Graphite electrodes yog cov khoom siv tseem ceeb tshaj plaws hauv hluav taws xob arc rauv (EAF) steelmaking. Lawv nqa cov dej ntws loj - feem ntau 100,000 amperes lossis ntau dua - mus rau hauv lub cub tawg, hloov hluav taws xob rau hauv cov cua sov uas melts cov hlau. Txawm li cas los xij, rau cov khoom siv uas zoo li lub tog raj kheej dub yooj yim, graphite electrodes yog cov khoom lag luam xav tsis thoob, txhais los ntawm cov khoom siv lub cev muaj zog thiab tsim los ntawm ntau lub lis piam, ntau cov txheej txheem.
Phau ntawv qhia no piav qhia txog cov khoom tseem ceeb ntawm graphite electrodes, yuav ua li cas cov khoom no txhais rau hauv kev ua yeeb yam hauv ntiaj teb, qhov sib txawv ntawm RP, HP thiab UHP qib, thiab tag nrho ntawm cov ntawv thov kev lag luam. Txawm hais tias koj yog tus tswv lag luam steel, tus thawj tswj hwm, lossis tus kws tshaj lij kev muag khoom, tsab xov xwm no yuav pab koj nkag siab tias yuav nrhiav dab tsi - thiab yuav xaiv cov hluav taws xob zoo li cas rau koj lub qhov cub.
Ib tug graphite electrode yog ib tug cylindrical conductor ua feem ntau ntawm roj av coke, koob coke thiab thee tar suab, uas yog ci thiab ces graphitized nyob rau hauv tsis tshua muaj kub kub. The result is a dense, low-resistance carbon body that can withstand the intense thermal, electrical and mechanical conditions inside an electric arc furnace.
Raws li txoj cai, lub tshuab electrode muaj ob ntu:
Vim tias tsis muaj ib qho ntev txaus kom ncav cuag los ntawm lub qhov cub hluav taws xob mus rau lub molten da dej, ntau cov khoom siv hluav taws xob raug ntsia hlau ua ke siv cov txiv mis tapered threaded. Raws li cov lus qhia tau noj thaum lub sij hawm yaj, cov ntu tshiab tau ntxiv rau saum toj - ib txoj kev "noj" tas mus li.
Peb lub tshuab hluav taws xob feem ntau yog teem rau hauv daim duab peb sab rau peb-theem AC hluav taws xob arc rauv. Txhua lub electrode, lub ru tsev rauv, thiab cov hlau molten ua ke tsim cov hluav taws xob hluav taws xob uas txhawb nqa lub arc.
Graphite yog xaiv rau electrodes vim hais tias nws txawv ntawm plaub yam khoom uas tsis muaj lwm yam khoom siv pheej yig muaj nyob rau hauv kev lag luam nplai:
Nkag siab txog cov txheej txheem tsim khoom piav qhia vim li cas cov khoom sib txawv ntawm cov qib thiab vim li cas qhov zoographite electrodestxib tus hwm. Txoj kev tsim cov txheej txheem muaj xws li cov kauj ruam tseem ceeb no:
Tag nrho lub voj voog tuaj yeem nqa ob peb lub lis piam, uas yog ib qho laj thawj vim li cas cov khoom siv hluav taws xob electrode rhiab rau kev lag luam mus ncig thiab vim li cas cov sij hawm txhuas tseem ceeb hauv kev yuav khoom.
Cov khoom hauv qab no yog dab tsi engineers thiab pab pawg muag khoom soj ntsuam thaum qhia txog electrode. Tus nqi yog muab raws li cov kab ntau yam rau qib kev lag luam; cov duab tseeb txawv ntawm cov chaw tsim khoom thiab qib.
Resistivity ntsuas yuav ua li cas cov electrode tawm tsam tam sim no ntws. qis dua yog zoo dua: qis resistivity txhais tau hais tias tsawg hluav taws xob poob thaum tshav kub nyob rau hauv lub electrode nws tus kheej, yog li ntau zog mus txog lub arc. UHP electrodes ua tiav qhov qis tshaj qhov tseem ceeb (feem ntau 5-7 µΩ·m) ua tsaug rau koob coke thiab tag nrho graphitization, thaum RP electrodes siab dua (kwv yees li 7.5-9.5 µΩ·m).
Flexural (khoov) lub zog qhia tau hais tias tsis kam mus rau cov khoom tawg thaum tuav, kem sib dhos, thiab thermal thiab mechanical stresses ntawm melting - tshwj xeeb tshaj yog seem qhov tsua-ins thiab ru tsev txav. Lub zog siab dua txo qhov kev pheej hmoo ntawm lub txiv mis thiab electrode tawg, uas yog ib qho tseem ceeb ntawm kev poob qis thiab kev tsim khoom ploj.
