The new technological requirements call for improvements in polymers: self-extinguishing, adhesion with other polymers, impact resistance, permeability. This forces to incorporate additives that change the properties.
Some of these additives, exposed to temperatures during the transformation are highly corrosive and attack all components of the plastification unit. Sometimes it is necessary to use stainless steels.
Stainless steels are generally classified into 5 families. Four by its crystalline structure: Martensitic, austenitic, ferritic and duplex, furthermore precipitation.
The martensitic stainless steels are of special interest for it’s features (some of them harden to 72HRC by plasma nitriding):
- 1.4028 X 30Cr13
- 1.4122 X 39 Cr Mo 17-1
- 1.4125 X10 5Cr Mo 17-1
For some specific applications, the austenitic stainless steels are used:
- 1.4301 X 5 Cr Ni 18-10
- 1.4401 X 5 Cr Ni Mo 17-12-2
For special ocasions and high performance applications, we use duplex and precipitation steels, normally under patent trademarks: HASTELLOY, INCONEL, etc.