API 5L X70 hauv Kab Yeeb Tsev Neeg
X70 yog qib siab -strength kab yeeb nkab qib tau teev tseg hauv API Specification 5L. Tus lej yog hais txog qhov tsawg kawg nkaus yield zog ntawm 70 000 psi, uas yog sib npaug rau 485 MPa. Nws zaum saum X65 thiab qis dua X80 hauv cov qib tsis tu ncua thiab yog qib ua haujlwm ntev - nrug, siab - cov kav xa hluav taws xob siab, qhov twg qib siab zog tso cai rau phab ntsa nyias thiab qis dua tag nrho cov tonnage ntawm cov hlau rau tib lub siab ntim.
API 5L lees paub ob qib khoom tshwj xeeb. PSL1 muab cov txheej txheem tshuaj lom neeg thiab cov khoom siv kho tshuab, thaum PSL2 ntxiv cov tshuaj txwv tsis pub siv, cov pa roj carbon sib npaug sib npaug, yuav tsum tau kuaj xyuas qhov cuam tshuam charpy thiab ntau yam tsis yog- kev kuaj xyuas puas tsuaj. Feem ntau X70 cov khoom siv rau kev sib kis tau raug txiav txim rau PSL2.
Chemical Composition Requirements
Cov lus hauv qab no muab API 5L PSL2 txwv rau lub hauv paus hlau ntawm qib X42 txog X70. Thaum tshav kub kub tsom xam qhov tseem ceeb yuav tsum tsis txhob tshaj cov duab no.
| Element | Seamless yeeb nkab, max | Welded yeeb nkab, max | Kev ua haujlwm hauv steel |
| Cov pa roj carbon (C) | 0.24 % | 0.22 % | Lub ntsiab ntxiv dag zog; nce hardness thiab txo weldability thaum nws nce |
| Manganese (Mn) | 1.40 % | 1.45 % | Nce lub zog thiab toughness thiab offsets cov nyhuv ntawm sulfur |
| Phosphorus (P) | 0.025 % | 0.025 % | impurity; embrits cov hlau thiab txo qis weldability |
| Sulfur (S) | 0.015 % | 0.015 % | impurity; Cov ntaub ntawv suav nrog uas txo qhov toughness thiab ductility |
| Niobium + Vanadium + Titanium | 0.15% tag nrho | 0.15% tag nrho | Micro-kev sib xyaw ua ke uas ua kom cov nplej loj thiab ua kom muaj zog |
Silicon feem ntau tshwm sim ntawm 0.10-0.35% raws li deoxidation thiab ntxiv dag zog ntxiv. Kev tswj hwm cov pa roj carbon sib npaug kuj tseem xav tau rau cov qib no, uas ua rau cov hlau ua haujlwm -weldable yam tsis muaj preheat nyob rau hauv feem ntau. Ib tug raug X70 kab yeeb nkab ntsuas cua sov yog li tuav cov manganese ntawm lossis qis dua tus qauv txwv es tsis yog nyob rau sab saum toj ntawm ntau lub zeb ntau, thiab ua rau cov sulfur qis los ntawm kev kho cov ladle kom suav nrog cov duab thiab lub zog nyob rau hauv kev tswj.
Mechanical Properties
| Khoom | PSL2 yeeb nkab lub cev yuav tsum tau |
| Yield zog, Rt0.5 | 485-635 MPa |
| Tensile zog, Rm | 570-760 MPa |
| Yield rau tensile ratio | Saib qhov siv tau API 5L clause rau qhov teev loj thiab qib |
| Elongation | Tau txais los ntawm API 5L cov qauv siv lub zog tensile uas tau teev tseg |
| Charpy impact, PSL2 | Yuav tsum tau; absorbed zog thiab ntsuas kub tau pom zoo hauv kev yuav khoom specification |
Welded yeeb nkab kuj muaj qhov tsawg kawg nkaus tensile lub zog yuav tsum tau rau ntawm weld seam. Vim hais tias cov qhab nia yog nqaim, X70 feem ntau yog tsim los ntawm cov thermo-txheej txheem tswj dov nrog ceev cua txias es tsis yog los ntawm cov pa kub dov, thiab cov khoom xa tuaj tau teev rau ntawm daim ntawv pov thawj zeb.
