Ua rau txias dov tawg ntawm tooj dag strips thiab lawv cov kev tiv thaiv
Brass yog ib qho tseem ceeb ntawm cov khoom siv tooj liab. Vim nws "kev ua haujlwm siab thiab tus nqi qis", nws tau siv dav hauv ntau yam kev lag luam hauv lub tebchaws. Brass strip muaj zoo nkauj luster, zoo zog, toughness thiab corrosion kuj. Nws tau nce siv hauv kev lag luam teeb pom kev zoo, kho kom zoo nkauj thiab lwm yam lag luam, thiab muaj kev lag luam dav dav.
Lub ntiaj teb cov peev txheej tooj liab yog txwv. Nyob rau hauv xyoo tas los no, nrog rau kev thov tooj liab, tus nqi tooj liab tau nce siab heev. Yog li ntawd, nyob rau hauv kev sib tw tooj liab ua kev lag luam, tshwj xeeb tshaj yog qee cov lag luam me thiab nruab nrab, lawv feem ntau siv cov khoom qub los tsim cov tooj dag strips. Txawm li cas los xij, qhov muag tsis pom kev siv cov khoom qub qub yuav ua rau muaj teeb meem ntau rau kev tsim khoom thiab cov khoom zoo. Nyob rau hauv kev tsim cov tooj dag strips nyob rau hauv lub Hoobkas uas tus sau ua hauj lwm, dov cov kab nrib pleb los yog tej kab nrib pleb feem ntau tshwm nyob rau saum npoo ntawm strips, uas ua rau ib tug txaus ntshai tus naj npawb ntawm cov khoom hloov kho thiab cov khoom seem, cuam tshuam loj heev efficiency thiab ua rau loj nyiaj txiag poob. Kab lus no feem ntau txheeb xyuas qhov ua rau txias dov tawg ntawm tooj dag strips, thiab tawm tswv yim kev tswj hwm thiab kev tiv thaiv kev ntsuas, uas muaj qee qhov theoretical thiab cov tswv yim tseem ceeb rau kev tsim khoom.
1. Brass sawb txheej txheem
Nyob rau hauv zus tau tej cov niaj hnub tooj dag daim hlau thiab strips, kab rov tav nruam casting feem ntau yog siv kom tau cov coils loj ntawm hnyav billet [2]. Tom qab homogenization annealing thiab nto milling, lub billet yog txias dov ntawm tus nqi siab, thiab ces intermediate annealing thiab tiav dov yog ua. thiab lwm yam txheej txheem. Tsis tas li ntawd, txhawm rau txhawm rau tshem tawm cov kev ntxhov siab sab hauv thiab txhim kho lub phaj zoo, kev kho cua sov thiab ncab, khoov thiab ncaj yuav tsum tau nqa tawm. Cov txheej txheem tseem ceeb yog: batching, smelting * kab rov tav nruam casting, homogenization annealing * milling, txias ntxhib dov * intermediate annealing - hauv qab dov - hauv qab annealing * tiav cov khoom dov * degreasing, tu, passivation kev kho mob * stretching dabtsi yog khoov thiab straightening * tsis tshua muaj kub. kev kho mob * tshuaj xyuas * slitting. Pob. Los ntawm kev tswj xyuas cov txheej txheem tsis zoo, kev tsim cov hlau nplaum zoo thiab cov strips tuaj yeem ua tiav.
2. Kev tshuaj xyuas ntawm qhov ua rau txias dov tawg
Thaum lub sij hawm dov txheej txheem, thaum lub zos deformation ntawm cov hlau ntau tshaj nws qhov kawg deformation degree, lub bonding quab yuam ntawm atoms raug puas tsuaj thiab tawg tshwm sim. Raws li hom kev tawg tawg, tawg tuaj yeem muab faib ua intergranular cracking thiab transgranular cracking. Kev nthuav dav ntawm cov kab nrib pleb ua raws li lub hauv paus ntsiab lus ntawm kev siv hluav taws xob tsawg kawg nkaus, uas yog, kev nthuav dav ntawm cov kab nrib pleb ib txwm ua raws cov kev taw qhia uas lub zog sib txuas ntawm atomic tsis muaj zog tshaj. Feem ntau ntawm cov kab nrib pleb nyob rau hauv cov ntaub ntawv polycrystalline yog intergranular fractures, uas yog tshwm sim los ntawm lub weakening ntawm grain interface rau ib co yog vim li cas [st]. Cov laj thawj no suav nrog: nag lossis daus ntawm lub nkig thib ob ntawm qhov ciam teb nplej; qhov kub kub cuam tshuam tsis muaj zog rau qhov sib cuam tshuam lossis kev sib cais ntawm impurity atoms rau thaj tsam lis; qhov tsis muaj zog ntawm kev sib cuam tshuam ntawm cov qoob loo ciam teb thiab ib puag ncig, xws li kev ntxhov siab corrosion, thiab lwm yam. Qhov tawg ntawm tooj dag strips feem ntau belongs rau thawj ob qho laj thawj. Thaum muaj teeb meem cov ntsiab lus los yog cov theem teeb meem tshwm sim, grain ciam ciam sib cais los yog rov qab segregation yog tshwm sim, uas ua rau lub weakening ntawm lub bonding quab yuam ntawm grain ciam teb, yog li ua rau intergranular cracking los yog puas nyob rau hauv qhov kev txiav txim ntawm kev nyuaj siab [`].
