Cobalt Based Alloy STP 12 and H13 Extrusion Dies

STP 12 and H13 are famous materials used in manufacturing extrusion dies, which are critical components in extruding plastic, aluminum, and other materials.

STP 12 is a cobalt-based alloy known for its excellent wear resistance, high-temperature strength, and corrosion resistance. It is often used in applications requiring high-speed machining, such as manufacturing extrusion dies. STP12 is also highly resistant to galling, a type of wear caused by adhesion between sliding surfaces.

H13, on the other hand, is a hot-work tool steel widely used in manufacturing extrusion dies due to its high hardness, toughness, and thermal conductivity. It also has good resistance to heat checking, a type of surface cracking that can occur in hot working applications.

STP 12 and H13 have their strengths and weaknesses, and the choice between them will depend on the specific requirements of the extrusion process. Factors to consider may include the material being extruded, the process’s temperature and pressure, and the die’s desired lifespan.

SYTOP can supply H13 and cobalt alloy extrusion dies by the hot assembly process. The most significant advantage of our cermet mold is that when extruding and stretching stainless steel material, there is no adhesion with stainless steel, and the service life is 4-6 times that of cemented carbide molds. Common cobalt alloy core materials are STP 3, STP 6 and STP 12.

Cobalt Alloy chemical composition

• STP 1  C: 2.2～2.8%, Mn: -, Si: ≤2.0%, Cr: 29.0～33.0%, Ni: ≤3.0%, Mo: ≤1.0%,  W: 11.0～14.0%, Co: Bal., Fe: ≤3%
• STP 3  C: 2.0～2.7%, Mn: ≤1.0%, Si: ≤1.0%, Cr: 29.0～33.0%, Ni: ≤3.0%, Mo: -,  W: 11.0～14.0%, Co: Bal., Fe: ≤3%
• STP 4  C: 0.8～1.3%, Mn: ≤1.0%, Si: ≤1.5%, Cr: 28.0～32.0%, Ni: ≤3.0%, Mo: ≤1.5%,  W: 12.5～15.5%, Co: Bal., Fe: ≤3%
• STP 6  C: 0.9～1.4%, Mn: ≤1.0%, Si: ≤1.5%, Cr: 27.0～31.0%, Ni: ≤3.0%, Mo: ≤1.5%,  W: 3.5～5.5%, Co: Bal., Fe: ≤3%
• STP 12  C: 1.1～1.7%, Mn: ≤1.0%, Si: ≤1.0%, Cr: 28.0～32.0%, Ni: ≤3.0%, Mo: -,  W: 7.0～9.5%, Co: Bal., Fe: ≤3%
• STP 19  C: 1.5-2.0%, Mn: ≤1.0%, Si: ≤1.0%, Cr: 29.5～32.5%, Ni: ≤3.0%, Mo: -,  W: 9.5～11.5%, Co: Bal., Fe: ≤3%
• STP 20  C: 2.2～3.0%, Mn: -, Si: ≤2.0%, Cr: 25.0～29.0%, Ni: ≤3.0%, Mo: ≤1.0%,  W: 14.0～19.0%, Co: Bal., Fe: ≤3%