KHOA HOC CONG NGHE
So 05/2020
Nghien cuu chat luong san pham vat lieu
thep khong gi 308L che tao boi cong nghe W/\AM
I ThS. DUONG VAN NGUY; TS. DOAN TAT K H 0 A ; T S . T R ! N H QUANG Hl/NG KS. PHAM VAN CHINH; TS. L£ V A N THAO
Hgc vien Ky thugt Qudn sd
TOM TAT: Bai bao nghien cdu qua trinh tao hinh va chat lucng chi tiet dgng thanh td v§t lieu thep khong gi 308L bang cong ngh§ WAAM Ket qu^
nghien cdu thuc nghi#m cho thay cong nghd WAAM cd the tao hinh duQC cac chi tiet kim logi Gidi han ben va gidi h^n chly tang theo chieu cao lop tao hinh Gidi han ben thay doi tu 497MPa den 565MPa, gioi hgn chly thay doi tu 46MPa den 565(vlPa Tren moi mgt Idp t^o hinh ton t^i hai trgng thai vat Ii0u 06 la su chuyen bien pha tu dgng hgt cd kich thudc Idn (ferrite) sang dang hat cd kich thudc nhd on djnh hon (peclit) do CBC yeu to I n h hudng vl nhi#t td Idp nay sang lop khac Sau khi nong chay, thep khong gi 308L hoa ran thanh cac pha ferrite va austemte
TL/ KHOA: Cong ngh# WAAM, chat luang san pham, thep khong gi 308L.
ABSTRACT; The forming process and product quality in WAAM technology were study by experimental Experimental result show that WAAM technology can fabricates metal parts The tensile strength and yied strength increase with height of forming layer, The tensile strength vary from 497Mpa to 565Mpa, the yied strength vary from 46Mpa to 565Mpa There are two states of material on each forming layer It is the pinase transition from the large size gram (ferrite) to the more stable small particle size (peclite) due to the factors affected by heat from layer to layer.
The stainless steel 308L solidifies into ferrite and austemte phases after were sintered, KEYWORDS: WAAM technology, product quality, 3 0 8 L stainless steel.
1.DATVANOE
Cdng nghe bdi dap vat lieu kim loai (Metal Additive Manufaeturing-MAM) hay cdn gpi la in 3D kim loai (3D-Printing) la cdng nghe ehe tao hien dai. Nguyen ly tao hinh eua MAM la dap vat lieu tdng Idp chong len nhau de
tao ra vat the 3D theo dd lieu t d md hinh CAD (Computer Aided Design). Ve v i t 1^, MAM dung tia nang lugng mat dp eao, nung ehay vat lieu de tao lien ket, rdi eho ket tinh thanh tUng Idp. Day la gua trinh phdc tap, ket hpp luyen kim, phit v l dieu khien tia nang lugng, tao va xd ly md hinh CAD-3D, dieu khien sd CNC (Computer Numerical Control) [1]. Cdng nghe nay tuy khdng mdi nhung cd vai trd ri't quan trgng trong edng nghiep. L/ng dung ehu yeu de che tao nhdng chi tiet quan trgng, v i t lieu sieu edng, sieu ben ma eac phuong phap gia cdng truyen thdng khdng gia cdng dUOe. Cdng nghe MAM duge dng dung rdng rai trong cae nganh edng nghiep trgng diem nhU hang khdng vu tru, cdng nghiep che tao d td, che tao thiet b| y te, edng nghiep qudc phdng an ninh [2].
