ảnh hưởng của gá kẹp đến ứng suất dư và biến dạng trong liên kết hàn giáp mối hai tấm thép không gỉ AISI 304

NGHIEN CO'U-TRAOD6| A N H HU'dNG C O A G A K E P o i N LTNG S U A T DU" V A BI^N DANG TRONG LIEN K^T H A N GIAP M | HAI T A M THEP KH6NGGiAISI304 EFFECT OF CLAMPING TO RESIDUAL STRESS AND DISTORTION IN BUTT WELDED JOINT OF TWO AISI 304 STAINLESS STEEL PLATES KS Lg Van Phi', TS H^ Xuan Hung^ ThS Nguyen H^ng Thanh^ 'Truong Cao dang nghe Lilama ^Truang Dai hpc Lao dgng va Xa hpi ^Tniong Dai hgc Su pham Ky thuat Nam Dinh TOM TAT Lien kit hdn gidp moi Id loai liin kit duac img dung rpng rdi che tgo kit cdu thep, thung chua chong an mon, chiu nhiit .Dif dodn img sudt du vd bien dang hdn Id mpt nhtem vu quan trpng tir thiit ki vd chi tgo Bdi bdo ndy su dung phuang phdp phdn tu hieu han de phdn tich vd du dodn suphan bd img sudt du vd btin dgng cua liin kit hdn gidp mdi hai thep tdm khong gi v&i cdc tdm duac gd kep a vi tri khdc Tir khoa: Md phdng sd; Bien dang gdc; (fngsudtdu; VdtmepchirX ABSTRACT Butt welded joint is a type of welded joint used widely in manufacturing structure steel, tank of corrosion and temperature resistant, The prediction welding residual stress and distortion is important task when designs welded structure This paper uses finite element method to analyse and predict the distribution of residual stress and distortion ofthe butt welded joint with two stainless steel plates, in each case that plate is clamped at different positions Keywords: Welding simulation; Angle distortion; Residual stress, Xgroove D.^T VAN DE Thep khong gi AISI 304 [2] la loai vat lieu CO the lam viec moi truang chiu an mon hoa hpc, c6 bin tuong ddi cao va thucmg dugc su dung de lam thung, bon be chua hoa ch^t, Khi han su nung n6ng va lam nguoi khong deu, anh huong cua thong so che han (dong dien, dien ap, van toe han, ) va cac dilu kien ga kep, din den su xuat hien ung suat du bp phan hoac toan ket cau han Chinh vi vay, kiem soat ung suat du va bien dang han la van de dang dugc rat nhieu nha khoa hoc trong'^ ISSN 0866 - 7056 TAP CHi CO KHi VlfiT NAM, S6 nam 2017 www.cokhivietnam.vn NGHIEN COU - TRAO D I va ngoai nuac quan tam Bai bao tac gia sir dung phSn mem Sysweld® cua tap doan ESI [4] de phan tich, du doan su phan bo ung suat du va bien dang lien kit han giap moi hai tam thep khong gi AISI 304, vat mep chir "X" kich thuac 140x lOOx 14 mm voi cac tam dugc ga kep a vi tri khac KY THUAT MO PHONG 2.1 Mo hinh ngu^n nhift Trong nghien cuu nay, tai bat ky thai diem nao nang Iugng eua ho quang han dupc mo ta bang su phan bo nhiSt Gau xa (Gao va Zhang, 2011), [3] Vi thl, dilm thupc bl mat viit han c6 ban kinh ciia cpt ho quang la r^ se n h ^ duac su phin b6 nhiet q^ theo cong thuc (1): cong thuc Cong thue mo ta su mit nhiet trao doi va biic xg, moi truang xung quanh, [4] ,S^T ,S^T t :r + k =-H Sx , ^ ^ p C k ^ ^ A(r-r„)+^E(r^-r;)= Trong do: Q la nang lugng nhiet toa hoac nang lugng duong (J/mm), q^ li nhiet lugng thdt thoit, T li nhiet dp khao sat, T^ la nhiet ban diu, t la thai gian (s), k la h? s5 dan nhiSt (W/mm °C), P la khoi Iugng rieng, C la nhiet dung rieng (J/g °C), h la he so nhi6t doi Iuu, P la hang so Stefan-Boltzman, [5] vi € la he s6 phat xa Lien quan den trang thii gii 6n dinh, eong thuc dugc viet lai nhu sau: 6-T 5Q (4) 5y^ V la van toe han, (mm/s) +K (1) Hinh 1, 2, 3, bieu dien cic tinh chat coly-kim loai hgc cua thep AISI 304 [4], Trong do: r^ ban kinh cua cpt ho quang va Q la nang lugng cua cpt hd quang Thong so nguon nhiet han su dung mo phong dugc cho bang Bdng Thdng so nguon nhiit hdn Thong so Gia tri a, 6mTn a 10 mm b c mm 4min Hinh He so ddn nhiit 2.2 Mo hinh truyen nhi^t Mo hinh truyen