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Recherche industrielle


As a part of the research project of an electronic diagnostics device in real time (on-line) for toothed gear purposed for general use called Vibrex along with expert program Gearexpert enabling detection of damaged drive, experimental research financed by the Scientific Research Committee was carried out with use of a special additive for oils named CERAMIZER ®.
That comprises a part of monograph of Doctor Engineer Jerzy Tomaszewski and Józef Drewniak, entitled “Toothed Gear Seizing”.
Source : zent

Impact of CERAMIZER® - oil additive on gear performance parameters.

Processes linked with gear seizing, are connected with friction ratio between two cooperating wheels as a result of wheel inter-tooth slip. Friction generates heat on teeth surface and under some conditions results in gear seizing. For the purpose of research we chose the CERAMIZER®, a gear oil additive manufactured by VIDAR from Warsaw.

Ceramization of metal surfaces results in generation of ceramic- metal layer on metal surfaces of machines and devices susceptible to friction during operating. By building up of a ceramic- metal layer CERAMIZER® regenerates and rebuilds metal surfaces susceptible to friction, permanently joining to metal on molecular level. The generated metal-ceramic layer is hard, durable and has a low friction ratio, superbly carry away heat and is high-temperature and mechanical load resistant. This layer fills, coats and smoothes micro-defects and deformations of metal surfaces subjected to friction. As e result of a high local temperature (above 900ºC) at places of friction follows melting of particles of CERAMIZER®. These particles of CERAMIZER® are characterized by a high level of adhesion to metal and carry particles of metal included in oil or grease into used spots (selective carrying) where there is raised temperature as a result of friction and then diffusion of them follows. In these spots particles of metal and CERAMIZER® rebuilt surfaces generating a ceramic – metal layer.

As a result of CERAMIZER® diffusion with metal surface a crystal structure of metal gets improved and outer layer gets hardened and filled up (a durable, inseparable ceramic- metal protective layer is generated).

Friction contact properties lubricated with oil and added CERAMIZER® were initially examined with Roll-Block test apparatus T-05 manufactured by ITE in Radom. Test apparatus T-05 is purposed for estimation of properties of plastic smears, oils and solid smears and wear resistance during friction of metals and plastics and to examine seizing resistance of low-friction coats applied on heavily loaded machine parts. Test apparatus is designed to carry out research according to methods stipulated in American standards: ASTM D 2714, D 3704, D 2981 and G 77. Due to applied solutions and equipment fitted to machine tests it was possible to carry out tests of smeared and dry slide contact of to and oscillatory motion with possibility to adjust a slide speed and an amplitude. The examined contact may be intensive or spread. Operation of test apparatus is presented on figure 7.10.

Sample grip 4 with semicircular insert 3 comprises self-adjusting clamping of block 1, that provides for tight fitting to roll 2 and the same uniform spreading of thrust on contact. Two-lever loading system allow for applying force pressing down block toward roll P with accuracy of 1%. Roll rotates with n monotonous, rotating speed or perform oscillation motion with f frequency. On research friction force, linear friction unit wear, temperature of block and oil were reported. Tested elements of T-05 stand is a sample of block and anti-sample-roll. Cylindrical surface of rotating roll along with side surface of block comprise a spread contact 6,35 mm wide.

A block-steel ŁH15 of 60HRC hardness, roll- steel ŁH15 of 60HRC hardness were used during research. Research included:


  • Mass wear calculated as block sample mass with use of a balance of 0,0001 g resolution.
  • Volume wear calculated on basis of mass consumption as of 7,85 g/cm ³ density of block.
  • Volume wear calculated as a linear wear of friction unit in µm measured with displacement converter in relation to distance in km.
  • An average friction ratio calculated as an average value of registered instants for given friction distance.

Applied research method included determination of parameters for a basic oil type FVA-2 without and with addition of CERAMIZER®. Research were carried out for unit load of 120kg, slide speed of 0,5m/s and friction distance of 10 800m. Table 7.1 presents results for a basic oil and oil with additive.