Trong sd eae edng nghe in 3D kim loai hien nay, cdng nghe sd dung ngudn nang lugng hd quang (Wire Arc Additive Manufacturing-WAAM) cd kha nang che tao cic ehi tiet kim loai ed kieh thude vda v l Idn, ed dp phdc tap hinh dang d mde trung binh, edng nghe niy cho phep sd dung vat lieu vdi hieu qua sd dyng len tdi 99% va cd ehi phi ehe tao thap. Cdng nghe n i y II sU ket hgp gida edng nghe han GMAW (Gas Metal Are Welding) va dieu khien sd thanh mdt he thdng hoan chinh, cd the ehe tao cac chi tiet kim loai theo nguyen ly in 3D [3]. Tren the gidi dacd nhieu edng trinh nghien cdu I n h hudng eie tham sd edng nghe eua WAAM den do chinh xac (kich thudc, hinh dang hinh hpc), do n h i m be m i t va chat lugng ben trong eua vat lieu (cau true te vi va tinh chat eo hge) cua ehi tiet dUOc che tao bdi edng nghe nay [4,5,6,7]. Tuy nhien, sU hieu biet hay kiem soat cic tham sd cdng nghe cCia WAAM de sin xuat hole t l i sin xuat eie ehi tiet van edn can phai nghien cdu sau sic tdi tdng loai vat lieu cu the. Cae thdng sd cua q u i trinh cdng nghe WAAM can p h l i duoc kiem soat v l tdi Uu hda de cd duge do chinh xac va chat lugng mong mudn eua eic chi tiet che tao.
Robot h i n hien nay dang phat trien rat manh v l pho bien trong cac nha may, xi nghiep, viee chi dng dyng robot han de ban la mdt lang phi rat Idn ve k h i nang edng nghe. Robot han hoan t o i n ed kha n i n g duoc dCing de che tao cic sin pham kim loai theo nguyen ly MAM, n i n g cao kha nang cdng nghe eua robot han. Hien
65
chUa cd nhieu nghidn cUu ve ITnh vuc nay. Viee ket hop nguyen ly cdng nghe han v l dieu khien CNC robot de nghien edu qua trinh tao hinh cac chi tiet kim loai, danh gilj:ac chi tieu ehat luong cua s i n pham la yeu cau cap thiet trong viec md rong k h i n i n g nghien edu va dng dung cdng nghe MAM. Nghien cdu n i y da k h i o sat qua trinh tao hinh va d i n h gia chat lUpng chi tiet dang t h i n h t d vat lieu thep khdng gi 308L bang cdng nghe robot han TAWERS1400.
2. THt NGHIEM
2 . 1 . Thiet bj va vat lieu t h i nghigm
Thiet bj t h i nghiem la robot han TAWERS 1400.
Thiet bi n i y sd dyng ngudn nang lugng han I I may h i n YD-350GR3, ket hop vdi he thdng dieu khien CNC 3 tryc, I p dyng theo quy trinh h i n DC MIG, so do cau tao nhu the hien tren Hinh 2.1 [8].
He dieu khien CNC
Hinh 2.1: SodS nguyen ly he Hiong tao hinh WAAM Vat lieu thi nghiem; t i m nen sd dung loai thep khdng gi 304 dang tam; vat lieu tao hinh sd dyng loai thep khdng gi 308L dang d i y dudng kinh cp = 01mm, thanh phan hda hgc vat lieu thep khdng gl 304 v l 308L n h d 6 d n g 2 . / v a Sdng 2.2 the hien [9].
Bing 2.1. Thanh phan vit lieu thep khdng gi 304 va 308L (%)
\ Thinh phan | Cr I NI I C I Mn I St "'" P | S | N [ Khai]
2.2 PhuTtfng phap thf nghiem
Oe khao sit k h i nang tao hinh sin pham cua robot han, tien hanh thi nghi§m theo 3 budc:
Budc 1: Khio sat cac tham sd cdng nghe de tao hinh cac dudng h i n don nhu Bang 2.2, t d do danh g i i chat luong dudng han dOn de lUa chgn bd tham sd edng nghe hgp ly.
Budc 2: Sd dyng bd tham sd cdng nghe tim dugc duac de tao hinh chi tiet dang thanh (tao hinh nhieu dudng han don chong len nhau theo ehieu eao),
Budc 3: OInh gia cic chi tieu cO tinh va to chdc eua mau tao hinh.
2.3. K^t q u i t h i nghiem va phan t k h 2.3.1. Tgo hinh cdc dudng ban dan
Tien hanh tao hinh cae dudng han don vdi cic thdng sd cdng nghe thay ddi trong Bdng 2.2, ket q u i thi nghiem nhutrong Hinh2.2 the hien.
