1. Nqe Lus Nug: Rau API 5L X52 PSL2 kab yeeb nkab daim ntawv thov, qhov tshwj xeeb vuam kev kho cua sov feem ntau yuav tsum tau, thiab nws cuam tshuam li cas rau microstructure thiab mechanical zog ntawm Heat Affected Zone (HAZ)?
Teb:
Rau API 5L X52 PSL2 ERW cov kav dej, cov txheej txheem tsim khoom yuav tsum muaj qhov chaw vuam kom tau txais kev tshaj tawm -weld heat treatment, tshwj xeebnormalizing. Qhov no tsis yog kev ntxhov siab xwb; Nws yog cov txheej txheem kev kho cua sov tag nrho qhov twg thaj tsam weld yog rhuab mus rau qhov kub siab tshaj qhov tseem ceeb tshaj plaws (feem ntau nyob ib ncig ntawm 900℃txog 980 degree) thiab tom qab ntawd tso cai rau cua txias -6.
Lub hom phiaj tseem ceeb ntawm qhov kev kho kom zoo no yog txhawm rau txhim kho cov qauv nplej hauv cov vuam seam thiab Heat Affected Zone (HAZ). Thaum lub sij hawm siab - cov txheej txheem vuam zaus, cov cua kub ceev thiab cua txias tuaj yeem tsim cov nkig, tawv microstructure (xws li martensite) thiab cov qauv cam khwb cia uas txawv ntawm cov niam txiv hlau cov qauv wrought. Normalizing hloov qhov microstructure no mus rau hauv ib qho sib tov sib xyaw ntawm ferrite thiab pearlite, uas zoo sib xws rau cov hlau puag ntawm X52 qib -1-4. Qhov no ua kom cov weld seam cov khoom siv kho tshuab- xws li lub zog tawm los (tsawg kawg 52,000 psi / 360 MPa), lub zog tensile, thiab ductility-zoo tib yam rau cov yeeb nkab lub cev. Nws tshem tawm qhov "tsis muaj zog taw tes" ib txwm cuam tshuam nrog cov vuam, tso cai rau cov yeeb nkab ua kom ntseeg tau raws li qhov nruab nrab-siab qhov xwm txheej rau X52 cov kav dej, xws li cov kav dej hauv nroog thiab cov chaw ua kom zoo-4-6.
2. Nqe Lus Nug: Thaum muab ERW cov kav dej hauv cov qib carbon steel xws li Q235 lossis Q345 rau kev siv cov qauv, qhov sib txawv tseem ceeb ntawm cov khoom siv tshuab thiab qhov kawg yog dab tsi - siv piv rau qib siab dua - cov khoom siv qib zoo li API 5L X70?
Teb:
Qhov sib txawv ntawm cov qib zoo liQ235 (ASTM A36 sib npaug) , Q345 (ASTM A572 Qib 50 sib npaug), thiabAPI 5L X70nyob rau hauv lawv lub zog yield, toughness, thiab npaj daim ntawv thov, uas dictates lub manufacturing thiab xeem raws tu qauv.
Q235 thiab Q345 (Suav GB / T Standards):Cov no yog cov txheej txheem steels. Q235 muaj qhov tsawg kawg nkaus tawm lub zog ntawm 235 MPa thiab siv rau lub hom phiaj dav dav, qis- kev siv kev ntxhov siab xws li laj kab, scaffolding, thiab cov kav dej uas tsim tau thiab weldability yog qhov tseem ceeb -1-9. Q345 muaj lub zog tawm los ntau dua (nyob ib puag ncig 345 MPa) thiab zoo dua qis- qhov kub thiab txias, ua rau nws tsim nyog rau lub tsev thav duab, kev txhawb nqa choj, thiab cov khoom siv tshuab. Kev ntsuam xyuas feem ntau suav nrog kev sib tw, kev sib tw, thiab kev sim hydrostatic, tab sis kev sim tsis muaj kev puas tsuaj (NDT) yuav tsis yog 100% yuav tsum tau ua ntawm cov vuam seam rau kev siv cov qauv tsis tseem ceeb -3-8.
API 5L X70 (American Petroleum Institute):Qhov no yog lub siab - lub zog steel rau kev siv lub zog tseem ceeb. Nrog rau qhov tsawg kawg nkaus tawm lub zog ntawm 70,000 psi (kwv yees li 483 MPa), nws yog tsim los rau siab -siab, ntev - kis tau tus mob ntawm cov roj thiab cov nkev roj -6. Cov txheej txheem tsim khoom rau X70 suav nrog kev tswj hwm nruj ntawm chemistry (cov ntsiab lus carbon tsawg heev thiab micro-alloys zoo li Niobium lossis Vanadium) thiab Thermo-Mechanical Controlled Processing (TMCP). Tsis tas li ntawd, API 5L PSL2 cov lus qhia tshwj xeeb rau X70 txoj cai txwv nruj ntawm cov pa sib npaug (kom tiv thaiv kev tawg) thiab yuav tsum tau 100% ultrasonic tshuaj xyuas ntawm weld seam -6-10. Tsis zoo li Q235 lossis Q345, X70 yog engineered rau pob txha toughness los tiv thaiv brittle fracture nyob rau hauv xav tau ib puag ncig, tab sis nws yog feem ntau tsis pom zoo rau qaub (H₂S) kev pab cuam yam tsis muaj kev ntsuam xyuas ntxiv -6.