Daim ntawv thov Pipeline
Ntev - kis tau tus mob ntawm cov roj ntuj, roj av thiab cov khoom ua kom zoo.
Siab -kev sib sau ua ke thiab cov kab hauv lub cev uas txo cov phab ntsa thickness txo cov khoom siv thiab cov nqi vuam.
Offshore thiab subsea flowlines, qhov twg qhov hnyav txuag ntawm lub nkoj thauj khoom yog qhov txiav txim siab.
Lub nroog gas mains thiab loj - txoj kab uas hla dej conveyance qhov siab ntsuas siab.
Welding thiab Inspection Notes
X70 yog yooj yim girth welded nrog cellulosic los yog qis - hydrogen electrodes thiab nrog mechanized gas hlau arc txheej txheem, muab cov pa sib npaug yog tswj thiab cov consumables phim lub zog yeeb nkab. Preheat thiab interpass kub txwv yuav tsum tau kho nyob rau hauv lub vuam txheej txheem tsim nyog, thiab lub tshav kub input range yuav tsum tau hwm yog li lub coarse grained tshav kub cuam tshuam cheeb tsam khaws nws toughness. Kab yeeb nkab rau kev pabcuam qaub hu rau kev txwv hardness ntxiv rau ntawm qhov chaw vuam thiab tshav kub. Kev tshuaj ntsuam xyuas muaj xws li kuaj ultrasonic ntawm longitudinal thiab kauv weld, radiography ntawm girth welds, seem checks, thiab hydrostatic kuaj ntawm lub zeb.
FAQ
Q: X70 txhais li cas hauv API 5L?
X70 xaiv ib qib uas nws tau teev tseg tsawg kawg nkaus lub zog yog 70 000 psi, los yog 485 MPa. Nws yog siab -lub zog micro- alloyed kab yeeb nkab qib siv tsuas yog rau siab - siab roj thiab roj kis.
Q: PSL2 tshuaj txwv rau X70 yog dab tsi?
Carbon 0.22% siab tshaj plaws rau welded yeeb nkab thiab 0.24% siab tshaj plaws rau seamless, manganese 1.45% thiab 1.40% siab tshaj plaws feem, phosphorus 0.025% siab tshaj plaws, sulfur 0.015% siab tshaj, thiab niobium ntxiv vanadium ntxiv titanium% 0.15.
Q: Dab tsi yog qhov kev tawm dag zog ntawm X70?
Rau PSL2 yeeb nkab lub cev, 485 MPa rau 635 MPa, nrog lub zog tensile sib xws ntawm 570 MPa rau 760 MPa.
Q: Puas yog X70 weldable hauv thaj teb?
Yog lawm, yog tias cov pa roj carbon sib npaug yog tswj tau, cov txheej txheem tsim nyog tau siv thiab tswj cov khoom cua sov. Tsawg-hydrogen xyaum thiab tswj preheat yog ib txwm rau girth welds nyob rau hauv phab ntsa thicknesses siab tshaj 12 hli.
Q: Vim li cas micro- alloying siv hauv X70 steel?
Niobium, vanadium thiab titanium nyob rau hauv me me ntxiv rau carbonitrides uas pin lis ciam teb thaum dov, yog li cov hlau mus txog ib tug siab yield zog thaum khaws cov zoo grain loj xav tau rau toughness.
Q: Qhov kev xa khoom zoo li cas rau X70 yeeb nkab?
Thermo- cov khoom siv kho tshuab tswj tau ua tiav yog txoj hauv kev ib txwm muaj, qee zaum nrog kev ua kom txias. Cov xwm txheej raug kaw rau ntawm daim ntawv pov thawj tshuaj xyuas ua ke nrog tus lej xov tooj cua sov thiab cov txiaj ntsig ntawm kev ntsuas tshuab.
