Phương trình hồi quy xác định kích thước vùng ảnh hưởng nhiệt của tấm thép trong gia nhiệt cảm ứng

NGHIEN COfU - TRAO eOl PHlfaNG TRiNH H | QUY XAC 0!NH KJCH THU'aC VUNG ANH H U ' ^ N G NHIET COA TAM THEP TRONG GIA NHIET CAM UNG REGRESSION EQUATIONS OF HEAT AFFECTED ZONE IN STEEL INDUCTION HEATING NCS Tran Thi Thuy Nga", TS Nguyen Trfldng ThinhS PGS.TS Train Thu Ha^ 'Trfldng Cao dang Ky thuat Cao Thing ^TrUdng Dai hpc SU pham Ky thuat Thinh phd Hd Chi Minh De tao hinh bien dang cua tdm thep bang nguon nhiet, phUdng phdp gia nhiit cdm Ung dUde sU dung dethay thi cho ngudn nhiet Oxy-axetylen, vdn khdng ed nhieu Uu diem Ung dung tao hinh thep tdm Tuy nhien, edc nghien cUu dd dUdc cdng bo, chUa the hien rd moi quan hegiUa kich thUdc viing dnh hUdng nhiet cua tdm thep vdi cdc thdng sd nhiet lien quan suot qud trinh gia nhiet cdm Ung, md dieu ndy Iqi tao nen bien dang khdc cua tam thep Trong nghien cdu ndy, thdng lUdng nhiet phdn bd tren tdm thep suot qud trinh gia nhiet cdm Ung dUdc phdn tich ddu tien bdi phUdng phdp so, dudi gid dinh rdng qud trinh Id mdt trang thdi dUng vd cdng dUdc xem xet rang, thdng lUdng nhiet phu thudc vdo nhiet vd cdc tinh chdt cua phdi Vdi thdng lUdng nhiet dUdc phdn tich, viec phdn tich ddng nhiet vd bien dang nhiet cua tdm thep dUdc thUc hiin vdi mdt chUdng trinh FEM, vdi cdc thdng sd gia nhiet tUdng Ung Kich thUdc vung dnh hUdng nhiet vd cdc thdng sd nhiet ddu vdo dUde tong hdp vdi phUdngphdp thdng ke de xdc dinh mdt edng thUc the hien moi quan he giUa kich thude vung dnh hUdng nhiet vdi cdc thdng so nhiet ddu vdo Kit qud dUdc suy tiiphUdng trinh hdi quy tot so vdi ket qud md phdng ABSTRACT To control the deformation ofplate in the steel forming process with heating, the electro-magnetic induction process has been used as the substitute of the flame heating process However, in these studies have been published, haven't clear the relationship between the size of heat affected zone of steel plate with heating parameters related during the heating process in induction heatingyet, which this makes a different deformation of the steel plate In this study, the heat flux distribution over a steel plate during the induction process is firstly analyzed by a numerical method under the assumption that the process is in a quasi-stationary state around the inductor and also with the consideration that the heat flux itself greatly depends on the temperature of the workpiece With the heat flux analyzed, heat flow and thermo-meehanical analyses on the plate are then performed with a commercial FEM program with heating parameters, respectively The size of the heat affected zone and the input heating parameters are then synthesized with a statistical method to produce simplified formulas, which can easily provide the relation between the heating parameters and the size of the heat affected zone The results obtained from the formulas are in good agreement with results of simulation Tfl khda: Steel forming