Alloy Steel Pipe yog dab tsi? Nws txawv ntawm Carbon Steel li cas?
Alloy steel yeeb nkab muaj kev xav ntxiv ntawm cov ntsiab lus alloying - chromium, molybdenum, nickel, vanadium, thiab lwm yam - los txhim kho cov khoom tshaj li cov pa roj carbon steel muaj peev xwm muab tau. Cov ntsiab lus alloying no hloov cov khoom siv microstructure thiab kev ua haujlwm zoo. Chromium (Cr) txhim kho oxidation thiab corrosion kuj los ntawm kev tsim cov txheej txheem chromium oxide ruaj khov. Molybdenum (Mo) nce siab -kub tensile thiab creep zog los ntawm cov khoom siv ntxiv zog. Vanadium (V) thiab niobium (Nb) refine grain qauv thiab muab nag lossis daus. Kev sib xyaw ua ke ntawm cov ntsiab lus no tsim cov ntaub ntawv uas tuav lub zog thiab tiv thaiv kev degradation ntawm qhov kub thiab txias qhov twg carbon steel yuav sai sai.
Qhov tseem ceeb sib txawv ntawm cov hlau alloy thiab carbon steel yog nyob rau hauv tag nrho cov ntsiab lus alloy. Cov pa roj carbon steel feem ntau tsuas muaj cov seem seem (tsawg dua 1.6% tag nrho) ntawm cov ntsiab lus tshaj carbon, manganese, silicon, thiab tswj impurities. Alloy steel txhob txwm tshaj tawm ntau dua 1% ntawm cov ntsiab lus alloying kom ua tiav cov hom phiaj tshwj xeeb. Cov ntsiab lus alloy ntxiv no ua rau cov yeeb nkab steel hlau kim dua - feem ntau 2-5x tus nqi ntawm cov pa roj carbon steel - tab sis ua kom muaj kev pabcuam nyob rau hauv cov xwm txheej uas carbon steel yuav tsis tsim nyog.
| Khoom | Cov pa roj carbon steel (A106 Gr.B) | Alloy hlau (A335 P22) |
|---|---|---|
| Max Service Kub | 538 degree | 593 degree |
| Creep Strength ntawm 550 degree | ~ 30 MPa | ~ 60 MPa |
| Oxidation Resistance | Nruab nrab (txog 500 degree) | Zoo heev (txog 650 degree) |
| Tus nqi txheeb ze | 1.0x | 2.0-3.0x |
| Weldability | Zoo heev | Yuav tsum muaj PWHT |
| Daim ntawv thov tseem ceeb | General industrial piping | Siab -temp, siab - kev pabcuam siab |
ASTM A335 Txheem Txheej txheem cej luam
ASTM A335 yog tus qauv tseem ceeb uas npog seamless ferritic alloy steel yeeb nkab rau siab -kev pabcuam kub. Tus qauv suav nrog qib P5, P9, P11, P22, P91, thiab P92, txhua tus muaj cov khoom siv tshwj xeeb thiab cov khoom yuav tsum tau ua. ASTM A335 yog siv los ntawm ASME Tshooj II Tshooj A raws li SA-335, thiab cov txiaj ntsig kev ntxhov siab tso cai muaj nyob rau hauv Tshooj II Ntu D rau txhua qib. Cov txheej txheem ASTM A213 suav nrog tib cov alloys tab sis nyob rau hauv daim ntawv raj (qhov me me) rau boiler thiab kub exchanger daim ntaub ntawv. Lub "P" ua ntej hauv A335 qhia cov yeeb nkab, thaum "T" hauv A213 qhia cov raj.
Tsawg Alloy Steel Pipe Qib
A335 P5 (5% Cr, 0.5% Mo)
P5 muaj 4.0-6.0% chromium thiab 0.45-0.65% molybdenum, muab kev tiv thaiv zoo rau siab -kub oxidation thiab sulfidation corrosion. Cov ntsiab lus siab chromium tsim muaj kev tiv thaiv oxide ruaj khov uas tiv taus qhov ntsuas kub txog 650 degree. P5 feem ntau yog siv nyob rau hauv cov ntaub ntawv refinery xws li FCC (Fluid Catalytic Cracking) units, coker heaters, thiab lwm yam high-temperature txheej txheem piping qhov twg sulfur-muaj ib puag ncig.
