1. IQ Technologies Inc., Akron, USA WSEAS, SYSTEMS (Part of CSCC’ 12)
A Concept on Thermal Equilibrium Establishment and Its Use in Heat Treating Industry
Nikolai I. Kobasko
Intensive Technologies Ltd, Kyiv, Ukraine
IQ Technologies Inc., Akron, USA
WSEAS, SYSTEMS (Part of CSCC’ 12)
Kos Island, July , 2012
GREECE

2. Contents What is thermal equilibrium?
Why is important to evaluate duration of transition from one thermal equilibrium to another?
The main postulate of thermodynamics.
The modified law on thermal equilibrium establishment.
Simple equations for cooling time calculations.
Summary

3. Equipment for IQ Processes
IQ system consisting of a 6,000-gallon IQ water tank equipped with four props and a atmosphere furnace. 
IQ system consisting of a 1,900-gallon water tank and one prop.
IQ system consisting of a 11,000-gallon water solution Na2(NO)3 tank equipped with four props and atmosphere furnace. 

4. Martensite start temperature MS and martensite finish temperature MF versus content of carbon in steel

5. Boiling processes that may occur during quenching

6. Mathematical Models for Determining the Duration of TNBP
The boundary and initial conditions during nucleate boiling process m = 10/3 Duration of transient nucleate boiling process is evaluated from the condition

7. High-velocity experimental IQ system sketch

8. A fixture for single part quenching

9. Production high-velocity IQ system

10. Equations for Evaluation Cooling Time of Quenching

11. Cooling time calculation for three dimensional plate

12. Regular Thermal Process

13. The beginning of regular thermal process vs
The beginning of regular thermal process vs. Fo, Bi, and an admissible calculation error e (%) at the axis of a cylinder

14. Equations for Cooling Time
Calculation

15. Equations for Cooling Time
Calculation

16. Kondratjev form factor K for some steel components
Part
Sketch
K,[ m2]
Plug
4.38 · 10-4
Shaft
6.65 · 10-4
Center
6.08 · 10-4

17. Explanation how thermal equilibrium is established

18. A role of free electrons in heat distribution in metals

19. Modified heat conductivity law of Fourier
m = 9.1 x 10-31kg)

20. Modified heat conductivity law of Fourier
m = 9.1 x 10-31kg)

21. Transition time from 100o C, 80oC… and 20oC to 0oC when cooling iron spherical probe of 60 mm diameter in water flow 1 m/s at 0oC
Initial tempe
rature
of probe
Average HTC, W/m2K
Transition time, s
Experiment
Calculation
Error, %
100
3014
127
125
1.2 80
2870
128
124
3.0 60
2715
130
4.6 50
2614 30
2440
129
122
5.4 20
2257
5.7

22. A mechanical model which shows how exponent works when amount of water from two barrels of 100 L and 200 L is taken with accordance the exponential law
Time, sec
Amount of water L1
Amount of water L2
Amount of water per s (I)
Amount of water per s (II)
100
200 1
95.12
190.24
4.88
9.76 2
90.5
181
4.62
9.24 3
86.07
172.14
4.43
8.86
500
N molecules of H2O
2N molecules of H2O
1000
1 molecular of H2O
2 molecules of H2O
1001
End
No water in barrel
No water in barrel

23. Scheme of Two Step Quenching Process

24. SUMMARY
1. The correlations for cooling time calculation of any configuration of steel part is proposed. The proposed correlation can take into account the effect of insulation layer at the surface of steel part which affect duration of its cooling process during hardening of steel parts

25. SUMMARY
2. Thermal equilibrium is established in finite time due to existing temperature fluctuations which destroy asymptotic law of cooling and equalizes temperature in closed system very quickly

26. SUMMARY
3. According to hyperbolic heat conductivity equation, distribution of heat has both wave and asymptotical character. It means that transition time from one thermal equilibrium to another doesn’t depend significantly on temperature difference between two thermal equilibriums

27. Thank you !