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A very warm welcome (Arial, 24-point bold font)
Discover what's under the surface (Arial, 20-point bold font in italics)
2
HORN Technology Days 2015
Technical presentation:
Wear parts - Reducing costs through the use of
high-performance carbide rods
Speaker: Mark Turnidge
3
Wear parts – Carbide rods
What is carbide?
A composite manufactured
by means of powder metallurgy and consisting of a hard material (tungsten carbide, WC) and a metallic binder (cobalt, Co)
Hard material ensures:
Hardness
Wear resistance
Metallic binder ensures:
Toughness
Co
WC
WC 5 µm
Micrograph of WC-Co carbide
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Wear parts – Carbide rods
Tungsten
oxide Tungsten
Tungsten
carbide
TiC, TaC, NbC
Cr3C2, VC, MoC
Reduce
Carburising
Mixing
Grinding
Co (Ni,Fe)
Spray drying Granulated
material
Carbide production
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Wear parts – Carbide rods
Final sintering
Presintering Green part
machining
Shaping
Pressing
Injection
moulding
Final machining
-Eroding
-Turning
-Grinding
-Polishing
-Coating
Granulated
material
Production of
feedstock
Carbide production
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Wear parts – Carbide rods
The aim of the shaping processes is to create a product with a shape that is
close to its final form.
During injection moulding, parts with rod or pipe-shaped cross-sections are
manufactured. Pressing aids are mixed with the powder and it is worked,
plasticised and granulated (feedstock). The mass is pressed through an extrusion
nozzle at high pressure.
During cold isostatic pressing, powder is poured into an elastic mould and
pressed into a moulded shape at a high level of fluid pressure. The moulded
shapes (green parts) are then machined mechanically using standard processes
(turning, milling, etc.) until they reach the desired shape (step drill/tree milling
cutter, etc.).
Carbide shaping
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Wear parts – Carbide rods
Usage properties of carbide are determined by
- Hardness
- Bending strength
- Fracture toughness
Properties of carbide grades are determined by
- Binder content ( % )
- Grain size ( coarse, medium, fine, superfine )
- Binder type ( Co, Ni )
- Composite carbide content (TiC, TaC, NbC )
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Wear parts – Carbide rods
The binder content affects:
- Hardness
- Bending strength
- Fracture toughness
- Abrasion resistance
- In some cases, corrosion resistance
The grain size
- Hardness
- Bending strength
- Fracture toughness
- Abrasion resistance
- Heat resistance
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Wear parts – Carbide rods
The binder type affects:
- Corrosion resistance
- Magnetic properties
- In some cases, hardness, bending strength and toughness
The composite carbide
- Hardness
- Bending strength
- Fracture toughness
- Abrasion resistance
- Heat resistance
- In some cases, corrosion resistance
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Wear parts – Carbide rods
Carbide properties as a function
of Co content and WC grain size
High degree of
hardness
(= wear resistance)
Fracture
toughness
Cobalt content
Grain size
Bending
strength Cobalt content
Grain size
Cobalt content
Grain size
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Wear parts – Carbide rods
Hardness
500
1000
1500
2000
2500
3000
0 2 4 6 8 10 12 14 16 Co [%]
HV30
[N/mm²]
0.5 µm
1-2 µm
3 µm
0.7 µm
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Wear parts – Carbide rods
Bending strength
1500
2000
2500
3000
3500
4000
4500
6 9 12 15 Co [%]
[Mpa]
0.7 µm
1 µm
< 0.5 µm
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Wear parts – Carbide rods
Fracture toughness
(KIC)
7
12
17
22
27
32
0 4 8 12 16 20 Co [%]
3 µm
1-2 µm
0.7 µm
[MN/m3/2]
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Wear parts – Carbide rods
Medium 1.0 µ -
3.0 µ
Fine 0.5 µ - 1.0 µ
Coarse > 3.0 µ
Super < 0.5µ
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Wear parts – Carbide rods
The most important variables for optimising properties, in relation
to the application, are – as demonstrated – the binder content and
the grain size.
To satisfy high toughness requirements, the binder content may be
up to 12% in the case of rods and blanks for precision tools.
The highest degree of hardness and wear resistance is ensured by a low binder
content of 6% and a fine to superfine grain size.
Grain sizes vary between superfine and fine in order to ensure a
cleanly ground cutting edge as well as cutting edge stability.
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Wear parts – Carbide rods
Text Text Text Text Text Text
Text Text Text (Arial, at least font size 18 up to a
maximum of 22, normal)
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Wear parts – Carbide rods
Conclusion
Every process has its own unique demands, whether it´s hardness or wear
resistance …or toughness… or corrosive.
No two applications are exactly the same. The performance and durability of any
tools is in the details and all you have to do is tell us what they are.
We will listen to your needs and develop or recommend a carbide grade that
works for you, that could very well turn out to be simpler, better and less
expensive.
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Wear parts – Carbide rods
Conclusion
Reduce your costs through the use of high-performance carbide rods of HORN.
We work one-on-one with customers all over the world to meet their individual
application challenges and obstacles.
So go ahead, please ask us. We are there for you.
If we don´t know the answer to your question, we will find the answer.
