High Pressure Gas Quenching
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- 1. High Pressure Gas Quench High Pressure Gas Quenching
Advantages of Gas Quenching
- 2. High Pressure Gas Quench Reduction of hardening distortion
and/or variation of distortion Quenching intensity adjustable by of
gas pressure and gas velocity Process flexibility Clean, non-toxic
working conditions Integration into manufacturing lines
Reproducible quenching result Clean and dry parts, no washing
Simple process control Advantages of Gas Quenching
- 3. High Pressure Gas Quench High Pressure Gas Quench Quench
Media vs. Heat Transfer Coefficient Data taken from: George E.
Totten, PhD, FASM Portland State University Department of
Mechanical and Materials Engineering Heat Transfer rate, W M-2
K-1
- 4. High Pressure Gas Quench 0 100 200 300 400 500 600 700 800
900 0 10 20 30 40 50 60 10 bar N2 10 bar He 20 bar He 40 bar He
Fast quenching oil Bellini FS (70C) Hot quenching oil Quench
Behavior 3D Loads Oil vs. HPGQ Time Temperature
- 5. High Pressure Gas Quench Bubble Boiling Film Boiling
Convection t = 10 s 750C 700C 700C 600C 500C 400C 300C 200C
Temperature distribution t = 10 s Heat transfer coefficient 5000
10000 15000 20000 l oil Wasser water [W/m K] 2 ref.: Stick, Tensi,
HTM 50, 1995 Heat Transfer & Temperature Distribution Immersion
Quenching
- 6. High Pressure Gas Quench Heat transfer coefficient 1000 2000
3000 4000 [W/m K] 2 Temperature distribution 750C 650C 550C 450C
350C 250C Gas direction Only convection Heat Transfer &
Temperature Distribution High Pressure Gas Quenching
- 7. High Pressure Gas Quench - Gas (N2, He, H2) - Gas pressure -
Gas velocity HPGQ Parameters Quenching Gas
- 8. High Pressure Gas Quench Chemical symbol Density at 15 o C
and 1 bar Density relative to air Molar mass (kg / kmol) Specific
heat capacity Cp (kJ / kg K) Dynamic viscosity (N s / m 2 ) Thermal
conductivity (W / m K) Argon Nitrogen Helium Hydrogen Ar 1,6687
1,3797 39,948 0,5024 177x10- 4 22,6x10- 6 N 2 1,170 0,967 28,0
1,041 259x10- 4 17,74x10- 6 He 0,167 0,138 4,0026 5,1931 1500x10- 4
19,68x10- 6 H 2 0,0841 0,0695 2,0158 14,3 1869x10- 4 8,92x10- 6 (at
25o C und 1 bar) Quench Gas Properties
- 9. High Pressure Gas Quench 0 2 4 6 8 10 12 14 16 0 2 4 6 8 10
12 14 16 18 20 N2 He H2 0 2 4 6 8 10 12 14 16 0 2 4 6 8 10 12 14 16
18 20 Relative Motorpower for cooling gas fans Relative Heat
Transfer Coefficient Gas pressure (bar) Gas pressure (bar) N2 He H2
HPGQ Parameters Influencing Factors
- 10. High Pressure Gas Quench Helium with Recycling, Consumption
per Quench 0.3 m = 10.6 cft Nitrogen without Recycling, Consumption
per Quench 55 m = 1942 cft HPGQ Cost Helium vs. Nitrogen
- 11. High Pressure Gas Quench - Gas Paths - Gas Fan(s) - Heat
Exchanger(s) - Loading - Process flow - Kind of Flow - Gas ( N2,
He, H2 ) - Gas pressure - Gas velocity HPGQ Parameters Quenching
Chamber
- 12. High Pressure Gas Quench HPGQ Parameters Quenching Chamber
Multi Chamber Furnace (Cold Chamber) Backfill time to final
pressure >> 10 sec Backfill time to final pressure