Stainless steels (SS) are iron-base alloys containing 10.5% or more chromium (Cr). The addition of Cr gives resistance to heat and corrosion. The properties of SS are further modified by the addition of other alloying elements such as carbon, nitrogen, aluminium, nickel and many others. The many permutations of alloying elements result in many SS grades, each with different hardness and resistance to temperature, each suited to different applications.

The properties of SS grades are also determined by their crystalline structure. There are four main types: Austenitic, Martensitic, Ferritic, and Precipitation hardening. Martensitic grades can be hardened with heat treatments, ferritic and austenitic cannot. Precipitation hardening grades can reach high hardness levels (HRC 44). Compared to other material groups, Stainless Steels represent some of the highest possible operating temperatures and highest hardness levels. All SS grades are conductors of electricity.

The most popular Stainless steels grades used in our Die Attach tools are of the SUS303 and SUS316L variety. As compared to other specialty alloys SS materials offer reasonable performance at a competitive price point.

The SUS grades are differentiated with a 3-digit number. The 300 series are austenitic chromium-nickel alloys, whereas 400 series are martensitic. The final 2 digits of the code indicate alloying elements and therefore indicate properties. For example, 316 has added molybdenum to increase corrosion resistance. 301 has lower Cr and Nickel to increase potential for work hardening, allowing it to be hardened to 41 HRC.

HSS grades are high speed steels, so called as they retain high levels of hardness at high temperatures with an improve wear rate. HSS grades are most commonly used on our Epoxy Stamping tools and Die Ejector Needles.

15-5PH and 17-4PH are precipitation hardened steels and are subjected to an annealing treatment in order to develop high strength. 15-5PH and 17-4PH SS are recommended for Pick Up Tools with small profiles, thin wall thickness and high bond force.