ASTM A252 npog dab tsi
ASTM A252 yog tus qauv Asmeskas rau welded thiab seamless steel yeeb nkab pawg. Cov yeeb nkab txuas tau raug tsav los yog tho rau hauv av kom nqa cov loads ntsug thiab tiv thaiv lub zog sab nraud, thiab lawv tau siv hauv kev tsim cov hauv paus, choj piers, wharves thiab jetties, khaws cov qauv, thiab kev ua haujlwm hauv hiav txwv. Cov yeeb nkab tuaj yeem tsav tau qhib- xaus lossis kaw- xaus, ntim nrog pob zeb tom qab tsav tsheb, lossis siv los ua lub qhov rooj rau cov dhuav pawg. Tus txheej txheem npog peb qib, Qib 1, Qib 2, thiab Qib 3, txawv los ntawm kev ua kom muaj zog, thiab nws teeb tsa cov tshuaj lom neeg, tensile, thiab qhov ntev ntawm cov khoom siv seamless thiab welded.
Kev xav tau tshuaj
ASTM A252 qhia txog cov kev cai tshuaj lom neeg feem ntau raws li qhov txwv siab tshaj plaws ntawm phosphorus thiab sulfur, uas yog cov impurities uas tseem ceeb tshaj plaws rau weldability thiab ductility hauv pawg tsav:
| Element | Qib 1, 2, 3 (max, %) |
|---|---|
| Phosphorus | 0.050 |
| Sulfur | 0.050 |
Tus qauv tsis kho cov pa roj carbon, manganese, lossis silicon txwv rau cov khoom siv hauv paus; tus neeg tsim khoom xaiv qhov muaj pes tsawg leeg kom ua tau raws li qhov xav tau ntawm kev siv tshuab. Hauv kev xyaum, cov hlau tsis tshua muaj - rau- cov pa roj carbon nruab nrab, thiab cov khoom sib xyaw yuav tsum tau lees paub ntawm daim ntawv pov thawj zeb rau cov haujlwm uas yuav tsum tau siv vuam.
Mechanical Properties
Peb qib ntawm A252 txawv nyob rau hauv lawv qhov tsawg kawg nkaus tensile thiab yield zog:
| Qib | Tsawg kawg tensile zog | Yam tsawg kawg yield zog |
|---|---|---|
| Qib 1 | 50,000 psi (345 MPa) | 30,000 psi (205 MPa) |
| Qib 2 | 60,000 psi (415 MPa) | 35,000 psi (240 MPa) |
| Qib 3 | 66,000 psi (455 MPa) | 45,000 psi (310 MPa) |
Qhov yuav tsum tau elongation yog 30% yam tsawg kawg nkaus nyob rau hauv 2 ntiv tes (50 hli) rau Qib 1, 25% rau Qib 2, thiab 20% rau Qib 3, siv rau cov qauv daim coupon nrog rau qhov tsim nyog thickness hloov. Qib yog xaiv los ntawm cov qauv tsim: Qib 1 rau cov qauv teeb thiab cov khoom nruab nrab, Qib 2 raws li qhov dav - qib piling hom phiaj, thiab Qib 3 rau cov pawg hnyav lossis ntev uas muaj zog dua txo cov phab ntsa thickness thiab kev tsav tsheb.
Kev Tsim Khoom
Cov yeeb nkab hauv qab A252 tuaj yeem tsim seamless lossis welded. Seamless piles yog tsim los ntawm kub tho thiab dov, muab cov qauv zoo ib yam tsis muaj qhov ntev seam. Welded pawg yog tsim los ntawm hluav taws xob tsis kam vuam (ERW) lossis los ntawm submerged arc vuam (SAW) rau cov kab loj. Lub weld nyob rau hauv ERW pawg yog tsim tsis muaj cov hlau muab tub lim thiab feem ntau kuaj xyuas tag nrho ntev; SAW pawg muaj qhov pom kev vuam seam uas tuaj yeem kuaj xyuas los ntawm radiography lossis ultrasonics thaum qhov project xav tau. Txoj kev tsim khoom tsis hloov cov khoom siv hauv qib, tab sis qhov zoo ntawm vuam thiab kev tsav lub zog ntawm cov yeeb nkab yuav tsum tsim nyog rau txoj kev teeb tsa.
