Principal engineering alloys Flashcards
What are the two classifications of metal alloys?
Ferrous and Nonferrous
What are the two classifications of ferrous metal alloys?
Steels and Cast irons
How are high strength low alloy steels produced?
Thermo-mechanical treatment
What are the five benefits of HSLA steels?
- Improved low temperature toughness
- Increased yield stress
- High strength to weight ratio
- Good manufacturability
- Available in sheet, bar, plate and tube
What are stainless steels?
Corrosion resistant ferrous alloys that contain at least 11 wt% Cr
What are the 8 benefits of stainless steels?
- Many grades available depending on application
- Good corrosion resistance
- Very high strength (duplex and superaustenitics)
- Austenitics are non magnetic
- Aesthetically appealing
- Good low temperature toughness
- Reasonable manufacturability
- Wide range of applications
What are 4 benefits of Aluminium alloys?
- Low density
- High electrical & thermal conductivity
- High corrosion resistance
- High ductility
What are 2 limitations of aluminium alloys?
- Low melting point
2. High coefficient of thermal expansion
When is it important to consider the max. service temperature?
- Where the components become hot in service
2. When the load applied is for many hours (>100h)
What does an anodising process do?
Increases the thickness of the natural oxide layer?
What do the final properties of a material depend on?
- Manufacturing process
2. Alloy composition
What should be done to protect stainless steel from intergranular corrosion?
- Heat treat
- Lower the content of carbon (0.3%C)
- Alloy the material with Nb or Ti
What is the principal disadvantage of many ferrous alloys?
Their susceptibility to corrosion?
