NGHIEN CUfU-TRAO D | \/NGHIEN CLTU S l / A N H HU'dNG C O A C H ^ DO C A T D i N SU' BIJ^N CCfNG B^ MAT GIA CONG KHI TIEN THEP 45 TREN M A Y TIEN CNC A STUDY ON THE EFFECTS OF CUTTING PARAMETERS ON THE DEGREE OF WORK-HARDENING SURFACE WHEN LATHING STEEL 45 ON CNC TURNESfG TS Pham Vdn B6ng Tmdng Dai hgc Cdng nghiep Ha Ndi TOM TAT Do cung vd chieu sdu lap biin cung be mgt chi tiit sau moi lat cdtphyi thugc vdo rdt nhieu yiu td nhu: Vgt lieu gia cong, dung dich ldm mdt, phucmgphdp gia cong, hinh ddng vd goc cua dao chi cong nghi (chi cdt ggt) w Cdc nghiin ciru da chi rdng, lap biin cimg tren bi mat chi tiit khong chi co dnh huang lan den bin cua chi tiit mdy md nd cdn dnh hudng din qud trinh cdt cua lat cdt tiep theo Bdng nghiin ciru ly thuyet kit hgp vai thuc nghiim, bdi bdo trinh bdy kit qud nghiin euu su dnh hudng ciia che cdt gom van tdc cdt V; Lugng tiin dao S, chiiu sdu cat t din biin cung bi mat tiin thep 45 trin mdy tiin CNC Kit qud nghiin euu Id ca sa giup cho viec lua chgn chi cdt hgp ly tiin thep 45 T\x khoa: Nghiin euu, su dnh hudng, biin cung, chi cdt, tiin thep 45 ABSTRACT Surface hardness and work-hardening thickness depend on many factors such as cutting materials, cutting fluids, machining methods, tool angles and technology parameters Researches indicated that work-hardening thickness affects not only machine parts durability but also next cutti process Therefore, it is important to choose a suitable cutting method This paper combines both qualitative and quantitative methods, which presents the effects of cutting methods including cuttin speed (V), S cutting feed (S), cutting depth (t) on the degree of work-hardening surface of 45 steel which was lathed using CNC machine The results of this study make a contribution to the selectio of appropriate cutting parameters for lathing steel 45 Keywords: Research, effects, hardness variables, cutting methods, lathing steel 45 ISSN 0866 - 7056 TAP CHI CO KHi VIET NAM, Sd 12 nam 2015 www.cokhivietnam.vn NGHIEN CUTU - TRAO D O I D^T VAN DE Cling ciia kim loai; C,; C^; C^: la cac hdng sd thyc nghiem; V,S, t la chd cdt; x, y, z la s6 mu thyc Qua trinh cdt la qua trinh dao tac dung nghidm vao vdt gia cdng mgt luc lam cho kim loai hi bidn dang va tdch khoi phdi tao phoi O van toe cdt thdp, bien dang kim loai Didn bidn ttong qua trinh cdt vd tao phoi ttong vung cat didn d miic chdm, dp luc len dd la mgt qua trinh phiic tap dugc dd cap ttong ben mat gia cdng chua ldn ndn ciing bd mat nhidu ttong tai lieu [4], [5]; [10]; va [11] Tdt thay ddi chua nhidu Khi van tdc cat thay d6i, ca cac nghidn euu dd deu chi ra, cd sy bidn nhidt cdt thay ddi lam khd ndng bidn dang deo dang ddo ciia kim loai ttong didu kidn nhidt cua kim loai ttong vung cat say manh liet ndn va ap lyc cao lam cho ldp kim loai trdn bd mat bidn Cling bd mat tang [4] Khi cdt voi budfc gia cdng hi bien dang manh Hdt, kdt qua sau tidn dao thay ddi thi