Cold forming Super Duplex: Springback xam thiab Tooling Design

Super duplex stainless hlaurov qab roughly ob mus rau peb npaug ntau elastic springback tshaj 316L nyob rau hauv qhov sib npaug txias- kev ua haujlwm, uas tau tsav los ntawm nws cov txiaj ntsig siab - lub zog - rau -modulus ratio. Phau ntawv qhia no muab cov fabricators thiab tooling engineers txoj kev xam, cov ntaub ntawv sib piv, thiab tuag-tsim cov cai uas xav tau los ntaus qhov ntev ntev ntawm thawj qhov kev tsim khoom.

Super duplex stainless steels - Chiefly UNS S32750 (SAF 2507) thiab UNS S 32760 - tau teev nyob qhov twg chloride kuj thiab txhua yam muaj zog ob qho tib si teeb meem: offshore platforms, subsea manifolds, desalination piping, thiab tshuaj txheej txheem nkoj. Lawv qhov sib npaug austenitic-ferritic microstructure muab kwv yees li ob npaug ntawm cov txiaj ntsig ntawm cov qauv austenitic qib xws li 316L, tab sis tib lub zog yog vim li cas txias - tsim qhov chaw caij nplooj ntoos hlav rov qab los ntawm cov cuab yeej geometry tshaj li cov neeg tsim khoom xav tau. Tau txais lub kaum sab xis ntawm thawj kab lus - tsis yog qhov thib peb - nyob ntawm kev suav cov springback kom raug thiab tsim cov nyiaj them rau qhov tuag ua ntej nws raug txiav. Kab lus no taug kev los ntawm ob qho tib si.

Dab tsi ua rau Super Duplex Stainless Hlau nyuaj rau daim ntawv txias?

Super duplex tsis yooj yim rau daim ntawv txias vim tias nws lub zog tawm los (Ntau dua lossis sib npaug ntawm 550 MPa) yog kwv yees li 2.5-2.7 npaug siab dua 316L thaum nws cov elastic modulus (≈200 GPa) yuav luag tsis hloov pauv - yog li cov kab mob uas tau zoo dua elastically tom qab lub load raug tshem tawm yog proportionally loj dua, lub caij nplooj ntoos hlav ntau dua, nyab xeeb-khoov- qhov rai qhov rai.

Cov cuab yeej cuab tam uas tswj hwm lub caij nplooj ntoo hlav tsis yog tawm los lub zog ib leeg, tab sis qhov piv ntawm cov khoom muaj zog rau elastic modulus (σy / E). Qhov sib piv ntau dua txhais tau tias ntau dua ntawm cov khoom siv tag nrho cov bending strain yog khaws cia elastically thiab zoo rov qab thaum lub punch retracts. Cov lus hauv qab no piv rau peb qib feem ntau sib tham ua ke hauv ib lub khw muag khoom.

Table 1 - Kev sib piv cov cuab yeej cuab tam muaj feem rau txias- khoov springback. σy/E piv thiab tus txheeb ze springback yog muab los ntawm cov teev lub zog thiab modulus qhov tseem ceeb; kho raws li cov lus qhia kwv yees, tsis yog hloov pauv rau kev kuaj daim coupon.

Peb qhov kev tshwm sim ua raws ncaj qha los ntawm Table 1:

Khoov radii yuav tsum feem ntau loj dua qhov sib npaug austenitic ib feem kom tsis txhob nto tawg ntawm cov fiber ntau, vim super duplex muaj qis elongation cia tshaj 316L ntawm ib theem zog.

Xovxwm tonnage yuav tsum tau nce roughly nyob rau hauv feem rau yield zog, yog li brakes thiab tuag loj rau 304/316L ua hauj lwm yog nquag nyob rau hauv -powered rau super duplex ntawm tib thickness.

Txias deformation tshaj li ntawm 10% strain feem ntau yog ua raws li cov tshuaj anneal thiab ceev quench, ob qho tib si los kho cov austenite-ferrite theem sib npaug thiab rov pib dua cov khoom ductility ua ntej tsim ntxiv.

Yuav Ua Li Cas Sau Springback rau Super Duplex Khoov?