A335 P9 (9% Cr, 1% Mo)
P9 nce cov ntsiab lus chromium rau 8.0-10.0% nrog 0.90-1.10% molybdenum. Cov qib chromium siab dua no ntxiv txhim kho oxidation thiab corrosion kuj piv rau P5. P9 yog teev rau refinery hydrodesulfurization units, sulfur rov qab nroj tsuag, thiab high-temperature hydrocarbon kev pab cuam. Nws 9% chromium cov ntsiab lus muab nws zoo dua rau polythionic acid kev nyuaj siab corrosion cracking (PASCC) thaum lub sij hawm kaw.
A335 P11 (1.25% Cr, 0.5% Mo)
P11 yog qhov feem ntau siv qis- alloy steel qib nrog 1.00-1.50% chromium thiab 0.44-0.65% molybdenum. Nws muaj kev txhim kho qhov kub thiab txias zog tshaj carbon steel ntawm tus nqi qis tshaj. P11 yog siv nyob rau hauv fais fab nroj tsuag kub reheat piping, refinery txheej txheem piping ntawm nruab nrab kub, thiab tshuaj nroj tsuag high-temperature kab. Nws yog yooj yim weldable nrog preheat thiab PWHT.
A335 P22 (2.25% Cr, 1% Mo)
P22 yog lub chaw ua haujlwm ntawm petrochemical thiab fais fab kev lag luam. Nrog 1.90-2.60% chromium thiab 0.87-1.13% molybdenum, nws muab lub zog zoo heev ntawm qhov kub txog li 593℃. P22 feem ntau yog siv rau hauv lub tshuab hluav taws xob lub ntsiab chav thiab kub reheat piping, refinery hydrocracker units, thiab high-pressure steam systems. Nws kev sib xyaw ua ke ntawm lub zog, kev tiv thaiv corrosion, thiab tus nqi nruab nrab ua rau nws xaiv qhov kev xaiv rau ntau qhov kev siv kub kub ua ntej tsiv mus rau qib 9Cr kim dua.
High Alloy Steel Pipe Qib - P91 & P92
A335 P91 (9% Cr, 1% Mo, V, Nb)
P91 yog hloov kho 9Cr{10}}1Mo steel nrog tswj kev ntxiv ntawm vanadium (0.18-0.25%) thiab niobium (0.06-0.10%). Cov ntsiab lus no tsim tau zoo precipitates uas dramatically txhim kho creep zog. P91 muaj kwv yees li peb npaug ntawm qhov creep rupture lub zog ntawm P22 ntawm 600 degree, tso cai rau cov phab ntsa nyias thiab txo qhov hnyav hauv cov kav dej kub. P91 xav tau kev kho cua sov kom raug (normalizing ntawm 1040-1080℃tom qab tempering ntawm 730-780 degree) los tsim nws qhov zoo tshaj plaws tempered martensite microstructure.
A335 P92 (9% Cr, 0.5% Mo, W, V)
P92 yog ib qho kev hloov pauv ntawm P91, qhov twg tungsten (1.5-2.0%) hloov pauv molybdenum ib nrab los txhim kho kev nkag siab ntxiv. P92 muaj kwv yees li 15-20% siab dua creep rupture zog tshaj P91 ntawm 600 degree, ua rau nws haum rau qhov siab tshaj plaws - qhov kub thiab txias ntawm ultra-supercritical fais fab nroj tsuag. Txawm li cas los xij, P92 yog qhov nyuaj dua rau vuam thiab yuav tsum tau nruj dua kev tswj hwm ntawm kev kho cua sov. Qhov siab tshaj plaws ua haujlwm kub rau P92 yog kwv yees li 620℃rau kev pabcuam mus sij hawm ntev.
| Khoom | P11 | P22 | P91 | P92 |
|---|---|---|---|---|
| Cr (%) | 1.00-1.50 | 1.90-2.60 | 8.00-9.50 | 8.50-9.50 |
| Mo (%) | 0.44-0.65 | 0.87-1.13 | 0.85-1.05 | 0.30-0.60 |
| Tsawg-yield (MPa) | 205 | 205 | 415 | 440 |
| UTS (MPa) | 415 | 415 | 585 | 620 |
| Max kub (degree) | 593 | 593 | 649 | 649 |
| Creep zog (600 degree) | Tsawg | Nruab nrab | Siab | Siab heev |
| Tus nqi txheeb ze | 1.5x CS | 2.0 x CS | 3, 5x cs | 4, 0x tzs |
Alloy Steel Pipe Applications
Roj refining thiab petrochemical cov nroj tsuag yog cov neeg siv khoom loj ntawm cov yeeb nkab steel hlau. FCC units siv P5 thiab P9 rau reactor thiab regenerator piping qhov siab -kub sulfur corrosion hnyav heev. Hydrocracking units siv P22 thiab P91 rau reactor effluent piping khiav hauj lwm ntawm 400{14}}450℃thiab 150-200 bar. Cov chav tsev coking siv P5 thiab P9 rau cov kav dej kub thiab hloov cov kab ua haujlwm siab tshaj 500 degree. Ultra-supercritical fais fab nroj tsuag siv P91 thiab P92 rau cov kav dej loj ua haujlwm ntawm 600-620℃thiab 250-300 bar. Rau cov ncauj lus kom ntxaws daim ntawv thov kev lag luam fais fab, saib pebFais fab Plant Pipe Guide.