Bulk density reflects how solid and compact the electrode is. Denser electrodes feem ntau muaj qis dua, muaj zog dua thiab zoo dua oxidation tsis kam vim tias muaj qhov porosity tsawg dua rau oxygen los tua. Cov txiaj ntsig zoo ib yam li ntawm 1.58 g/cm³ (RP) txog 1.75 g/cm³ (UHP).
Elastic modulus piav qhia txog qhov tawv nqaij. Qhov nruab nrab modulus yog qhov xav tau: ib qho hluav taws xob uas nruj dhau ua rau cov kev ntxhov siab thermal thiab nws yooj yim rau kev tawg, thaum ib qho uas mos dhau lawm yuav deform. Qhov sib npaug ntawm lub zog thiab modulus yog ib feem tseem ceeb ntawm kev tsim electrode.
Tsawg thiab tsis sib xws thermal expansion minimizes cracking thaum lub electrode ntsis heats sai heev thaum lub sij hawm arc ignition. Koob coke's oriented qauv muab HP thiabUHP electrodesCTE qis dua thiab zoo dua qub, uas yog lub hauv paus rau lawv cov thermal-shock tsis kam.
Graphite pib oxidize lub ntsiab lus nyob rau hauv huab cua saum toj no roughly 400-500 ° C. Txij li thaum sab saum npoo ntawm ib qho electrode raug rau qhov cub cua, oxidation yog ib qho khoom noj tas li. Manufacturers reduce oxidation through densification, surface coatings, water-cooled electrode systems and inert-gas shielding at the furnace.
Tshauv yog cov tsis-carbon residue tom qab combustion. Cov hmoov tshauv tsawg (<0.3% rau cov qib zoo) yog qhov tseem ceeb vim tias cov hmoov tshauv impurities qis conductivity, nce oxidation thiab tuaj yeem paug cov hlau da dej.
| Khoom | RP | HP | UHP |
|---|---|---|---|
| Qhov ceev (g/cm³) | 1.58–1.65 Nws | 1.65–1.72 Nws | 1.68–1.75 Nws |
| Hluav taws xob tiv taus (µΩ·m) | 7.5–9.5 Nws | 6.5–8.0 Nws | 5.0–7.0 Nws |
| Flexural zog (MPa) | 7–10 | 8–11 | 9–13 |
| Young tus modulus (GPa) | 7–11 | 8–12 | 9–14 |
| CTE (× 10⁻⁶/° C) | 1.8-2.5 Nws | 1.2–1.8 IB | 0.9–1.5 hli |
| Cov ntsiab lus tshauv (%) | <0.5 | <0.3 | <0.3 |
Nco tseg: Cov no yog qhov qhia txog kev lag luam, tsis yog qhov tshwj xeeb. Nco ntsoov thov lub chaw tsim khoom daim ntawv pov thawj ntawm kev tshuaj xyuas rau qhov tseeb batch koj yuav.
Graphite electrodes tau muab faib ua peb qib tseem ceeb raws li cov khoom siv raw thiab qhov siab tshaj plaws uas tau tso cai tam sim no. Xaiv cov qib zoo ncaj qha cuam tshuam rau cov khoom siv hluav taws xob hluav taws xob, kev siv hluav taws xob thiab tag nrho cov nqi ib tonne ntawm cov hlau.
RP electrodes feem ntau yog tsim los ntawm cov roj av coke thiab tso cai rau qhov qis tshaj tam sim no (feem ntau txog li 17-24 A / / cm²). Lawv yog cov kev xaiv pheej yig tshaj plaws thiab tsim nyog rau cov cub tawg me me, kev ua haujlwm qis zog, thiab kev thov tsawg dua. RP electrodes feem ntau nkag rau hauv txoj kab uas hla ntawm 75 hli mus txog 500 hli.
HP electrodes siv cov roj av coke thiab rab koob coke, cia siab dua tam sim no (kwv yees li 18-25 A / cm²). Lawv muab kev tiv thaiv qis dua thiab zoo dua thermal-shock tsis kam tshaj RP, ua rau lawv haum rau nruab nrab thiab loj rauv qhov twg yuav tsum tau muaj peev xwm ntau dua. Hom kab uas hla yog li ntawm 200 hli mus rau 600 hli.