3. Nqe Lus Nug: Rau ERW cov kav dej uas tsim los raws li ASTM A53 Qib B, dab tsi yog qhov tseem ceeb ntawm kev kuaj tsis muaj kev puas tsuaj (NDT) txoj kev siv los kuaj xyuas cov khoom tsis zoo xws li nuv kab nrib pleb lossis tsis muaj fusion, thiab vim li cas lawv tsim nyog?
Teb:
ASTM A53 Qib B ERW kav, siv dav hauv kev siv tshuab thiab kev siv siab, yuav tsum tau kuaj xyuas tshwj xeeb kom tsis txhob muaj kev puas tsuaj rau kev sib tsoo. Cov txheej txheem tseem ceeb yogEddy Current Testing (ET)thiabKev kuaj ultrasonic (UT) -3-8.
Cov txheej txheem no yog qhov tsim nyog vim tias cov khoom siv -theem vuam txheej txheem siv hauv ERW tuaj yeem tsim cov teeb meem tsis xws luag uas nyuaj rau kev kuaj pom ntawm qhov muag liab qab lossis kuaj hydrostatic ib leeg.
Kev Tshawb Nrhiav Tsis Muaj Fusion (LOF):Yog hais tias qhov vuam tsis sib xws (kub los yog siab) poob rau sab nraud txwv, qhov kev sib txuas ntawm vuam yuav ua tsis raug. UT, tshwj xeeb tshaj yog Phased Array Ultrasonic Testing (PAUT), muaj txiaj ntsig zoo ntawm kev kuaj xyuas LOF qhov tsis xws luag los ntawm kev xa cov suab nthwv dej los ntawm qhov vuam thiab tshuaj xyuas qhov kev xav -5-10.
Kev txheeb xyuas ntawm Hook Cracks:Cov no yog cov kab nrib pleb uas tshwm sim hauv Heat Afected Zone (HAZ) vim qhov elongation ntawm non{0}}hlau inclusions thaum lub sij hawm tsim txheej txheem -2-7. High-frequency eddy tam sim no lossis tshwj xeeb UT probes tuaj yeem ntes cov kev tsis sib haum xeeb ntawm cov kab txuas.
Kev tshuaj xyuas niaj hnub no feem ntau siv cov khoom siv vuam vuam nrog PA sojntsuam los tshuaj xyuas ob qho tib si vuam thiab HAZ. Qhov no ua kom ntseeg tau tias txawm tias qhov tsis xws luag xws li laminations txiav tawm ntawm qhov vuam (uas tsim cov qhov tsis zoo geometries) raug kuaj pom, ua kom cov yeeb nkab ua tau raws li cov cai yuav tsum tau ua rau cov kev pabcuam xws li dej, chav dej, lossis cov kab cua mus txog qhov txwv tau teev tseg los ntawm ASME B31.1 lossis B31.3 -4-2.
4. Nqe Lus Nug: Puas tuaj yeem ERW cov yeeb nkab hauv qib S355J2H (EN 10219) ncaj qha hloov cov yeeb nkab seamless hauv qhov txias txias - tsim cov qauv siv, thiab qhov kev txiav txim siab dab tsi txog qhov vuam seam yuav tsum tau hais txog?
Teb:
Yog, ERW yeeb nkab hauv qibS355J2HFeem ntau tuaj yeem hloov cov yeeb nkab seamless hauv kev siv cov qauv, muab cov qauv tsim nyiaj rau lub xub ntiag ntawm cov vuam seam. S355J2H yog ib qho zoo -cov khoom ua haujlwm hollow seem teev nyob rau hauv EN 10219 rau txias-tsim welded seem -8.
Kev txiav txim siab rau Kev Hloov:
Weld Seam Zoo:Niaj hnub nimno ERW mills tsim ib tug weld seam uas muaj zog raws li lub hauv paus hlau vim normalizing kev kho cua sov. Txawm li cas los xij, lub npe "J2H" qhia tau hais tias cov khoom tau lees tias muaj kev cuam tshuam toughness ntawm -20 degree. Nws yog ib qho tseem ceeb uas lub weld seam kuj ua tau raws li qhov yuav tsum tau muaj qhov toughness. Tus neeg muag khoom yuav tsum muab daim ntawv pov thawj zeb xeem (EN 10204 3.1) ua pov thawj tias cov qauv welded tau dhau los ntawm Charpy impact tests -3-8.