bien ciing bd mat cimg cat ldp kim loai dd cd ciing khdc ciing ciia thay ddi theo vd moi quan he gifia chiing Id mdt chi tidt gia cdng traoc cdt Nguydn nhan true ham ddng bidn (ty Id thudn) [11], tidp cua nd Id tac dung ciia luc cdt lam xd lech mang tinh thd cua kim loai ldp bd mat, gdy bidn Chidu sdu cat la ydu td dnh hudng it nhdt dang deo d vung trade va sau luoi cdt lam cho den bidn ciing bd mat gia cdng Cdc nghidn kim loai cua ldp bd mat bi ciing nguoi, chdc lai Cliu thuc nghidm cho thay rang chidu sdu cat va CO cung td vi cao [4] Tuy nhien, nguydn thay ddi thi luc cdt don vi thay ddi Nhung lyc nhdn xau xa la su anh hudng mdt s6 ydu td gdy tnigt tten be mat tinh thd theo hudng due ttong cd chd dd cdt Mdi quan he giiia chd thay ddi it, lyc theo phuong tidp tuydn dgc true cat vdi Cling bd mat nhu thd nao cdn dugc gdy tragt trdn be mat tinh thd gdy xd lech nghidn cihi bang thuc nghiem ttong timg trudng mang tinh thd, vd su ddn li lech khdng nhidu ndn miic dnh hudng ciia chidu sdu cat den bien hgp gia c6ng cu thd Cling la nhd [4], [5] Trong trudng hgp dac biet (it NGHIEN ClTU SlT ANH HlTOfNG CUA xdy qua trinh cat thyc te) la sy tmgt CHE DO CAT DEN BO ClTNG BE MAT daottenbe mat phdi cdt vdi chidu sau cat nhd vd buac tien nhd se lam cho bd mat bi bidn ciing KHITI£NTHEP45 nhidu Thyc nghidm cho thay cat vdi chidu 2.1 Nghien curu thuc nghidm anh huvng cila sau cat tr= 0,02-0,03mm thudng say hien tugng timg yen to che dp cat den biln cihig bk mat tragt dao Khi kim loai chu ydu bi nen chat lam cho lech tang dot nggt va bi ddn li cyc dai thi liic klii tifn thep 45 tren may tifn CNC bien ciing lai tdng rdt manh [4], [6] Ldp kim loai trdn bd mat chi tidt sau m6i lat cdt cd tinh chdt co ly khdc hdn vdi lop vdt hdu Qua cac nghien ciiu d tten cd thd thdy ro trade cdt Id bidn dang ddo Miic bidn dnh hudng cua chd cdt ddn bien ciing bd dang deo cua vdt lieu ttong vung cdt chiu sy dnh mat De thay ro hon vd muc dnh hudng dd, ta huong cua chd cdt Mdi quan he giua tung ydu tien hanh cat thu thep 45 vdi chd cdt khac td chd cat vdi ciing HV (Hardness Vickers) tren may tidn CNC cho ket qua bidn ciing nhu sau: bd mat la mgt ham phi tuydn cd dang: HV^ = CjV (1); }W^= C,S> HV = Cjt^ (2) Cat thu vdi van tdc cdt thay ddi cho kdt (3) qua bang Cdt thu vdi budc tidn dao thay d6i cho kdt qud bdng 2, Cat thii vai chidu sau cdt Trong dd: HV^; HV^; HV^ la bidn thay d6i cho kdt qua bang '^ ISSN 0866 - 7056 TAP CHl CO KHi VIET NAM, Sd 12 ndm 2015 www.cokhivietnam.vn NGHIEN CUlU-TRAODOI Bdng 1: Ket qud do biin cimg van tdc cdt thay ddi 10 11 12 13 14 15 V (m/ phut) 50 55 60 65 70 75 SO 85 90 95 100 105 no 115 120 S (mm/ v6ng) 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0.1 0,1 0,1 0,1 STT Che cat T (mm) 1.5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1.5 1,5 Ket qua dp bien cung HV 230, 33 236, 55 239, 77 245, 64 250, 07 257, 94 265, 66 269, 87 278, 73 285, 35 295, 66 304, 59 