2.1 Kev cuam tshuam ntawm metallographic qauv
Siv 6H5 tooj dag ua piv txwv, nws tuaj yeem pom los ntawm Cu-Zn theem daim duab qhia tias H65 yog ib theem ntawm tooj dag nyob rau hauv qhov txias txias. Txawm li cas los xij, hauv kev tsim khoom tiag tiag, qhov txias txias yog nrawm dua thiab nws tsis yog-equilibrium crystallization. Cov riam theem tsim los ntawm cov tshuaj tiv thaiv peritectic tsis muaj nyob rau lub sijhawm. Nws tau hloov dua siab tshiab rau hauv theem A thiab tseem nyob hauv lub koom haum [']. Lub plasticity ntawm riam theem ntawm chav tsev kub yog txawv los ntawm cov theem. Thaum lub sij hawm dov txheej txheem, lub deformation ntawm ob theem yog unevenly, uas yuav inevitably ua rau lub tsim ntawm plam dislocations ntawm lub interface ntawm ob theem. Thaum cov kev ntxhov siab hauv zos tshwm sim los ntawm kev tsis sib haum xeeb mus txog ib theem ntawm lub sijhawm no, lub hli theem matrix tau tawg los ua qhov tawg, thiab tom qab ntawd cov kab nrib pleb yog tsim nyob rau hauv qhov kev txiav txim ntawm kev ntxhov siab ntxiv tensile. Yog li ntawd, tus naj npawb thiab kev faib tawm ntawm Yin theem muaj kev cuam tshuam tseem ceeb rau qhov txias dov tawg ntawm H65 tooj dag.
muaj qhov cuam tshuam tseem ceeb. Thaum muaj ntau lub hli theem, lawv tsis tu ncua ntawm cov dendrites nyob rau hauv ib tug network duab. Cov qauv network no tuaj yeem tiv taus kev ntxhov siab ntau dua thiab tsis tshua muaj peev xwm tsim cov kab nrib pleb; thaum muaj ob peb lub hli theem, vim qhov kev ncua deb ntawm cov riam theem, nws tsis yooj yim rau cov kab nrib pleb. Kev ntxhov siab concentration yog tsim, yog li cov kab nrib pleb yuav tsis tshwm sim. Kev tshawb fawb qhia tau hais tias v1 [, thaum lub ntim feem ntawm riam theem yog ntau tshaj 20% los yog tsawg tshaj li 5%, lub high-temperature plasticity ntawm H65 tooj dag yog kuj zoo. Txawm hais tias lub plasticity ntawm lub hli theem yog zoo dua li ntawm ib theem nyob rau hauv kub dov tej yam kev mob, yog hais tias qhov kev nyuaj siab ntawm lub theem ciam teb yog concentrated, tawg kuj yuav tshwm sim.
Cov nplej loj ntawm tooj dag kuj muaj qee yam cuam tshuam rau nws qhov tawg. Qhov loj ntawm cov nplej loj, qhov ntau dua qhov nyiam ntawm kev tawg. Los ntawm kev tsom xam ntawm cov qauv metallographic ntawm tooj dag, nws paub tias cov nplej nyob rau hauv txheej txheej yog thicker dua li txheej txheej, thiab txheej txheej yog nyob rau hauv ncaj qha kev sib cuag nrog nruab nrab, yog li nws yog ib qho yooj yim mus ua cracking. Kev tshawb fawb qhia tias kev tawg yog cuam tshuam rau qhov tsis sib xws txias deformation; Kev sib cais ntawm cov ntsiab lus hlau kuj muaj qhov tsis zoo.
