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NGHIEN cufu - TRAO D(^l NGHIEN c f l u ANH Hl/ONG CUA CHE DO EP T H I E U KET D U O I AP LUc DEN DO XOP VA MAT DO VAT LIEU BQT THEP HOP KIM HOA THAP LAM BANH RANG A STUDY ON THE INFLUENCE OF CAKING CONDITIONS ON MATERIAL POROSITY AND DENSITY OF POWDER LOW-ALLOY STEEL FOR CHAIN SPROCKETS DS Dinh Luvng, H i Minh Hiing Vien Nghien ciiu Co - Bd Cdng Thucmg TOM TAT Bai bdo dh cap dSn sit dnh hicdng ciia nhiet do, thoi gian vd dp lice ep nong bdt thep h kim hoa thap, nhgn du^c nghien trgn them vdo hot sdt cua hang HOGANAS mpt vdi nguyin to v hdm Iuang dti&i % khdi lifong Cr, Ni, W, den xdp vd mat dg tuang ung cua vgt lieu, nhdm nd cao tinh chdt sir ditng ldm bdnh rdng xich ddu hop sd bo truydn ddng xe mdy HONDA C nghe ep ndng cho phep nit ngdn thdi gian thieu ket xudng chi khodng 2^3 phut du&i dp life bdng khodng 10 ldn nhd han dp luc ep bdi tgo hinh a trgng thdi ngugi truae thieu ket md vdn d bdo dugc vgt lieu thieu ket sa bd Tuy nhien, de ddm bdo ca ly tinh yeu edu cho viec che tgo bdnh r vgt lieu bdt thep hgp kim hda thdp sau ep nong ldn cdn phdi dugc biin dgng a trgng thdi nong ldn khudn kim logi nhdm tgo ung sudt nen nhieu chieu mai dgt dugc mdt gdn kim logi dd xit ABSTRACT In this paper, the influence of temperature, time and pressure when hot pressing a special kind ofpowder low-alloy steel on its porosity and the corresponding density is studied to enhance physico-mechanical properties of driven chain sprockets for HONDA motorbikes The experimentd material was made by milling and adding an amount ofless than 2% ofCr, Ni and W into the HOGAN iron powder The hotpressing technology makes it possible to shorten sintered time to 2-3 minute the pressing force is 10 times smgller than that ofcold forming To satisfy requirements physico-mec properties for chain sprockets, the material must be hotformed again cfier apreliminary hotpressin above 2-stage process needed to induce multi-direction compressive stresses, making the materia as high as that ofsolid metals TAP OHi CO KHl VlfiT NAM • S6 10 (Thing 10 nim 2012) NGHIEN CIJfU-TRAODCl D^T VAN Dfe Ta da bidt rang hai yeu td quyet dinh chdt lugng cfla chi tidt ldm bdng cdng ngh? luy?n kim bdt la dd xdp ho$c mdt dd va phan hda hoc Cac nguyen td hop kim bgt sdt cd tac dyng tuong tu nhu sdt thep thudng Vi du: Neu cho thdm mdt lugng nhd Ni, Cr, Mo, Mn, Cu, W, TiC ed tdc dyng lam tdng CO ly tinh Thdm C tdng khd nang nhiet luydn t^o pha mactenxit, cdn neu tang Cr, Ni, Mo thdnh thep khdng ri Rieng ddi vdi Cu vdi hdm lugng kha ldn la trudng hgp rieng bi|t cfla sdt bgt va Ihep cd hieu qua hda ben cao vd hay dugc flng dyng nhat Sy cd m^t cfla Cu sd ndng cao