Txias Rolling nyhuv ntawm Weld Microstructure thiab cov khoom ntawm ntshiab Titanium phaj Gr1-Gr4
Nov 26, 2024
Vim li cas Cold Rolled Titanium Coil muaj Welds
Tsis tu ncua ntawm kev lag luam ntshiab titanium kauj pib los ntawm kub dov phaj uas tau koom nrog kawg mus rau qhov kawg los ntawm cov roj tungsten arc vuam (GTAW, feem ntau hu ua argon arc vuam), kom ib daim kab xev txuas ntxiv tuaj yeem dhau los ntawm pickling, txias dov, annealing thiab slitting kab. Ib qho ua tiav txias txias ntawm Qib 1, Qib 2, Qib 3 lossis Qib 4 titanium yog li ntawd tsis yog metallurgically zoo ib yam: nyob rau lub sijhawm tsis tu ncua nws nqa cov pob qij txha sib txuas uas nws cov qauv, hardness thiab tsim tus cwj pwm txawv ntawm niam txiv hlau. Cov neeg yuav khoom uas kuaj xyuas cov qauv ntawm lub cev nkaus xwb thiab tsis quav ntsej cov pob qij txha raug cuam tshuam rau cov khoom hauv zos tawg, cov cim saum npoo thiab tawg ntxov ntxov thaum lub sij hawm sib sib zog nqus nqus los yog raj.
Unalloyed titanium phaj, ntawv thiab sawb tau muab rau ASTM B265 lossis GB / T 3621, nrog Qib 1 txog 4 cais feem ntau los ntawm cov pa oxygen thiab hlau. Cov pob qij txha yog tsim nrog ERTi-1 rau ERTi-4 cov xaim xaim cais raws li AWS A5.16, siv cov txheej txheem tsim nyog rau AWS D17.1 lossis ASME BPVC Tshooj IX. Peb cheeb tsam tswj tus cwj pwm: thaj tsam fusion, thaj chaw kub ntxhov (HAZ) thiab cov hlau tsis cuam tshuam niam txiv. Nyob rau hauv qhov zoo li-welded cheeb tsam fusion yog ib tug ntxhib cam qauv ntawm transformed beta nrog acicular alpha, thaum lub HAZ muaj koob zoo li alpha nqa ntau oxygen thiab nitrogen tshaj cov niam txiv hlau, vim hais tias titanium absorbs cov ntsiab lus sai heev thaum nws yog rhuab saum toj no roughly 400 C nyob rau hauv cov huab cua.
| Qib | UNS | O max,% | N max, % | C max,% | H max,% | Fe max,% |
|---|---|---|---|---|---|---|
| 1 | R50250 | 0.18 | 0.03 | 0.08 | 0.015 | 0.20 |
| 2 | R50400 | 0.25 | 0.03 | 0.08 | 0.015 | 0.30 |
| 3 | R50550 | 0.35 | 0.05 | 0.08 | 0.015 | 0.30 |
| 4 | R50700 | 0.40 | 0.05 | 0.08 | 0.015 | 0.50 |
ASTM B265 yam tsawg kawg nkaus annealed tensile zog rau Qib 1 txog 4 yog 240 MPa, 345 MPa, 450 MPa thiab 550 MPa, nrog rau qhov tsawg kawg nkaus yield zog ntawm 138 MPa, 275 MPa, 380 MPa thiab 483 MPa thiab yam tsawg kawg nkaus 4% elongations 2%. Ib qho kev sib koom ua ke nyob rau sab saum toj ntawm Qib 4 qhov rais thiab ib qho nyob rau hauv qab ntawm Qib 1 qhov rais coj txawv txawv nyob rau hauv tib lub sij hawm zeb, uas yog vim li cas txoj hauj lwm ntawm txhua qhov sib koom tes yuav tsum nyob twj ywm traceable nyob rau hauv lub kauj.
Dab tsi Cold Rolling Ua rau Weld Joint
Txias dov siv compressive deformation ntawm chav tsev kub, thiab nyob rau hauv ib tug weld peb mechanisms ua tib lub sij hawm.
Geometry.Lub weld crown thiab cag reinforcement tsim ib kauj ruam tuab. Cov cheeb tsam tsa ceg dov ua ntej thiab hauv zos nyuaj, ua rau pom cov kab weld, ib lub thickness hump thiab, thaum sib koom tes tawm ntawm qhov chaw, ntug tawg.
