Dab tsi yog qhov zoo ntawm kev xaiv A387 Qib 12 Chav Kawm 1 tshaj carbon steel?
Qhov zoo ntawm kev xaiv A387 Qib 12 Chav Kawm 1 tshaj cov pa roj carbon steel yog khi rau nws cov ntsiab lus alloy, uas muab kev ua tau zoo hauv kev ua haujlwm siab kub thaum tseem tshuav tus nqi - txhim kho zoo.
Cov txiaj ntsig tseem ceeb ntawm A387 Qib 12 Chav Kawm 1:
Siab zog ntawm qhov kub siab
Qhov Tseem Ceeb Tseem Ceeb: Cov pa roj carbon steel poob lub zog sai dua li ~ 370℃(700℃F). Qib 12, nrog nws cov 1% Chromium thiab 0.5% Molybdenum, tswj cov tensile ntau dua thiab tawm lub zog ntawm qhov kub txog li 425-480℃(800-900℃F), raws li tau pom nyob rau hauv cov txiaj ntsig kev ntxhov siab siab dua hauv ASME cov lej tsim.
Txhim kho Oxidation & Scale Resistance
Cov ntsiab lus chromium tsim kom ruaj khov, tiv thaiv oxide txheej ntawm cov hlau saum npoo, txo tus nqi ntawm cov nplai thiab cov hlau poob hauv chav, cov pa roj, lossis cov txheej txheem oxidizing qhov chaw siab tshaj 400℃(750℃F). Qhov no txuas ntxiv lub neej tivthaiv piv rau carbon steel.
Txhim khu kev tiv thaiv rau Hydrogen Attack
Txawm hais tias tsis tsim nyog rau kev pabcuam hydrogen hnyav (tsis zoo li Qib 11 lossis 22), cov ntsiab lus molybdenum muab qee qhov kev tiv thaiv rau siab -kub hydrogen nres ntawm qhov kub thiab txias, ua rau nws siv tau rau qee cov ntawv thov ua kom zoo dua qhov twg carbon steel yuav raug txwv raws li API 941 Nelson Curve.
Zoo dua Microstructural Stability
Ntawm qhov kub thiab txias, carbon steel lub microstructure tuaj yeem degrade (graphitization, spheroidization), ua rau embrittlement. Cov ntsiab lus alloying hauv Qib 12 pab kom ruaj khov microstructure, txhim kho lub sijhawm ntev - kev ntseeg siab.
Tus nqi -Kev ua tau zoo rau Kev Pabcuam Nruab Nrab
Nws muaj qhov muaj txiaj ntsig kev ua tau zoo dua cov pa roj carbon steel ntawm tus nqi qis dua li cov alloys siab dua li Qib 11 lossis 22. Qhov no ua rau nws xaiv kev lag luam zoo rau kev ua haujlwm nruab nrab.
Cov lus sib piv: Cov Ntsiab Lus Sib Txawv
| Yam | Carbon Steel (xws li SA-516 Gr.70) | A387 Qib 12 Chav Kawm 1 |
|---|---|---|
| Kev txwv tsis pub siv (Temp.) | Mus txog ~ 370℃(700℃F) | Mus txog ~ 480℃(900℃F) |
| Oxidation Resistance | Tsis zoo tshaj 400 degree | Zoo mus txog ~ 540℃(1000℃F) |
| Kev Pabcuam Hydrogen | Feem ntau tsis tso cai nyob rau hauv siab -temp hydrogen. | Tso cai rau cov mob me me (hauv thaj tsam tshwj xeeb ntawm Nelson Curve). |
| Tso cai Stress (ASME) | Poob sharply nrog kub. | Tseem nyob siab dua ntawm qhov kub siab. |
| Nqi | qis tshaj. | Nruab nrab (siab dua carbon steel, qis dua Cr-Mo qib). |
Thaum twg los ua qhov kev xaiv no:
Xaiv A387 Qib 12 Chav Kawm 1 thaum:
Tus qauv tsim kev khiav hauj lwm kub siab tshaj qhov txwv tsis pub siv cov pa roj carbon steel (ib ASME Sec. I lossis Sec. VIII).