313, 56 321, 53 329, 76 Bang 2: Kit qud do biin cdng budc tiin dao thay ddi 10 11 12 13 14 IS 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 120 0,06 0,07 0,08 0,09 0,10 0,11 0,12 0,13 0,14 0,15 0,16 0,17 0,18 0,19 0,20 0,1 1,5 Ket qu^ biln Cling HV 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1.5 261, 54 265, 17 269, 55 271, 38 276, 35 279, 48 284, 45 287, 63 291, 48 292, 93 295, 78 298, 93 299, 78 302, 42 305, 66 STT Che d« cat Bang 3: Ket qud do bien cimg chieu sdu cdt thay ddi Che bien cihig HV Tu ket qua thyc nghidm, xac dinh ham hdi quy thyc nghidm theo phuong phap binh phuong nhd nhdt cho ham mdt bien sd tten ca sd hd trg ciia phdn mdm MatLab, Microsoft EXCELL thu dugc kdt qua: Mdi quan he giua dg bidn ciing vdi chieu sdu cdt: H V = 233,451""" Dd thi bidu didn mdi quan he (hinhl) Mdi quan he gifia bidn ciing vdi van tdc cdt: HV^= 43,49 V«-^'*« M6i quan he giua bidn ciing vdi buoc tidn dao: HV - 377,28 S"-'"* Hinh 1: Dd thi bieu dien mdi quan hi giira bien cung be mat vdi che cdt ISSN 0866 - 7056 T ^ P CHi CO KHi VlfiT NAM, Sd 12 ndm 2015 www.cokhivietnam.vn NGHIEN CUfU - TRAO 061 * Nhcin xet: Trong pham vi nghidn ciiu X , - 1/2 (lnxj^^+ Inx, ^ ) =l/2(hil50+ ln50) thi vdn tdc cat cd dnh hudng ldn nhat va chidu = 4,462 """ "^ sau cat cd anh hudng nhd nhdt ddn sy bien ciing X / ) 1/2 (hix^ ^^+ kx^ ^ J = l/2(hi0.25+ be mat ln0.05) =-2,191 X^O - 1/2 (hiX3^_^+ Inx^^J = 1/2 (hi3+ hiO.2) 2.2 Nghien ciru thvc nghifm anh hudfng dhng = -0,262 thM cua cac ylu t6 che dg cdt din bien c ^ g Khoang bidn thidn: p_ = l/2{ hix^ ^^ - hix ) be mat ti^n thep 45 tren mdy tifn cnc p , - l/2( Inx,^^ - hix,"^J = l/2('Tnl50 -Tn50) = 0,549 2.2.1 He thdng thuc nghidm p = l / { l n x ^ ^ - l n x ^ J = l/2(ln0.25-ln0.05) = 0,805 * Mo hinh thuc nghiem: Lya chgn he P3= l/2( Inxj ^^ - hiXj ^ ) - l/2( hi3 - hiO.2) = thdng thuc nghidm cd md hinh nhu hinh 2: 1,353 =^— > ^ ^ ^ , " ^ Hinh 2: Md hinh cdt thuc nghiem Tii kdt qua tinh toan ta cd cac gia tri chd cat thyc nghidm: V^^ = 150; V_^^ - 50; V^ = 86,6 s j ^ - 0,25; S ^ - 0,05; S^ - 0,11 t ^ = 3;t^^^='a2;t„ = 0,77 * Dung CU cat: Dao tien vai cd gan manh * Mdy diing thuc nghidm: Qud hgp kim ciing TCMT hang Mitsubishi che tao trinh thi nghidm dugc thyc hidn tten may tien Dao cd kich thudc can 25X25 Gdc trudc ciia CNC -DOOSAN -LYNX220 dao 5" gdc sau 7°, ban kinh mui dao R^^ 0.4mm * C h i cdt cat thg'c nghifm: Tham khao tai lieu [3] vd lya chgn chd cat gia cdng thep 45, de ttanh hien tugng phoi bam hay tragt dao ttong qud trinh gia cdng dnh hudng ddn kdt qud thi nghiem thi ta chgn midn chd cat gia cdng thuc nghidm nhu sau: * Phoi diing thuc ngliiem: Su dung phdi che tao bdng thep 45, cd ciing ban ddu la 170HV, kich thuac dudng kinh 035mm, kich thuoc chidu ddi L=150nim V^=150m/phut; S^=0.25mm/vdng; t^=3nim V^=50m/phut; S^=0.05mm/vdng; t^-0.2mm Rockwell (JHR-30C) cd ket ndi vdi mdy tinh *Thiet bi df ciing: May do ciing Vi ham