Lim partitioning.Lub ntxhib cam khwb cia fusion cheeb tsam thiab acicular HAZ ua hauj lwm harden ntawm tus nqi sib txawv los ntawm equiaxed niam txiv hlau. Kev txo qis yog li tsis sib xws nyob rau hauv kev sib koom tes, thiab shear concentrates ntawm fusion kab thiab ntawm HAZ ciam teb.
Kev puas tsuaj.Nrog rau txhua kis tus qauv cam khwb cia elongates rau hauv fiber ntau raws li cov kev taw qhia dov. Tshaj li ib qho kev txo qis tag nrho cov kab weld dhau los ua txoj hauv kev nyiam rau delamination thiab hydrogen pab tawg.
Ib qho microhardness traverse coj hla ib qho kev sib koom ua ke feem ntau qhia tau hais tias lub ncov ntawm txoj kab fusion lossis HAZ ciam teb thiab cov niam txiv lub hauv paus hlau softer. Lub ncov ntawd yog lub cim qhia tau hais tias qhov kev sib koom ua ke tsis tau recrystallised tag nrho los ntawm cov anneal uas ua raws.
Kev txo qis, Annealing thiab cov qauv uas tau tshwm sim
Lub rooj qhia txog cov kev taw qhia ntawm kev hloov pauv siv thaum teem caij txias txo thiab inter-dhau annealing rau welded titanium coil. Nws yog cov txheej txheem kev taw qhia rau lub hom phiaj kev npaj, tsis yog ib qho kev hloov pauv rau kev tsim nyog dov thiab kev kho cua sov txheej txheem validated ntawm ib lub zeb tshwj xeeb.
| Tag nrho cov txias txo | Weld cheeb tsam mob | Hardness sib txawv ntawm qhov sib koom ua ke | Hom kauj ruam tom ntej |
|---|---|---|---|
| 15-25% | Reinforcement flattened, cam khwb cia qauv tseem pom | Me ntsis nce, ncov ze ntawm txoj kab fusion | Kev ntxhov siab 540-600 C rau li 1 h feem ntau xaiv tau |
| 30-45% | Weld kab txawv, fusion nplej elongated | Ntshiab ncov, niam txiv hlau kuj nce | Kev ntxhov siab los yog anneal 540-650 C hauv lub tshuab nqus tsev lossis qhuav argon |
| 50-70% | Strongly banded weld kab, HAZ ua raws li cov kev taw qhia dov | Peak roughly 1.3 mus rau 1.5 npaug niam txiv hlau | Tag nrho anneal 650-750 C rau 1-2 h, ces pickle |
| Tshaj 75% | Risk ntawm ntug cracking thiab weld kab delamination | Siab hauv zos peaks nrog nkig teb | Ntau qhov kev hla nrog kev sib tshuam - dhau qhov kev sib tw, lossis txiav cov kev sib koom ua ke ua ntej qhov kawg dov |
Vim hais tias recrystallisation yog tsav los ntawm lub zog khaws cia, thaj tsam fusion feem ntau recrystallises ua ntej HAZ ciam teb, thiab HAZ ciam teb yog thaj tsam kawg kom muag. Qhov kub tsis tshua muaj kev ntxhov siab txo qis qhov kev ntxhov siab uas seem tab sis tsis tshem tawm cov kab vuam los yog sib npaug ntawm cov nplej, yog li qhov kawg anneal saum qhov kub ntawm recrystallisation yuav tsum tau nyob qhov twg lub kauj yuav tsum tsim los yog nthuav dav uniformly.
Annealing, Pickling thiab Weld Kho Cov Cai
Lub tshuab cua sov yog qhov txiav txim siab. Titanium annealed nyob rau hauv cov huab cua saum toj no txog 600 C ua ib tug nyuaj, brittle oxygen enriched txheej uas yuav tsum tau muab tshem tawm tom qab ntawd, thiab rov raug dua nce bulk oxygen thiab hydrogen. Qhov twg cov khoom yuav tsum tau khaws cia, anneal nyob rau hauv lub tshuab nqus tsev los yog qhuav, siab purity argon nrog ib tug tswj dew point, thiab paub meej tias qhov tshwm sim nrog ib tug hardness traverse.
Pickle hauv nitric -hydrofluoric da dej, feem ntau 20-30% HNO3 nrog 2-4% HF, kom tshem tawm cov nplai thiab cov txheej txheej oxygen ua ntej txo qis dua los yog zaum kawg tshuaj xyuas.
