1. Lo lus nug: Rau daim ntawv thov welded yeeb nkab uas yuav tsum tau zoo heev corrosion kuj ntxiv rau lub zog siab, uas ntawm peb qib, Q390, Q420, los yog Q460, yuav yog tus nqi ntau tshaj - pib taw tes zoo?
Teb: Tsis muaj ib qho ntawm cov qib hauv qab no muaj qhov "stainless" qib corrosion kuj. Lawv cov corrosion kuj zoo ib yam li cov pa roj carbon steel thiab tso siab rau kev tsim cov patina tiv thaiv. Txawm li cas los xij, txhawm rau txhim kho kev tiv thaiv corrosion, lawv tuaj yeem siv rau hauv "tej huab cua" tsim (feem ntau nrog ntxiv Cu, P, Cr, thiab Ni). Pib los ntawm lub zog qis dua li Q390 yuav raug nqi ntau dua - siv tau, raws li cov nyiaj siv rau kev tiv thaiv corrosion tuaj yeem ntxiv yam tsis pub tshaj tus nqi siab heev - lub zog zoo li Q460. Yog tias muaj zog thiab siab corrosion kuj yog ob qho tib si yuav tsum tau hloov kho Q420NQR ( huab cua- qib resistant) yog ib qho kev xaiv ntau dua thiab sib npaug tshaj Q460.
2. Lo lus nug: Dab tsi yog qhov txawv ntawm tus nqi thiab muaj nyob ntawm Q390 thiab Q460 welded kav hauv khw tam sim no?
Teb: Q460 welded kav feem ntau kim dua thiab tsis yooj yim dua li Q390 kav. Tus nqi siab dua yog vim kev tsim cov alloying ntau dua (ntau dua Mn, ntxiv rau Nb, V, Ti), kev tswj xyuas nruj dua (txheej dov thiab txias), thiab feem ntau qis dua cov khoom lag luam. Q390 sawv cev ntau dua, "ntaus-theem" siab- cov khoom siv zog, ua rau nws cov khoom lag luam dav dav los ntawm cov neeg xa khoom thiab muaj rau kev xa khoom sai. Q460 feem ntau yog "ua-rau- xaj" cov khoom lag luam rau cov haujlwm tshwj xeeb uas xav tau nws lub zog kawg, ua rau tus nqi siab dua thiab lub sijhawm ua haujlwm ntev dua.
3. Lo lus nug: Yuav ua li cas lub flattening kuaj xyuas qhov zoo ntawm longitudinal weld seam ntawm Q420 welded yeeb nkab?
Teb: Qhov kev sim flattening yog ib qho yooj yim tab sis muaj zog ua kom puas tsuaj. Ib lub nplhaib qauv txiav los ntawm Q420 yeeb nkab yog muab tso rau ntawm ob daim hlau sib txuas. Cov phaj yog nias ua ke kom flatten lub nplhaib kom txog thaum qhov kev ncua deb ntawm daim hlau mus txog tus nqi teev, feem ntau muaj feem xyuam rau cov yeeb nkab sab nraud txoj kab uas hla thiab phab ntsa thickness (piv txwv li, H=(1+e) * t / (e + D / t)). Rau cov kav dej Q420 uas siv tau, cov qauv flattened yuav tsum tsis txhob pom cov kab nrib pleb lossis qhov tsis zoo ntawm sab hauv, sab nrauv, lossis qhov kawg kom txog thaum cov phiaj tau mus txog qhov kev ncua deb. Yog hais tias muaj qhov tsis xws luag, tsis muaj fusion, lossis thaj tsam brittle, nws yuav ua rau muaj qhov tawg qhib rau hauv qhov deformation heev, ua tsis tiav qhov kev xeem.
4. Nqe Lus Nug: Rau qhov sib koom ua ke ntawm cov welded tuab tuab ntawm -cov yeeb nkab Q460 phab ntsa, dab tsi ua ke ntawm preheating, interpass kub, thiab PWHT feem ntau tau teev tseg?
Teb: Rau xws li daim ntawv thov, cov txheej txheem thermal nruj yog qhov yuav tsum tau ua. Ua ntej, lub siab preheat ntawm 120-150℃yog siv rau tag nrho cheeb tsam sib koom ua ke. Qhov thib ob, qhov kub ntawm qhov sib cuam tshuam (qhov kub ntawm cov hlau ntawm qhov txuas txuas txuas ntxiv) yuav tsum tau tswj xyuas, feem ntau yuav tsum tsis txhob poob qis dua qhov kub thiab txias, piv txwv li, 150-250 degree, kom ua kom txias txias. Tam sim ntawd tom qab vuam, qhov sib koom ua ke tau raug xa mus rau ib qho kev tshaj tawm - cua sov lossis "hydrogen ci- tawm" ntawm 250-300℃rau tsawg kawg 2 teev kom diffuse tawm hydrogen. Thaum kawg, tag nrho Post-Weld Heat Treatment (PWHT) anneal stress-relief anneal yog ua, ua kom sov tag nrho cov sib koom ua ke rau 600-650 degree, tuav rau ib teev ib nti ntawm thickness, ces maj mam txias.
5. Lo lus nug: Dab tsi yog qhov tseem ceeb ntawm "sab saum toj yield zog" (ReH) piv rau "lower yield zog" (ReL) hauv cov qauv hloov kho rau Q390, Q420, thiab Q460, thiab vim li cas qhov kev hloov pauv no?
Teb: Cov qauv qub tau teev tseg lub zog qis zog (ReL), uas yog qhov kev ntxhov siab ntawm cov khoom siv tawm los thiab pib deform plastically tom qab qhov pib taw tes poob. Cov qauv kho dua tshiab tau hloov mus rau qhov qhia txog lub zog siab tshaj plaws (ReH), uas yog qhov siab tshaj plaws ua ntej qhov kev poob qis no tshwm sim. Qhov kev hloov pauv no tau ua los ua kom cov qauv hlau suav nrog cov qauv thoob ntiaj teb feem ntau (xws li ISO 6892). ReH yog qhov muaj txiaj ntsig zoo dua qub thiab rov tsim dua los ntsuas, tshwj xeeb tshaj yog rau siab - lub zog steels zoo li Q460 uas tej zaum yuav tsis pom qhov tseeb, tsis tu ncua yielding cwj pwm. Nws muab qhov pom tseeb dua, kev ntsuas ntau dua ntawm qhov pib ntawm cov yas deformation.