toan hgc bidu dien mdi quan he Id mgt ham phi tuydn, tmh toan va xac dinh ta phdi chuydn sang hdm Id ga rit ndn cac thong s6 thuc nghi?m dugc xac dinh nhu sau: M u c ttdn: X^C) ~ '^"'imax' ^^'^ ^^^' Miic CO so: Xj(0) = 1/2 (lnx_ ^ ^^'^) ^ ^ i m m lnx_ ) 2.2.2 Kit qud vd xu ly so lieu thuc nghifm * Ket qua Tidn hanh thuc nghiem vgi 11 thi nghidm, do Cling tai didm ddu, didm giua, diem cuoi doan cdt thyc nghiem cua chi tidt vd lay gid tri trung binh, ta dugc kdt qua nhu sau (bang 4) ^ ISSN 0866 - 7056 TAP CHi CO KHf VlfiT NAM, Sd 12 ndm 2015 www.cokhivietnam.vn NGHIEN CUlU - TRAO Ddi Bang 4: Ket qud do cung Bien thirc nghidm Bien ma hoa X, X, X3 V (m/phut) S (mm/vong) T(min) G i i tri d o d crnigHV STT -1 -1 -1 50 0.05 0.2 285.3 +1 -1 -1 150 0.05 0.2 317.2 -1 +1 +1 -1 50 0.25 0.2 315.4 +1 -1 334.8 -1 -1 +1 +1 0 +1 +1 +1 +1 0 0.25 0.05 0.2 -1 +1 -1 +1 0 150 50 150 3.0 0.05 0.25 3.0 3.0 286.8 324.4 0.25 0.11 0.11 0.11 3.0 0.77 0.77 311.6 353.6 342.4 334.4 0.77 337.3 10 11 50 150 86,6 86,6 86,6 Gia thidt mdi quan he giua chd cat va dg bien ciing cd tudn theo quy ludt ham sd mu, ta cd: HV = C.V.S^f Ma ttdn[x] la ma trdn cdt bidn ciing; Trong do: HV la dd ciing bd mat; C la Ma tran[7] la ma ttan he sd tuong ling hang sd; a,b,c la sd mii ke den anh hudng cua che dg cat den dd bidn ciing bd mat- dugc xac Ma ttdn[^]ld ma ttan he sd tuong ling dinh bdng thyc nghidm Kdt qua tinh toan ta dugc: Logarit hda vd ta se thu dugc phuang trinh mdi: '5,4437" Ln(HV) = Ln(C) + a.Ln(V) + b.Ln(S) + c.Ln{t) Ddt y=Ln(HV); a,,-Ln(C); a,=a; a^-b; a3-c; x,=Ln(V); Xj=Ln(S); X3=Ln(t) 0,0542 Ta dugc phuang trinh mdi: 0,0986 0,0099 Suv ra' HV — e^''"^' V"'"^^^ §0.0542 ^0,0099 HV = 231,296.V^'°'^^S°'"^''^t°''"*^ * Danh gia df tin cdy cua hdm hdi quy Xac dinh ham hdi quy thyc nhiem bdng thuc nghiem: phuang phap binh phuong nhd nhdt, trdn co Do tm cay dugc danh gia bdng cdng thiic sd hd frg ciia phdn mdm Microsoft EXCELL, MATLAB R6.5 [6] ta thu dugc kdt qud nhu sau: [8]: Tacd: [x].[y] = [^] Ma ttdn la ma ttdn bidn ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd 12 nam 2015 www.cokhivietnam.vn NGHIEN CUfU - TRAO D | Trong do: suyra^^ =0.0157 Xac dinh sy tdn tai cua a V=-^?(.,-r) Co C =- ^W.(«-'"-l.l-(«/2)) Sj.Jm„ Voi: y,: Gia tri do ciing HV thuc m,, la ma tran thii ii cua ma tran nghich dao M' nglligm; (ma trjn nghich dao cua ma tran M=X^.X) yi: Gia tri trung binh cua HV thuc nghiem; y;: Gia tri tiung binh HV theo ham h6i quy thuc nghiem KSt qua ta tinh iagc: 3688,96-182,33 3688,96 Voi ma tran fl6812,31 43.566 9.456 -34.345 3.554 0,4531 55.467 ^.243 M-' = 65.356 2.356 0,2255 4.653 I, 4.436 3.256 6.346 0,1426 j Ket qua ta tinh dugc: *Kiem tra sir ton tai cua c4c tham s6 a, ' L = Ta CO phuang sai du dugc tinh theo cong thiic: Ta CO phucmg sai du S duoc tinh theo cong thuc [8]: 231,296 = 113,61; 0,0157^16812,31 0,0986 = 9,33; 0.0157^0,4531 'L = , 7,27; 0,0157.75:^^ 0,0099 1,993; 0,0157^0,1426 