5605/2020 Bing 2.2. Thong so cdng nghi tao hinh dudng han dan
8 1
9 '
10 1
11 120 100 120 100
18 18 18 18
0,4 0,3 0,4 0,5 12
13 14 15 16 17
120 120 140 120 120 140
16
L 18
16 16 16
^ 20
0,3 1
0,4
0,4 '
0,5
0,3 1
0,4
Hinh 2.2: Cac dudng han dan
Tren Hinh 2.2 cho thay, dudng han sd 1 ed chat luong tUOng ddi tdt, d i m b i o suddng deu ve hinh d i n g va kich thude, tuong dng vdi eac tham sd cdng nghe eudng do ddng dien 120A, didn I p han 18V va tdc do hin 0,4 m/ph.
2.3.2. Tgo hinh chi tiet dgng thdnh
Sau khi lua ehgn bd thdng so cho dudng han don, thuc hien han chdng cac Idp han vdi nhau tao thanh chi tiet dang thanh theo hai each nhd Hinh 2.3 the hien. Moi ehi tiet cd chieu dai la 150mm v l dugc tao hinh bdi 35 dudng han ehdng len nhau, ket qua tao hinh nhu Hinh 2.4 the hien.
Thdng sdedng nghe tao hinh nhu6dng2.3 the hien.
Bing 2.3. Cac thdng sd'thi nghiim eua hai chi tiit tim mdng Chi tiet I 1 ^ I Dong dien , Oten Ap Tdc do han
(A) I (v^ | _ I . ' " ' _ P ! I L _ Thcri gian l^m nguoi (s)
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KHOA HOC CONG NGHE
So 05/2020
Mo sunQ han
'X'hng hon l=40s
X ,' 150
~ XX
1 /
3;
U6 sung han
Duong han
1
_
Hmh 2.3: Phuong in in ehi tiit dang thanh theo cdng nghe WAAM
Hmh 2.4: Hal chi tiet dang thanh tao hinh theo hai each khae nhau Ket qua thi nghiem eho thay, hai phuong p h i p tao hinh khae nhau tao nen hai san pham vdi chat luong khae nhau. Ddi vdi phuong phap tao hinh thd nhat (Hinh 2.3a).
sd dyng phuong phap quet 1 chieu, d cuoi eac dudng han nhiet do ndng chly cao do dd lam cho kieh thudc ehieu rdng be ndng chly fdn, dan den chieu rdng dUdng han tang, chieu cao g i i m so vdi cac vj tri phia trUdc. Qua
trinh tao hinh quet mdt ehieu dien ra lien tuc se tich luy sai sd dan, dan den ehieu cao cua thanh se g i l m dan t d dau dudng han den cudi dudng han (Hinh 2.4a). Ddl vdi phuong phap tao hinh thd2 ('Hin/)2.5d;, sddung phuong phap quet hai chieu ziczac. DUdng han thd hai ngUgc vdi dudng han trUde dd, do dd se bu dugc sai sd ve hinh dang va kieh thude do dudng ban thU nhl't tao nen. Do dd, qua trinh tao hinh se d i m b i o duac do chinh xae ve hinh d i n g v l kieh thUde (Hinh 2.4b)
2.3.3. Do gidi hgn be cCia vdt lieu
Che tao mau thi nghiem: Mau do gidi han ben dUOc ehe tao theo edng nghe WAAM la chi tiet Hinh 4b. Chi tiet nay duoc cat thanh hai mau, mau so 1 d phia tren, mau sd 2 d phia dUdi, hinh d i n g va kich thudc can eU theo tieu chuan ve mau thi nghiemTCVNI 97-1:2014 nhu trong Hinh 2.5a the hien [10]. Cin cd theo hinh dang, kieh thudc Hinh 2.5a sd dyng phuong phap eit d i y tia Ida dien (WEDM) de eat thanh cae mau thi nghiem nhU Hinh 2.56the hien.
Hinh 2.5: Hinh ding va kich thudc miu do ung suit ben theo tiiu ehuan VN: (a) hinh dang va kich thudc mau; (b) Mau thdkio
Trong dieu kien phdng thi nghiem, sddung may do dng suat keo DVT FU/R tien h i n h gidi han ben, gidi ban chay va do gian dai. Ket qua do tuong dng nhu Hinh 2.6 the hien.
