Proceedings of SerbiaTrib '13

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safe to use it in furter exploitation (to apply regenerationor the part) or should it be rejected. The size of expecteddeformation and residual stresses are also importantfactors in making such a decision [7-8]. Afterdetermination of the chemical composition of the basemetal and working conditions, it is possible to create thebasic conditions for the design of technologicalprocesses. Based on those facts and previouslyconducted detailed techno-economic analysis, themethod of regeneration should be chosen, taking intoaccount the local possibilities of the company. The basicrequirement is to obtain the required properties of theregenerated part and, ofcourse, the reliability of the partduring the estimated working life.To achieve the above requirements it is necessary tomake the proper selection of filler material for hardfacing.In some cases of reparation of working parts itis necessary to apply two or more kinds of additionalmaterial to insert an intermediate layer, the so calledbuffer layer, between the layer and the substrate. Thisreduces the large differences in the chemicalcomposition, structure and, consequently, the thermophysicalproperties, of the substrate and the deposit.Next follows the selection of the regeneration processparameters, resulting from the properties of the baseand filler metal, and form demands concerning the sizeand shape of regenerated parts. The final stage ofplanning, before the experimental surfacing, is theassessment of the necessity for implementation ofspecial measures and the previous, current andsubsequent heat treatment.For verification of the proposed technologies, thecomparative tests in laboratory and in workingconditions have been performed, and, in some cases,comparative test of imported parts, which were nothard-faced and the new-hardfaced parts. Laboratorytests are related to the microstructure, hardnessdistribution and tribological tests and working tests ofcomparing the working life of the new and repairedparts installed in the same machine [2-3,9].From the point of view of techno-economicanalysis, reparation welding technology is a complexset of different types of mandatory procedures, whichtake into account: the conditions of work, damageidentification, estimation of weldability, weldingprocess, filler material, welding and hard-facingregimes, heat treatment applied, model and real tests.Having in mind the complexity of the process, it isnecessary to determine the optimal technicaltechnologicalsolutions to bring the reparation processto a stage when it is possible to make a final decision,wheter to buy a new part or to repaire it.3. EXAMPLES OF IMPLEMENTED REPAIRSHere is considered the justification for applicationof the production and reparation hard-facing and it ispointed to profitabilityof repairs on examples ofdamaged forging hammer, forging press frame andlarge gear of eccentric presses. The subject matter is thereparatory welding and surfacing of the damaged orcracked forging hammers, broken and cracked frames,forging presses and large gear eccentric presses [10-11]. To determine the optimal technology of hardfacing,it was necessary to carry out tests on model andreal working parts. Test hard-facing and testing ofmodels have served to establish the initial reparationtechnology, and to "transfer" thus approvedtechnologies to the working parts, which are thenfurther checked under actual working conditions.This paper mainly deals with the techno-economicadvantages of the hard-facing technology, while thecomplete procedures of determining the optimaltechnology for each particular part were presented inpapers [2-3,5,9-11].3.1. Regeneration equipment’s for forginghammer and press frameFor regeneration of responsible parts with complexgeometries and large masses, made of material sutiblefor tempering, a detailed analysis of the working partsis required as well as the precisely proposed reparationtechnology.Hammers mallets and presses frames are exposed,during the long operation, to thermal fatigue due tocyclic temperature changes and to impact loads. Due tothe high costs and often to impossibility of purchasingthe new working parts, it is necessary to evaluate thepossibility of their repairs. Harsh working conditionssometimes lead to a complete fracture of the part andendangering the workplace safety. Figure 1 showsfracture of a forging mallet, which has originated fromfatigue crack propagation.Mallet of forging's hammer, shown in Fig. 2, andframe forging press, shown in Fig. 3, are primarilysubjected to impact compression loads, and, in partiallyto temperature gradient, that is thermal stresses causedby uneven temperature field [2,7-8]. After a long workof these parts, i.e., large number of repeated cycles onhammer mallet and on the press frame, visible crackswere observed, and on one portion of the frame and ona single occurred the complete fracture (Fig. 1 and 3).Taking into account that these are parts of largedimensions and complex shapes, and that componentsare subjected to dynamic and thermal loads, they aredimensioned on the basis of the increased safetydegrees; thus the special measures are required for themanufacturing and reparatory technologies, as well.Forging press frame is madeby casting in sand, from the medium carbon cast steel.On the other hand, pneumatic forging hammer mallet,as one of the most loaded mechanical parts, is made oflow alloyed steel for tempering.282 13 th International Conference on Tribology – Serbiatrib’13
Figure 1. Appearance of fractured forging hammer mallet.900920250200748.2150170 802102600480a) b)Figure 2. Forging hammer malleta) Sketch of mallet with observed crack; b) Apperance of the regenerated mallet of mass of 6000 kgSection S-S75S10075160S1211902400a) b)Figure 3. Frame of vertical forging press.a) sketch of the frame (1 – fracture site; 2 - observed cracks); b) regenerated, heat treated and machined partThe complete technology for regeneration ofdamaged forging hammers' mallets and presses'frames is shown in [6, 10-11]; here are presented onlythe techno-economic indicators for the mallets'regeneration.The following data are relevant for comparison:A. The price of the new part is: 83987 Є(This price includes price of a new part - 67470 Є,tax -12144 Є, the customs 3373 Є and the cost ofshipping and transportation services - 1000 Є);B. The total real costs of reparation of 4912 Єinclude: Identification and damage detection:3 days × 8 (nh*/day) × 10 (Є/nh) = 240 Є;13 th International Conference on Tribology – Serbiatrib’13 283
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SerbianTribologySocietyFacultyofEng
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Serbian Tribology SocietyUniversity
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Supported byMinistry of Education,
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PrefaceThe International Conference
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ContentsPlenary Lectures1. THE GREE
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27. WEAR CHARACTERISTICS OF HYBRID
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Tribometry57. PRELIMINARY STUDY ON
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Plenary Lectures13 th International
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Serbian TribologySocietySERBIATRIB
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Figure 4. Diagram of the height and