Siv lub elastic-rov qab (Gardiner) vojvoog- piv piv nrog rau K-factor khoov- kev suav nyiaj: suav qhov σy·R/(E·t) piv rau qhov khoov, daws rau lub vojvoog dawb tom qab tshem tawm, ces hloov lub vojvoog hloov mus rau hauv ib qho. Rau ib tug raug 3 hli S32750 khoov ntawm 3t nyob rau hauv lub voj voog, qhov no kwv yees kwv yees li 3-6℃ntawm angular springback, piv rau roughly 1-2℃rau 316L ntawm tib geometry.

Kauj ruam 1 - Khoov nyiaj pub dawb thiab K-factor

K-Qhov tseem ceeb nrhiav qhov nruab nrab dabtsi yog khoov axis raws li ib feem ntawm cov khoom thickness ntsuas los ntawm sab hauv nto, thiab yog siv los xam tsim (paj qauv) ntev:

BA=π (R + K·t) (A / 180)

Qhov twg BA yog qhov khoov nyiaj, R yog sab hauv khoov vojvoog, t yog cov khoom tuab, K yog qhov nruab nrab -axis yam, thiab A yog qhov khoov lub kaum sab xis hauv degrees. Rau austenitic thiab duplex stainless daim ntawv, khw kev xyaum feem ntau siv K ≈ 0.33 rau R < 2t thiab K ≈ 0.40–0.50 rau R Ntau dua lossis sib npaug 2t. Super duplex's ntau dua strain- hardening exponent hloov lub nruab nrab axis me ntsis mus rau sab hauv lub vojvoog piv nrog 316L, yog li K-cov ntsiab lus tau txais los ntawm cov rooj austenitic yuav tsum tau lees paub nrog kev sim khoov dua li qhov xav tau.

Kauj ruam 2 - Elastic springback ratio (Gardiner equation)

Rau kev khoov dawb huv ntawm daim ntawv lossis phaj, cov qauv elastic- rov qab kev sib raug zoo ntawm cov cuab yeej (loaded) vojvoog Ri thiab lub vojvoog dawb (unloaded) Rf yog:

Ri / Rf=4 (Ri·σy / E·t)³ − 3 (Ri·σy / E·t) + 1

Qhov kev sib npaug no qhia tau hais tias yog vim li cas qhov σy/E piv rau hauv Table 1 yog qhov sib txawv ntawm kev tswj: raws li σy/E nce, sab xis - sab tes poob qis dua 1, lub ntsiab lus Rf loj dua piv rau Ri - qhov qhib ntau dua tom qab lub cuab yeej tso tawm.

Ua piv txwv ua haujlwm

Xav txog 3 hli S32750 phaj khoov mus rau 9 hli hauv lub vojvoog (3t) nrog σy=550 MPa thiab E=200,000 MPa:

Ri·σy / (E·t)=(9 × 550) / (200,000 × 3)=4,950 / 600, 000=0.00825

Ri/Rf=4(0.00825)³ − 3(0.00825) + 1=0.00000226 − 0.02475 + 1=0.9753

Rf=Ri / 0.9753=9.23 mm - 2.5% vojvoog loj hlob tom qab unloading

Qhov kev suav tib yam rau 316L ntawm qhov zoo tib yam geometry (σy=190 MPa) muab Ri/Rf ≈ 0.9905, kwv yees li 40% tsawg dua kev loj hlob. Vim hais tias angular springback tebchaw nrog arc ntev tshaj qhov khoov tag nrho, qhov sib txawv ntawm lub vojvoog no feem ntau txhais mus rau angular overbend yuav tsum 2-3 zaug loj dua rau super duplex dua li 316L - raws li daim teb - qhia 3-6℃piv rau 1-2℃ntau yam siv thoob plaws hauv kev lag luam.

Kauj ruam 3 - Hloov mus rau angular overbend

Thaum Rf paub, lub springback lub kaum sab xis Δ yog qhov sib txawv ntawm lub cuab yeej (lub hom phiaj) lub kaum sab xis thiab lub kaum sab xis ntawm qhov dawb tau tuav. Tooling yog ces txiav mus rau lub kaum sab xis pib ntawm (lub hom phiaj + Δ ) kom tom qab elastic rov qab qhov chaw so rau lub hom phiaj. Qhov no overbend tus nqi - tsis yog lub nominal print lub kaum sab xis - yog dab tsi yuav tsum tshwm sim nyob rau hauv lub punch thiab tuag drawings.

