Dab tsi yog cov khoom thiab kev siv ntawm A387 Qib 12 Chav Kawm 2?
ASTM A387 Qib 12 Chav Kawm 2yog ib tug normalized thiab tempered chromium-molybdenum (1.25Cr-}0.5Mo) alloy steel phaj tsim los rau high-temperature kev pab cuam nyob rau hauv welded siab hlab ntsha thiab boilers, muab siab zog dua Class 1 los ntawm nws cov kev kho cua sov.
Cov khoom ntawm A387 Qib 12 Chav Kawm 2
Qhov no chromium-molybdenum alloy steel yog txhais los ntawm cov khoom sib npaug ntawm cov khoom zoo tagnrho rau siab - kub, siab - qhov chaw siab.
Cov khoom tseem ceeb:
Mechanical Strength:Nws yog nkag rau hauv qhov normalized thiab tempered (N&T), uas muab nws lub zog ntau dua piv rau nws cov annealed Class 1 counterpart.
Tensile zog:485 - 620 MPa (70 - 90 ksi)
Yield zog(min): 275 MPa (40 ksi)
Ua haujlwm kub siab:Lub hom phiaj tseem ceeb ntawm nws cov alloying.
Chromium(0.80-1.25%): Muab kev tiv thaiv oxidation (scaling) thiab corrosion ntawm kub kub.
Molybdenum(0.44-0.65%): Txhim kho lub zog ntawm qhov kub thiab txias thiab txo qhov cuam tshuam rau creep thiab temper embrittlement.
Fabricability: Nws muaj qhov zoo weldability thiab formability, tab sis yuav tsum tau nruj me ntsis ua raws li preheating (feem ntau 150-}250 ° C / 300-480 ° F) thiab yuav tsum tau ua tom qab-Weld Thaum tshav kub kub kho (PWHT) los tiv thaiv hydrogen-induced cracking thiab restore zog nyob rau hauv lub weld cheeb tsam.
Hardness:Feem ntau nyob rau hauv qhov ntau ntawm 140-207 HBW nyob rau hauv lub normalized thiab tempered mob.
Cov ntawv thov tseem ceeb ntawm A387 Qib 12 Chav Kawm 2
Cov khoom siv no yog cov neeg ua haujlwm hauv kev lag luam uas cov khoom siv ua haujlwm nyob rau hauv kev kub siab thiab kub siab. Nws cov ntawv thov tseem ceeb yog nyob rau hauv kev tsim cov welded siab hlab ntsha thiab cov khoom.
Kev siv yam muaj xws li:
Petroleum Refining & Petrochemical Plants:
Cov reactors thiab cov hlab ntsha hauv hydroprocessing units (piv txwv li, hydrotreaters, hydrocrackers).
Thaum tshav kub kub exchangers, separators, thiab distillation kem tuav cov roj kub thiab gases.
Kev tsim hluav taws xob:
Cov hlab ntsha siab rau cov pa thiab nuclear fais fab nroj tsuag.
Ntu ntawm chav boilers thiab lwm yam siab -kub ntim tshuab.
Cov Txheej Txheem Txheej Txheem Kev Lag Luam: Txhua daim ntawv thov yuav tsum tau them tus nqi- siv tau, yooj yim weldable alloy steel rau kev pabcuam kub feem ntau txog li 540 ° C (1000 ° F).
Hauv qhov tseem ceeb, A387 Qib 12 Chav Kawm 2 yog tus qauv kev xaiv rau kev tsim kho qhov tseem ceeb, code- ua raws li qhov siab- muaj cov khoom uas yuav tsum muaj lub zog thiab tiv thaiv kev puas tsuaj nyob rau hauv qhov chaw kub, corrosive kev pab cuam.
1. Dab tsi yog qhov kev tshaj tawm -weld heat treatment (PWHT) kub thiab tuav lub sij hawm rau A387 Gr.12 Cl.2?
Rau A387 Qib 12 Chav Kawm 2, qhov raug pom zoo Post-Weld Heat Treatment (PWHT lossis kev ntxhov siab) qhov kub thiab txias yog 1100 ° F txog 1250 ° F (595 ° C txog 675 ° C). Lub sij hawm tuav feem ntau yog tsawg kawg yog 1 teev ib nti (25 hli) ntawm tuab, nrog rau qhov tsawg kawg nkaus ntawm 1 teev tag nrho. Cov txheej txheem no yog ib qho tseem ceeb los txo cov kev ntxhov siab ntawm vuam, ua kom sov sov- thaj tsam cuam tshuam (HAZ), thiab rov ua kom muaj zog corrosion, ua kom muaj kev ncaj ncees ntawm cov khoom siv hluav taws xob siab.
2. Vim li cas qhov preheating yuav tsum tau ua ntej vuam A387 Gr.12 Cl.2 steel?
Preheating, feem ntau nyob rau hauv thaj tsam ntawm 300 ° F txog 450 ° F (150 ° C txog 230 ° C), yog qhov yuav tsum tau ua rau vuam A387 Qib 12 Chav Kawm 2 los tiv thaiv hydrogen -induced cracking (HIC), los yog txias cracking. Qhov no alloy lub hardenability yuav ua rau ib tug nkig microstructure nyob rau hauv lub weld cheeb tsam thaum txias ceev. Preheating slows tus nqi cua txias, tso cai rau hydrogen diffuse tawm thiab txo txoj kev pheej hmoo ntawm kev sib tsoo - martensite susceptible martensite, yog li ua kom lub suab, tsis xws luag - weld dawb.
3. Dab tsi yog qhov siab tshaj qhov kev pabcuam kub rau A387 Gr.12 Cl.2 daim hlau?
Qhov siab tshaj plaws tau pom zoo ua haujlwm kub kub rau ASTM A387 Qib 12 Chav Kawm 2 daim hlau feem ntau yog mus txog 1000 ° F (540 ° C). Ntawm qhov ntsuas kub siab no, cov ntsiab lus chromium muab kev tiv thaiv zoo rau oxidation (scaling) thiab corrosion, thaum molybdenum txhim kho lub zog thiab txo qis. Rau kev pabcuam saum toj no qhov kub thiab txias, qib nrog cov ntsiab lus chromium siab dua (zoo li Qib 11 lossis 22) feem ntau suav hais tias.
Tag nrho cov specification thiab cov ntsiab lus muaj nyob rau ntawm kev thov. Cov ntaub ntawv saum toj no yog muab rau kev taw qhia nkaus xwb. Rau kev tsim tshwj xeeb thov hu rau peb cov neeg ua haujlwm muag khoom.
