The document discusses the enhancement of tungsten carbide tools through a cryogenic processing method that improves their hardness and reduces wear rates. It outlines the characteristics of tungsten, the challenges faced during machining, and details the cryogenic treatment stages involving cooling, soaking, and heating. The findings indicate that a 24-hour soaking time results in optimal hardness and reduced tool wear, though tempering cycles have a marginal impact on performance.

1. “Enhancement of Tungsten Carbide tool through
Cryogenic Process”
MKL

2. • Tungsten has melting point temperature 3420 oC and density 19.3
Mg/m3, which make it suitable for application where high temperature
strength, good thermal conductivity, Hardness and toughness
required
• It is used as heating element, incandescent bulbs filament, electronic
emitter, kinetic energy penetrator, high temperature furnace, X-ray
electrode Fusion reactor and cemented carbide tool.
• Cutting tools are normally made of Tungsten Carbide
Introduction
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3. • Flank wear is primarily attributed to the rubbing of the tool along the
mechanical surfaces abrasive, diffusive and adhesive wear
mechanisms
• Notch wear appears as a result of a combination of oxidation and
adhesion wear mechanisms
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Introduction

4. Problem Statement
• When Machining Tungsten transform from ductile to brittle under
various temperature condition
• At the higher temperature Oxygen, Carbon and nitrogen present in
form of oxides, carbides and nitrides at the grain boundaries.
• These impurities can alter the physical and mechanical properties of
the tungsten
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5. Cryogenic Techniques
It consist of following steps
• 1st stage Cooling with cryogenic liquid from room temperature till
cryogenic temperature
• 2nd stage Soaking for a specific time period, so properties changes
• 3rd stage slow and steady heating till room temperature.
• If there is any stresses remaining after 3rd stage then tempering is
carried out to reduce these stresses
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6. 6
• H, He, Ar, Ne, Kr, Xe, N, CH4, C2H6 and C3H8 are cryogenic chemicals
• Liquid nitrogen is preferred because it is cost effective, nonflammable,
safe and environmental friendly gas.
Cont..

7. Effect of Soaking Temperature
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8. Scanning Electron Microscopy images
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SEM images of (a) DCT-00; (b) DCT-24; (c) DCT-48; (d) DCT-72.

9. Micro hardness observation
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10. Tool wear rate (TWR)
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11. Reduction in Tool wear rate
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12. Effect of Tempering Cycles
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13. Hardness
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14. Conclusion
• Cryogenic treatment improve the surface morphology
• Hardness Improved and Tool wear rate reduced at 24 hour
soaking time.
• micro-hardness decreased with an increase in the number of
tempering cycles after the treatment
• At the low cutting conditions, number of tempering cycles
influenced the performance marginally
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