov thermal oxidizer sab hauv, cov txheej txheem loj cov hlab ntsha uas yog teb -welded, thiab siab - cov kav dej kub. Rau qhov chaw uas tsis tau welded los yog tsuas yog siv rau qhov kub thiab txias, siv 321 tshaj 304 tsis muaj txiaj ntsig thiab ntxiv cov nqi tsis tsim nyog.

Puas yog titanium stabilization cuam tshuam rau fabrication lossis machining ntawm 321 piv rau 304?
Fabrication zog zoo li formability zoo sib xws. Lub ntsiab fabrication txawv yog nyob rau hauv vuam. Vuam 321 yuav tsum muaj kev tiv thaiv roj zoo heev (feem ntau nrog argon rov qab) los tiv thaiv oxidation ntawm titanium, uas yuav txo qis nws cov nyhuv stabilizing ntawm weld seam. Machinability yog piv rau 304. Rau fabricators, tus yuam sij yog kom ntseeg tau tias cov txheej txheem vuam raug ua raws; txwv tsis pub, ua haujlwm nrog 321 zoo ib yam li kev ua haujlwm nrog 304.

Dab tsi yog tsob ntoo txiav txim siab yooj yim rau cov engineers xaiv ntawm ob qib no?
Ua raws li cov lus qhia no: 1)Cov khoom puas yuav welded?Yog tsis yog, mus rau kauj ruam 2. Yog tias YOG, mus rau kauj ruam 3. 2)Nws puas yuav ua haujlwm siab dua 425 degree?Yog tias TSIS TAU, siv 304. Yog tias YOG, xav txog 321 lossis lwm yam cua sov- qib resistant. 3)Puas yuav welded tivthaiv ua haujlwm ntawm 450-850 degree?Yog tias TSIS TAU, 304L zoo li txaus. Yog tias YOG, koj yuav tsum siv 321 (lossis 347). Cov txheej txheem no ua kom koj tsis ua raws li - qhia thiab muaj kev pheej hmoo corrosion tsis ua haujlwm.