stainless steel Flashcards
stainless steels
ALWAYS MORE THAN 10% chromium
plain carbon steels 4
dead mild, mild, medium carbon, tools and steels
low alloy steel
small amts of other added elements
high alloy steel
high amt of added elements
eg stainless
ferritic
- BCC
- less than 0.02% carbon
11-27 chronium - good strength + moderate ductility
- can be welded
nuts bolts screws
martensitic
0.15-1.2 carbon
11.5-18 chronium
quenched and tempered to produce high hardness and tensile strength
less corrosion resistance
turbine blades, surgical instruments
austenitic
addition of nickel >6%
<0.25 % carbon
16-26 chronium
good durability, formability and corrosion resistance
non magnetic
cookware etc
dupplex
chronium 22% more
good strength
high toughness and ductility
dual phase structure of ferrite and austenite
precipitation hardening
similar composition to austenitic but addition of aluminium, niobium or tantalum