Qhov twg Springback Prediction Method yog qhov tseeb tshaj?

Cov qauv tshuaj ntsuam xyuas (K-factor plus Gardiner) yog qhov tseeb txaus rau thawj-pass tuag tsim thiab quoting; empirical sim khoov yuav tsum tau ua kom tiav cov cuab yeej ua ntej ntau lawm; thiab nonlinear finite element tsom xam nrog ib tug calibrated anisotropic hardening qauv yog qhov tseeb tshaj plaws txoj kev thiab yog tsim nyog thaum twg kam rau ua nruj, ib feem yog loj, los yog tuag rework yuav raug nqi.

Table 2 - Kev sib piv ntawm springback twv ua ntej txoj kev rau super duplex txias sib sau.

Kev ua haujlwm tau zoo sib xyaw ua ke tag nrho peb qhov: siv cov qauv ntsuas ntsuas kom loj qhov tuag thiab hais txog txoj haujlwm, khiav FEA kom kho lub kaum sab xis thiab chij txhua qhov kev pheej hmoo ntawm kev tawg ntawm cov fiber ntau sab nraud, thiab paub meej nrog kev sim khoov ntawm lub cev ntawm kev tsim khoom-ntau cov khoom ua ntej txiav hardened tooling. Vim tias cov qib duplex qhia cov cua sov- rau- qhov sib txawv ntawm qhov sib txawv ntawm cov khoom siv hluav taws xob nyob rau hauv tib qhov kev qhia tshwj xeeb, rov- siv lub caij nplooj ntoos hlav rov qab thaum daim ntawv pov thawj zeb hloov yog qhov kev coj ua zoo txawm tias rov ua haujlwm dua.

Yuav ua li cas Tooling yuav tsum tau tsim los them rau Super Duplex Springback?

Tsim cov xuas nrig ntaus thiab tuag rau lub kaum sab xis uas suav nrog hauv Tshooj 2 (tsis yog lub kaum sab xis luam), qhia qhov dav dav hauv qhov khoov lub vojvoog ntawm yam tsawg kawg 3-4 × cov khoom tuab, siv cov hauv qab lossis npib es tsis yog cua dabtsi yog khoov qhov twg los xij tso cai, thiab qhov loj ntawm cov xovxwm rau 2-3 × lub tonnage xav tau rau qhov sib npaug 316L.

Overbending

Txoj kev them nyiaj ntau tshaj plaws yog tsuas yog txiav cov cuab yeej mus rau lub kaum sab xis loj dua li cov ntawv luam tawm, yog li ntawd elastic rov ua rau qhov rov qab mus rau lub hom phiaj lub kaum sab xis. Tus nqi overbend tuaj ncaj qha los ntawm Δ hauv Tshooj 2, thiab yuav tsum tau rov qab- tshawb xyuas thaum twg cov khoom tuab, coil ntau, lossis khoov vojvoog hloov.

Hauv qab thiab npib nyiaj

Huab cua dabtsi yog khoov - qhov twg lub punch tsis tag lub rooj zaum cov khoom tiv thaiv qhov tuag - yog ceev tab sis tawm springback loj heev uncontrolled vim lub khoov vojvoog tsis kho los ntawm tooling. Hauv qab (chaw qhov chaw tag nrho tiv thaiv phab ntsa tuag) thiab npib (siv lub zog txaus rau hauv zos re- tawm tsam qhov khoov) ob qho tib si mechanically txwv lub vojvoog zaum kawg thiab lub kaum sab xis, txo qis qhov tawg ntawm qhov tawg. Kev npib yuav tsum muaj lub tonnage siab tshaj plaws ntawm peb txoj kev tab sis muab lub kaum ntse ntse tshaj plaws ntawm siab - cov khoom siv zog zoo li super duplex.