2 - Mau so 2 (mau 36): 3- Mau sd 1 (mau xanh) Hinh 2.6: Kit qui do gidi han bm gidi han ehiy
va dp gian dai cac mau
S6 05/2020 Ket qua t h i nghiem cho thay dng suat ben ddi
vdi mau 1 la 497Mpa va mau 2 la 565Mpa; Ung suat ehay ddi vdi mau 1 la 342Mpa va mau 2 la 370Mpa.
C/ng suat t r u n g binh eua v i t lieu 308L: U'ng suat ben 531MPa, dng suat c h l y 356MPa. Nhu vay, cang len cao Ung sul't cua chi tiet eang giam dan; tinh ehat dan hdi cua chi tiet eung giam manh. Dieu nay dugc ly giai do qua trinh lam mat cua chi tiet. Ldp ben dudi chi tiet dugc lam m i t nhanh va cung giong nhu qua t r i n h tdi va ram chi tiet nen l i m tang gidi han ben, gidi han chay va do dai va dap cao. Ldp tren eua ehi tiet dugc l i m ngudi cham hon nen gidi han chay thap hon. Theo tieu chuan AISI, gidi han ben cua thep khdng gi 308 la 515Mpa [10]. NhU v i y cho thay, neu cae t h d n g sd cdng nghe hgp ly cd the che tao dugc chi tiet cd gidi han ben cao bang phuong phap WAAM.
2.3.4. To chdc tevi vgt lieu tgo hinh
Cau true vi md vat lieu cua ehi tiet thanh mdng duac quan sit dudi kinh hien vi cd dd phdng dai 100 lan. Tai cac vung tren, mau kiem tra cd sUthay doi trang thai hat vat lieu theo sU thay ddi nhiet v l tdc dp lam mat cua mdi Idp h i n nhu Hinh 2.7 the hien.
Hinh 2.7 eho thay, cau true vi md cua 3 mau tai eae vung la gan nhU nhau. Cie soi nhinh austenit chinh p h i n t i n theo hudng lam mat (hudng vudng gdc vdi tam de han. Vat lieu sau khi bi nung ehay bdi hd quang va lam ngudi ddng dae lai b i n g khdng khi nen td chdc nhan dugc gan ddng deu va on dinh.
Vung tren (Hinh 2.7a) I I phan vat lieu cua Idp han tiep theo cd sU bien ddi nhiet dot ngdt (vat lieu nung tdi nhiet do ndng chay sau dd ehuyen sang nhiet do ddng die) v l toe dd l i m mat cao nen ban chat eua thep khdng gi luc nay la ban chat hat Idn. Do yeu t d dd ma cau true te vi xuat hien ba loai hat ferrite:
Allotriomorphie ferrite o, widmanstatten ferrite o^, aeieular ferrite o^.
Vung trung gian (Hinh 2.7b) la vung tiep xue eua Idp han tiep theo vdi Idp han trude dd. Trong vung nay xuat hien eau true gom hai loai hat: Hat dang kich thudc Idn va hat can bang vdi sU p h i n bd day dae.
Nguyen nhan eua sU xuat hien hai Idp chdng lan nay ia do nhiet cua hd quang lam ndng chly vat lieu kim loai, hinh thanh Idp kim loai tren la vat lieu mdi dugc bdi d i p them nhuvung tren, Idp kim loai dudi bj nung chay tao sU tang trudng eua hat v l ket tinh lai tao sU chuyen bien pha.
Mat khac, cau true vi md d vung dudi bao gdm eae hat ferrite dUOc on dinh va can b i n g to chUc, tdn tai cac dai mdng dai (Hinh 2 7c). To chdc hat kieh thudc nhd cd do edng se g i l m va tang dp deo cho vat lieu kim loai. Nguyen nhan cua eau true nhU nay duefe giai thich bdi do nhiet cua hd quang. Phan vat lieu luc nay duoc nung ndng tdc thdi tdi q u i nhiet do Ac, tao ra su ehuyen bien pha sau dd dugc lam ngudi cham; to chdc nhan dugc dang peclit hat, tUOng t u nhu qua trinh u d i n g nhiet tdc thdi.
'(a).
^4 n
<^)\-r\. /.