2.2 Cov nyhuv ntawm impurities
Cov teebmeem ntawm ob peb impurities ntawm tooj dag ntau lawm yog raws li nram no [']:
Hlau: muaj nyob ua ib qho impurity thiab tsis muaj kev cuam tshuam loj rau cov khoom siv tshuab. Lub solubility ntawm hlau nyob rau hauv tooj dag yog heev me me, thiab hlau-nplua nuj theem impurity ntsiab lus feem ntau faib nyob rau hauv lub matrix, uas muaj cov nyhuv ntawm refining cov nplej;
Lead and lead: Lead is a harmful impurity in simple brass and is distributed in granular form on the fusible eutectic at the grain boundary. when. When the lead content of brass is >0.03%, tawg feem ntau tshwm sim thaum lub sij hawm dov. Cov nyhuv ntawm kev paub tsis meej yog kwv yees li qub;
Antimony: Raws li qhov kub thiab txias, qhov solubility ntawm antimony nyob rau hauv ib tug tooj dag txo sharply, thiab nkig compound CuZbS precipitates, uas yog muab faib nyob rau hauv ib tug network, heev ua rau lub txias ua hauj lwm zoo ntawm tooj dag; Phosphorus: tsis tshua muaj cov tshuaj hauv Cu-zn alloy, hauv a Phosphorus cov ntsiab lus hauv tooj dag
Yog tias nws tshaj {{0}}.05% mus rau 0.06%, ib theem nkig Cu3P yuav tshwm sim, txo cov yas ntawm tooj dag;
Arsenic: Lub solubility ntawm arsenic nyob rau hauv tooj dag nyob rau hauv chav tsev kub yog<0.1%. Excessive amounts will produce a brittle compound Cu3sA, which is distributed on the grain boundaries and reduces the plasticity of brass. Containing 0.02% to 0.05% As, which can prevent dezincification of brass and improve corrosion resistance.
2.3 Kev cuam tshuam ntawm kev tsim khoom siv tshuab
Feem ntau, tooj dag strips yog tawg ntawm cov npoo tab sis tsis tawg hauv nruab nrab. Muaj ob qho laj thawj. Ua ntej, thaum qhov tseeb yob hom nyob rau hauv ntau lawm yog ib tug ca yob, lub ntug hlau muaj ib tug nyiam ntws mus rau sab, yog li nws longitudinal txaus ceev yog qis dua cov hlau nyob rau hauv nruab nrab ntawm lub sawb. Txij li cov sawb yog tag nrho, qhov deformations ntawm nruab nrab thiab ntug qhov chaw yog kev sib nrig sib tuav. Yog li ntawd, cov hlau nyob rau hauv nruab nrab ntawm lub phaj yog raug rau compressive kev nyuaj siab, thaum cov hlau ntawm ob sab yog raug rau tensile kev nyuaj siab. Thaum lub zog tensile ntawm cov npoo tshaj lub zog txwv ntawm cov hlau, kev tawg (cracking) yuav tshwm sim. Thib ob, thaum lub sij hawm dov, qhov kub nce siab ua rau lub yob tsim thermal convexity, uas ua rau nruab nrab yob qhov sib txawv me me thiab cov npoo yob qhov sib txawv kuj loj dua. Yog li ntawd, lub hauv paus txo tus nqi yog loj thiab cov ntug txo tus nqi yog me me. Qhov no yuav ua rau cov hlau ntws hauv nruab nrab siab tshaj qhov ntawm cov npoo, ua rau muaj kev nyiam ntawm ntug kev tawg ntawm cov sawb. Tsis tas li ntawd, cov yam ntxwv xws li kev tswj tsis raug ntawm kab rov tav nruam casting txheej txheem tsis zoo thiab ntau dhau ntawm dov tus nqi yuav ua rau yellowing. Cov kab nrib pleb tshwm sim thaum lub sij hawm dov ntawm cov sawb tooj liab.
3. Kev tiv thaiv kev tiv thaiv txias dov tawg
3.1 Cov khoom siv raw
① Cov impurity muaj pes tsawg leeg ntawm cov ntaub ntawv qub hloov pauv zoo heev, yog li cov ntaub ntawv qub ntawm tib pawg yuav tsum sib xyaw ua ke ua ntej siv, uas yuav pab kom cov impurity muaj pes tsawg leeg ntawm txhua tus nqi kom zoo ib yam. Qhov yuav tsum tau ua ua ntej yog tswj Pb cov ntsiab lus ntawm qhov kawg ingot hauv 0.02%. Yog tias cov ntsiab lus bP siab dhau lawm, kev tawg yooj yim tuaj yeem tshwm sim;
② Txheeb xyuas cov ntsiab lus bP ntawm cov khoom qub yuav. Thaum cov ntsiab lus bP loj heev, nws yuav tsum tau siv rau hauv kev faib ua feem kom txo tau cov ntsiab lus bP nyob rau hauv ingot;
③Thaum txheeb cov khoom qub, ua tib zoo saib xyuas kev tu cev kom tsis txhob muaj lwm yam hlau tsis huv thiab cov khoom siv tooj dag qub los ntawm kev sib xyaw.