Electro-magnetic induction Heat flux analysis, Thermo-meehanical analysis Finite element method, Simplifiled formula Heat flow Heat area zone (HAZ) ^ CO KHi VlfiT NAM • Sd (Thing nam 2012) ^ NGHIEN CtfU-TRAODCl I.GICJI THIEU Viec tao hinh bien dang lam ih^p vd liu trflde lap ghep vao eae phan cua than tiu la mpt khiu quan trpng nginh ddng liu, tao nen chat Iflpng eua mpt chiec liu vi ning cao nang canh tranh tren thi iruniig Qui trinh tao hinh bien dang thep lam vd liu liicn chu yeu sfl dyng cae phfldng phip truyen thdng, vdn khdng linh boat vi kem hi^u qui kinh te Dac bi^t la phfldng phip tao hinh bien dang vd tiu bing ngudn nhiet, sfl dyng dau dot Oxy-axetylen ll] Chat lupng tao hinh be mat cung nhU bien dang ciia tam thep phy thupc i-il nhieu vio tay nghe ngfldi thp, khd kiem soat ngudn nhi?t diu vao sudt qua trinh gia nhi^t mi dieu niy lim giim hi^u qua eua phfldng phap Gia nhiet cam flng li phfldng phip dupe sfl dung de thay the cho ngudn nhi?t Oxy-axetylen, vdn khdng cd nhieu flu diem viec tao hinh bien dang tam thep Khi gia nhiet cam Ung dUde ip dung cung vdi viec tich hdp robot cho viec tU ddng, qui trinh udn bien dang tam thep se trd nen de dang dieu khien vi kinh te hdn cac phUdng phip eu Die biet, ddi vdi cic tam thep bien dang vd tau ed bien dang phfle tap, phfldng phip gia nhiet cim flng the hi^n rd nang toiflu.Cic de tii nghien cflu ve phfldng phip gia nhiet camflngtrong bien dang thep tam da dflpc cdng bo, phan bd nhiet hai chieu sudt qui trinh gia nhiet cam Ung vdi tan sd gia nhiet cao li nhflng chu de chinh hau het eae nghien cflu [2-^7] vi trang thii bien dang ba chieu cua tam thep dfldc md hinh hda bdi phin tich [8] Tuy nhien, cic nghien cflu di dflpc edng bd, chfla the hien rd mdi quan he gifla kich thfldc vung inh hfldng nhiet cua tam thep vdi eae thdng sd gia nhiet lien quan sudt qua trinh qua trinh gia nhiet cim flng ma dieu niy, nd tao nen bien dang khae cua tam thep Trong nghien cflu nay, hai cdng thflc ddn gian dfldc de xuat de xic dinh kich thUdc cua vung anh hfldng nhiet cua tam thep vdi cic thdng sd gia nhiet lien quan sudt qui trinh gia nhiet cam flng vdi tan so cao Cdng thflc cd TAP CHi CO KHi V I £ T NAM • th^' rit hflu ich vi?c phat trien dfl doan quy d?io di chuyen cua dau tU, dfla vio edng thflc xac djnh biefn dang theo phUdng vudng gdc cCia tam da dupe cdng bd [9], cho van de tUdng lai I )e xic dinh edng thflc Ai xuat, vi^c phin tich thdng Iflpng nhi^t ddng nhiet va phin tich bi^n dang nhi?t dflpc thflc hi$n vdi cic thdng s6 nhiii diu vio Phfldng phap phan tfl hflu han (FEM) dflpc sfl dyng phin tich bdi vi cac die tinh phi luyen gia nhi^t camflng.Tuy nhien, ngudn nhiet gay nen bdi dau cim flng tU di ehuyen tren be mat tim thep vdi van toe khdng ddi, mdt mien giii phip bao gdm tim thep, cupn diy vi khdng dd vi tri cupn day va phan khdng thay ddi lien tuc vi nhflng thay ddi giy nen khd khin cho phan tich ddng thdng Iflpng tfl, ddng dien xoay va thdng lUpng nhi?t sinh tren tam thep sudt qui trinh