STAINLESS STEEL OVERVIEW: TUTORIAL
First Branch
Chromium Containing
As we mentioned, to be a stainless, the iron base must contain at
least 10.5% Cr. and the carbon content is less that 1%. These two things made
stainless "Steel" totally different from mild "Steel."
The basic stainless with 12 to 18% chromium are called "Martensitic" (based on the structure) and have the following characteristics:
- Are magnetic
- Can be hardened by "heat treatment"
- Have "poor" welding characteristics
Common Uses:
- Knife blades
- Surgical instruments
- Fasteners
- Shafts
- Springs
Common Grades:
Stainless is designated by three different systems
- Metallurgical structure - Martensitic
- Grade: 410 (most used), 420 (cutlery), 440C (for very high hardness)
- Unified Numbering System UNS: S41000, S42000, S44004
(Note chemistry and
properties given for 410)