UHP electrodes yog tsim los ntawm hwm koob coke thiab sawv cev rau sab saum toj ntawm ntau yam, txhawb nqa tam sim no ntom ntom ntawm kwv yees li 20-30 A / / cm² thiab siab dua. They deliver the lowest resistivity, highest density and best oxidation resistance, and are essential for large modern UHP furnaces (100+ tonne capacity) where electrode life per tonne of steel is critical. UHP electrodes feem ntau muab nyob rau hauv txoj kab uas hla ntawm 300 hli mus txog 800 hli.
| Feature | RP | HP | UHP |
|---|---|---|---|
| Cov khoom siv tseem ceeb | Petroleum coke | Petroleum + koob coke | Premium koob coke |
| Tam sim no ceev (A/cm²) | 17–24 : kuv | 18–25 | 20–30 + IB |
| Txoj kab uas hla (mm) | 75-500 Nws | 200-600 Nws | 300-800 Nws |
| Nqi | qis tshaj | Nruab nrab | Siab tshaj |
| Zoo tshaj rau | Me me furnaces, foundries | Nruab nrab / loj rauv | Loj UHP steelmaking rauv |
EAF steelmaking tso nyiaj rau feem coob ntawm graphite electrode noj thoob ntiaj teb. Hauv EAF, peb lub tshuab hluav taws xob dhau los ntawm lub qhov cub hluav taws xob thiab ntaus ib qho arc mus rau cov nqi seem. Lub arc ua rau kub siab tshaj 3,000 ° C, melting cov seem, uas yog ces refined rau hauv hlau.
Raws li kev lag luam hlau thoob ntiaj teb hloov pauv ntawm txoj kev tawg-rooj mus rau qis-carbon EAF ntau lawm, kev thov rau cov khoom siv hluav taws xob zoo UHP tseem loj tuaj. Niaj hnub nimno EAFs kuj tau nce "UHP" - kev ua haujlwm ntawm lub zog hloov hluav taws xob siab - uas qhov chaw xav tau ntau dua ntawm electrode thermal-shock kuj thiab oxidation kuj.
Tom qab thawj melting, molten hlau yog feem ntau pauv mus rau ib tug ladle rauv rau theem nrab refining - kho chemistry, kub thiab inclusions ua ntej casting. Ladle furnaces siv graphite electrodes los ua kom sov thiab tuav cov hlau ntawm qhov kub thiab txias. Vim hais tias cov ladle furnaces ua haujlwm ntawm qis zog thiab luv arc tshaj li melting furnaces, electrode noj ib tonne qis dua, tab sis zoo ib yam, txhim khu kev qha electrodes tseem tseem ceeb rau kev tswj kub.
Submerged arc furnaces tsim ferroalloys (ferrosilicon, ferrochrome, ferromanganese), silicon hlau, phosphorus, thiab lwm yam khoom uas tsis yog-ferrous. Ntawm no cov electrodes yog immersed nyob rau hauv tus nqi, thiab tam sim no dhau los ntawm lub nra los ua kom sov los ntawm kev ua hauj lwm. Cov tshuab hluav taws xob no tuaj yeem siv graphite electrodes lossis, nce, loj dua kab hluav taws xob electrodes loj rau kev ua haujlwm tsis tu ncua ntawm kev sib tw ntev.
Kev xaiv cov electrode kom raug yog qhov sib npaug ntawm cov khoom siv hluav taws xob, kev ua haujlwm thiab cov nqi tag nrho ntawm cov tswv cuab. Ua haujlwm los ntawm cov kauj ruam no:
Electrode noj yog ib txwm hais nyob rau hauv kilograms ib tonne ntawm steel tsim (kg / t). Kev nkag siab txog cov txheej txheem poob tseem ceeb pab koj cov neeg muab khoom lag luam thiab txo cov nqi:
Cov khoom siv tag nrho yog los ntawm kwv yees li 1.2-2.5 kg / t rau niaj hnub UHP rauv kom muaj nuj nqis ntau dua rau RP electrodes thiab cov cub tawg me me. Txhua 0.1 kg / t txo yog tus nqi ncaj qha txuag ntawm cov khoom siv hluav taws xob siab - uas yog vim li cas electrode zoo thiab xaiv qib raug teeb meem ntau heev.
Xaiv cov qib zoo electrode, txoj kab uas hla thiab lub txiv mis configuration muaj qhov cuam tshuam ncaj qha rau koj cov khoom tsim tau melting thiab tus nqi ib tonne ntawm cov hlau. Raws li cov kws tshaj lij graphite electrode chaw tsim khoom thiab cov chaw muag khoom, peb muab RP, HP thiab UHP electrodes hauv txoj kab uas hla ntawm 75 hli mus rau 800 hli, nrog rau daim ntawv pov thawj tag nrho ntawm kev tshuaj xyuas thiab kev txhawb nqa rau qhov cub sizing.
QhiaZhen Ib koj lub cub tawg hom, transformer fais fab thiab tam sim no xav tau, thiab peb yuav pom zoo cov lus qhia tshwj xeeb nrog cov lus sib tw.
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