Khaws cov hydrogen qis dua 0.015% siab tshaj plaws ntawm ASTM B265 los ntawm kev txwv lub sij hawm pickling thiab siv cov tshuaj chloride tsis muaj dej yaug.
Kev kho welds tsuas yog tso cai raws li tus txheej txheem tsim nyog; tom qab kho qhov sib koom ua ke yuav tsum tau rov-annealed, re- tshuaj xyuas thiab cim rau ntawm daim ntawv qhia vuam.
Sau txhua txoj haujlwm sib koom ua ke kom slitting, blanking thiab downstream tube welding tuaj yeem tso lossis txiav qhov sib koom ua ke tsis txhob sib ntsib ntawm random.
Kev Ntsuas thiab Txais Cov Txias Rolled Coil Nrog Welds
Kev lees txais yuav tsum muab cov qauv khoom kuaj nrog kev sib koom ua ke - cov tshev tshwj xeeb.
Kev ntsuam xyuas nruj rau ASTM E8 ntawm cov qauv longitudinal thiab transverse strips ntxiv rau cov qauv hauv nruab nrab ntawm cov vuam, txhawm rau txhawm rau ua kom muaj txiaj ntsig sib koom ua ke.
Kev taw qhia khoov lossis flattening xeem rau ASTM E290, uas nthuav tawm cov vuam kab ductility uas txo qis rau feem ntau.
Microhardness traverses mus rau ASTM E384 hla kev sib koom ua ke, qhia cais rau niam txiv hlau, HAZ thiab fusion zone.
Kev ntsuam xyuas metallographic rau ASTM E407 txhawm rau txheeb xyuas cov qauv vuam, ntsuas ua ntej beta grain loj thiab nrhiav hydride lossis oxygen enriched txheej.
Kev kuaj pom thiab qhov loj me rau cov kab txuas txuas, cov kauj ruam tuab, dov - hauv nplai thiab laps.
Thaum lub kauj yog tom qab hloov dua siab tshiab rau hauv welded raj rau ASTM B338, tus thawj strip sib koom ua ib qho ntxiv rau hauv lub raj tiav thiab yuav tsum tau them los ntawm tib lub hydrostatic, flattening thiab eddy tam sim no los yog ultrasonic txais.
FAQ
Q: Puas yog txias dov ntxiv dag zog rau titanium vuam?
Nws txhawb nqa lub zog los ntawm kev ua haujlwm hardening, tab sis tsis sib xws. fusion zone thiab HAZ harden ntawm tus nqi sib txawv los ntawm niam txiv hlau, yog li kev sib koom ua ke tau txais lub zog ntawm tus nqi ntawm ductility thiab thickness uniformity kom txog rau thaum tag nrho cov anneal yog thov.
Q: Cov kab vuam puas tuaj yeem raug tshem tawm los ntawm dov ib leeg?
Tsis yog. Rolling flattens lub reinforcement thiab aligns lub cam khwb cia qauv, tab sis cov muaj pes tsawg leeg sib txawv nyob rau hauv lub HAZ tseem. Cropping los yog mechanically tshem tawm qhov ntev ntawm lub kauj yog tib txoj kev los tshem tawm qhov sib koom ua ke ntawm cov khoom.
Q: Lub sij hawm annealing twg rov qab ductility tom qab txias dov?
Unalloyed titanium feem ntau yog kev ntxhov siab ntawm 540 thiab 650 C thiab tag nrho annealed ntawm 650 thiab 750 C rau 1 mus rau 2 teev hauv lub tshuab nqus tsev lossis qhuav argon. Lub sijhawm caij nyoog yog nyob ntawm qib, tag nrho txo qis thiab muaj peev xwm ua kom sov.
Q: Vim li cas ho siv hardness los txiav txim ib dov weld?
Hardness teb rau oxygen thiab nitrogen enrichment, ua hauj lwm hardening thiab ua tsis tiav recrystallisation, tag nrho cov no yog cov teebmeem hauv zos. Ib qho traverse yog li qhia tau hais tias ib qho kev sim tensile ntawm lub cev tsis tuaj yeem ua tau.
Q: Puas yog ASTM B265 cov khoom siv rau cov vuam?
No. ASTM B265 teev cov kev cai rau cov khoom siv sawb nws tus kheej. Weld cov khoom sib koom ua ke yog tsim los ntawm cov txheej txheem vuam thiab raug txheeb xyuas nyias nrog weld-centred nro thiab khoov kuaj ntxiv rau microhardness.
