NGHIEN cuu-TRAO001 / GIA CONG CO NHIET CHE TAO TAM VAT LIEU CO TO CHUfC HAT NHO MjN TLT PHOI DUC HOP KIM NHOM HE AL-MG THERMO-MECHANICAL PROCESSING TO MANUFACTURE SHEET WITH ULTRAFINE GRAIN STRUCTURE FROM BILLET OF ALUMINUM ALLOY AL-MG SYSTEM TS Nguyin Truong An', ThS Nguyin Manh Tiln', NCS Le Manh Hiing", ThS Hoang Manh Gioi^ 'Khoa Co khi, Hgc vien Ky thuat Quan su ^Nha may Z157, Tong cue Ky thuat TOM TAT Bdi bdo trinh bdy cdc kit qud nghien ciru xdy dung sa gia cdng ca nhiet vd thuc nghiem chi tgo tdm vdt lieu cd td chirc hgt nhd tit phdi due hgp kim AMg6 T u Idioa: Gia cdng ca nhiet; Hgp kim nhdm; Hap kim AMg6 ABSTRACT This paper presents the research results build diagrams of thermo-mechanical processing and experimental to manufacture sheet with ultrafine grain structure from billet of alloy AMg6 Keywords: Thermo-mechanical processing; Aluminum alloy; Alloy AMg6 \ DAT VAN DE dong tau va cac cong trinh bien dao, Hien Hap kim nhom he Al-Mg la mot nhung '™"8 ""'"'^ ' = ^ ^^ ^ju tu cho viec ndu luyen cac nhom cua hgp kim nhom khong hoa bSn bang ^ a c hgp kim (AMg2, AMg6 ) Tuy nhien, nhiet luyen (khi ham luang Mg < 8%), co dp b & mpt nhirng vSn dk dat la lam thi nao khai cao, kha nang ch6ng an mon va tinh han t6t Chinh thac het kha nang biSn dang ciia vat lieu, dam bao vi vay, chung duoc su dung nhieu linh vuc hieu qua va giam so lugng phe phim niirt, rach khac nhau: Trong cac thilt bi bay, cong nghiep qua trinh gia cong Do do, bai bao tap trung •»• TAP CHi CO KHi VIET NAM, So nam 2014 www.cokhivietnam.vn NGHIEN cuu-TRAODO! tim hi^u, xay dung chi gia cong co nhiet hgp ly tao tam vat lieu co to chuc hat nho dh giai quy6t vin d^ tren d6i vdi hgp kim AMg6 dugc che tao nude XAY D^NG SO DO GIA CONG CO NHIET Phuang phap gia cong ca nhiet la phuang phap gia cong cho phep cai thien cac tinh chat ciia hgp kim dap ung tot hon nhu cau sir dung Co sd cua phuang phap la su kk hgp giua bien dang deo va gia cong nhiet, bien dang deo CO anh hudng manh tdi hieu qua cua nguyen cong nhiet luyen tiSp theo Hien nay, phuong phap gia cdng CO nhiet ap dung doi vdi hgp kim nhom dugc phan ba nhom chinh nhu sau [2]: Gia cong ca nhiet nhiet cao (BTMO), gia cong ca nhiet nhiet thap (HTMO) va gia cong ca nhiet kk hgp gida cac nguyen cong (MTMO) Phuang phap MTMO dugc dimg de chuan bi ban phim tir phoi diic, nhSm muc dich: Nang cao su ddng dhu tinh chit th^ tich, lam giam tinh di hudng, dac biet la nang cao cac dac trung dec theo ca chi8u cao va chilu ngang cua ban pham Tir ket qua nghien cuu ve cac phuang phap gia cdng co nhiet, tren co sd muc tieu dat ra, lua chgn phuang phap MTMO de gia cong nang cao tinh deo hgp kim AMg6, trSn ca sd tao to chiic hat nhd va ddng deu Hgp kim AMg6 dugc nau luyen va due tai ca sd san xuat nude, phoi d dang billet Tren CO sd nghien cuii co sd ly thuyet, ket hgp vdi viec phan tich gian trang thai cua hgp kim AMg6 tiSn hanh xay dung sa gia cong co nhiet de tao vat lieu tam vdi chieu day 1,5 mm tir billet nhu hinh 1, lam ca sd de tien hanh khao sat thuc nghiem T-c Ai 12 18 M g , % (Theo klldl ilroug) - Hinh I: Sa dd gia cdng ca nhiet hgp kim AMgd Phdi due dugc u dong deu hoa d nhiet 520 "C thdi gian 7h Tiep theo, tien hanh bi§n dang nong d 360 - 420"C dam bao mire bi6n dang 60 - 70%, lam nguoi nhanh nude Sau biin dang nguoi vdi muc bien dang lin cu6i 50 - 60% Cu6i ciing ii kk tinh lai d 310 - 350 "C 50 - 90 phiit Hifj TAP CHI CO KHI VIET NAM, S6 nam 2014 •••• www.cokhivietnam.vn NGHIEN ciiu-TRAO001 THirC NGHIEM THEO SO BO GIA CONG CO NHIET Tien hanh thuc nghiem theo so da xay dung doi voi hgp kim nhom AMg6 dugc nau luyen nuoc, nham muc dich nang cao khii nang bien dang deo cua hgp kim 3.1 Thiet bj va