CO tinh cfla hgp kim d tr^ng thai fl hdm lugng Cu la -^10 % khdi lugng, va cd the tien hanh hda gia de cd sy bien cflng bdi tiet pha phdn tdn Xuat phdt tfl quan didm do, cdc cdng trinh [1], [3], [4] dd dd cdp ddn kdt qua nghidn cuu thuc nghidm dnh hudng cfla thdi gian nghien trdn bdt thdp ndn nhdp cfla hang HOGANAS (Thyy Didn) h$ [Fe - Cu - Zn-Steorat - C-graphit] vdi mdt sd nguyen td hgp kim hda d ham lugng thdp nhu: Cr, Ni, W, TiC (% kh6i lugng 0,5 -^ 2,5 % m6i nguyen td) vdi cae mflc quy hoach lya chgn va nhan dugc thdnh hdn hgp bdt nguyen lieu dau vdo khac sfl dyng cho chd tao tay bien HD-GF6 ddng CO HONDA-ClOO/110 vd banh rang xich HDGF6 Trong bdi bao ndy, nhdm nghidn cflu trinh bdy mdt sd kdt qud ep ndng (tflc thidu kdt dudi dp lye thdp) bdt thep hgp kim hda thdp vdi myc tidu chi tao bdnh rang xich tdi truydn ddng cfla xe may HONDA [4] PHlTOfNG PHAP THI NGHIEM Trong cdng trinh [4] da gidi thi^u dieu ki?n quy ho^ich thye nghidm phdi lieu ddu vao dd nghidn trdn t^o bgt thdp hgp kun hda thdp, chuin bi cho cdc thi nghidm dp ndng phdi bdnh rdng xich HD-GF6 Thanh phin hda hgc bOt sdt HOGANAS lam co sd la he [2 % Cu + 0,8 % C + 0,8 % Zn-Steorat va Fe - cdn lai], cdn cac bdt hgp kim hda trgn them la [0,5 -^ 2,5 % Cr + 0,5 - 2,5 % Ni + 0.5 - 1,5 % W] Tren hinh la la dnh SEM hot sdt H O G A N A S ; hinh lb bdt niken; hinh Ic — bgt crdm; hinh I d - b0t vonphram trudc nghien trdn Hinh la dnh SEM bdt thep hgp kim hda thdp sau nghien trgn vdi thdi gian vd gid Sau nhan dugc bgt ddu vdo nghidn trOn tfl hot sdt cfla hang HOGANAS va cdc b^t hgp kim hda Ni, Cr, W cd phdn thay ddi nhu da trinh bay d phin trdn, chgn cac ehd thi nghidm dp ndng tao mdu quy hoach thye nghidm vdi didu kidn quy hoach thuc nghidm nhu sau: 1) Ap lye ep ndng p^^ = 10; 20; 30 MPa, bude didu chinh Id 10 MPa; 2) Nhidt dd ep ndng T^„ = 1200; 1250; 1300°C, bude didu chinh la 50°C; 3) Thdi gian gift nhidt t^^ = 2,0; 2,5; 3,0 phflt, budc didu ehinh la 0,5 phflt KET QUA THf NGHIfM VA BAN LUAN: 3.1 Chuan bi bot nguy&n lidu: Bdt nguydn lidu ndn vd bgt hgp kim hda bd sung trudc dua vao nghien trgn dugc phan tich thdnh phdn hda hgc bang phuofng phdp X-ray, sfl dung thi^t bj VNU-HNSIEMENS D5005 va ddng thdi chup dnh SEM de xac djnh hinh thai hat cfla chflng tren kinh hien vi dien tfl quet tai bg mdn "Vdt if chdt rdn", Trudng Dai hgc Qudc gia Hd Ndi Trdn hinh la la dnh SEM bdt nguyen li?u nen h? [Fe - Cu- Zn-Stporat - C-graphit] nhap cfla hang H O G A N A S (Thyy Didn), edn hinh b - bgt niken (Ni); hinh Ic la bgt crdm (Cr); hinh Id - bdt Vonphram trudc nghien trgn vdi bgt sdt ndn Ta nhdn thdy bpt tiiep Thyy Didn (hinh la) vd bgt crdm (hinh c) ed hinh ddng cdc hat bdt khac vdi hinh cau, ^ cdn