Die radius thiab punch qhov ntswg radius

• Sab hauv khoov vojvoog: yam tsawg kawg nkaus 3 × thickness rau S32750 / S32760 daim ntawv thiab phaj txog li 12 hli, piv rau 1–2 × tuab yam tsawg kawg nkaus siv rau 316L, kom tsis txhob sab nraud - fiber ntau tawg muab qhov qis elongation cia.
• Tuag lub xub pwg vojvoog: me me kom tsis txhob galling - duplex ua hauj lwm- hardens sai, yog li ib tug me me los yog ntse tuag vojvoog tsub kom nto rub thiab yuav tau qhab nia lub phaj nto, compromising lub passive corrosion- resistant txheej.
• Tuag qhib (V-dav): feem ntau 8–10 × thickness rau txheem cua / hauv qab dabtsi yog khoov; nqaim qhib tsa tonnage xav tau ntxiv thiab ua rau muaj kev pheej hmoo ntawm qhov punch qhov ntswg cim rau sab nrauv.

Clearance thiab lubrication

Punch-rau- tuag tshem tawm yuav tsum tau nce ntau dua kev xyaum austenitic - kwv yees li 10-15% ntau dua li qhov kev tshem tawm siv rau 316L ntawm tib lub thickness - kom haum rau cov khoom siv ntau dua yam tsis muaj cov cuab yeej siv ntau dhau. Yuav tsum muaj cov tshuaj chlorine-dawb tsim cov roj nplua nyeem rau cov hlau tsis muaj steel, ob qho tib si los tswj lub plab los ntawm kev ua haujlwm tawv thiab kom tsis txhob muaj cov tshuaj chloride uas tuaj yeem pib pitting thaum qhov chaw ua haujlwm.

Ntau npaum li cas Springback Compensation puas Super Duplex xav tau piv nrog 316L thiab 2205?

Raws li cov lus qhia dav dav, cia siab tias kwv yees li 1-2℃ntawm angular springback rau 316L, 2-4℃rau tus qauv duplex 2205, thiab 3-6℃rau super duplex S32750 / S32760 ntawm qhov sib npaug 90℃khoov - cov duab uas yuav tsum tau ib txwm raug lees paub los ntawm cov khoom siv hluav taws xob, los yog kev sib tw ntawm cov khoom siv hluav taws xob los yog kev sib tw ua ntej kev sib tw, kev sib tw ntawm FEA thiab mill ntau.

Table 3 - Sib piv txias- ua cov nyiaj pub dawb thoob plaws cov tsev neeg tsis muaj zog. Cov txiaj ntsig yog kev tsim kho dav dav- kev npaj kev lag luam, tsis yog hloov rau qib- thiab ntau- kev sim tshwj xeeb.

Dab tsi xovxwm Tonnage thiab txheej txheem Parameters Yuav tsum tau qhia?

Qhov loj nias tonnage siv cov khoom siv lub zog tawm los tiag tiag (tsis yog cov khoom siv tsis zoo), qhia meej V- tuag qhib ntawm 8-10 × thickness, khiav khoov ceev qeeb dua rau qib austenitic kom txwv adiabatic cua sov hauv thaj tsam khoov, thiab txoj haujlwm dhau los ntawm 100% kev tshuaj xyuas qhov ntev tom qab lub caij nplooj ntoos hlav es tsis siv cov cuab yeej pib.

Feem ntau siv cua-bending tonnage formula yog:

F = (1.42 × L × σt × t²) / V

Qhov twg F yog quab yuam hauv kN, L yog khoov ntev hauv mm, σt yog tensile zog hauv MPa, t yog thickness hauv mm, thiab V yog tuag qhib dav hauv mm. Vim tias super duplex tensile zog (795-930 MPa rau S32750) khiav ze li ob npaug ntawm 316L, tib qhov sib npaug qhia tau hais tias tonnage roughly ob npaug rau qhov sib npaug geometry - vim li cas ntau cov fabricators pom lawv cov cuab yeej 316L uas twb muaj lawm nyob rau hauv -plexed ib zaug lawv txav mus rau super du.

Puas yog Intermediate Annealing yuav tsum tau thaum lub caij txias?

Yog - tshuaj annealing thiab ceev ceev quench yog pom zoo thaum twg cumulative txias deformation tshaj roughly 10% strain, thiab yuav tsum tau tom qab lub kawg tsim cov kauj ruam tsis hais theem ntawm strain, los kho cov austenite -ferrite theem tshuav nyiaj li cas thiab cov alloy tag nrho corrosion kuj.