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Realization of the approach is base
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edge without chamfer and smaller ra
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Figure 7. Accumulated tool life in
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Figure 13. Calculated and measured
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Friction deformation of the bronze
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engine cylinders of 2-cylinder-twot
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Table 1: Chemical composition of sa
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Table 4: Comparative wear-resistanc
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- measuring of coating thickness h
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Figure 5. Functional scheme of the
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Table 2. Test results for massive w
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knowledge transfer in the field ofm
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Table 1. Parameters of the electroc
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Figure 6. Wear resistance by linear
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coatings and observed their good we
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c)a)Figure 2: SEM images and micros
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Room temperature 300°CNi/µSiCNiNi
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COF [-] COF [-]Fig.9: COF graphs at
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about 260 nm is related to isolated
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contact’s conformity [18] they ob
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In order to calculate the metallic
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microscopic inspection of the Rp3 s
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otating plate. The shaft passes thr
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similar trends of variation are obs
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smooth, gear fiber-mild steel rough
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[2] Tabor, D.: “Friction and wear
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(10, 50 and 100 N) against surface
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[9] B.R. Gligorijevic, A. Vencl, B.
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dielectric properties, high resista
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parameter, Sv, was slightly influen
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dependence of roughness height and
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Polyethylenes with a molecular weig
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[9] K.S. Kanaga Karuppiah, A.L. Bru
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MgCO3•CaCO3 (13% Mg), and carnall
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fully compatible with MRI/MSCT imag
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5. CONCLUSIONThe magnesium alloys a
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Zinc dialkyldithiophosphate (ZDDP)
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C- Lower deposits with NPNA on comb
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films. Carraro et al. [10] examined
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PlateCount No.Critical Load ( N)120
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solid melt of ZA27 alloy using mech
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SiC particles are uniformly distrib
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in number of micro-cracks and clust
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PBT has the average values of the f
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mechanical pressure and thermal loa
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3. EXPERIMENTAL RESULTSTaking into
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[12] L. Blunt De, X. Jiang: Advance
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2. EXPERIMENTALTESTING2.1 MaterialT
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figure 3a it could be seen that the
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and lubrication is done so that the
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5. CONCLUSIONFigure 11. The accumul
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esistance was found for composite c
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onze, which is embedded within the
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The test contact pair meets the req
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complete. The SEM analysis maycontr
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tg( ) tg 100, [%] (2)tgwhere are:
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corresponding to the maximum value
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electrostatics [17]. Due to the fle
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250nm size have been observed, acco
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ETH Zurich, Switzerland, where all
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comparison with the synthetic reinf
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3. RESULTS AND DISCUSSION3.1 Micros
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(a)(b)Figure 4. Showing (a) variati
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composites. But the composite compo
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coated and uncoated region after ad
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has been measured between the top s
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Fig. 9 shows the wear track obtaine
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Mica samples preparationFor the ads
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According to the AFM results in fig
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[21] B. G. Sharma et al.: Character
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chemical vapor deposition method wi
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analysis (a) and an approximate che
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Table 3. Friction coefficients of s
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A.K.Oleynik, V.M.Matsevity, ea.]. /
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Most of the friction units of produ
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In order to provide both high parts
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Fig. 3. The comparison the criterio
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Table 3. Experimental and calculate
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For developing the numerical model
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,eccentricities and hydrodynamic pr
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hydrodynamic regime. However, for b
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to obtain the temperature distribut
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force (pressure) between two contac
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5E-06The total displacement [m]4.5E
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[11]. Figure 5 shows s the influenc