bdt niken (hinh b) - gan cau TAP CHf CO KHl VlfiT NAM V Sd 10 (Thdng 10 ndm 2012) NGHIEN cufu - TRAO D I c) Hinhl Anh SEM bgt sat HOGANAS (a): bgt Niken (b): bot Crdm (e); bSt Vonphram (d) trudc nghiin trgn - Ket qua phan tich vat lieu sau nghito trdn chp thSy vdi thdi gian nghidn tr^n t„^= * h da dam bao dd ddng ddu cac phank^ tdt, kich thudc ctia hat bdt phto ciing giai| dang ke (hinh a, h) Hinh Anh SEM bgt hgp kim hoa thdp sau nghiSn trgn: a) 3h: b) 4h Tren cac hinh 3a -^ d la kdt qua phan tich X-ray cac Ipai bpt dau tuong ling la bpt sat HOGANAS (a); bpt Ni (b); bdt Cr (c) va bdt W (d) trudc vao cho nghidn trdn tren may ly tam hanh tinh nang lupng cao, hinh - bpt thep hpp kim hoa thap sau nghidn trdn vdi thdi gian gid sii dung lam nguyen lieu dau vao ep ndng Hinh X-Ray mdu bgt sdt HOGANAS (a): bgt Ni (b): bgt Cr (c) truae nghiln trgn vd bgt thip hgp kim hoa thdp sau nghiin trgn vai thdi gian h (d) TAP CHl CO KHl VIETNAM • Sd 10 (Thang 10 nSm 2012) NGHIEN C U T U - T R A O D O I Phan tich ket qua cho tren cdc hinh a -^ d cho thdy; Ngoai bdt sdt cfla hang HOGANAS (hinh a), phdn cfla cac bOt phdi lidu trgn them (hinh b -^ c) ddu cd mdt lugng nhd cac hgp chat khac, didu dd dugc gidi thich bdi cac thi nghidm da sfl dung bdt phun hgp kim trdn CO sd ndn Cr, Ni va cd the cdn lugng dxy cd chung tuong ddi cao nen tdn tgi mdt sd dxit kim loai Ngoai ra, tfl hinh d cdn cho thiy sy cd mat cfla cdc nguydn td hgp kim hda (Cu, Cr, Ni), dxit va bdi tron ran (Zn-Stearat, C-grafit) 3.2 Ep nong tao mSu thi nghiem Trdn hinh Id mdt sd dnh tu hdu qua trinh ep ndng bdt thep sau nghien trdn, cdn hinh la dnh chyp man ep ndng chua dugc Idy khdi khudn graphit d) a) b) c) , , Hinh Anh chup qud trinh ep nong bQt thep hap kim hoa thdp: a) gd lap mdu chudn hi ep nong; h) bdt ddu qud trinh gia nhiet say khudn vd bot ep; c)Thdi diem ndng nhiet den nhiet ep nong; d) Gia luc vd kiem sodt thai gian ep nong , "-^ b) Hinh Anh ch^ip mgt so mdu thi nghiem ep nong tu bot thep hop kim hda thdp: a) Mdu ep nong epdchedQp = 10 MPa, Te.n = 1250 OC, t = 2.5 phut; b) Mdu ep nong khudn ep a che p = MPa, r J= 1250OC, t^= 2.5phut Cac budc thi nghidm' dp ndng tien hdnh edn tidn hdnh budc gia nhidt bang ddng didn cam flng den nhidt say phdi (khoang 400 OC) nhu sau: mdt thdi gian cho trudc (khoang ^ phut) dd 1) Mdu v$t lieu bdt thep hgp kim hda thdp sau ddt chay ede chdt ket dinh huu co cd vdt nghien trOn dat dinh mflc thdi gian yen edu cd lieu dp ndng (hinh b) Khi dd quan sdt thdy hi?n su phan bd ddng ddu cua cac nguyen td hgp kim tugng bdc khdi tfl khudn dp cflng mdu vat lieu hda ndn bdt sat H O G A N A S d mflc tdt nhdt, kha manh lidt, kdt thflc hien tugng dd thi cd dugc cho vdo bg khudn cdi