gia nhipt cim flng chi sfl dung mpt chfldng trinh FEM Bdi vay, mpt chfldng trinh FEM cho phin tich trfldng dien tfl cua qui trinh gia nhiet cam Ung dfldc phat trien dfldi gia dinh ring qua trinh la mpt qui trinh trang thai dflng vdi mdt he tpa dp di chuyen, COMSOL 3.4 Chfldng trinh FEM tinh toin thdng Ifldng nhiet tfl dau gia nhiet den chi tiet sudt qui trinh niy Phan tieh ddng nhiet vi bien dang nhiet cho tam thep sau dd, dfldc thflc hien vdi chfldng trinh FEM Abaqus 6.5, sfl dpng thdng Iflpng nhiet dUpc suy tfl phin tich trUdng dien tfl nhU la mpt nguon nhi^t dau vio De xiy dUng mpt cdng thflc ddn giin xic dinh kich thfldc vung inh hfldng nhiet cua tam thep vdi thdng so gia nhi^t bat ky, phan tich thdng Ifldng nhiet vi bien dang nhiet dflpc thpc hi^n vdi nhflng thdng so gia nhiet nhfl be diy tam thep, tdc dp di chuyen dau tfl vi cU6ng dp ddng dien trpng cupn day Mdi quan he gifla kich thfldc vung anh hfldng nhiet va cic thong sd gia nhi?t bdi thUe nghiem sau dd dfldc tong hdp vi phin tich bdi phfldng phip thdng ke de xac dinh mpt cdng thflc tfldng flng Mdt loat cac phin tich md phdng gia nhiet cim flng dflOC thflc hipn sau dd, de chflng minh tinh kha thi cua cdng thflc Sd (Thang nam 2012) NGHIEN COfU-TRAODOl PHAN TICH THONG LUONG NHlfiT SINH RA TRONG GIA N H I £ T CAM TTNG hpp veetd Khi phfldng trinh (1), dfldc giii bang phfldng phip phan tfl hflu han, nd dUpe viet nhU 2.1 Phan tich trUdng dien tfl cho thdng Ifldng nhiet Khi cho ddng dien xoay chieu, cd tan sd cao chay qua mdt cudn diy, dUdc dat tren mpt tam thep, nhfl hinh 1, mdt chum tfl thdng xuyen qua be mat cua tam thep m i nd ddng tryc vdi cudn day Vi vay, ddng dien xoay dflpc sinh tai be mat cua tam thep Ddng dien cam flng sinh nhi^t dien trd tren tam th^p theo hieu Ung Joule vi dieu niy cd the dung de udn tam thep PhUdng trinh can bing cho ddng dien xoiy phan bo qui trinh gia nhiet cam Ung ed the dflpc suy tfl he phfldng trinh Maxwell vung tan sd cho phep 110] I „' , , — V A^}Q}uA-J, /i\ ^ (2) [KM'IJ] \B!J w \eN\\m\ iat,«,llnil«\Jn(3) [j]=jj.[N]'da (4) Vdi vecto dien tich dUpc rut tfl phfldng trinh (2), nhiet dien trd ed the dflpc tinh (5) (^ d.ky J, = a{-dA! dl) la mat dp cua ddng ^j^j^ j^^^y -jl^^ng Ifldng nhiet trung binh mien tan sd cd the dfldc tinh - C^ l i t \ CSday:V- gpi l i toin tfl Laplace, A li veetd dien the tfl, J^ mat dp ddng dien eua nguon eudn day, n li dp tfl tham, w la van toe gdc vi a li dp din dien Truong difn lit lh) ^6 16 16 16 -22 22 11 5.1 5.' 10.IS 8.91 Kft 9.87 ?.< 9.9 52.3 - 42.9 6.3 42.9 4.8 q u i the hien gia tri niia be rpng HAZ \h inpt du6ng cong bac hai Sit „„ =-103.804,0, =502.672.0 =-482.816 VSy phuong trinh t6ng quat nfla be rgngb dupc tim vdi h? s6 tflong quan R = 0.89 * = -103,«O4t502,(i72(- Tit so lieu bang kich thiidc nila be rong ctia viing anh hil6ng nhiet la mpt ham phu thupc vao van toe va be day tam thep nhii sau: b = av-t'' (10) log(6) = log(a) + a log(v) + p log(0 (11) -482.81«-; (14) Hinh 12, the hi?n moi quan