Kev ua haujlwm txias hloov cov theem sib npaug ntawm super duplex deb ntawm qhov kwv yees li 50/50 austenite-ferrite piv uas muab qib nws cov kev sib xyaw ua ke thiab kev ua haujlwm corrosion, thiab tuaj yeem txhawb nqa embrittling intermetallic theem yog tias cov khoom siv tom qab raug rau qhov kub thiab txias. Mill thiab cov ntaub ntawv tsim tawm rau S32750 qhia qhov tsawg kawg nkaus kev daws teeb meem kub ib ncig ntawm 1052℃(1925℃F) ua raws tam sim ntawd los ntawm huab cua ceev los yog dej quench, nrog pickling thiab passivation tom qab ntawd kom tag nrho cov txheej txheej txheej txheej uas txias txias thiab cov cua sov cuam tshuam tuaj yeem cuam tshuam.

Cov lus nug nquag

Ntau npaum li cas super duplex stainless hlau caij nplooj ntoos hlav rov qab tom qab txias dabtsi yog khoov?

Ntawm 90℃khoov, super duplex stainless hlau (UNS S32750 / S32760) qhia roughly 3-6℃ntawm angular springback, piv nrog txog 1-2℃rau 316L austenitic stainless hlau ntawm tib lub thickness thiab vojvoog. Tus nqi pes tsawg nyob ntawm thickness, khoov vojvoog, thiab cov khoom siv lub zog tawm los tiag, yog li nws yuav tsum tau lees paub nrog kev sim khoov.

Dab tsi yog cov qauv siv los xam cov springback hauv stainless hlau dabtsi yog khoov?

Gardiner kab zauv yog tus qauv analytical formula: Ri/Rf=4(Ri·σy/E·t)³ − 3(Ri·σy/E·t) + 1, qhov twg Ri yog lub cuab tam vojvoog, Rf yog lub vojvoog dawb tom qab unloading, σy yog yield zog, E yog elastic modulus, thiab t yog elastic modulus. Nws feem ntau yog ua ke nrog K-factor khoov- nyiaj pab xam rau kev tiaj tus- qauv tsim.

Dab tsi yog qhov tsawg kawg khoov vojvoog rau super duplex stainless hlau?

Yam tsawg kawg hauv lub vojvoog khoov ntawm 3 mus rau 4 npaug ntawm cov khoom tuab yog ib qho kev pom zoo pib rau S32750 thiab S32760, piv rau 1 txog 2 zaug tuab rau 316L, vim tias super duplex muaj tsawg dua elongation cia ntawm nws qib siab zog thiab yog ntau dua rau sab nraud - fiber ntau tawg ntawm nruj radii.

Vim li cas super duplex stainless hlau yuav tsum muaj zog ntau dua li 316L?

Super duplex muaj qhov tsawg kawg nkaus lub zog ntawm kwv yees li 550 MPa thiab tensile lub zog ntawm kwv yees li 795-930 MPa rau S32750, ze rau ob npaug ntawm qhov tseem ceeb rau 316L. Txij li thaum dabtsi yog khoov quab yuam scale nrog tensile lub zog, nias tonnage yuav tsum tau nce proportionally - feem ntau 2.3 mus rau 2.7 lub sij hawm lub tonnage xav tau rau ib tug sib npaug 316L ib feem.

Puas yog super duplex stainless hlau xav tau annealing tom qab txias txias?

Yog lawm. Kev daws annealing ua raws li huab cua ceev los yog dej quench yog pom zoo ib zaug cumulative txias deformation tshaj roughly 10%, thiab feem ntau yuav tsum tau tom qab lub kawg tsim cov kauj ruam los kho cov balanced austenite -ferrite microstructure thiab cov alloy tag nrho corrosion kuj.

Puas yog kev ntsuas ntsuas lossis FEA zoo dua rau kev kwv yees super duplex springback?

Cov qauv tshuaj ntsuam xyuas yog txaus rau kev kwv yees thaum ntxov thiab pib tuag sizing. Nonlinear finite element tsom xam nrog rau tus qauv calibrated hardening yog qhov tseeb dua thiab tsim nyog rau lub sij hawm ntxiv rau nruj - qhov kam rau ua, loj lossis tuab phaj, los yog ib txoj hauj lwm uas txiav cov cuab yeej tshiab ob zaug yuav raug nqi.