ep ndng ldm bdng thd tang nhiet dp ldn mflc quy dinh theo bdng kd vdt li$u graphit ddng rdn edng nghiep vd dua vao hoach thue nghiem cho d phdn tren vflng bao phfl cfla vdng cam fliig cfla Id ep ndng 3) Khi tidn hdnh gia tdng nhidt ep ndng tdi thdi thi nghidm (hinh a) diem dat gid tri cho trudc theo quy hoach thye 2) Sau khudn ep ndng cflng vat lieu bgt can nghiem (hinh c) thi bat ddu qua trinh gia tang dp ep thidu ket dd dugc dinh vi tdt trdn may ep ndng, luc ep ndng (hinh d) ^ TAP CHf CO KHi VIETNAM V Sd IO(Thang 10nam2012) NGHIEN ClJU - TRAO eOl 3.3 Ban luan ve kit qua ep nong Phan tich kdt qua thi nghiem ep ndng mlu didn hinh nhan dupe d chd dp ep ndng cung nhiet dp (Te.n) va thdi gian ep (te.n), nhimg vdi ap luc ep khac (p,„ = 10 MPa va p „ = 30 MPa) cho thay: tnidng hpp sau Iam ngupi khudn ep ndng cho thiy cd hien tupng khudn bi nih vo dpc theo dudng sinh, nhidn, chua ddn miic bi pha huy hoan toan (hmh b) Didu dd, chiing td ap Iuc ep ndng chpn d miic cao quy hojch thuc nghidm la nguyen nhan chinh din tdi hien tupng khudn ep graphit hi nut vo Ngoai ra, cdn cd thi nhidu nguyen nhin khac cd thd gay s\r niit v8 khudn dp ndng, vi du nhu chit lupng vat Ueu lam khudn thip; vi tri hai chay ep sc voi dudng tam cua cdi ep bi Idch hudng yii bit dlu qua trinh ep; Chit lupng bd mjt mlu vat lieu bpt thep sau ep ndng d chd d0 v4 da dupe thao khdi khudn graphit dat ydu ciu vii chit lupng thidu kdt tdt (hinh 5b), Vdi chd dp ep ndng: p^^= 10 MPa, T^,,= 1250 °C, t = 2,5 phiit, mlu iihjn dupe sau lam ngudi khudn ep ndng cd hinh thai be mat ngoai -khudn rit tdt, khudn ep graphit khdng cd hien tupng hi mit vd vi ap luc ep chpn d gidi han dudi trpng bang quy hoach thuc nghiem (hinh a) Chat lupng mlu vat lieu bdt thdp sau ep nong d chd dp qua quan sat be mat sau dupe thdo khdi khudn graphit cho thay dat yen cau, Dp xdp va mat dp tuong ling ciia mlu hot chiing td cd kha nang thieu ket tdt thep hpp kim hda thip sau ep ndng dupe xac dinh ngoai phuang phap can thuy tmh (bang I) Ld Uii Vdi che dp ep ndng: pe.n= 30 MPa, T^,^ nghidm dlu tien dd dinh hudng cdng nghe cin = nSO^C, t^^= 2,5 phut, hinh thai bd mat ngpai chpn 05 chd dp didn hinh quy hoach thye khudn ep bang graphit cung vdi mdu vat heu bpt nghidm kiSu N = 3' = 27 [4], sau dd mdi lap lai thep hpp kim hda thlp bdn trpng nhan dupe d dly du tit ca cac chd dd thi nghi?m Bdng 4.2 Dg xdp vd mat mdu bQt thep hgp kim hda thdp sau ep ndng ldn SdTN Ma sd QHTN 000 110 120 HI 222 Chd dp ep ndng lan I 1200 1250 1250 1250 1300 2,0 2,5 3,0 2,5 3,0 Phan tich ket qua cho bang cho thdy: - Mau thi nghidm sd (ma sd: 000) nhdn duge ep ndng vdi eac thdng sd cdng nghe chinh chgn d can dudi: Te.n= 1200°C; t ^ 2,0 phflt va p^^^ 10 