Among the materials constituting dies, these are the materials that are mainly the materials that form the structure.

(1) Rolled steels for ordinary structures (SS materials)

This is a material used most commonly as the base material for molds, punches, and dies. The very frequently used type is SS400. This is usually referred to as the SS material.

The number in the material name SS400 indicates the tensile strength. SS400 has a tensile strength of 400 to 510N/mm².

Since this is a soft material with tenacity, and there is also the opinion that it is difficult to process because during hole drilling the cutting chips (cut pieces) connect to each other in the form of a long spiral.

(2) Carbon steel for machine structures (SC materials)

These materials are also used in a manner similar to SS materials. The SC materials come in varieties from S10C to S58C. The number here expresses the amount of carbon (C) contained in the steel material. The amount of carbon ranges from 0.08% to 0.61%. When the amount of carbon exceeds 0.61%, the material then becomes carbon tool steel (SK materials).

The interesting fact about this material is that its mechanical properties have not been indicated. Only some reference values are given. The reason for this is that the tensile strength stipulated in JIS is the test result for a material of 25mm diameter. This is a consideration for the fact that the conditions change in the case of large structures.

Various materials were being used earlier in the standards. For example, they were S35C, S45C, S50C, S55C, etc. At present, due to standardization of plates, it has been standardized to use either S50C or S55C. The reason why the steels with larger numbers have remained is that the materials with more carbon content are stronger.

From the point of view of ease of machining, these materials are considered to be easy to use since the cutting chips do not become long as in the case of SS materials and the handling of scrap becomes easier. This is due to the difference in the carbon content. In the case of SS materials, there is no specification of the amount of carbon content (extremely small).