List of results of tribiliological parameters. Table 7.1

Along with decrease of friction ratio a block temperature fell by 28% in relation to block temperature with the reference oil.

Obtained results on test apparatus shall be verified for conditions of contact prevailing during meshing and an impact of additive on other parameters of gear shall be defined. The main object of research was to determine impact of oil additive on dynamic properties of cylindrical gear. According to description provided by manufacturer of mechanisms generating a coat an oil gear additive generate a metal-ceramic layer on cooperating tooth surfaces that during generation are subject to self-smoothing. The ceramic-metal coat provides for smoothing of micro-cracks, scratches and spalling. As a result of performed ceramization a proper profile of tooth is obtained and considerable decrease of inter-teeth friction. The main objective of research was to determine an impact of ceramic layer generated on teeth surface on gear performance parameters. Research included measurement of following parameters:

  • Oil and gear body temperature.
  • Gear body vibrations- noise from gear (acoustic pressure ) - deviation, meshing before and after additive operation.
  • Residual stress on surface of tooth before and after ceramization.

Research were carried out on closed power stand SB-J2 presented on figure 7.12.

Research were carried out on three pairs of wheels of cinematic- construction parameters that are included in table 7.4. Wheels were made from steel 18HGT and subjected to carburizing up to 0,2 depth of module and subjected to hardening up to 56 ±2 HRC hardness. During every experiment pinion was loaded with 650 +6 Nm twisting moment.

During every test a fresh oil, type TRANSOL SP-150 with addition of CERAMIZER® was used.

Parameters of wheels used for testing. Table 7.2

Table 7.3 includes number of tests, number of used samples and anti-samples and values of instants loading pinion.

List of numbers of gear wheels used for tests and values of load moments for pinion. Table 7.3

Every test was carried out for 48 hours (according to manufacturer of CERAMIZER®, the whole process shall follow up to 40 hours of gear work under loading).

Figure 7.13 shows measurement stand applied for the purpose of determining gear performance parameters. In casing 1 were fixed wheels of sample and anti-sample listed in table 2. Sensor 8 measures acceleration of gear body vibrations. Temperature sensors 9,14 measure temperature of gear body and temperature of inner oil casing. Sound level gauge 10 records fluctuations of acoustic pressure every 2 minutes. Results were recorded with DasyLab system, version 4.0 item 12,13.

Shaft torque moment with pinion was measured with extensometer system 6 with telemetric transfer of signal 7 to data logistics system 12. Rotating speed of inlet shaft tested gear 1 was adjusted with inverter 15. Measurement of residual stress on teeth surface was made with x ray diffraction instrument type ASTX2002 presented on figure 7.14.

Measurement of performance deviation teeth was obtained with the Hoefler measurement machine. On every of measurement test performance deviations were determined with reference to a wheel before and after ceramization.
Measurement results will be presented for every measured performance parameter respectively. These results were recorded during the whole experiment that is since gear turning on, later on during ceramization and during operating of ceramizer® sides of teeth.
Oil temperature inside gear and body was measured with thermocouples type J every 1 minute during the whole test.
Figure 7.16 presents fluctuations of temperature of gear body during three measurement tests.
In both cases given values determine gain in temperature in relation to environment temperature.
Analysis of charts shows that during ceramization there are not any significant changes of temperature within area of heat flow
(horizontal line). Only in case of test 1 ( figure 7.15 and 7.16) a significant oil temperature and body gear temperature decrease was reported especially in final phase of test. A large thermal inertia of gear may cause significant delays in temperature fluctuations of oil and gear casing what results in undetected temperature fluctuation during heat flow.

On ceramization of side teeth surface an amplitude of vibration acceleration was measured. Figure 7.17 presents fluctuations of vibration acceleration amplitude with reference to three tests.