•^:z
a) - Viing tren, b) - Vung trung gian. c) - Vung dudi Hinh 2.7: Ciu true be mat mau & kich thuoc phong dai 100
Nhu viy, tren moi mdt Idp tao hinh se ton tai hai trang thai vat lieu. Dd la sU chuyen bien pha t d dang hat cd kich thude Idn (ferrite) sang dang hat ed kieh thUde nhd dn dinh hOn (peclit) do eac yeu td I n h hudng vi nhiet t d Idp nay sang Idp khac. Thep 308L ndng chly thudng hda ran thanh eac pha ferrite va austenite, cac pha sam nhu cie vien da la ferrite edn pha xam lien tuc nhU nhanh cay la pha austenite.
3. KET LUAN
Ket qua nghien edu da md ra k h i nang Ung dung cua cdng nghe WAAM trong che tao eie ehi tiet kim loai theo nguyen ly in 3D. Ket qua thUc nghiem cho thay eic chi tiet che tao t d vat lieu thep khdng gi 308L cd ca tinh tdt. Gidi han ben va gidi han chay khdng ddng nhat ma tang theo chieu eao eua ehi tiet, gia tn n i m trong khoing td497MPa den 565MPa, tUOng dUOng vdi gidi han ben eda thep 308 theo tieu chuan AISI (515MPa). Dieu nay eho thay duoe kha nang dng dung cua cdng nghe WAAM che tao eac chi tiet kim loai trong eae nganh cdng nghiep trgng diem.
Tai lieu tham khao
[1]. Shamsaei Nima, et al. (2015), An overview of Direct Laser Deposition for additive manufacturing; Part 11:
Mechanical behavior, process parameter optimization and control. Additive Manufacturing, 8, pp.12-35.
[2]. Vilar, R (2014), Laser Powder Deposition, in Bataiha, Gilmar Ferreira, Tyne, Chester J. Van, and Yilbas, Bekir, Editors, Comprehensive Materials Processing, Elsevier, Oxford, pp.163-216.
[3]. All Waqas, Xiansheng Qin, Jiangtao Xiong, Hongbo Wang and Chen Zheng (2019), Optimization of Process Parameters to Improve the Effective Area of Deposition in GMAW-Based Additive Manufacturing and
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Its Mechanical and Microstructurol Analysis, School of Mechanical Engineering, Northvt/estern Polytechnical University, Xi'an 710072, China.
[4], C.V. Haden , G. Zeng, P.M. Carter 111, C. Ruhl, B.A. Krick, D.G. Harlow/ (2017J, Wire and arc additive manufactured steel: Tensile and wear properties, Additive Manufacturing, ISSN 2214-8604, pp.n5-123.
[5]. Jun Xiong, Guangjun Zhang, Weihua Zhang (2015), Forming appearance analysis in multi-layer single- pass GMAW-based additive manufacturing. Advanced Manufacturing Technology, Issue 9-12, pp 1767-1776.
[6], Jun Xiong, Guangjun Zhang, Weihua Zhang (2016), Forming appearance control of arc striking and extinguishing area in multi-layer single-pass GMAW- based additive manufacturing. Advanced Manufacturing Technology, Issue 1-4, pp.579-586.
[7]. Miao Li, Tao Lu, Jianw/en Dai, Xiaojian Jia, Xuhan Gu, Ting Dai (2019J, Mlcrostructure and mechanical properties of 308L stainless steel fabricated by laminar plasma additive manufacturing. Materials Science &
Engineering A, Pll 50921-5093(19)31309-7.
[8]. William (2014), Metal additive manufacturing:
A review, Journal of Materials Engineering and Performance, pp.1917-1928.
[9]. Miao Li, Tao Lu (2020), Mlcrostructure and mechanical properties of308L stainless steel fabricated by laminar plasma additive manufacturing. Material Science and Engineering'A.
[10]. Https://www.makeitfrom.com/compare/Ai5l- 308L-S30880-ER308-Stainless-Steel/AISI-312-S31200- Stainless-Steel.
Ngay nhan bdi: 28/02/2020 Ngay chap nhan dang: 19/3/2020 Ngudi phin bien: TS. Dang Xuan Hiep
TS.H6 Viet Hdi