I) Answer True or False: (4 pts.) 1. ----------- A given phase can have more tha
ID: 1857541 • Letter: I
Question
I) Answer True or False: (4 pts.)
1. ----------- A given phase can have more than one crystal structure.
2. ----------- In a eutectic reaction a liquid reacts with a solid phase and transforms to another solid phase.
3. ----------- Brasses and bronzes have aluminum as the major element in them.
4. ________ Maximum solubility of nickel in copper is 40 wt.%.
II) Find and circle the correct answers in each of the following: (6 pts.)
1. AISI 52100 steel has: a) 10% C b) 1.0% C c) 10% Fe d) 0.1% C. e) NoA
2. Stainless steel has: a) low ductility b) about 0.4% C c) more than 12% Cr. d) close to 95% Fe. E) NoA.
3. Tempering produces in the steel microstructure: a) sheets of carbide mixed with ferrite sheets b) rods of carbide scattered at random. c) fine crystals of ferrite. d) very fine ellipsoid type crystals of carbide dispersed in ferrite matrix e) NoA
III) Fill in the blanks with appropriate answers: (11 pts.)
1. The hardness of the quenched AISI 1080 steel would be roughly: _________. (give number and unit involved) (3 pts.)
2. Bainite has the phases __________ and ____________. (2 pts.)
3. In the TTT diagrams of some steels containing two C-curves, the first C-curve represents _____________________________________________________
______________________________________ (2 pts.)
4. The impact strength of martensite is ___________ (2 pts.)
5. Hardenability of a steel is indicated by _______________________________
________________________________________. (2 pts.)
IV) Give in steps the procedure for annealing a specific steel. (4 pts.)
Explanation / Answer
I)
1)T
2) F
3)F (Cu)
4)F (70%)
II)
1) b (1% C)
2) c
3) a
III)
1)174 BHN
2)ferrite and carbide
3) the time when the transformation of austenite phase just begins.
4) 50 Rc
5) BHN (brinell hardness number)
IV) STEP a) the stell is heated to the temperature above upper critical critical temperature for the hypoetectoid steel and above the lower critical temperature for the hypereutectoid steel
STEP b) the stell is kept at this temp. for a considerable period of time.
STEP c) the steel is then cooled slowly generally furnace cooling is employed.