INFLUENCE OF RELATIVE SPEED DRAWING ON THE MECHANICAL CHARACTERISTICS ULTRASONIC METAL WIRE DRAWING

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1 TEHNOMUS - New Technologie and Product in Machine Manufacturing Technologie INFLUENCE OF RELATIVE SPEED DRAWING ON THE MECHANICAL CHARACTERISTICS ULTRASONIC METAL WIRE DRAWING Suan Mihai, Bălănecu (Priacaru) Dănuţa Mihaela, Critodulo Orete Technical Unierity,,Gheorghe Aachi of Iaşi România, mihaiuan@yahoo.com Abtract: The paper preent the influence of the relatie rate of awing to the platicity and reitance mechanical characteritic during the ultraonic awing-uvd of the cylinical ymmetry metallic wire able to be work-hardening, when the die i placed in the maximum of the wae ocillation and it i actiated along the awing direction. Keyword: cylinical ymmetry metallic wire, work-hardening, ultraonic awing, relatie rate of awing, platicity and reitance mechanical characteritic. Introduction Claical Technology-CT ued for the obtaining of the metallic wire proceed by cold platic deformation (at the enironmental temperature) i called awing. The awing proce i characterized by a work hardening phenomenon (an under tre hardening) which goe to the increaing of the reitance mechanical characteritic with the decreaing of the platicity characteritic, in the ame time. When the platic deformation take place at high degree, the integrity of the metallic material may be detroyed (the generating of mooth fracture). In thi condition, the awing proce (big reduction of cro ection, obtained by awing) become poible after the applying of a tructure remaking thermal treatment []. A a rule, pecial phenomena may happen in the indutry of high reitance teel wire. For thee ituation, the author recommend the ultraonic ibration awing UVD, becaue thi proce allow the technological checking of the work hardening mechanical reitance, in dependence with the relatie rate of awing. The technological cheme of the ultraonic awing-uvd of the metallic wire with cylinical ymmetry, with the die placed in the maximum of the wae ocillation (antinode) and actiated along the awing direction, i preented in Fig.. Figure : Technological cheme of the metallic wire with cylinical ymmetry ultraonic awing-uvd: a) wae ocillation in wire: B-wae ocillation in the emi-finihed wire; C- wae ocillation in the wire; b) wae ocillation at the ocillator ytem leel; c) proper technological cheme: -emi-finihed wire; 2, 5-ultraound energy reflector; 3-die; 4-awn wire; O-x-awing and propagation of the ultraonic wae direction; A-amplitude of the wae ocillation at the ocillator ytem leel and in wire; B ' -wae ocillation for the ocillator ytem; D 0, D -diameter of the emifinihed, repectiely, of the awn wire; R-radiu of the emi-finihed wire; u-wae moement for the actie/ocillator ytem; -maximum of the die ibratory rate; rate of awing; F UVD -awing force, UVD technology; a ' and b ' -poitioning ditance of the ultraonic energy reflector: running wae; regreie wae. 240

2 TEHNOMUS - New Technologie and Product in Machine Manufacturing Technologie The platic deformation with ultraonic ibration mean the actiation of the deformation tool with high frequencie (more than 6000 Hz), along the platic deformation direction or normally on it. The ultraonic awing along the awing direction, with the die placed in the maximum of the wae ocillation (antinode), goe to the reduction of the metal-tool contact friction, repectiely of the work hardening in the ame proportion, baed on the ultraound urface effect ; thi effect i explained baed on the Seerdenko model and conidering the reeral of the mean friction mechanim, a a function of the relatie rate of awing. The ultraonic energy reflector (the preure roll), placed at well defined ditance, are ued to generate a table ytem of tanding wae into the wire (ertexe and antinode generating), [2, 3]. The relatie rate of awing i expreed uing the ratio between the rate of awing ( ) and the maximum of the die ibratory rate ( ), meaning, [3]. 2. About the relatie rate of awing during the ultraonic awing of the metallic wire with cyllinical ymmetry, able to be work hardened For the relatie rate of awing defining, Fig.2 gie a chematic preentation of the awing platic deformation proce, in the UVD cae, of the metallic wire with cylinical ymmetry and it how epecially, deformation kinetic: the ariation of the die ibratory rate ( ) at the leel of one ocillation complete period (T), the metal lip rate on the element of the die cone ( )-direction A-B, the axial rate 0, and -before the deformation area, in the deformation area and repectiely, the rate of awing. The hypothei of the UVD platic deformation proce are: the metallic material i incompreible; the die i a rigid body; the metal deformation i realized in the Von Mie condition; the field of rate proide the Bernoulli type continuity; the metal-tool contact friction i a Coulomb type one (it i a contant one for a gien awing proce); only longitudinal wae, a tanding wae, action at the leel of the ocillator ytem (ertexe and antinode are generated); the platic deformation proce i an iothermal one. Figure 2 Procedure of platic deformation by awing, during the ultraound awing-uvd of the metallic wire with cylinical ymmetry: a) cheme of the platic deformation procedure by ultraound awing-uvd, along the awing direction, the actiation angle β=0ᴼ; b) ariation of the ibratory rate ( ) during one period (T) of the ultraound ocillation, the rate of awing ( ) being a contant-the cae ; P- point arbitrary choen at the metal-tool interface; τ- tangential tre; σ-normal tre; α-half-angle of the die cone; R 0, R -half-thickne of the emi-finihed wire, repectiely the rate of the awn wire. The kinetic of the platic deformation and the influence of the relatie rate of awing to the metal-tool contact friction are expreed baed on the Seerdenko model, Theoretical model, a a completion of the claical model, and taking into account the reeral of the mean friction mechanim, meaning: the friction i poitie (F f + ) during T/2-2t time, when ; the friction i negatie (F - f ) during T/2+2t time, when, at the leel of a complete period of ocillation (T), Fig.3, [2]. 24

