parts. This process of joining the bimetal assembly is recommended for joining over closed, m ated or cylin drical surfaces, using the effect of therm al shrinkage and reduction.
1. Ishchenko, A.Ya., Khokhlova, Yu.A., Fedorchuk, V.E. et al. (2010) Technological features o f producing joints o f commercial aluminium w ith A M g 5 alloy at activation o f surfaces being joined by molten gallium: Transact. Nikolaev: NUK, 68-74.
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3. Khokhlova, Yu.A., Fedorchuk, V.E., Khokhlov M.A. (2011) Peculiarities of intergranular mass transfer of gallium in aluminium alloy during solid phase activation of surfaces being joined. The Pa ton w eld in g J ., 3, 13-15.
4 Ishchenko, A.Ya.. Khokhlova, Yu.A. (2009) Evaluation of mechanical properties of microstructural constituents of welded joints. ib id ., 1, 34-37.
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of different mechanisms of self-diffusion to fee metals in equilibrium conditions. Fiziha Tv. Tela, 52» Issue 6, 1075-
1082.
9. K'K'tt'.s v a rk a -lib .c o m /n o d e /2 9 8 /p rin t/6 4 .h tm l 10. rt'it'U/.autodcla.ru/ m a i n / t o p / t e s t / s v a r
INFLUENCE OF VIBRATION OF PARTS ON STRUCTURE
AND PROPERTIES OF METAL IN SURFACING
Ch.V. PU LK A ', O .N . SHABLY', V.S. SENCHISHIN1, M.V. SHARYK' and G.N . GORDAN 'Ternopol Ivan Pulyuj National Technical University, Ternopol. Ukraine
E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
Presented are the investigation results of structure and properties of metal deposited by induction method with super position of vibrations in a period of inciting of a surfacing consumable. It is shown that the superposition of vibrations leads to improvement of wear resistance of the deposited metal due to refinement of its structure.
K e y w o r d s : induction surfacing, inductor, specific power, vertical and horizontal vibrations, deposited metal, structure, wear resistance
An induction surfacing using powders from high-car bon chromium alloy PG-S1 (sormite 1) is widely used for manufacture of operating elements of agricultural machines: plough shares, blades of top cutters, chisels of cultivators etc. At that a deposited metal has a coarse-grain structure with inclusions of coarse chro mium carbide [1, 2].
A new technology of induction surfacing using vi brations [3—6 J was proposed for refinement of struc ture and improvement of properties of the deposited metal. It lies in the fact that a part is subjected to vertical and horizontal vibration at the moment when a powder charge is in a molten state. At that, direction of oscillation application (Figure 1) as well as their frequency and amplitude have a great importance.
Investigations of structure, microhardness of struc tural constituents and wear resistance of the metal deposited by induction method with and w ithout vi bration superposition were performed for evaluation of the efficiency of developed technology. The flat samples from steel St3, i.e. sample 1 w ithout vibra tion, 2 and 3 with vertical ancl horizontal vibrations, correspondingly, were deposited for performance of the investigations by induction method using a charge containing PG-S1 alloy powder. Surfacing was carried out on a high-frequency generator of VChG 6-60 0.44
«0 C h .V , P U L K A , O .N . S H A B L Y , V .S . S E N C H IS H IN . M .V . S H A R Y K m id G .N . G O R D A N . 2012
The W l
type at constant specific power W and time of depo sition I: (Figure 1, b ) . The modes were similar for all three variant of surfacing, i.e. circuit voltage 5.4 kV; anode voltage 10 kV; circuit current of lamp 1.2 A; anode current of lamp 2 A; deposition time 35 s; os cillation am plitude 0.2 mm at 50 Hz frequency.
'/ /у iv /.v X -i: v
Figure 1. Surfacing scheme {a: 1 part being deposited; 2 powder-like charge; 3 — inductor; arrows show direction of vibra tion application vertical or horizontal), and specific, power IV of gener;itor in the process of surfacing (6)
1/2012
Figure 2. M icro stru c tu re (x 2 0 0 ) o f th e deposited metal of sam ples 1 -3 (r/-c )
S am ples for in v e stig a tio n of s tru c tu re and w ear re sistan ce of th e d e p o sited m etal w ere c u t o u t from th e d ep o sited b lan k s.
E tch in g of th e sam ples for perform ance of m etal- lo g rap h ic in v e stig a tio n s w as m ade by stages. S tru ctu re of th e d ep o sited m etal w as d e term in ed by e le c tro p la t in g te c h n iq u e in 20 % s o lu tio n of chrom ic acid (20 V v o lta g e an d tim e of e tc h in g 10 s) th ro u g h a chem ical e tc h in g in 4 % so lu tio n of n itric acid.
M ic ro stru c tu re of th e base m etal consists of ferrite an d p e a rlite an d m ic ro stru c tu re of th e d eposited m etal in all in v estig ated sam ples is m ade of prim ary carbides (com plex carb id es o f (F e, C r)yC3 and (F e , C r ^ C
F u s i o n li n e J O L u ll i. . I г uStton lint Metal | .10 ц т
ЭС
J'igurc 3. D istribution of carbon and chrom ium on thickness of the deposited m etal in sam ples 1 - 3 ( a - c)
ty p e ) in a form of coarse p la te s of «pencil» ty p e, having hexagonal c u t w ith w ell-defined interface to m a trix , of carb id e eu tectics and m atrix a u ste n ite s tru c ture.
