Test 2 Flashcards
plain carbon steel
10xx
resulfurized carbon steel
11xx
chromium 0.5-0.95%
molybdenum 0.12-0.2%
41xx
nickel 1.8%
chromium 0.5-0.8%
molybdenum 0.25%
43xx
chromium 1.45%
52xx
aids nitriding
restricts grain growth
removes oxygen in steel melting
Aluminum (Al) < 2%
adds machinability
reduces weldability, ductility and toughness
Sulfur (S) and Phosphorus (P) <0.5%
increases resistance to corrosion and oxidation
increases hardenability (significant effect)
increases high-temperature strength
can combine with carbon to form hard, wear-resistant microconstituents
Chromium (Cr) 0.3-0.4%
promotes austentic structure increases hardenability (mild effect) increases toughness
Nickel (Ni) 0.3-5%
promotes tenacious oxide film to aid atmospheric corrosion resistance
Copper (Cu) 0.2-0.5%
increases hardenability, lowers hardening temperature
promotes an austentic structure
combines with sulfur to reduce its adverse affects
Manganese (Mn) 0.3-2%
removes oxygen in steelmaking
improves toughness
increases hardenability
improves the fluidity of molten metal
Silicon (Si) 0.2-2.5%
promotes grain refinement
increases hardenability
improves high-temperature strength
Molybdenum (Mo) 0.1-0.5%
promotes grain refinement
increases hardenability
will combine with carbon to form wear-resistant microconstituents
Vanadium (V) 0.1-0.3%
added in small amounts to increases hardenability
Boron (B) 0.0005-0.003%
added only to aid machinability
Lead (Pb) <0.3%
acts like carbon in strengthening
Nitrogen (N) <0.1%
cold work water hardening
W
cold work oil hardening
O
cold work medium alloy air hardening
A
cold work high C, high Cr
D
shock resisting
S
hot work
H
high speed molybdenum
M
high speed tungsten
T
mold
P
special purpose
L
99% pure or higher
used in electrical and chemical fields
excellent corrosion resistance
high thermal and electrical conductivity
low mechanical properties and excellent workability
moderate increases in strength from strain hardening
iron and silicon major impurities
1000 series
non heat treatable
copper – principal alloying element
may require artificial aging
do not have as food corrosion resistance as most other Al alloys
often clad with 6000 series or pure Al
2000 series (2024 best known alloy) heat treatable - require solution heat treatment to obtain best properties in heat treated condition, mechanical properties close to or even exceed mild steel
manganese – major alloying element
limited Mn addition - 1.5%
moderate strength
good workability
3000 series (3003 – general purpose alloy) non heat treatable
silicon – major allowing element
Si lowers melting point without causing brittleness
Used in welding wire and brazing alloys
When diluted with heat treatable alloys in welding become moderately heat treatable
Become dark gray when anodized
4000 series
Non heat treatable
Magnesium – major alloying element
Mg most effective and widely used alloy for Al
Moderate to high strength
Mg more effective than Mn as hardener (0.8% Mg ≈ 1.5% Mn)
Mg has greater solubility in Al than does Mn
Good welding characteristics
Good resistance to marine atmospheric corrosion
May have problems with stress corrosion cracking at higher service temperatures, higher cold work higher Mg content
5000 series
Non heat treatable
Silicon and Magnesium – major alloying elements Forms magnesium silicide Less strong than 2000 or 7000 series Good formability Good corrosion resistance Medium strength
6000 series (6061 – most widely used and versatile Al alloy) heat treatable
Zinc – major alloying element
High strength
Used for highly stressed parts and aircraft applications
Not arc welded well – resistance welded
7000 series
heat treatable