Kev kho cua sov ntawm Alloy Steel Yeeb Nkab
Tag nrho cov yeeb nkab steel hlau yuav tsum tau kho cua sov los tsim cov khoom siv kho tshuab. Tsawg- cov qib alloy (P5, P9, P11, P22) feem ntau yog qhov qub ntawm 900-980℃tom qab tempering ntawm 650-750℃. Cov kauj ruam normalizing refines lub grain qauv, thaum tempering muab qhov yuav tsum tau hardness thiab toughness. P91 thiab P92 yuav tsum tau tswj kom meej meej: normalize ntawm 1040-1080℃(sab saum toj ntawm Ac3 kub kom siab austenitize), ua raws li tempering ntawm 730-780 degree. Qhov txias txias tom qab tempering kuj tseem ceeb heev kom tsis txhob rov tawv dua. PWHT (Post-Weld Thaum tshav kub kub kho) yog yuav tsum tau rau tag nrho cov alloy steel yeeb nkab welds, feem ntau ntawm 680-760℃rau 1 teev ib 25 hli thickness. Saib pebPhau Ntawv Qhia Txog Kev Kho Hniav Kub(51) rau cov ncauj lus kom ntxaws.
Welding Considerations rau Alloy Steel
Vuam alloy steel yeeb nkab yuav tsum tau ceev faj rau preheat, interpass kub, thiab PWHT. P11 yuav tsum tau preheat ntawm 150-200 degree, thaum P22 yuav tsum tau 200{11}}300℃. P91 vuam yog tshwj xeeb tshaj yog xav tau: preheat ntawm 200{13}}250 degree, nruj interpass kub tswj (max 300 degree), thiab tam sim ntawd PWHT tom qab vuam. Kev siv qis-hydrogen vuam electrodes thiab cov khoom siv hluav taws xob kom zoo yog qhov tseem ceeb rau txhua qhov kev sib txuas steel hlau los tiv thaiv hydrogen{15}}induced txias cracking. Qhov sib txawv ntawm cov hlau welds ntawm qis-alloy thiab high-alloy steels yuav tsum tau ceev faj muab cov hlau xaiv thiab tom qab-weld kho cua sov tsis ua kom haum rau ob qho tib si.
International Standards Cross -Reference
ASTM A335 P11 yog sib npaug rau EN 10216-2 13CrMo4-5 (1.7335), JIS G3458 STPA23, thiab GB/T 5310 15CrMoG. P22 yog sib npaug rau EN 10216-2 10CrMo9-10 (1.7380), JIS G3458 STPA24, thiab GB/T 5310 12Cr2MoG. P91 yog sib npaug rau EN 10216-2 X10CrMoVNb9-1 (1.4903), JIS G3458 STPA27, thiab GB/T 5310 10Cr9Mo1VNb. Saib pebPipe Standards Comparisonkom tiav cov ntawv hla -cov ntaub ntawv.
Yuav Ua Li Cas Tau Txais Alloy Steel Pipe
Thaum xaj alloy steel yeeb nkab, muab cov hauv qab no: tus qauv thiab qib (xws li ASTM A335 P91), qhov loj thiab lub sijhawm (piv txwv li, 12 "SCH 80), tus me nyuam tus mob (normalized thiab tempered), thiab tej yam tshwj xeeb uas yuav tsum tau. Alloy steel yeeb nkab yuav tsum tau muab nrog ua tiav MTC qhia tshuaj ntsuam xyuas, txhua yam khoom, thiab cov ntsiab lus kho kub. nrog rau kev kho cua sov tag nrho thiab muaj peev xwm NDT, thiab tuaj yeem npaj thib peb -kev tshuaj xyuas tog rau kev txheeb xyuas qhov zoo.