MPa, ed dp xdp thd tich trung binh ldn nhdt (yoi^ 39,233%) vd mat dg tuong ung cfla nd nhd nhdt (poi= 4,77 g/em^); - Mau thi nghiem sd (ma sd: 110) nhdn dugc ep ndng vdi hai thdng sd cdng nghd TAP CHf CO KHf VIET NAM 10 10 10 20 30 Mat dp Dp xdp thd tich trung tuong ling, po, g/cm' binh, yo,% 4,77012 39,2333 5,26996 32,8666 5,43743 30,7333 5,60228 28,6333 6,25645 20,3000 chinh chgn d mflc trung binh: T^ = 1250°C; te.ii= 2,5 phflt, edn ap lye ep ndng Pg„= 10 MPa chpn^ can dudi, cd xdp the tich trung binh gidm dang ke (YO2 = 32,866%) va mat dp tuong ung cfla no tang rd ret (po2 = 5,2699 g/cm') Didu chung td: tang nhiet dp va thdi gian ep ndng thi dO xdp thd tich trung binh gidm khoang 19,37 %, mat dd tang ldn khodng 10,478 % so voi mdu s6 1; Sd 10 (Thang 10 nam 2012) NGHIEN cufu - TRAO DOI - Mdu thi nghiem sd (ma sd: 120) nhan duge ep ndng vdi thdng sd cdng ngh? chinh: nhidt ep ndng chgn d mflc tnmg hmh: T^^^ 1250°C; thdi gian ep ndng chgn d mflc cao t^^= 3,0 phflt; cdn dp luc ep ndng - d mflc thdp p^ = 10 MPa, cd dd xdp the tich trung binh gidm so vdi mdu sd (yo3 = 30,733 %) vd mdt dd tuong flng cfla nd tang len mdt it (po3 = 5,437 g/cm^\ nhung khdng manh Dieu chflng td: Jdii tang nhiet vd thdi gian ep ndng thi dp xdp thd tich trung binh cd giam xudng 6,94 %, cdn mdt dd tang ldn 3,17 % so vdi mdu sd neu tren; tuong flng cfla nd tang rd ret po5 = 6,256 g/cm^) Didu dd ehumg td: tang nhiet dp vd thdi gian ep ndng thi xdp the tich trung binh giam manh xudng ddn 41,05%, cdn mat t ^ g ldn deu 11,67 %, tflc vdi cudng rat dang ke so vdi mdu sd 4; - Nhin chung tang hai thdng sd cdng nghd chinh la nhidt vd thdi gian ep ndng ldn gia tri can tren theo bang quy hoach thye nghiem (T ^ - 1300°C, t^^- 3,0 phflt), edn thdng sd ap lye ep ndng ehi didu chinh khoang p^ „^ 10 MPa vd pe.n= 20 MPa, thi chat lugng be mat mau vdt lieu hot thep hgp kim hda thdp nhdn dugc rat tdt - Mdu thi nghiem sd (ma sd: HI) nhdn dugc ep ndng vdi tat cd ba thdng sd cdng nghe 3.4 Mo hinh hda ham muc tidu dd x6p, mat chinh chon d mflc trung binh: T - 1250°C; t - trdn mlu thi nghidm sau ep nong =• ^n , ' e n 2,5 phflt; p^ = 20 MPa, cd dp xdp the tich tnmg binh gidm hon nfla (yo4 ^ 28,633 %) va mdt dd tuong flng cfla nd tang rd ret (po4 ^ 5,602 g/cm^) Didu chflng td: tdng nhidt dd va thdi gian ep ndng thi dp xdp the tieh trung binh giam xudng ddn 7,334%, cdn mdt dd tang ldn ddn 3,03 % so vdi man sd d tren; - Mdu thi nghidm sd (ma sd: 222) nhdn dugc ep ndng vdi tdt ca ba thdng sd cdng nghe chinh chgn d mflc trung bmh: T ^- 1300°C; t^^= 3,0 phut; p^^= 30 MPa, cd dp xdp thd tich trung binh gidm manh hon nfla (yos ^ 20,3 %) va mat dp Sfl dung phdn mem tin hpc chuyen dung dd xfl ly sd lieu