Cov khoom siv hluav taws xob yog siv dav hauv kev tsim kho tshuab vim tias lawv qhov kev zoo, ntau ntawm cov khoom siv cav thiab cov nqi qis dua. Tseem, cov khoom siv uas tsis yog siv los kuj tseem siv rau hauv ntau cov ntawv thov rau lawv cov khoom tshwj xeeb piv rau ferrous alloys txawm tias lawv cov nqi ntau dhau los. Cov cuab yeej xav tau no tuaj yeem tau txais hauv cov hlau no los ntawm kev ua haujlwm tawv, muaj hnub nyoog ua haujlwm tawv tawv, thiab lwm yam, tab sis tsis dhau los ntawm cov txheej txheem kev kho cua sov siv rau cov khoom siv hlau tsis haum. Qee qhov tseem ceeb ntawm cov khoom siv uas tsis yog tub luam ntawm kev txaus siab yog aluminium, tooj liab, zinc, thiab magnesium
1. Aluminium
Ntawm tag nrho cov ntawv tsis muaj hlau, txhuas thiab nws cov khoom txhuas yog qhov tseem ceeb tshaj plaws vim tias lawv cov khoom zoo heev. Qee qhov ntawm cov khoom ntawm ntshiab txhuas rau qhov uas nws siv rau hauv kev ua haujlwm tshuab yog:
1) Kev ua zoo thermal conductivity (0.53 cal / cm / C)
2) Kev siv hluav taws xob zoo (376 600 / ohm / cm)
3) Tsis tshua muaj huab hwm coj tsawg (2.7 g / cm)
4) Cov ntsiab lus qis (658C)
5) zoo corrosion kuj
6) Nws yog qhov tsis zoo txog.
7) Nws muaj ib qhov kev xav ntau tshaj plaws (85 txog 95%) thiab emissivity tsawg heev (4 txog 5%)
8) Nws yog qhov muag heev thiab ductile los ntawm qhov ua tau los ntawm qhov nws muaj cov khoom lag luam zoo heev.
Qee qhov kev siv uas cov ntshiab txhuas feem ntau siv yog nyob rau hauv cov hluav taws xob hluav taws xob, tshuab hluav taws xob fin cov khoom, cua txias, cov khoom siv kho qhov muag thiab lub teeb, thiab cov ntawv ci thiab cov khoom ntim.
Txawm hais tias cov ntawv thov tau pab saum toj saud, txhuas ntshiab tsis tau dav siv vim yog cov teeb meem hauv qab no:
1) Nws muaj lub zog qes qis (65 MPa) thiab hardness (20 BHN)
2. Nws yog qhov nyuaj heev rau weld lossis solder.
Cov cuab yeej lub zog ntawm aluminium tuaj yeem txhim kho ntau yam los ntawm kev ua kom haum. Tus thawj alloying cov ntsiab lus siv yog tooj, manganese, silicon, nickel thiab zinc.
Aluminium thiab tooj liab tsim cov tshuaj sib txuas ua ke CuAl2. Tshaj li qhov kub ntawm 548 C nws yaj tag nrho hauv cov kua txhuas. Thaum qhov no tau quenched thiab artificially hnub nyoog (tuav ntev ntawm 100 - 150C), lub zog ntawm cov alloy tau. Tus CuAl2, uas tsis muaj hnub nyoog tsis muaj lub sijhawm los nag los ntawm cov kev daws teeb meem ntawm txhuas thiab tooj liab thiab yog li nyob hauv qhov tsis ruaj khov (super-saturated ntawm chav tempera ture). Cov txheej txheem kev laus ua rau cov txheej txheem zoo heev ntawm CuAl2, uas ua rau kom muaj zog ntawm cov xaim. Txoj kev no yog hu ua kev kho cov tawv tawv.
Lwm cov ntsiab lus alloying siv yog li 7% magnesium, txog 1. 5% manganese, nce txog 13% silicon, txog li 2% npib tsib xee, txog 5% zinc thiab li 1.5% hlau. Dhau li ntawm no, titanium, chromium thiab columbium kuj tseem yuav ntxiv cov feem pua me me. Cov sib xyaw ua ke ntawm qee cov txhuas alloys siv nyob rau hauv cov chaw ruaj ruaj molding thiab tuag casting yog muab rau hauv Table 2. 10 nrog lawv cov ntawv thov. Cov cuab yeej siv zog xav tau ntawm cov khoom tom qab cov no tau nrum siv pwm ntev lossis siab tuag casting yog qhia hauv Daim Ntawv 2.1
2. Tooj liab
Zoo ib yam li aluminium, ntshiab tooj liab kuj pom dav daim ntawv thov vim tias nws cov khoom hauv qab no
1) Qhov hluav taws xob hluav taws xob ntshiab ntawm tooj liab yog siab (5.8 x 105 / ohm / cm) nyob rau hauv nws daim ntawv purest. Tej impurity me me coj kev conductivity ruaj. Piv txwv li, 0. 1% phosphorous txo qhov kev coj ua los ntawm 40%.
2) Nws muaj cov ua haujlwm siab heev thermal (0. 92 cal / cm / C)
3) Nws yog cov hlau hnyav (qhia tshwj xeeb zoo 8.93)
4) Nws tuaj yeem tuaj yeem sib koom ua ke los ntawm kev txhuam
5) nws tiv taus corrosion,
6) Nws muaj lub ntsej muag zoo nkauj.
Cov ntshiab tooj liab yog siv rau hauv kev tsim cov xov hluav taws xob, tsheb npav thaiv kab, kis cab hluav taws xob, tubing tub raj thiab xa dej.