dung cu thi nghiem BiSn dang nong dugc thuc hien tren may ep thuy luc YH-32, mau dugc nung 16 MD - 2yM va 16 nung LHl 20/13 (hinh 2-a,b,c) Nhiet kiSm tra bang thigt bi gian tilp (hinh 2-d) Bien dang nguoi dugc tien hanh tren may can (hinh 2-e) tai Ph6ng Thi nghiem Vat lieu, Khoa Co To chiic vat lieu dugc xac dinh tai Vien Cong nghe - TC CNQP va Ph6ng Thi nghiem Vat lieu, Khoa Ca (kinh hiln vi - hinh 2-f) Hinh 2: Thiet bi vd dung cu thuc nghiem 3.2 Kit qua va phan tich Phoi ban dju la phoi dugc die tai ca so san xujt, tuong duong mac vat lieu AMg6, da dugc u dong diu hoa Thuc hien cac buac theo sa d6 gia cong co nhiet nhu hinh 1, cu the nhu sau; Chu4n bi mSu cho bien dang nong (hmh 3-a), vai miic bien dang hi 50% den 60%, a nhiet 420°C din 360°C, thuc hien bing nguyen cong chon, dung cu dugc gia nhiet den 300-C a) b) Hinh 3: Phdi vd mdu sau bien dgng ndng; a) Mau tnrac bien dgng ndng: b) Mdu sgu bien c I nong TAP CHi CO KHI VIET NAIM, S6 nam 2014 [ f f l www.cokhivietnam.vn NGHIEN cuu-TRAODOI Ban san phin sau biln dang nong co chiiu day 8mm (hinh 3-b) Sau biln dang nong, lam ngupi nhanh nuac va chuin bi mlu de can nguoi Tiln hanh can mlu qua hai giai doan: Giai doan can hi chilu day 8mm xuing 3,5 mm (~56%>); Tien hanh ii gitta hai giai doan can a nhiet 325°C 50 phiit, sau tilp tlic can giai doan hai til' chilu day 3,5 xudng 1,5 mm (-57%) Hinh 4: Mdu sau biin dgng ngudi cdn giai dogn I; a) Sau cdn giai dogn 2; b) Bdn sdn phdm sau diin ep vd cdn tdm tgi ca sa sdn xudt (c) Kit qua cac buac biln dang cho phep nhan dugc cac tam ban siin pham bang phuang phap can nguoi vai miic biln dang rit Ion (gjn 60%) ma khong xuat hien cac vit mit, rang cua a hai ben mep mlu, d6 c6 thi thuc hien lien tuc cac budc can mgt giai doan ma khong can cat mep (hinh - a, b) Trong a co so san xuit, gia cong thuang xiiy tinh trang mit mep, hinh rang cua nhiing lan bien dang cuoi (hinh - c), dan den phe pham cao Tiln hanh xac dinh tl chiic ciia vat lieu mlu li ket tinh lai tam sau can nguoi Ket qua to chuc ciia mlu tim li kit tinh lai sau can nguoi o nhiet 350 "C thai gian 60 va 90 phiit dugc the hien tren hinh Hinh 5: Td chirc hgt sgu ti ket tinh lai a 350°C, 60 phut (a) vd 90 phut (b) v&i phon dgixSOO Qua khao sat cho thiy, thoi gian 60,90 va 120 phiit thi tl chiic hat da xuit hien ro net va co thi xac dinh dugc kich thuoc hat trung binh Kit qua cho thiy tim vat Heu co kich tl chiic hat nho voi kich diuoc hat binh tir 10 din 15 mm thay d6i thai gian u la 60,90 va 120 phiit Kich thuac hat trung binh nho nhit 10 den 13 mm tuong img vdd thoi gian u 90 phut Kit qua thu dugc dam bao co the bien dang tao hmh ban siin phim (tim vat lieu 1,5 mm) dilu kien sieu deo vairaiicdo bien dang deo rat Ion TAP CHi CO KHi VIET NAIM, S6 nam 2014 www.cokhivietnam.vn NGHIEN cuu-TRAO DOI Tien hanh xac dinh cimg mlu sau ii kk tiet tir phoi diic che tao nude (tuang duong tinh lai HB ^ 77, qua ket qua ciing cho thiy vdi hgp kim AMg6), co the chuin bi dugc t6 chuc hoan toan co the bien dang tao hinh (ch6 tao cac hat nho min, cd hat trung binh dat d^n 10 dgn 13 chi tiet) d trang thai nguoi tir ban san phim dang mm li kgt tinh lai nhiet 350 "C thdi tam sau ii ket tinh lai gian 90 phiit KET LUAN the sir dung so co nhiet da xay dung de ap Ket qua thuc nghiem cho thay, hoan toan co Qua cac kk qua nghien ciiu ly thuyit va ti^n dung thuc te san xuit cho hgp kim AMg6 (nau luyen nude), dam bao nang cao tinh hanh thuc nghiem co thg kk luan nhu sau: deo ciia vat lieu va han che phe pham qua Xay dung dugc sa gia cong co nhiet chuin trinh chuan bi phoi dang ban pham va bi tam vat Heu cho viec bien dang tao hinh cac chi qua trinh bien dang tao hinh san phim tilp theo.