nhiet theo chilu (3D) a hang thai gia on dinh dupc thl hien bing ISSN 0S66 - 7056 TAP CHi CO KHi VIET NAM, S6 nam 2017 www.cokhivietnam.vn Hinh Khdi luang neng NGHIEN CLfU - TRAO efil Bdng Tinh chdt vgt ly Dac tinh Mo dun dan hoi (ksi) Gioi han chay (ksi) He so Poisson Nhiet dp nong chay ("C) Nhiet dp dong dac ("C) Hinh Nhiit dung riing Gii tri 29.000 31.200 0,29 1455 1400 2.5 Mo hinh hoa lien ket han 2.3 Mo hinh biin dang Ung suit nhiet hinh vat han dugc xac dinh tren ca sa cac ung suat phan theo chieu (x,y,z), cong thuc (5) Lien ket hin dugc thilt ke bang cac phin mem vai mo hinh solid (3D), xem hinh (5) Biln dang tong (e) gom: Biln dang dan h6i (e^^), biln dang deo (g^) vi bien dang nhiet (s*) theo cong thtic (6) g = E= + eP + gth (6) 2.4 Cac thdng so cua vat li^u Hinh Mo hinh lien kit hdn Lien kit hin dugc mo hinh hoa voi 86.812 phin tu (element) vi 69.231 nut (node) Thanh phin hoa hgc vi ca tinh cua thep 304 dugc cho d bing va Bdng Thdnh phdn hod hoc Nguy§n tS C Si Mn P S Cr Ni Ham liTQUg, % 0,08 0,75 2,0 0,04 0,03 18+19 8+9 Hinh Mo hinh hod lien ket hdn (a); Viing chia lu&i (b) D I kit qui mo phong dugc chinh xac vimg moi han va vtmg inh hudng nhiet (HAZ) dugc chia ludi (vung 1) va vung lan can chia ludi thua hon (vung 2) ^ ISSN 0866 - 7056 T^-P CHi CO KHi VlfiT NAM, S6 nam 2017 www.cokhivietnam.vn NGHIEN c u u - T R A O D | Bdng ChS dp hdn thifc nghiim 2.6 Trinh ty thyc faien cac diromg han Trong nghien ciiu eiia minh, lua chpn phuang phap han ho quang que hin thudc bpc (SMAW) v i chilu day tim hin ciing nhu kieu vat mep dupc mo ta d tren tie gia chpn hin dudng, hinh v i dugc thuc hien cimg chieu Dircmg ban KW 80 120 120 120 120 0,8 0,8 0,8 0,8 0,8 ^ V (mm/s) 3,5 3,5 3,0 3,5 3,0 (mm) 2,5 3a 3,2 3,2 3,2 Trong do, v: Van tdc hau [mm/s]; D^: Dudng kinh que han [mm] Hinh Thu tu cdc du&ng hdn Bdng Thdng sd mo phdng 1,1 Dieu kien ga k^p Sudng han Dieu kien ga kep md phdng dugc thuc hien gidng nhu thuc nghiem, xem hinh 7, bang 4 NanglutfDg dirong (J/mm) 800 880 940 880 940 v^ (mm/s) 3,5 3,5 3,0 3,5 3,0 KET QUA VA THAO LUAN Giii bai toan ta thu dupc ket qua: Hinh Vi trigd kep hdn 3.1 Trudng nhiet 36 Bdng Truang hop vd vi tri kep chgt Trirong hop Vj tri kep A, B, C, D A,B A, C A,B(x,y);C(x);D(y) 2.8 Thong so han va md phong Thdng sd, che han thuc nghiem \ md phdng dugc md ti bing va Hinh Kich thu&c bi hdn mo phong vd thuc nghi&m ISSN 0866 - 7056 TAP CHi CO KHi VlfiT NAM, Sd nam 2017 www.cokhivietnam.vn NGHIEN cuu-TRAO OOl Hinh 8, the hien hinh dang kich thuac be han giua mo phong va thue nghiem ta thay cac viing tuong ddi gidng Hmh 11, thl hien gia tri bien dang goc cua trudng hgp, vi tri dudng xac dinh bien dang cich cudi dudng han 30 mm Bien dang ldn nhit thupc trudng hop 3.3 Trirdng ung suat II j ~' Hinh Chu trinh nhiet hdn Tren hinh 9, bilu diln chu trinh nhiet hin tai mit 6.244 phia tren va niit 22.396 phia dudi cua tim han thupc vimg HAZ each chin dudng hin phu 4,2 mm 3.2 Trtrong bien d^ng { "; TnAtas btfp 1s TnlOng h^p \l 11 j j; Tn«nebi3p3 [^ Tnfflngh(Jp4 Hinh 12 O'ng sudt du tong Hinh 12, md ta su phan bd iing suit du tdng (von mises stress) cua trudng hgp Ta thay ring, ling suit tap trung chu yeu tai chan mdi hin va ldp han cung Tn«rB« ^tfp Hinh 10 Biin dgng tong Hinh 10, thl hien miic dp bien < tdng cua trudng hgp Hinh 11 Biin dgng gdc Hinh 13 Phdn bo img sudt du long Hinh 14 Phdn bo ungsudtphdp theophuangX ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd nam 2017 www.cokhivietnam.vn NGHIEN c u u - T R A O D I Hinh 13, la phan bd ung suat du tdng v i Hinh 14 md ti su phan bd irng suit du phap theo dudng dpc dudng han, phia tren va dudi cua tam hin v i each chin mdi han phii khoang 2,5 mm