KNIFE MATERIAL

1. Selection of the knife material with regard to steel composition is governed primarily by the material to be cut. Because steel is to be cut by steel, the cutting quality is always the prime criteria for selection. This means that the knife material must be harder than the material to be cut. The second most important criteria for the material selection must be the capability of holding its cutting edges, that is to say, the cutting quality under load must be impaired in anyway. Thus the material suitable for knives is the kind of alloy steel that can be hardened in principle, can be hardened in depth and is resistant to plastic eformation under pressure.

2. When selecting the material, it is essential to decide which of these three main characteristics, namely hardness, tenacity and resistance to wear, should be given preference or which optimum combination of all three characteristics is desirable and possible.

3. The loads to which knives are subjected on a slitting line, vary considerably, as the thickness of the material to be cut can vary from 0.05 mm to 20 mm. Besides thickness, the composition and tensile strength of the material to be cut also governs the loading on the slitting line. Ageneral rule : the thinner the material to be cut, the higher should be the hardness of the knife.