NGHIEN CUfU - TRAO B6\ NGHIGN ClJU MO PHONG T R U O N G NHIGT DO LI€N KGT HAN GIAP MOI MOT PHiA BANG QUA TRINH HAN AUTO-FCAW SIMULATION STUDY OF FIELD TEMPERATURE IN T H E O N E SIDE BUTT JOINT BY AUTO-FCAW WELDING PROCESS Vu \ ^ n Ba', PGS,TS Nguyin Thue Ha^ PGS.TS Biii Van HanhS Vu Dmh Toai= 'Bo mon C6ng nghe Han, TrUdng Dai hoc Su pham Ky thuat Nam Dinh ^Trfldng Dai hpc Bach Khoa Ha Noi TOM TAT Bdi bdo nghien ciiu md phong trUdng nhiet Uen ket hdn gidp moi mot phia nhieu Idp, d vi tri dUng bdng qud trinh hdn tu dong ho quang ddy loi thuoc (Auto-FCAW) Vat lieu sH dung nghien ciiu Id thep che tao vd tau cap A, mdc NVA 36 theo ddng kien DNV, ddy 13mm Trong nghien citu nay, sii dung SYSWELD 2010 mo phongphUdngphdp phan til hiXu han (FEM); Svt dung mo hinh nguon nhiet "Goldak's double ellipsoid" demo phdng vd phdn tich trUdng nhiet moi hdn nhieu Idp Phdn thdo luq.n kit qud trinh bdy cdc bUdc md phdng so lien kit hdn tong doan gom sU luyen kim vd cdc dieu kien nguSn nhiet, xay dUng mo hinh ludi lien ket hdn bang Visual-Mesh 6.5, phdn tich vd xii ly ket qud Muc dich ciia nghien cUu nham xdc dinh cdc thong so cong nghe hdn hdp ly trUdc Idm thi nghiem tren mo hinh that Tfl khoa: FCAW; Cong nghe ddng tau theo tong doan; Hdn vd tdu; FEM; Thep hdp kim thap; Hdn nhieu Idp; FEM nhiet - ddn hoi - deo ABSTRACT This paper simulation investigates field temperature of the Auto-flux core arc welding process (Auto-FCAW) in the one side multi-pass butt joint in position vertical The material used steel group A, mark steel NVA36 by the Det Norske Veritas, yield strength: 355 N/mm2, thickness 13mm In this research, simulation thermo-elastic-plastic finite element (FE) menthod by using SYSWELD 2010 to analysis distributed field temperature in per pass in multi-pass butt joint welding Using the heat source of GMAW model Goldak's double ellipsoid for the Auto-FCAW process Prior to the results discussion, this paper also shows the step-bystep procedures to simulate which begins with metallurgical and customized heat source modeling, and is followed by creating geometrical mesh using Visual-Mesh 6.5 for analyzing and processing the results Final objective of this research is aimed to be a baseline study to provide preliminary information in preparing the tools and equipment for experimental investigation Key word: FCAW; Assembly of the block; Welding ships' hull; FEM; Low alloy carbon steel; Multipassed welding; Thermo - elastic - plastic FEM ^ TAP CHf CO KHi VIET NAM, Sd 12nam2013 ^ H NGHIEN COfU-TRAODOl GlCfl THIEU Trong cac nganh cong nghiep nang nhU ddng tau va xay dUng, cdng nghe han va thiet ke ket cau han ddng mdt vai trd quan Han la phUdng phap hieu qua dUOc sit dung de noi cac phan tii kim loai Han ciing la nguyen nhan gay cac sai hdng ve ket cau nhU bien dang va cac khuyet tat cua mdi han; Cac to chdc kim loai khdng mong mudn sinh kim loai moi han, tat ca chiing deu anh hUdng den ben cua mdi han va kha nang lam viec ciia ket cau Viec che tao lai hoac sifa chfla khac phuc cac sai hdng qua trinh han gay rat la mdt cdng viec rat khd khan, phdc tap; gay ton kem vat lieu, keo dai thdi gian dU an, tang gia san pham Hinh 1.1: Mo hinh nguon nhiet Goldak vd Akhlaghi NGUYEN LY C O BAN CUA P H U O N G P H A P PHAN TLT H U X J HAN NHIET - D A N HOI DEO (THERMO-ELASTIC-PLASTIC FEM) 2.1 Mo hinh nguon nhiH Lien ket han mot phia, nhieu nhieu Idp d vi tri han ddng dUdc sii dung lap rap cac phan doan va tong doan vd tau De nang cao nang suat, chat luong va giam gia san pham che tao vd tau, nganh cdng nghiep ddng tau Viet Nam can phai nghien ciiu ap dung cac qua trinh han hieu suat cao; nghien ciiu day dii ve cac thdng sd cong nghe han va xay dUng quy trinh han hop ly Ngay nay, phUdng phap md phdng sd dang dUpc ling dung sau rdng linh vUc nghien ciiu va thiet ke quy trinh han, ling suat va bien dang, ket cau han SYSWELD 2010 la mdt phan mem chuyen dung va tien tien de nghien cflu md phdng qua trinh che tao cac ket cau han b&ng cac qua trinh han khac Dfla tren co sd ly thuyet ve phuong phap phan tii hflu han PTHH nhiet dan hdi - deo, SYSWELD cd the md phong chinh xac nguon nhiet, trUdng nhiet dp, chuyen bien to chiic kim loai va flng suat bien dang han, Cac ket qua dUpc the hien dfldi dang md hinh trflc quan 2-D, 3-D, dUdi dang cac thi d bat ky nflt phan tfl md hinh hen ket han Md hinh hda nguon nhiet cap vao la mot nhflng phan quan nhat phflong phap phan tfl hflu han FEM Md hinh nguon nhiet thdng dung cua qua trinh han GMAW (FCAW) la hinh eUip kep dfldc de xuat bdi Goldak and Akhlaghi (2005) Ddi vdi qua trinh han FCAW, pham vi hieu suat cua nguon nhiet 65% d^n 85% Nhi^t cap vao tfl nguon han (nguon nhi^t) vao be han truyen vao kim loai ccf ban bdi tinh ch& din nhiet be mat xung quanh bang sU ddi lUu va bflc xa (Parmar 2005) Khuech tan nhiet sU dan nhi^t duoc dua tren dinh luat Fourier, dd la ngu6n nhiet q (W/m^) truyen tfl vung ndng sang vung ngupi hon va phu thupc tuyen tinh tren gradient nhiet dp, dd k la he sd dan nhiet (trong W/ mK) Dd la kha nang cua mot vat li^u dan nhiet va cd the phu thupc vao nhiet dp hoac mot tensor cac trfldng hpp di hfldng ~k(gradT).n - —l^j (1) Khi sfl truyen nhiet dUpc xet theo cdng thflc enthalpy cd ban, de giai van de thupc linh vflc Idng va ran va neu k la he so dflpc cai vao phflpng trinh bao toan nang lupng, phuung trinh truyen nhiet trUdng hpp toe dp nhanh co the dflpc viet nhU sau: 'ã'-S = s('('-)f)-J('(n=)*^(Mr)S).ô (2) Nhiet lii(?ng toa ciia sd truyen nhi?t diioc cho bdi dinh luat Stefan-Boltzmann a, e va h^^lan laot la hing so Stefan Boltzmann, nhiet toa va he so biJc xa truyen nhiet; TAP CHI C O KHi VIET NAIVI, S6 12 nam 2013 NGHIEN CUU-TRAODOI moi ghep nhfl hinh 2,1