Kev sib sau thiab Vuam:Tsis zoo li cov kav dej seamless, uas yog extruded los ntawm cov khoom siv hluav taws xob, ERW cov kav dej yog tsim los ntawm lub kauj thiab welded. Rau cov txheej txheem thav duab lossis cov khoom siv tsheb, qhov txias formability ntawm lub hauv paus hlau yog zoo heev, tab sis qhov weld cheeb tsam yuav tsis ductile dua cov niam txiv hlau yog tias tsis zoo cua sov- kho. Nyob rau hauv daim ntawv thov yuav tsum tau tseem ceeb txias dabtsi yog khoovtom qabcov yeeb nkab ntau lawm, khoov yuav tsum tau taw qhia kom deb ntawm qhov vuam seam (feem ntau yog 45 txog 90 degrees los ntawm qhov vuam) kom tiv thaiv vuam tawg -9.
Dimensional Tolerances:ERW cov kav dej feem ntau muaj cov phab ntsa tuab tuab dua thiab zoo dua concentricity dua li cov kav dej kub - tiav seamless kav. Qhov no tuaj yeem ua rau muaj txiaj ntsig zoo rau kev siv tshuab ua kom zoo, txo cov khoom hnyav thiab ua kom muaj kev sib haum xeeb - nce hauv cov qauv lattice -4.
5. Nqe Lus Nug: Dab tsi yog qhov kev txwv ntawm kev siv tus qauv API 5L Gr.B ERW yeeb nkab nyob rau hauv "kev pabcuam qaub" ib puag ncig uas muaj H₂S, thiab qhov kev hloov kho rau qib thiab kev xeem yuav tsum ua kom haum?
Teb:
TxujAPI 5L Qib BERW kav dej feem ntautsis pom zoorau kev pabcuam qaub (ntub H₂S ib puag ncig) tsis muaj kev hloov pauv tseem ceeb. Lub xub ntiag ntawm H₂S tuaj yeem ua rau Sulfide Stress Cracking (SSC) lossis Hydrogen Induced Cracking (HIC), tshwj xeeb tshaj yog nyob rau hauv cov txheej txheem nyuaj uas pom nyob rau hauv weld seam thiab HAZ ntawm cov kav dej txheem qib -6.
Txhawm rau ua kom lub ERW yeeb nkab haum rau kev pabcuam qaub, cov kev hloov kho hauv qab no yuav tsum tau ua raws li qib hauv qab thiab cov txheej txheem kev xeem:
Chemistry Control:Cov hlau yuav tsum muaj cov ntsiab lus tsawg heev ntawm impurities, tshwj xeeb:
Sulfur (S):Feem ntau txwv rau<0.002% or even <0.001%. Low sulfur reduces the number of manganese sulfide inclusions, which are initiation sites for HIC.
Phosphorus (P):Yuav tsum tau tswj nruj heev.
Carbon sib npaug (CE):Yuav tsum tau khaws cia kom tsawg heev kom ntseeg tau tias tsis muaj hardness thiab weldability zoo, tiv thaiv kev tsim ntawm tawg -sensitive martensitic zones -6.
Hardness Test (HV10):Sour cov kev pabcuam tshwj xeeb (xws li API 5L PSL2 nrog Annex H) txwv qhov siab tshaj plaws ntawm cov yeeb nkab lub cev, vuam seam, thiab HAZ (feem ntau yog qhov siab tshaj ntawm 250 HV lossis 22 HRC). Standard Gr.B tsis muaj cov kev txwv no. Micro-hardness mapping thoob plaws qhov vuam yuav tsum tau ua kom tsis muaj qhov nyuaj nyob -2-6.
Kev xeem HIC/SSC:Tshaj li tus qauv NDT, cov yeeb nkab yuav tsum dhau qhov kev kuaj sim tshwj xeeb uas cov qauv ntim rau hauv cov tshuaj saturated nrog H₂S thiab tshuaj xyuas kom tawg tom qab lub sijhawm teem tseg. Qhov no txheeb xyuas cov khoom tiv thaiv rau hydrogen-induced blistering thiab stepwise cracking -6.
Yog tias cov xwm txheej no tau ua tiav, kev hloov kho "Sour Service" Qib B ERW yeeb nkab tuaj yeem siv tau, tab sis feem ntau cov neeg tsim qauv yuav dhia mus rau qib siab dua xws li L245NS lossis L290NS (nrog rau 'NS' denoting qaub kev pab cuam) los yog qhia cov kav dej seamless kom tsis txhob muaj kev pheej hmoo cuam tshuam nrog welded seam nyob rau hauv ib qho tseem ceeb qaub-6.