The excess carbides, as a rule, are situ a te d in a form of sep arate p la te p recip itates in th e c e n tra l p a rt along th e w idth and th ickness of th e deposited bead. R ectan g u lar and hexagonal p recip itates are th e car bides of different: dispersion. P a rt of them is th e excess p late carbides being su fficien tly uniform d istrib u te d in lh e m atrix. M icrohardness of th e carbides varied in th e ranges / / Vr0 .5 -1 1710—12830 M Pa.
Common for all v a ria n t of th e deposited m etal is: • presence in th e deposited layer of hyp o eu tectic zone ad jo in in g to a jo in in g line w hich is characterized by form ation of th e d en d rites of solid so lu tio n (allo y ed a u ste n ite ) w ith axes of th e first and second order, as well as th e carbide eu tectics crystallized in an inter- d en d ritic space. M icrohardness of au sten ite for sam ples 1 and 2 m ade / / V 0 .5-4120-4410 M P a and th a t for sam ple 3 was H V 0.5-4800-5090 M Pa. Besides, a stru c tu ra l inhom ogeniety represented by th e fact th a t the hyp o eu tectic d e n d rite zone had non-uniform dis trib u tio n was found along th e jo in in g line from th e sorm ite side;
• form ation of b o undary w h ite strip of th e solid solution (alloyed a u ste n ite ) of variable w id th 1 0 - 20 j.im betw een the deposited and base m etals w ith m icrohardness //1 /0 .5 -3 0 3 0 -3 4 1 0 M P a for sam ple 1, and / / V 0 .5-3410-3810, / / V 0 .5-3860 M P a for sam ples 2 and 3, correspondingly;
• existence of a diffusion zone from th e base m etal side near th e jo in in g line rep resen tin g itself fine p la te p earlite and ferrite along th e g rain boundaries some tim es w ith o rien tatio n on W id m a n sta tte n stru c tu re w ith m icrohardness I i V 0.5-2440 M P a appeared as a resu lt of carbon diffusion from th e sorm ite in to th e base m etal.
M icrohardness of th e s tru c tu ra l c o n stitu en ts for three sam ples is given in th e Table.
Microhardness o f structural constituents o f the deposited metal o f P C 'S I type, MPa
F " 1 11 "ui [ Sample
No. Chromium carbide Matrix White strip
I
_ L _ 11710-12830 41 2 0 -4 4 1 0 3030-34102 11710-12830
4 1 2 0 -4 4 1 0 -4 8 0 0 3410-3810 .
3 11710-12830 48 0 0-5090 3860
v ib ra tio n ( F ig u re 2, b ) a n d 3 .5 - 7 jam a t h o rizo n ta l o n e ( F ig u r e 2, c ).
T h e m ax im u m d e p th o f th e e u te c tic zone is in sam p les 1 an d 2 (see F ig u re 2, a , b ) an d in sam ple 3 (F ig u re 2, c ) — th e m in im u m one. Zone of a u ste n ite d e n d rite s ta k e s th e s m a lle st p e rc e n t alo n g th e len g th of d e p o sit in sa m p le 3 in c o m p ariso n w ith sam ples 1 a n d 2. T h e jo in in g lin e from so rm ite side a t horizo n tal v ib ra tio n m a in ly re p re se n ts itse lf th e w h ite s trip w ith fo rm a tio n o f a lm o st e q u ia x ia l a u s te n ite g rain s (see F ig u re 2, c ).
M icro X -ray sp e c tru m a n a ly sis on th e Cam eca m i c ro a n a ly z e r C A M E B A X SX -50 (F ig u re 3 ) was carried o u t for in v e stig a tio n of d is trib u tio n of th e elem ents (c h ro m iu m , c a rb o n ) a t tra n s fe r from th e base m etal to th e d ep o site d one. T h e a n a ly sis for all cases was p erfo rm ed a p p ro x im a te ly in a c e n tc r of th e deposited la y er n o rm al to fu sio n lin e a t d e p th up to 350 (am from th e fusion b o u n d a rie s. I t is d eterm in ed th a t carb on is b o u n d e d in th e c a rb id e s of (F e , 0 ) 7 6 3 and (F e, 0 ) 3 0 ty p e in m etal o f th e in v e stig a te d sam ples and n o ta b le re d is trib u tio n o f c a rb o n n e a r th e fusion line w as n o t observ ed .
M easu rem en ts o f h ard n e ss o f th e d ep o sited m etal on th e L E C O h ard n e ss m e te r a t 0.5 an d 3 N loading (F ig u re 4 ) sh o w ed th a t sam p le 3 has th e h ig h est h a rd ness. L a b o ra to ry te s ts on w ear resistan ce of th e de p o site d m e ta l of sam p les 1 -3 on m achine N K -M [7] w ere also p erfo rm ed . T e st c o n d itio n s w ere th e follow ing: ab ra siv e — q u a rtz sa n d w ith p a rtic le size 0 .2-0 .4 mm; fric tio n p a th 415 m; pressure .2-0.466 M Pa;
Mrt.l K * 2 t fe .8
Figure 4. Relative wear resistance ( / ) and hardness of the deposited metal (? ) of samples t - 3
sta n d a rd sam ple — an n ealed steel 45. F ig u re 4 show s th a t sam ple 1 has th e lo w est w ear resistan ce (2.2) and sam ples 2 and 3 — th e h ig h e st (3.1 a n d 3.4, respec tiv e ly ). S u rfacin g on schem e accepted for sam ple 3 provides th e h ig h est w ear resistan ce th a t is ex p lain ed by favorable s tru c tu re of th e dep o sited m etal an d for m ation m ainly of (F e , C r )7C3 carb id es an d ce rtified by th e re su lts of m icro X -ray spectrum analysis.
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