Green Cross Alloy Sharpener (Lead) SCM415L

SUM11,22,22L
This is a type that emphasizes machinability and is also known as low-carbon free-cutting steel. This steel is chosen when machinability is more important than mechanical properties (such as strength).

SUM31,32,41,42,43,31L
It has a medium carbon content and high strength, and is also known as medium carbon free-cutting steel. SUM31 has the same strength as SS400, while SUM41, 42, and 43 have the same strength as S35C, S40C, and S45C, respectively. It is used after heat treatment (tempering). The proportion of Mn (manganese) is increased to prevent a decrease in strength due to S (sulfur). Composite free-cutting steel (also known as S free-cutting steel) has an orientation in its mechanical properties. The higher the S (sulfur) content, the slightly worse the ductility and toughness perpendicular to the rolling direction. Pb free-cutting steel, with the addition of Pb as a free-cutting element, has good ductility and, due to its uniform elemental distribution, is not as anisotropic as S free-cutting steel. However, since the mechanical properties of this product depend on the melting point of Pb, the mechanical properties decrease at temperatures above 327°C. Generally, lead-free steel is used after heat treatment such as quenching and tempering.