Qhov ntau thiab tsawg
A252 yeeb nkab pawg muaj nyob rau hauv ntau qhov ntau thiab tsawg. Seamless piles feem ntau khiav los ntawm 1/4 nti mus rau 36 nti hauv txoj kab uas hla, thiab welded pawg ntawm li 8 ntiv mus rau 60 ntiv tes lossis loj dua, nrog phab ntsa thicknesses li ntawm 3 hli mus rau 50 hli nyob ntawm txoj kev. Qhov ntev yog muab rau qhov kev xav tau ntawm qhov project, feem ntau yog 6 mus rau 12 meters raws li ib daim, nrog rau tag nrho - nkag teb welds lossis mechanical splices siv mus txog qhov tob tsim. Phab ntsa thickness thiab txoj kab uas hla yog xaiv los ntawm tus qauv engineers los ntawm kev tsim load, cov av tej yam kev mob, thiab lub peev xwm ntawm pawg.
Kev tsim thiab kev txiav txim siab
Cov qauv tsim pawg yuav tsum xav txog qhov muaj peev xwm axial, khoov los ntawm kev thauj khoom tom qab, kev tsav tsheb ntawm cov phab ntsa uas xaiv, thiab kev tiv thaiv corrosion rau ib puag ncig kev pabcuam. Qhib- cov pawg kawg yog tsav nrog khau los tiv thaiv lub ntsis; kaw- cov pawg xaus yog haum nrog lub ntsiab lus tsav tsheb. Nyob rau hauv cov av corrosive los yog marine splash aav, pawg yog tiv thaiv los ntawm ib txheej, pob zeb encasement, los yog nce phab ntsa thickness, vim hais tias cov steel seem nws tus kheej yog ib tug sacrificial khoom nyob rau hauv xws li ib puag ncig. Field welding ntawm splices yuav tsum ua raws li tus txheej txheem tsim nyog, thiab cov vuam yuav tsum raug tshuaj xyuas raws li qhov yuav tsum tau ua.
Cov lus nug nquag
Q: Qhov txawv ntawm A252 Qib 1, 2, thiab 3 yog dab tsi?
Cov qib sib txawv ntawm lub zog: qhov ua tau zoo tshaj plaws yog 30 ksi (205 MPa), 35 ksi (240 MPa), thiab 45 ksi (310 MPa), thiab lub zog tensile yam tsawg kawg nkaus yog 50, 60, thiab 66 ksi feem. Cov qib siab muaj peev xwm nqa tau ntau dua ib tonne ntawm cov hlau.
Q: A252 puas tuaj yeem welded?
Yog lawm. Cov pawg tau koom ua ke los ntawm tag nrho - nkag mus rau qhov chaw welds lossis los ntawm cov khoom sib txuas. Vuam yuav tsum ua raws li tus txheej txheem tsim nyog, thiab cov hlau muaj pes tsawg leeg yuav tsum tau lees paub rau weldability.
Q: Puas yog A252 zoo ib yam li API 5L?
No. A252 yog tshwj xeeb rau cov yeeb nkab hauv kev tsim kho hauv paus. API 5L yog kab yeeb nkab rau roj thiab roj kis tau tus mob. Ib qho zoo sib xws ntawm cov yeeb nkab yuav raug tsim los rau tus qauv, tab sis cov tshuaj, kev sim, thiab cov ntawv pov thawj yuav txawv.
Q: Yuav ua li cas cov yeeb nkab pawg tsav?
Los ntawm kev cuam tshuam rauj, vibratory hammers, los yog hydraulic presses, nyob ntawm seb cov av thiab pawg loj. Qhib- cov pawg kawg yog tsav nrog khau; kaw- cov pawg xaus siv qhov chaw tsav tsheb.
Q: Qhov kev tiv thaiv corrosion yog siv rau cov yeeb nkab pawg?
Nyob rau hauv ib puag ncig corrosive pawg yog tiv thaiv los ntawm coatings, pob zeb encasement, cathodic tiv thaiv, los yog ib tug tuab phab ntsa raws li ib tug corrosion nyiaj. Qhov kev xav tau yog teem los ntawm cov av thiab dej chemistry ntawm qhov chaw.
Q: Yuav tsum kuaj dab tsi ntawm A252 yeeb nkab pawg?
Kev ntsuam xyuas tus qauv yog kuaj tensile, tshuaj ntsuam xyuas, flattening los yog khoov kuaj raws li muaj, thiab kev ntsuam xyuas hydrostatic thaum xav tau. Daim ntawv pov thawj zeb sau cov txiaj ntsig rau ntau.