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efficiency of use, product quality,
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38GSA. The chemical composition, de
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niobium. It should be noted that fo
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Figure 1. Friction force on side su
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exploitation this changing is signi
Page 245 and 246: 2. EFFICIENCY OF CYCLO DRIVEEfficie
Page 247 and 248: Figure 6. Dependence of cyclo drive
Page 249 and 250: common for their ability to be inst
Page 251 and 252: FNF (11)R sin cos11 21 22FNF
Page 253 and 254: Normal force [N]4000350030002500200
Page 255 and 256: analytical tests. The analytical te
Page 257 and 258: Table 4. Results of zero samples of
Page 259 and 260: noticeable, and by the end of explo
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Page 263 and 264: 4. PLASTIC BEARING APPLICATIONSRega
Page 267 and 268: For Elastohydrodynamic film thickne
Page 269 and 270: The results concluded for different
Page 271 and 272: For Thrust Force of 40KNKrytox 215
Page 273 and 274: Krytox 215 (µ = 0.03204 Pa.s)Figur
Page 277 and 278: - Reliable exploitation tools, prim
Page 281 and 282: In addition, as a result of cyclic
Page 283 and 284: AcknowledgementThe part of this res
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Page 287 and 288: mechanism these parameters are fina
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Page 293 and 294: Table 2. Impact toughness of some t
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Page 299 and 300: implementation of these new manugac
Page 301 and 302: additional energy is dissipated due
Page 303 and 304: The adopted geometry parameters are
Page 305 and 306: 4. CONCLUSIONTools of virtual produ
Page 307 and 308: Figure 2. Structure of the machinin
Page 309 and 310: 3. ANALYSIS OF RESULTSThe results o
Page 311 and 312: Figure 15. Surface roughness regard
Page 313 and 314: From the analysis of the diagram it
Page 315 and 316: comparison from economic, energy co
Page 317 and 318: Advantages and disadvantages of tra
Page 319 and 320: The information provided by footwea
Page 321 and 322: Force (N)5,554,543,532,521,510,50Ex
Page 323 and 324: additives, that had been, until rec
Page 325 and 326: Figure 1. Test results for samples
Page 327 and 328: Table 7. Test results of oil sample
Page 329 and 330: Input parameters- Current intensity
Page 331 and 332: edge formed into a thin line. At th
Page 333 and 334: Lower values of current are not res
Page 335 and 336: Table 1. Chemical composition of si
Page 337 and 338: flowable at high temperatures and v
Page 339 and 340: holes (pits) emerge in the shape of
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assumption allows us to use, instea
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where P is the load, a - radius of
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determination (total running in tim
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μm, compared with Figure 17, wich
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Serbian TribologySocietySERBIIATRIB
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Especially when the chain transfer
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is obvious that this isa so-calledw
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winches. The authors are inclined t
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find parameters of robot laser hard
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each of which is measured by the le
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Fractal dimensions were determined
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Figure 3. Modified force acting sch
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0.25Lubricant: L3DC 04Friction coef
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nanocomposites. The influence of fi
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4. RESULTS AND DISCUSSION4.1 Morpho
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Figure 6. Loading and unloadin vers
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3 8 12 1 4 2 4
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The material after qualifying the r
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It has already been mentioned that
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Degradation & Stability, Vol. 69, N
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conformance to researchers’ requi
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This part is assembled of pneumatic
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matrixes describe the state of the
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values influence of themeasurement
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Figure 1. Friction stir weldinga -
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(t 2 t
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M fr / T [-] [-]10.90.80.70.60.50.4
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M fr / T [-]10.90.80.70.60.50.40.30
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experimentally determined that for
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4. DISCUSSIONAccording to the theor
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2.1 The life cycle of the reportThe
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Obviously the report is checked and
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uticaja na osnovu kompozita, a time
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5. ZAKLJUČCIStruktura tiksolivene
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dobijene različite karakteristike
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vizuelno, na dnevnoj svetlosti, pod
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LITERATURA[1] Зинченко В.
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Slika 1. Rotorni bager - glodar VII
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stvaraju sliku stanja i svoja zapa
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njihovih kotrljanih elemenata. Mere
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postupka i uticaja parametara depoz
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posledica različite raspodele mikr
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ZrO 2 Y 2 O 3 je takođe zbog oksid
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3.2 Pneumatska osetljivostOblast pr
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p mg (δ), koji je zbog malih struj
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PNEUMATIC PROBE HEAD SELECTION FOR
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1. Podsistem kopanja2. Podsistem pr
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Slika 3. Kriva habanjaNa tom dijagr
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Mjereni su parametri habanja i pril
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preše prevladavaju kombinirani uvj
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a) b)Slika 5. Karakteristična mikr
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varijantnih materijala u dostavnom
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Jovanović D. 414, 446KKaleicheva J
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CIP - Каталогизација
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