Tsis-ferrous hlau Casting

Ferrous hlau yog dav siv nyob rau hauv engineering kev lag luam vim hais tias ntawm lawv superiority, ntau yam ntawm txhua yam khoom thiab cov nqi qis. Txawm li cas los xij, cov hlau tsis muaj hlau kuj tseem siv rau hauv ntau daim ntawv thov rau lawv cov khoom tshwj xeeb piv rau ferrous alloys txawm tias lawv feem ntau raug nqi siab. Cov khoom siv uas xav tau tuaj yeem tau txais hauv cov alloys los ntawm kev ua haujlwm hardening, hnub nyoog hardening, thiab lwm yam, tab sis tsis yog los ntawm cov txheej txheem kev kho cua sov uas siv rau ferrous alloys. Qee cov ntaub ntawv tseem ceeb uas tsis yog-ferrous nyiam yog aluminium, tooj liab, zinc, thiab magnesium

1. Aluminium

Ntawm tag nrho cov non-ferrous alloys, aluminium thiab nws cov alloys yog qhov tseem ceeb tshaj plaws vim lawv cov khoom zoo heev. Qee yam ntawm cov khoom ntawm ntshiab txhuas uas nws siv hauv kev lag luam engineering yog:

• 1) Cov thermal conductivity zoo (0.53 cal / cm / C)
• 2) Cov khoom siv hluav taws xob zoo heev (376 600 / ohm / cm)
• 3) Qhov hnyav tsawg (2.7 g / cm3)
• 4) Tsawg melting point (658C)
• 5) Zoo heev corrosion kuj
• 6) Nws yog nontoxic.
• 7) Nws muaj ib qho ntawm qhov siab tshaj plaws reflectivities (85 mus rau 95%) thiab tsawg heev emissivity (4 mus rau 5%)
• 8) Nws yog mos heev thiab ductile vim nws muaj kev tsim khoom zoo heev.

Qee cov ntawv thov uas cov ntshiab txhuas feem ntau yog siv rau hauv cov khoom siv hluav taws xob, cov khoom siv hluav taws xob, cov cua txias, cov khoom siv kho qhov muag thiab lub teeb pom kev, thiab cov ntawv ci thiab cov khoom ntim.

Txawm hais tias cov kev siv tau zoo saum toj no, cov ntshiab aluminium tsis yog siv dav vim tias muaj teeb meem hauv qab no:

• 1) Nws muaj zog tensile tsawg (65 MPa) thiab hardness (20 BHN)
• 2. Nws yog ib qho nyuaj heev rau welding los yog solder.

Txhua yam khoom ntawm aluminium tuaj yeem txhim kho tau zoo los ntawm alloying. Cov ntsiab lus tseem ceeb ntawm alloying siv yog tooj liab, manganese, silicon, nickel thiab zinc.

Aluminium thiab tooj liab tsim cov tshuaj lom neeg CuAl2. Tshaj qhov kub ntawm 548 C nws dissolves tag nrho hauv cov kua txhuas. Thaum qhov no yog quenched thiab artificially aged (ntev tuav ntawm 100 - 150C), ib tug hardened alloy yog tau. Lub CuAl2, uas tsis yog hnub nyoog tsis muaj sij hawm los nag los ntawm cov khoom siv ntawm txhuas thiab tooj liab thiab yog li nyob rau hauv ib qho chaw tsis ruaj khov (super-saturated ntawm chav tempera ture). Cov txheej txheem kev laus precipitates zoo heev ntawm CuAl2, uas ua rau lub zog ntawm cov hlau. Cov txheej txheem no hu ua kua hardening.

Lwm cov ntsiab lus alloying siv yog li 7% magnesium, mus txog 1. 5% manganese, mus txog 13% silicon, mus txog 2% npib tsib xee, mus txog 5% zinc thiab txog li 1.5% hlau. Dhau li ntawm cov no, titanium, chromium thiab columbium kuj tseem tuaj yeem ntxiv rau hauv feem pua ​​​​me me. Cov muaj pes tsawg leeg ntawm ib co raug txhuas alloys siv nyob rau hauv tas mus li molding thiab tuag casting yog muab nyob rau hauv Table 2. 10 nrog rau lawv daim ntawv thov. Cov cuab yeej cuab tam xav tau ntawm cov ntaub ntawv no tom qab cov no tau nrum siv cov pwm ruaj khov lossis siab tuag casting yog qhia hauv Table 2.1

2. Tooj

Zoo ib yam li txhuas, tooj liab ntshiab kuj pom dav siv vim nws cov khoom nram qab no

• 1) Cov hluav taws xob conductivity ntawm cov tooj liab ntshiab yog siab (5.8 x 105 / ohm / cm) hauv nws daim ntawv purest. Tej yam me me impurity coj mus rau qhov conductivity drastic. Piv txwv li, 0. 1% phosphorous txo cov conductivity los ntawm 40%.
• 2) Nws muaj cov thermal conductivity siab heev (0. 92 cal / cm / C)
• 3) Nws yog cov hlau hnyav (qhov tshwj xeeb lub ntiajteb txawj nqus 8.93)
• 4) Nws tuaj yeem nkag tau ua ke los ntawm brazing
• 5) Nws tiv taus corrosion,
• 6) Nws muaj xim zoo nkauj.

