Tool materials need to meet some basic requirements

　　Tool materials need to meet some basic requirements: 

　　(1) high hardness

　　The kitchen knife is to remove material from the workpiece, so the hardness of the tool material must be higher than the hardness of the workpiece material.

　　The minimum hardness of the tool material should be above 60HRC.

　　For carbon kitchen knife steel materials, the hardness should be above 62HRC at room temperature; high-speed steel hardness of 63HRC ~ 70HRC; carbide tool hardness of 89HRC ~ 93HRC.

　　(2) high strength and toughness

　　Tool materials are subject to great cutting forces and impact during cutting.

　　Such as turning 45 steel, in the back draft ap = 4 ㎜, feed f = 0.5 ㎜ / r conditions, the cutting force suffered by the insert to 4000N, it can be seen that the tool material must have a high strength and toughness.

　　The toughness of general tool material is expressed by impact toughness aK, which reflects the resistance of tool material to brittleness and chipping ability.