3 TEHNOMUS - New Technologie and Product in Machine Manufacturing Technologie Figure 3: Kinematic of the platic deformation by awing-u VD technology: a) wae moement (u), metal lip rate ( ) and ibratory rate ( ); b) mean friction reeral (F f + and F f - ), baed on the Seerdenko model : claical ariant ; theoretical ariant; c) moement direction of the elocitie ector and, in point P placed at the metal-tool interface; d) alue of the relatie rate of awing in the conidered point P, during T/2+2t and T/2-2t time. The Figure 3 how that in the deformation area, the metal realize iochronal ocillation with a certain ibratory rate gien by die rate uperpoed oer the lip rate, which i a contant one. A thoe preiouly preented, any point P arbitrary choen in the platic deformation area, at the metal-tool interface, ha two motion: one of them i a feed motion and it i along the die cone element, A-B, with a rate ibratory motion with a rate The friction ector, F f and the other i a., in the cae of the claic awing technology-ct, i oppoed to the direction of the metal moing elocity and in the cae of the ultraonic awing technology- UVD, it i oppoed to the direction of the reultant elocity (the reultant ector of the compoition between the two ector, ). During the ultraonic awing technology-uvd, the reultant ector of the relatie rate will change the moing direction of the point P, in function of the ene of the two ector and, and of the ize of their projection on the die cone element or on the friction direction A-B. During the T/2-2t time of the ocillation period (T), the diplacement of point P i identical with that of the metal when the projection of the ibratory rate ector on the friction direction A-B i bigger than the projection of the lip rate on the ame direction, ; the ame diplacement i in a contrary ene during the T/2+2t time of the ocillation period (T), when the ratio between the two ector projection on the friction direction A-B i an inere one,. Knowing that, in the cae of the awing of the wire made of metallic material able to be hardened, the half-angle of the die cone α 0ᴼ, meaning coα,0, it can approximate becaue = co, [3, 4]. Conidering the wae moement (u) which follow the motion law, relation (): 2 u Ain x t. () the ibratory rate ( ) i obtained baed on the time deriatie, relation (2): du 2 A co x t. (2) dt with the maximum alue for 2 co x t. where: 2π/λ wae factor; λ wae length; ω wae angular frequency, (ω=2πf). So, the maximum of the ibratory rate ( ) i gien in the relation (3): 2 f A. (3) 242

4 TEHNOMUS - New Technologie and Product in Machine Manufacturing Technologie where f i the reonant frequency at the ocillator/actie ytem leel. In other word, in the cae of the ultraonic awing-uvd, the platic deformation take place in pule in thi way: during the T/2+2t time, the proper platic deformation take place; during the T/2-2t, motly the metal elatic deformation take place. Auming the Seerdenko model for the reduction of the metal-tool contact friction deeloping, the ratio υ expreed in the relation (4), [2]: T 2 2t T 2 2t T 2 2t T 2 2t. (4) repreent the reduction degree of the mean friction in point P, arbitrary choen at the metaltool interface, in the deformation focu. Equalizing the two rate, =, it reult the relation for t, (5): t arcco. (5) co Subtituting both t, gien in the relation (5) and T (T=/f), in the relation (4) and knowing that β=0 (meaning that coβ=) when the die i actiated along the awing direction, (ee Fig.2), it reult the relation (6), [2]: 2. (6) arcco Conidering the mean alue for the rate of awing ( ) (baed on the equation of the metal flow continuity), the input-output ection in the focu area of the platic deformation, the reduction degree of the mean friction (coefficient υ) on the entire metal-tool contact friction i gien in the relation (7): i co 2i co :. (7) 2 where λ i i the wire elongation by pa, calculated uing the relation (8), [, 3]: 2 S 0 D 0 i. (8) S D For example, Fig.4 how the ariation f / for a gien UVD awing proce (relation (7)), [2, 3]. Figure 4: Variation of the coefficient (υ) in function of the relatie rate of awing, for a gien ultraound awing proce-uvd: D 0 =3.50mm; D =3.00mm; α=8ᴼ; δ i =9%; f=22000hz; λ i =.8; =0.06m/; A=25μm; =3.45m/. The maximum of the ibratory rate i calculated with the relation (3) and for the determination of the ection reduction degree by pa it i ued the relation (), [2, 3]: i 2 D / D 00 %. (9) i 0 3. Material and reearch methodology 3. Reearched material The reearch ha ued the ample made from hot rolled hardened wire Φ 3,50mm, C80, manufactured by S.C. CORD S.A. Buzau / The chemical compoition of the teel C80 wa determined uing a pectrometer with optical emiion DV6 BAIRD type, made in USA, (belonging to S.C.ARCELOR MITTAL S.A. Iai). Chemical compoition of the teel C80 (mean alue), [%] i preented in Table *). The chemical compoition i according to EN 006-2/