n—m—l Vol tin cay P = 0.95 tta bang phdn Trong do: n la so thu nghiem; m la cac phdi Student cd t(,^g(7;0.95)=1.895 thong so can xac dinh, trir a^ Tong du binh phuang; s{2t'j={Y-x2iJ (Y-X2] Nensj = ^ = 0.000246 Vdy t'^^ > t^^^ ; Nhu vay, cac he sd a thuc sy tdn tai KET LUAN Tu ket qua thi nghidm va cdng thiic bidu didn mdi quan he giiia chd cdt vd ciing bd mat, pham vi thyc nghidm cdt thep 45 vdi van ^ cdt cdt V = 50 - 120m/phut; Lugng chay dao S = 0,1 - 0,25 mm/vdng; Chidu sdu cdt t = 0,2 - 3mm'^ ISSN 0866 - 7056 TAP CHi CO KHI VIET NAM, So 12 nam 2015 www.cokliivietnam.vn NGHIEN C U T U - T R A O D O I thi mdi quan he giua ciing bd mat HV vai chd cdt dugc xac dinh bdng cdng thiic: HV — 231 296 V"'"'^^ 50.0542 ^*.oo99 Trong ydu td thi chidu sdu cat anh hudng it nhdt vd van tdc cdt cd dnh huong nhieu nhdt ddn dg bidn ciing be mat Didu hodn toan phu hgp vdi cac nghidn ciiu ly thuyet Ket qua nghidn ciiu la co sd cho viec lya chgn chd cdt tdi uu tifn thep • Ngay nhdn bai: 17/11/2015 Ngay phdn bidn: 10/12/2015 Tdi lifu tham khao: [1] Tran Van Dich; DQ chinh xdc gia cdng ca khi, NXB Khoa hpc va Ky thuat, Ha Ngi (2011) [2] Nghiem Hiing; Vgt lieu hoc, NXB Khoa hpc va Ky thuat Ha Nfi (2000) [3] Nguyin Ddc Lgc (chu bign), Nguydn Trong Binh, Nguyin Thd Dat, Trdn Vdn Djch, Le Van Tidn, D6 Diic Tdy, Trdn Xuan Viet, Le Van Vinh; Cdng nghi chi tgo mdy, NXB Khoa hgc vd Ky thu^t Ha Nfi (2008) [4] Bdnh Tien Long, Trdn Thd Lyc, Trdn Sy Tiiy (2001); Nguyin ly gia cdng vgt lieu, NXB Khoa hpc vi Ky thu^t, Hd Npi [5] Phung Xudn San, Nguydn Xuan Chung, Hoang Van Di^n; Gido trinh nguyen ly cdt vd dung cu cdt, NXB Khoa hpc va Ky thuat Ha Npi (2004) [6] Nguyen Thdng; Ung dyng Excell hoi guy tuang quan, NXB Giao dye [7] Nguydn Tdt Tidn; Ly thuyet bien dgng deo kim logi, NXB Giao dye (2003) [8] Nguyin Doan Y(2003); Quy hogch thuc nghiem, NXB Khoa hpc va K^ thu^t, Hd Nfi [9] Dan and J Matthew, Tool wear and failure monitoring techniques for turning - a review^nt J Mach Tool Manufact [ 10] D A Gustafson, The Effect of Tool Geometry and Tool Wear on the Force System in Tuming.M.S Thesis, University of Illinois at Urbana-Champaign, 1990 [11] William D CalHster, Jr.J^undamentals of Materials Science and Engineering ISSN 0866 - 7056 TAP CHi C O KHi VIET NAM, Sd 12 nam 2015 www.cokhivietnam.vn ... M=X^.X) yi: Gia tri trung binh cua HV thuc nghiem; y;: Gia tri tiung binh HV theo ham h6i quy thuc nghiem KSt qua ta tinh iagc: 3688,96-182,33 3688,96 Voi ma tran fl6812,31 43.566 9 .456 -34. 345 3.554... 25X25 Gdc trudc ciia CNC -DOOSAN -LYNX220 dao 5" gdc sau 7°, ban kinh mui dao R^^ 0.4mm * C h i cdt cat thg''c nghifm: Tham khao tai lieu [3] vd lya chgn chd cat gia cdng thep 45, de ttanh hien tugng... dao ttong qud trinh gia cdng dnh hudng ddn kdt qud thi nghiem thi ta chgn midn chd cat gia cdng thuc nghidm nhu sau: * Phoi diing thuc ngliiem: Su dung phdi che tao bdng thep 45, cd ciing ban ddu