3.2 Cov txheej txheem ntau lawm
① Tswj cov txheej txheem melting thiab casting txheej txheem, tsim nyog txo qhov kub ntawm casting, ua kom txias txias, thiab txhim kho cov txheej txheem nres kom txo cov teeb meem ntawm bP, iB thiab lwm yam impurities;
② Txo qhov ua tiav thiab nce qhov nruab nrab annealing tuaj yeem ua kom tsis txhob tawg los ntawm kev ntxhov siab nyob rau theem ciam teb. Txoj kev no yog qhov yooj yim thiab yooj yim rau kev siv, thiab tau raug txheeb xyuas hauv kev tsim khoom tiag tiag;
③ Rau cov kab nrib pleb tsis tu ncua, cov yob yas tuaj yeem raug txo kom tsim nyog lossis cov yob dabtsi yog khoov tuaj yeem hloov kho kom txo tau cov ntug tensile kev nyuaj siab, yog li zam los yog txhim kho ntug tawg.
3.3 Tswj kev ntsuas rau metallographic qauv
① Nws yog qhov tsim nyog rau kev hloov pauv ntawm cov qauv casting ntawm cov tsis sib xws columnar crystals thiab equiaxed crystals rau hauv cov qauv nrog cov yas zoo thiab tsim nyog rau kev ua haujlwm, thiab kev ua haujlwm dhau los thiab dov ceev tsis yooj yim kom loj dhau;
② Qee qhov kev hloov pauv yuav tsum tau ntxiv kom tsim nyog thaum smelting kom ua tiav cov txiaj ntsig ntawm kev tshem tawm impurities, degassing thiab refining nplej. Yuav kom daws tau qhov teeb meem ntawm cov kab nrib pleb tawg, nws yog ib qho tsim nyog yuav tsum tau txo cov ntsiab lus bP ntawm cov ciam teb, qhov tsawg dua qhov zoo dua. Txog rau qhov kawg no, ib qho me me ntawm lub ntiaj teb tsis tshua muaj ntxiv. Cov ntsiab lus tsis tshua muaj hauv ntiaj teb tuaj yeem tsim cov ntsiab lus siab melting point CePb3 nrog Pb ntawm qhov kub siab tshaj 1100 degree. Thaum cov alloy crystallizes, nws thawj zaug precipitates thiab dhau los ua ib tug uas tsis yog-spontaneous crystal nucleus. Qhov nce ntawm cov siv lead ua nuclei tuaj yeem kho cov nplej thiab ua kom cov qoob loo nce ntxiv, yog li txo Pb cov ntsiab lus ntawm cov ciam teb. CebP3 ntawm cov ciam teb nplej tuaj yeem ua rau muaj zog ntawm cov ciam teb nplej thiab pab tiv thaiv cov qoob loo tawg.
Tus yuam sij rau kev tiv thaiv txias dov cracking ntawm tooj dag strips yog los xyuas kom meej qhov zoo ntawm cov ntaub ntawv raw, tswj cov txheej txheem ntau lawm thiab cov txheej txheem tsis, thiab txhim kho cov qauv alloy.
4. Cov lus xaus
① Muaj ntau yam cuam tshuam rau lub neej ntawm tooj liab alloy extrusion tuag. Ntxiv rau qhov tseem ceeb ntawm kev tuag nws tus kheej xws li cov khoom siv tuag, kev tsim qauv, txheej txheem kev kho cua sov, thiab lwm yam, kev siv thiab kev tu cov tuag kuj tseem ceeb heev;
② Rau qhov loj-tonnage tooj liab alloy extrusion presses, tshwj xeeb tshaj yog thim rov qab extrusion presses, zoo heev yuav tsum tau them rau lub txias ntawm pwm. Txoj kev ua kom txias tsim nyog tuaj yeem tswj xyuas qhov kub thiab txias ntawm qhov extrusion tuag hauv qab lub tempering softening kub yam tsis muaj overcooling qhov khoob thiab tuag, yog li tsis txhob txhaws thiab cuam tshuam qhov zoo ntawm cov khoom extruded;
③ Txoj kev ua kom txias tam sim no yog kua nitrogen txias. Los ntawm kev kho cov kua nitrogen txaus thiab siab, qhov txias txias ntawm pwm tuaj yeem tswj tau, yog li ua kom lub neej ua haujlwm siab tshaj plaws ntawm pwm.
