POSCO succeeds in mass production of environmentally friendly steel

POSCO announced that it was the first in the world to develop and begin mass production of an environmentally friendly, graphite-free cutting steel called PosGRAM (GRAphitic Steel for Machinability).

POSCO's PosGRAM is expected to increase the competitiveness of the national industry as it replaces lead-free cutting steel, which was completely dependent on imports.

Free-cut steel is a type of wire rod that is specially designed for chip removal with high productivity. It is mainly used for making parts for automotive, electronic and OA equipment where complex shapes and dimensional accuracy are required.

The existing free-cutting steel contained lead to improve machinability. However, during the manufacturing, processing and recycling of products, lead is dispersed in the air as small micrometer (μm) particles, causing various side effects such as inflammation and damage to the nervous system of workers.

Because of these concerns, RoHS and ELVs, which are international guidelines to restrict the use of hazardous substances, have limited the amount of lead in products to 0.1 percent.

RoHS (Restrictions on Hazardous Substances) is an EU directive restricting the use of hazardous substances in electrical and electronic products, and ELV (End of Life Vehicle) is also an EU directive concerning the end of life of automotive products.

However, in the case of lead-free cutting steel, for which there is no alternative, the standards allow up to 0.35%. With the ban on lead-containing parts spreading to global companies, it is also expected to strengthen the guidelines for regulating the general use of lead.

The development of POSCO's graphite-free cutting steel, PosGRAM, is important in that it has successfully achieved better machinability characteristics than lead-free cutting steel using graphite, an environmentally friendly material. Thanks to heat treatment, PosGRAM displays flat surfaces in any cutting direction for efficient machining. It is also suitable for the manufacture of precision control parts such as solenoid valves, as it is easily magnetized by the surrounding magnetic fields.
* Solenoid valve: A valve that works by moving a plunger (iron rod) with an electromagnetic force generated by passing electricity through a solenoid (electric coil) wound in a cylindrical shape. Free-cutting steel is used here as material for the plunger.

In 2017, POSCO embarked on the development of free-cutting steel, starting with research into the distribution and control of graphite particles. Having completed the development and �