Ib puag ncig cuam tshuam nrog ncu, flue roj, lossis me me oxidizing / corrosive tej yam kev mob siab tshaj 400 degree.
Cov txheej txheem cuam tshuam nrog qis mus rau nruab nrab ib feem ntawm qhov siab ntawm hydrogen ntawm qhov kub siab, thiab nws ntog nyob rau hauv qhov chaw txais tau rau Qib 12 ntawm Nelson Chart.
Tus nqi optimizationyog ib qho tseem ceeb, thiab cov kev pab cuam tsis raug cai rau cov nqi ntawm Qib 11 (1.25Cr-0.5Mo).
Kev txiav txim siab tseem ceeb:
Cov xwm txheej 1 txhais tau hais tias lub phaj tau muab tso rau hauv ib txwm muaj thiab yuav tsum muaj qhov kawg Post-Weld Heat Treatment (PWHT) tom qab kev tsim khoom-ib kauj ruam tsim nyog kom ua tiav cov khoom zoo uas tau teev tseg saum toj no. Qhov no ntxiv cov txheej txheem tsim piv rau qee cov pa roj carbon steel, uas tsuas yog xav tau kev ntxhov siab lossis tsis muaj PWHT.
Hauv cov ntsiab lus, A387 Qib 12 Chav Kawm 1 yog cov khoom nyiam tshaj cov pa roj carbon steel thaum cov khoom siv ua haujlwm ntawm qhov kub siab uas cov hlau tsis muaj zog thiab oxidation tsis txaus, tab sis cov kev pabcuam tsis loj txaus kom xav tau chromium kim dua - molybdenum alloys.
1. Dab tsi yog qhov zoo ntawm kev xaiv A387 Qib 12 Chav Kawm 1 tshaj carbon steel rau lub nkoj siab?
Cov lus nug no tsom mus rau kev lag luam thiab kev ua tau zoo rau kev kho dua tshiab los ntawm cov pa roj carbon steel, feem ntau rau cov kev pabcuam kub nruab nrab uas Qib 12 muaj kev txhim kho lub zog thiab oxidation tsis kam ntawm tus nqi tsim nyog.
2. Vim li cas ib tug engineer yuav qhia Qib 12 es tsis yog qib 11 ntau dua?
Lo lus nug no tshawb txog kev lag luam tawm - tawm ntawm kev ua haujlwm ntawm cov khoom siv thiab cov phiaj xwm kev lag luam, raws li Qib 12 muaj tus nqi -txuag kev xaiv thaum cov kev pab cuam nyob rau hauv nws qhov kev txwv siab dua - kub thiab corrosion kuj muaj peev xwm.
3. Dab tsi yog qhov siab tshaj - qhov ntsuas kub ntawm A387 Qib 12 piv rau Qib 11 yog dab tsi?
Cov lus nug no hais txog cov kev ciam teb ntawm cov hlau, tsom rau nws cov ntsiab lus chromium thiab molybdenum uas ua rau txo qis oxidation tsis kam, creep zog, thiab hydrogen nres tsis kam ntawm qhov kub siab.
4. Txoj kev kho cua sov thiab vuam txheej txheem rau Qib 12 Chav Kawm 1 piv rau cov hlau li cas?
Lo lus nug no qhia txog qhov kev cuam tshuam ntawm kev siv cov hlau tsis tshua muaj- alloy steel, sau tseg tias thaum zoo li cov pa roj carbon steel, nws feem ntau yuav tsum nruj dua preheat, tswj kom txias, thiab yuav tsum tau Post-Weld Heat Treatment (PWHT) kom ua tiav cov khoom zoo.
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.