thuc nghiem nhan dugc d cac che ep ndng theo quy hoach thuc nghidm ddy dfl da giflp cho vide tinh toan xay dyng ham myc tieu dp xdp va mat vat lieu sau ep ndng bang phuong phap binh phuong nhd nhat mdt each nhanh chdng Dd thi quan he giua cac ham muc tieu xdp vd mat vdi eac ydu td edng nghe ep ndng chinh p^„ vd t^„ (T ^ = 1200 ^ 1300OC) cho tren cdc hinh va hinh Tfl dd cho thay dO xdp cd xu hudng giam, cdn mat dp tdng theo chidu tang cfla hai thdng sd p^^ va t^^ Hinh Suphu thuoc cua dd xdp vdt lieu bot thep hop kim hoa thdp vdo dp luc (p^ J vd thdi g nhiet ep nong: a) r„ = nOO^C; b) T^ = 125(PC; c) T^ = 1300'>C TAP CHl CO KHf VIETNAM •t* Sd 10(Thang 10nam2012) NGHIEN Cl/U-TRAO DOI Ap|.jcPen(MPa) '0 Tim, ,„.n l«-,(phut) Ap luc Pe.nlMPs) ID Thoi g i n l , n(,ih»I) Ap luc Pe nlMPa) 10 = Tho, gian le n(ph(l!) a) b) ^-^ , //IM/) Sifphv thuoc cua mat vgt lieu bdt thep hop kim hda thdp vdo dp luc (pj vd thai gian (tJ nhiet ep nong: a) T„ = 1200°C; b) T^ = 125(PC; c) T^ = 1300°C 3.5 Nghien cuu dac tinh td chih; vkt li^u ep nong tu bgt th£p hop kim hoa th^p Kdt qua khdo sdt chyp anh td chflc td vi vat lieu bdt thep hgp ldm hda thap sau ep ndng l&i cho tren cde hinh va hinh 9, tfl dd cho thdy: 1) Mdu thi nghi?m (ed ky hieu 3B ) sau ep ndng dudi dp lye Pg„= 10 MPa, nhiet dp ep T^^ - 1250°C, thdi gian giu nhiet t^^= 2,0 phflt, dugc khdo sdt dpc theo hudng ep vdi dp phdng dai x 100 va X 500: cac vimg td chflc man den dugc cho la Id xdp, cdn nguyen td hpp kim hda cd mdu sac hai sdm tdi phdn bd tugng ddi deu nen bdt sat, cd phat hidn thay mdt vung td chflc kim loai mau sang trang ed kich thudc ldn, dd cd thd la nguydn td W hoac hgp chdt cua nd vdi cac nguyen td khde (hinh a) Ngodi cdc Id xdp d day cd hinh dang phflc tap vd kich thudc khdng ddng ddu (hinh b), didu dd ehi rang sau ep ndng lan v|it lieu chua dat duge ca tinh vd edu trflc cdn thidt Do dd, de sfl dung vat lieu sau ep ndng cdn phai qua budc bien dang deo d tr^ng thai ndng dd lam giam Id xdp den mflc nhd nhdt va tai edu true cac bgt phdn hgp kim hda ndn bdt sdt mdi dam bao dieu Iden chiu tai trpng ldn va chiu mdi mdn cao; TAP CHl CO KHf VlfiT NAM V 2) Mdu thi nghiem sau ep ndng dudi dp luc p^^= 30 MPa, nhiet dp ep T „ = 1250**C, thdi gian giu nhiet t^_^= 2,0 phut, cd ky hidu BO dugc khdo sdt dpc theo hudng ep vdi phdng dai xl00 va x200 (hinh a, b): cac vung td chflc mau den la Id xop d day cd hinh dang phflc tap, nhung da gdn dang edu va kich thudc da nho hon ddng ke so vdi cae mdu dd xet tiiidc dd, phan bd kha dong ddu (hinh a) Didu cd thd dugc gidi thich bdi tang ap luc ep ndng ldn mflc cdn trdn theo che quy hoach thye nghiem, mdc dfl hai thdng so Te.n vd te.n giu d mflc trung binh, nhung da cai