Cov cuab yeej khoom siv ntawm tooj liab hauv nws lub xeev purest tsis zoo heev. Nws yog qhov muag muag thiab cov qaug zog. Nws tuaj yeem ua cov hlau ntau kom tau cov txiaj ntsig los txhim kho cov neeg kho tshuab zog. Lub ntsiab alloying siv tau yog zinc, tin, txhuas thiab phosphorous.
Cov alloys ntawm tooj liab thiab zinc yog hu ua brasses. Nrog cov ntsiab lus zinc li 39%, tooj liab ua ib theem (phase-theem) tus qauv. Xws li cov alloys muaj qhov siab ductility. Cov xim ntawm cov alloy tseem liab mus txog ib lub ntsiab lus zinc ntawm 20%, tab sis dhau ntawd los ua daj. Ib qhov txheej txheem thib ob hu ua β-theem tshwm sim li ntawm 39 txog 46% ntawm zinc. Nws yog qhov tseeb nyob hauv qhov chaw sib txuas ntawm cov hlau sib xyaw CuZn uas yog lub luag haujlwm rau qhov kev ua kom muaj zog. Lub zog ntawm tooj dag tau txais ntxiv nce ntxiv thaum mentsis cov manganese thiab npib tsib xee tau ntxiv.
Cov alloys ntawm tooj liab nrog tin yog hu ua tooj liab. Lub hardness thiab lub zog ntawm tooj dag nce nrog ib lub crease hauv cov ntsiab lus tin. Lub ductility tseem txo nrog qhov nce ntawm tin feem pua saum toj 5. Thaum txhuas kuj ntxiv (4 txog 11%), cov txiaj ntsig tau yog lub npe txhuas txhuas bronze, uas muaj qhov xav tau ntau dua corrosion kuj. Bronzes yog qhov muaj nqis sib piv rau cov brasses vim muaj cov tin uas yog hlau kim.
3. Lwm Cov Tsis Muaj Hlau
Zinc
Zinc yog siv ua ntej siv rau hauv kev ua haujlwm engineering vim tias nws lub siab tsis txias (419.4 C) thiab siab dua corrosion, uas nce nrog cov ntshiab ntawm zinc. Qhov kev tiv thaiv corrosion yog qhov tshwm sim los ntawm kev tsim cov tshuaj tiv thaiv oxide rau ntawm qhov chaw. Cov ntawv thov tseem ceeb ntawm zinc yog nyob rau hauv galvanizing los tiv thaiv cov hlau los ntawm kev xeb, hauv kev lag luam luam ntawv thiab rau kev ua kom tuag.
Qhov tsis zoo ntawm cov zinc yog qhov muaj zog anisotropy nthuav tawm nyob rau hauv kev mob tsis zoo, tsis muaj qhov ntev ntawm qhov kev nyab xeeb nyob rau hauv cov laus, qhov txo ntawm kev cuam tshuam lub zog ntawm qis dua kub thiab qhov cuam tshuam rau inter-granular corrosion. Nws tsis tuaj yeem siv rau kev pabcuam saum toj no kub ntawm 95.C vim tias nws yuav ua rau txo ntau hauv lub zog tensile thiab lub zog tawv.
Nws siv dav hauv cov tuag castings yog vim nws xav tau qis qis dua, uas ua rau lub siab tuag lub neej ntau dua piv rau lwm cov tuag casting alloys. Ntxiv mus, nws muaj qhov zoo heev machinability. Qhov ua tiav tau los ntawm zinc diecasting yog feem ntau txaus los lav cov txheej txheem txuas ntxiv, tsuas yog tshem tawm ntawm lub eeb tam sim no hauv qhov dav hlau.
Hlau nplaum
Vim tias lawv lub teeb yuag thiab cov khoom siv dag zog zoo, magnesium alloys siv nyob rau hauv qhov chaw nrawm heev. Rau tib lub nruj, cov hlau nplaum alloys xav tau tsuas yog 37. 2% ntawm qhov hnyav ntawm C25 steel yog li txuag hauv qhov hnyav. Ob lub hauv paus ntsiab lus ntawm alloying siv yog txhuas thiab zinc. Magnesium alloys tuaj yeem xuab zeb nrum, ruaj khov pwm nrum lossis tuag cam khwb cia. Cov yam ntxwv ntawm cov xuab zeb-cam khwb cia magnesium alloy Cheebtsam yog sib piv nrog cov ntawm cov pwm uas nyob ruaj khov los yog tuag-cam khwb cia Cheebtsam. Cov hlau-tuag alloys feem ntau ally muaj cov ntsiab lus tooj liab yog li tso cai rau lawv los ua los ntawm cov hlau theem nrab kom txo nqi. Lawv siv rau kev tsav tsheb cov tsheb sib tw, cov rooj plaub crank, thiab lwm yam Cov ntsiab lus siab dua, kev siv lub zog ntau dua ntawm cov hlau nplaum uas muaj hlau ntau xws li dov thiab cov khoom sib xyaw. Hlau nplaum alloys tuaj yeem nkag tau yooj yim los ntawm feem ntau ntawm cov txheej txheem vuam ib txwm muaj. Cov khoom siv tau txais txiaj ntsig zoo ntawm cov hlau alloys yog lawv lub siab siv tau. Lawv tsuas xav tau kwv yees li 15% ntawm lub zog rau kev machining piv nrog cov hlau qis.
Sijhawm Post: Dec-18-2020