Ntshiab tooj liab yog siv nyob rau hauv kev tsim hluav taws xob xaim, tsheb npav, kis kab mob, tubing tub yees thiab kav.

Mechanical zog ntawm tooj liab nyob rau hauv nws purest lub xeev tsis zoo heev. Nws yog mos thiab kuj tsis muaj zog. Nws tuaj yeem raug alloyed profitably los txhim kho cov khoom siv kho tshuab. Lub ntsiab alloying ntsiab siv yog zinc, tin, lead thiab phosphorous.

Cov alloys ntawm tooj liab thiab zinc yog hu ua tooj dag. Nrog zinc cov ntsiab lus mus txog 39%, tooj liab tsim ib theem (α-theem) qauv. Xws li alloys muaj siab ductility. Cov xim ntawm cov hlau tseem liab mus rau zinc cov ntsiab lus ntawm 20%, tab sis dhau ntawd nws dhau los ua daj. Ib qho khoom siv thib ob hu ua β-theem tshwm sim ntawm 39 txog 46% ntawm zinc. Nws yog tiag tiag inter-metallic compound CuZn uas yog lub luag hauj lwm rau qhov nce hardness. Lub zog ntawm tooj dag tau nce ntxiv thaum me me ntawm manganese thiab npib tsib xee ntxiv.

Cov alloys ntawm tooj liab nrog tin yog hu ua bronzes. Lub hardness thiab lub zog ntawm bronze nce nrog ib tug crease nyob rau hauv cov ntsiab lus tin. Lub ductility kuj raug txo nrog qhov nce hauv tin feem pua ​​​​ntawm 5. Thaum txhuas ntxiv (4 mus rau 11%), qhov tshwm sim alloy yog hu ua aluminium bronze, uas muaj kev cuam tshuam ntau dua corrosion. Bronzes yog cov nqi sib piv piv rau tooj dag vim muaj cov tin uas yog cov hlau kim.

3. Lwm yam uas tsis yog-ferrous hlau

Zinc

Zinc feem ntau yog siv rau hauv engineering vim nws qhov kub tsis tshua muaj melting (419.4 C) thiab siab dua corrosion kuj, uas nce nrog purity ntawm zinc. Kev tiv thaiv corrosion yog tshwm sim los ntawm kev tsim cov oxide txheej tiv thaiv ntawm qhov chaw. Cov ntawv thov tseem ceeb ntawm zinc yog nyob rau hauv galvanizing los tiv thaiv hlau los ntawm corrosion, nyob rau hauv kev lag luam luam ntawv thiab rau tuag casting.

Qhov tsis zoo ntawm zinc yog qhov muaj zog anisotropy nthuav tawm nyob rau hauv deformed tej yam kev mob, tsis muaj qhov seem stability nyob rau hauv cov laus tej yam kev mob, ib tug txo nyob rau hauv tej lub zog ntawm qhov kub thiab txias thiab susceptibility rau inter-granular corrosion. Nws tsis tuaj yeem siv rau kev pabcuam siab tshaj qhov kub ntawm 95.C vim tias nws yuav ua rau txo qis zog tensile thiab hardness.

Nws siv dav hauv kev tuag castings yog vim nws yuav tsum tau qis qis, uas ua rau muaj kev tuag ntau dua piv rau lwm cov hlau tuag casting. Ntxiv mus, nws muaj machinability zoo heev. Kev ua tiav tau los ntawm zinc diecasting feem ntau yog tsim nyog los lav kev ua haujlwm ntxiv, tshwj tsis yog tshem tawm cov flash tam sim no hauv lub dav hlau parting.

Magnesium

Vim lawv lub teeb yuag thiab zoo txhua yam muaj zog, magnesium alloys yog siv nyob rau hauv high speeds. Rau tib lub zog, magnesium alloys yuav tsum tsuas yog 37. 2% ntawm qhov hnyav ntawm C25 steel yog li txuag hauv qhov hnyav. Ob qho tseem ceeb alloying ntsiab siv yog aluminium thiab zinc. Magnesium alloys tuaj yeem yog xuab zeb cam khwb cia, pwm mus tas li lossis tuag cam khwb cia. Cov khoom ntawm cov xuab zeb-cam khwb cia magnesium alloy Cheebtsam yog piv nrog cov ntawm cov pwm mus tas li cam khwb cia lossis cov khoom pov tseg tuag. Cov alloys tuag-casting feem ntau cov phooj ywg muaj cov ntsiab lus tooj liab siab kom tso cai rau lawv los ntawm cov hlau thib ob kom txo cov nqi. Lawv yog siv los ua lub tsheb log, crank case, thiab lwm yam. Cov ntsiab lus siab dua, qhov siab dua qhov kev siv lub zog ntawm magnesium-wrought alloys xws li dov thiab forged Cheebtsam. Magnesium alloys tuaj yeem yooj yim welded los ntawm feem ntau ntawm cov txheej txheem vuam ib txwm. Cov cuab yeej tseem ceeb ntawm magnesium alloys yog lawv cov machinability siab. Lawv tsuas xav tau li 15% ntawm lub zog rau machining piv rau cov pa roj carbon tsawg.