he gifla van toe di chuyen cua dau tfl vdi nfla be rpng HAZ bdi mo phong, thflc nghiem va phflPng trinh hoi quy cua tam day 22 mm khoang each tfl cu$n day den tam thep la 3mm va efldng dp dong dl?n 720A, tflong flng Tflong tfl, tfl so lieu bang 2, kich thfldc (!J day: a, a, |3 la nhiing he so, la van toe chieu sau cita HAZ cung la mpt ham phy thuQC di chuyen dau tit, t la be day tam thep va b la nifa vao v^n toe va be day tam thep nhfl sau: be rpng ciia viing anh hu6ng nhiet Khi lay logarit (15) hai ve, phuong trinh (10) CO the dupc viet lai nhu /i = a,v'''r Dat B = log(*), A = log(o), V = log(v), T = log(() Phuong trinh (11) co the dflpc viet l?i B=A+aV+pT (12) day: a.,a.,fi la nhflng he so, (nunys) la van toe di chuyen dau tfl, t (mm) la be day tim thep va h (mm) la chieu sau cua vung anh hfldng nhift Khi lay logarit hai ve, phfldng trinh (15) Tfl so li?u bang v4 sfl dung phan mem CO the dflpc viet lai nhu sau: log(A) = log(a) + a, log(v) + p, log(0 (1*) Statgraphics plus 5, cac h? so a va [3 co the dflpc tinh toan: a = - 0.244215, (5 = 0.100563 Bdi vay, mia b^' rpng vung anh hfldng nhiet la mpt ham Djt W = log(A), = l o g ( a , ) , K = log(v), cua v""""" va / - » " « Khi do, v""*"" va ,-ằãôằ'" r = log(/) PhflOng trinh (16) ed the dflpc vift Iji dflpc xem la nhflng bien dpc l|p va b la mot bi^n H = A,+a/ + p,T („) phij thupc Phfldng trinh ham dang tong quat ciia TAP C H l C O KHl VIET NAM s a (Thang nam 2012) N G H I E N ClifU - TRAO DPi ; Hinh 12 Mdi quan he giUa bi rdng HAZ vdi van tdc Hinh 13 Moi quan he giUa chieu sdu HAZ vdi van toe di chuyen cda ddu td tronggia nhiet cdm Ung di chuyen cua ddu tU tronggia nhiet cdm Ung Tfl sd lieu bang vi sfl dung phan mem Statgraphics plus 5, cac he sd a l va p ed the dUde tinh toin: a l = - 0.734497, (3l = -0.322719 Bdi vay, chieu sau vflng inh hudng nhiet li mdt ham eua v"""'"'' v i / "' "'^ Khi dd, v "''•'•'"'vi ,"''-"'"' duac xem li nhflng bien ddc lap v i h li mdt bien phu thude PhUcfng trinh h i m dang tdng quit cua h luc cd the dUde viet lai dudi dang tdng quit sau: ^'-'„^-^|loJ, -,J-'':il,„-.J„.:-,j'-".' „-J„i J (18) Khi ket qui td phUong trinh hdi quy dUOc so sinh vdi thUc nghiem, sai sd ti le phan trim cua nfla be rdng vung anh hUdng nhiet dUpc tinh toin la 11% v i 3% cho sai sd kich thude chieu siu vung anh hudng nhiet Khi ket qua tfl phUOng trinh hdi quy dUoe so sinh vdi ket qua md phdng, ta thay sai sd nfla be rdng vung anh hUdng nhiet dUpc tinh toan la 13.35% va 26.12% cho sai sd kich thUdc chieu sau vflng anh hudng nhiet Ket qua ed sai sd niy li do: sfl khdng ddng deu eua vat lieu, tam cd sfl bien dang ban dau nen khoang eich tfl vdng diy den be mat tam thep cd sai lech sudt q u i trinh gia nhiet vi inh hUdng cua bfle xa nhiet Tfl ket q u i dUcfe d sd lieu bing 2, ta thay gii tri chieu siu HAZ l i mdt dUdng cong bae hai Sfl dung phan mem Statgraphics plus va sd lieu bing 2, cic he sd a,^,,a^,va a,, dUcfc Ket qui phan tich the hien rang phuong tinh: UQ, =-7 00105,