Analysis of charts shows decrease of gear body vibrations during ceramization. Clearly seen is time zone for generation of layer and breaking in of wheels. After this process levels of vibrations stabilize and fluctuate around a constant value. If we consider vibration amplitude level as of a starting one then we finally receive almost twice as much decrease of vibration amplitude. Table 7.4 presents average values vibration speed and acceleration amplitude in the first and the last hour of an experiment.

Comparison of effective vibrations amplitude. Table 7.4

Equivalent acoustic pressure was as a measured noise parameter in period of two minutes with the use of filter type A. Noise was measured with gauge type SVAN-912 E class I with recording of results. Figure 7.18 presents results with reference to noise measurement for test 1.

Taking into consideration results it is possible to distinguish two zones: the first one with clear tendency for ceramization of teeth side surface and resulting in decrease of noise level and the second one of stabilized noise fluctuation around an average value. Table 7.5 includes results of calculations for an average acoustic pressure value on the right and on the left of a red line shown on figure 7.18.

Comparative results of acoustic pressure measurement. Table 7.5

Measurement of residual stress was made for wheel sample No. 61-03-05-30 for tooth No. 1,5,10,15,20,15 on the right. Measurement was taken for teeth after ceramization and grinding.
Table 7.6 includes measurements results of residual stress for direction tangent to tooth profile according to figure 7.19.

Taking into consideration an impact of ceramization on residual stress values it shall be noted that this process is indifferent to residual stress values. Obtained fluctuations of residual stress before and after ceramization are analogical as of the wheel working with oil without additive.

The results of the measurements of residual stress on teeth surface. Table 7.6

As a result of relaxation processes there are stress fluctuations and they are within a measuring error. It shall be noted that volume of ceramization process for residual stress values is an advantageous trait of apparatus as entering negative residual stress for carbonizing and hardening results in increasing of surface strength and resistance to tooth base bending fatigue. Every process decreasing negative values of residual stress would be disadvantageous and would decrease tooth strength.

Measurement of teeth deviations for wheels before and after ceramization were determined respectively for tooth No. 1,5,10,15. Measurement of performance deviations for teeth after ceramization were performed on active surface of teeth excluding lower area of cone apex entering into tooth root. Reference analysis of meshing performance deviations after ceramization shows significant impact of this process on forming of reference apex. Probably a hard ceramic layer causes significant grinding of common apex what consequently gives the same effect as a modification of tooth head profile (comparison of charts for the purpose of determination profile of tooth deviation F before and after ceramization).

Impact of oil additive for toothed gear of skewed teeth was analyzed on stand described in chapter 6. Cerazmization process of surface was obtained thanks to addition of CERAMIZER® to oil and work of gear under nominal load of 50 hours. After this time a mass temperature of tooth side surface was determined and it was compared to mass temperature obtained for tooth without ceramic layer. Table 7.7 contains measurement results along with calculated values of heat generated on teeth surface.

Comparison thermal parameters of meshing after and before the ceramization. Table 7.7

Obtained results of decreased friction ratio for gear are comparable with results obtained with device T-05.

There are following main effects of generating ceramic layer of tooth surface:

  1. CERAMIZER® has a significant impact on the level of vibrations of gear. Almost twofold decrease of vibrations parameters as an effective amplitude of speed and acceleration is reported.
  2. Decrease of vibration goes along with decrease of noise of equivalent acoustic pressure level. This value is around 1,6 dB(A).
  3. On ceramization there is not any process of reduction of initial negative residual stress caused by hardening what is very advantageous. Ceramization does not directly has an impact on reduction of tooth side wear resistance as well as on fatigue breaking of teeth basis.
  4. Due to very high toughness of surface a ceramic coat makes for easier and faster wearing in. It is evident on common apex. Effects of this process are comparable to modification of common apex profile.
  5. After ceramization process inter-tooth friction ratio decreases by 30%.
  6. Also mass consumption falls significantly by around 60%.