5 TEHNOMUS - New Technologie and Product in Machine Manufacturing Technologie Table The chemical compoition of the teel C80 (mean alue) [%] C Mn Si P S Cu Cr Ni Al N A Sn *) The chemical compoition i according to EN 006-2/ Reearch methodology The objectie of the experimental tudy i to gie a characterization for the ultraound awing technology / UVD Technology, of the wire which hae cylinical ymmetry and high reitance, through conergent conical die, in comparion with the claic technology / CT (without ultraound actiation of the die). The cheme of the ocillator ytem / OS ued in the reearch proce i preented in Fig. 5. die, on a awing equipment UDZSA TO63 type. There were ued die with core made from metallic carbide, (WCr), belonging to S.C. MECHEL S.A. Campia Turzii, and which had the half-angle of the die cone α = Determination of the reitance and platicity mechanical characteritic, (R m, R p0,2, and A 0 ) The characterization of the platic deformability for the hardened tyre cord C80, Φ3mm claic awing technology / CT / A and ultraonic awing technology / UVD / B, C and D, (B / A = 5 μm; C / A = 20 μm; D / A =25 μm) wa made baed on the reult obtained after the awing rupture tet; the tet wa made uing the unieral machine MTS 824.0, (the rate of tre wa 20mm/). Variation of the reitance and platicity mechanical characteritic, in the cae of the CT and UVD Technology proceed ample, f = 7500Hz; D 0 = 3,50mm; D = 3mm. Experimental reult obtained for tenile teting according SR EN 0002, are preented in table 2 and figure 6. Figure 5: Scheme of the ocillator ytem ued for the experimental reearch: a) wae ocillation in the emi-finihed and awn wire; b) wae ocillation at the ocillator ytem leel (magnetotrictor tranducer, conical concentrator and graded cylinical concentrator/working part); c) proper cheme: -magnetotrictor tranducer; 2- conical concentrator; 3-noduled flange; 4- experimental hyaulic wire-awing bench BTL ; 5-emi-finihed wire; 6, 0-ultraonic energy reflector (preure roll); 7- graded cylinical concentrator/working part; 8-die; 9-awn wire. Sample ymbol tr - Table 2 R m [MPa] R p0,2 [MPa] A 0 [%] A/TC ,60 B/UVD, 5 μm C/UVD, 20 μm D/UVD, 25 μm 0, ,66 0, ,84 0, ,04 The reearche were made baed on the ingular awing principle / through one ingle 244

6 TEHNOMUS - New Technologie and Product in Machine Manufacturing Technologie Cumulatie diagram of the tenion tre for the four type of tet piece: A, B, C and D. Figure 6: Cumulatie diagram of the awing tre, ample A, B, C, and D. 5. Concluion The modification of the reitance and platicity mechanical characteritic, (R m, R p0,2, and A 0 ), are analyzed in dependence with the relatie rate of awing, ( tr ). It wa obered that the alue of the mechanical characteritic, (R m and R p0,2 ), decreae and the alue of the platicity characteritic (expreed by the elongation, A 0 ) increae in the ame time with the decreaing of the relatie rate of awing. Thi mean that, when both, tr and f, hae contant alue, the amplitude of the die ocillation mut increae. The modification of the reitance and platicity mechanical characteritic, depending on the relatie rate of awing, ( tr ), goe to an eentual control of the train hardne for the wire awn in ultraound field. Reference [] Cazimiroici E. et. al., Teoria și tehnologia deformǎrii prin tragere, Editura tehnicǎ, București, Romȃnia, 990. [2] Seerdenko,V.P.,Kluboici, V.V., Stepanenko, A.V., Prokatkia i olocenie c ulitrazukom, Nauka Tehnika, Mink, 970; [3] Suan, M.,Tragerea metalelor cu ibratii ultraonice. Editura Cernei, Iai, [4] Iliecu V., Ph.D Thei, Faculty of Material Science and Engineering, The Gh.Aachi Technical Unierity from Iași, 200. [5] Suan M., et al., Re. Metal, Maid 40 (2004), pp