thien mdt each dang ke tinh chdt v$.t li?u sau ep ndng ldn Cac nguyen td hgp kim hda cd mdu sdc hoi sdm tdi hau nhu khdng phat hien thay ndn bdt sdt (hinh b) Didu ddng chfl y hon ca la cd phat hidn thay vai vflng td chflc kim lo^ mdu sang trdng cd kich thudc ldn vd khac (hinh a), didu dd dugc giai thich tuong ty nhu ddi vdi mdu sd 3B (hinh a), tflc la sy cd mat cua nguydn td W hode hgp nguyen td hgp kim h6a khac Trong trudng hgp nay, dd sfl dung vat lifu sau ep ndng can phdi qua budc bidn dang deo trang thdi ndng dd nang cao co tinh cua nd mdi ddm bao didu kign chiu tai trpng ldn va chiu mai mdn cao theo dy kiln chd t^o banh rdng xich Sd 10 (Thdng 10 nam 2012) NGHi£N CUTU - TRAO DCi K£T LU^ ,^;^'" Tfl k i t qua thye nghi?m ep ndng bgt thdp hgp kim hda thdp ta cd mgt vai kit luan nhu sau: 1) Dg xdp v|it Ufu sau ep ndng so bp lan khudn graphit cdn d mflc cao (yo = 39,23 ^ 20,3 % ) , khdng cd cac 16 x6p vdi kich thudc hinh hgc qud ldn, cdn mdt dp tuong flng mdi chi d^t khodng po = 4,77 ^ 6,256 g/ cm^ Td chflc t l vi vdt lidu tuong ddi tdt, cdc nguydn td hgp kim hda t ^ g bdn cho v^t li^u phan bd kha ddng deu ndn bgt sdt; b) Mdu so 3B, xSOO a) Mau so 3B xlOO Hinh Anh cfmp to chue te vi mau so 3B sau ep ndng tu hdn hap bot sal HOGANAS + Cr + W + Ni nghien trgn VJ • • ^ ^ f 7' 1^- * ::M 2) Khi tang nhidt dd (T„) va #^i°ii_ thdi gian dp ndng (t^ J vdi muc ap lire d)MausoBO xSOO e) Mau so BO xlOO dp cho trudc khpang p^^ = 10 -^ 30 Hinh Anh ehup to ehue te vi mdu so BO sau ep nong tit hon MPa, dd x6p v^t lipu sau thidu kdt cd xu hgp bgt sit HOGANAS + Cr+W+Ni nghiin trdn hitdng gi&m t^ 1$ thuan, cdn mat dp tiiong dng ciia v|t li^u thi ngitpc l^i, tang ctmg chilu tang ciha thdng sd cdng nghd chinh dang xet Dieu dd cho thSy bSng philpng phap quy hoach thi^c T i i li^u tham khdo: nghidm v i tinh todn md hinh todn hpc ham muc tidu dd xdp ho^c m^t dd, cd the tim che dp ep [1] Ha Minh Hiing, (2000): "Nghiln ciJu 4p dijng ndng thich hpp, dam bao cP ly tinh theo ydu cSu; cdng nghl luyin kim bdt chl t^o bdnh ring mdy cdng cu (m = 2, Z = 28)", Bio c4o Khoa hpc Chuyin dl KHCN05.06-03, Vi|n nghiln ciJu Co Hi Ndi, 3) D l chi t i l t mdy lam viec tot can thiet 1998,120 trang: phdi tiln hdnh ep ndng hoac dap ndng lai ldn [2] Trln Sy Khing, TrSn Bi Hing, Cao VSn Thiiy, Bill cdc phdi sau ep ndng lan d l gidm thieu dp Doan Dong (2004): "Nghign ci2u cdng nghl nghiln xdp vd tdng co tinh cija vdt lieu Kit qua thi bot sat" Tap chi Ky thuit vi trang bi sd 43/2004, trang nghilm ep ndng ldn khudn kim lo^i 27-29 8c 14; cCia nhdm n g h i l n ciJu se trinh bdy mdt [3] Hi Minh Himg, Vii Trung Tuyin, D6 Dinh Luong bdi bdo khac
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