37Cutting Tools
3. Milling of WC with cobalt binder to obtain uniform and
homogenous mixture
4. Pressing the powder at 1000–4800 atmosphere to form tips
5. Sintering at 700°C–1000°C in hydrogen atmosphere
6. Machining to the nal shape
7. Final sintering at 1400°C–1700°C
8. Grinding
Properties of sintered carbides include
• High strength and hardness
• Used for cutting at 1200°C
• Operate at speeds 16–25 times that of carbon tool steel and 6 times
that of HSS
• Very brittle and have low resistance to shocks
• Used with rigid machine tools having a wide range of speeds
• Sharpened dry and not quenched
• Used with effective and sufcient cooling
According to ISO, cemented carbides are divided into three main groups
identied by the let